Merge branch 'multi-coin'

author: Determinant <[email protected]> 2020-07-30 14:18:44 -0400
committer: Determinant <[email protected]> 2020-07-30 14:18:44 -0400
commit: 0444e66f640999c15496066637841efcc0433934 (patch)
tree: c19aec2dced2e9129c880c19c52ca0f87b3d62f6 /rpc
parent: cffa0954bbdb43821d1b71d00f99fb705cecd25b (diff)
parent: 1f49826de2bb8bb4f5f99f69fd2beb039b1172d9 (diff)
14 files changed, 2995 insertions, 0 deletions
diff --git a/rpc/client.go b/rpc/client.go
new file mode 100644
index 0000000..1c7058b
--- /dev/null
+++ b/rpc/client.go
@@ -0,0 +1,625 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "bytes"
+ "context"
+ "encoding/json"
+ "errors"
+ "fmt"
+ "net/url"
+ "reflect"
+ "strconv"
+ "sync/atomic"
+ "time"
+
+ "github.com/ava-labs/go-ethereum/log"
+)
+
+var (
+ ErrClientQuit = errors.New("client is closed")
+ ErrNoResult = errors.New("no result in JSON-RPC response")
+ ErrSubscriptionQueueOverflow = errors.New("subscription queue overflow")
+ errClientReconnected = errors.New("client reconnected")
+ errDead = errors.New("connection lost")
+)
+
+const (
+ // Timeouts
+ defaultDialTimeout = 10 * time.Second // used if context has no deadline
+ subscribeTimeout = 5 * time.Second // overall timeout eth_subscribe, rpc_modules calls
+)
+
+const (
+ // Subscriptions are removed when the subscriber cannot keep up.
+ //
+ // This can be worked around by supplying a channel with sufficiently sized buffer,
+ // but this can be inconvenient and hard to explain in the docs. Another issue with
+ // buffered channels is that the buffer is static even though it might not be needed
+ // most of the time.
+ //
+ // The approach taken here is to maintain a per-subscription linked list buffer
+ // shrinks on demand. If the buffer reaches the size below, the subscription is
+ // dropped.
+ maxClientSubscriptionBuffer = 20000
+)
+
+// BatchElem is an element in a batch request.
+type BatchElem struct {
+ Method string
+ Args []interface{}
+ // The result is unmarshaled into this field. Result must be set to a
+ // non-nil pointer value of the desired type, otherwise the response will be
+ // discarded.
+ Result interface{}
+ // Error is set if the server returns an error for this request, or if
+ // unmarshaling into Result fails. It is not set for I/O errors.
+ Error error
+}
+
+// Client represents a connection to an RPC server.
+type Client struct {
+ idgen func() ID // for subscriptions
+ isHTTP bool
+ services *serviceRegistry
+
+ idCounter uint32
+
+ // This function, if non-nil, is called when the connection is lost.
+ reconnectFunc reconnectFunc
+
+ // writeConn is used for writing to the connection on the caller's goroutine. It should
+ // only be accessed outside of dispatch, with the write lock held. The write lock is
+ // taken by sending on requestOp and released by sending on sendDone.
+ writeConn jsonWriter
+
+ // for dispatch
+ close chan struct{}
+ closing chan struct{} // closed when client is quitting
+ didClose chan struct{} // closed when client quits
+ reconnected chan ServerCodec // where write/reconnect sends the new connection
+ readOp chan readOp // read messages
+ readErr chan error // errors from read
+ reqInit chan *requestOp // register response IDs, takes write lock
+ reqSent chan error // signals write completion, releases write lock
+ reqTimeout chan *requestOp // removes response IDs when call timeout expires
+}
+
+type reconnectFunc func(ctx context.Context) (ServerCodec, error)
+
+type clientContextKey struct{}
+
+type clientConn struct {
+ codec ServerCodec
+ handler *handler
+}
+
+func (c *Client) newClientConn(conn ServerCodec) *clientConn {
+ ctx := context.WithValue(context.Background(), clientContextKey{}, c)
+ handler := newHandler(ctx, conn, c.idgen, c.services)
+ return &clientConn{conn, handler}
+}
+
+func (cc *clientConn) close(err error, inflightReq *requestOp) {
+ cc.handler.close(err, inflightReq)
+ cc.codec.Close()
+}
+
+type readOp struct {
+ msgs []*jsonrpcMessage
+ batch bool
+}
+
+type requestOp struct {
+ ids []json.RawMessage
+ err error
+ resp chan *jsonrpcMessage // receives up to len(ids) responses
+ sub *ClientSubscription // only set for EthSubscribe requests
+}
+
+func (op *requestOp) wait(ctx context.Context, c *Client) (*jsonrpcMessage, error) {
+ select {
+ case <-ctx.Done():
+ // Send the timeout to dispatch so it can remove the request IDs.
+ if !c.isHTTP {
+ select {
+ case c.reqTimeout <- op:
+ case <-c.closing:
+ }
+ }
+ return nil, ctx.Err()
+ case resp := <-op.resp:
+ return resp, op.err
+ }
+}
+
+// Dial creates a new client for the given URL.
+//
+// The currently supported URL schemes are "http", "https", "ws" and "wss". If rawurl is a
+// file name with no URL scheme, a local socket connection is established using UNIX
+// domain sockets on supported platforms and named pipes on Windows. If you want to
+// configure transport options, use DialHTTP, DialWebsocket or DialIPC instead.
+//
+// For websocket connections, the origin is set to the local host name.
+//
+// The client reconnects automatically if the connection is lost.
+func Dial(rawurl string) (*Client, error) {
+ return DialContext(context.Background(), rawurl)
+}
+
+// DialContext creates a new RPC client, just like Dial.
+//
+// The context is used to cancel or time out the initial connection establishment. It does
+// not affect subsequent interactions with the client.
+func DialContext(ctx context.Context, rawurl string) (*Client, error) {
+ u, err := url.Parse(rawurl)
+ if err != nil {
+ return nil, err
+ }
+ switch u.Scheme {
+ case "http", "https":
+ return DialHTTP(rawurl)
+ case "ws", "wss":
+ return DialWebsocket(ctx, rawurl, "")
+ //case "stdio":
+ // return DialStdIO(ctx)
+ //case "":
+ // return DialIPC(ctx, rawurl)
+ default:
+ return nil, fmt.Errorf("no known transport for URL scheme %q", u.Scheme)
+ }
+}
+
+// Client retrieves the client from the context, if any. This can be used to perform
+// 'reverse calls' in a handler method.
+func ClientFromContext(ctx context.Context) (*Client, bool) {
+ client, ok := ctx.Value(clientContextKey{}).(*Client)
+ return client, ok
+}
+
+func newClient(initctx context.Context, connect reconnectFunc) (*Client, error) {
+ conn, err := connect(initctx)
+ if err != nil {
+ return nil, err
+ }
+ c := initClient(conn, randomIDGenerator(), new(serviceRegistry))
+ c.reconnectFunc = connect
+ return c, nil
+}
+
+func initClient(conn ServerCodec, idgen func() ID, services *serviceRegistry) *Client {
+ _, isHTTP := conn.(*httpConn)
+ c := &Client{
+ idgen: idgen,
+ isHTTP: isHTTP,
+ services: services,
+ writeConn: conn,
+ close: make(chan struct{}),
+ closing: make(chan struct{}),
+ didClose: make(chan struct{}),
+ reconnected: make(chan ServerCodec),
+ readOp: make(chan readOp),
+ readErr: make(chan error),
+ reqInit: make(chan *requestOp),
+ reqSent: make(chan error, 1),
+ reqTimeout: make(chan *requestOp),
+ }
+ if !isHTTP {
+ go c.dispatch(conn)
+ }
+ return c
+}
+
+// RegisterName creates a service for the given receiver type under the given name. When no
+// methods on the given receiver match the criteria to be either a RPC method or a
+// subscription an error is returned. Otherwise a new service is created and added to the
+// service collection this client provides to the server.
+func (c *Client) RegisterName(name string, receiver interface{}) error {
+ return c.services.registerName(name, receiver)
+}
+
+func (c *Client) nextID() json.RawMessage {
+ id := atomic.AddUint32(&c.idCounter, 1)
+ return strconv.AppendUint(nil, uint64(id), 10)
+}
+
+// SupportedModules calls the rpc_modules method, retrieving the list of
+// APIs that are available on the server.
+func (c *Client) SupportedModules() (map[string]string, error) {
+ var result map[string]string
+ ctx, cancel := context.WithTimeout(context.Background(), subscribeTimeout)
+ defer cancel()
+ err := c.CallContext(ctx, &result, "rpc_modules")
+ return result, err
+}
+
+// Close closes the client, aborting any in-flight requests.
+func (c *Client) Close() {
+ if c.isHTTP {
+ return
+ }
+ select {
+ case c.close <- struct{}{}:
+ <-c.didClose
+ case <-c.didClose:
+ }
+}
+
+// Call performs a JSON-RPC call with the given arguments and unmarshals into
+// result if no error occurred.
+//
+// The result must be a pointer so that package json can unmarshal into it. You
+// can also pass nil, in which case the result is ignored.
+func (c *Client) Call(result interface{}, method string, args ...interface{}) error {
+ ctx := context.Background()
+ return c.CallContext(ctx, result, method, args...)
+}
+
+// CallContext performs a JSON-RPC call with the given arguments. If the context is
+// canceled before the call has successfully returned, CallContext returns immediately.
+//
+// The result must be a pointer so that package json can unmarshal into it. You
+// can also pass nil, in which case the result is ignored.
+func (c *Client) CallContext(ctx context.Context, result interface{}, method string, args ...interface{}) error {
+ msg, err := c.newMessage(method, args...)
+ if err != nil {
+ return err
+ }
+ op := &requestOp{ids: []json.RawMessage{msg.ID}, resp: make(chan *jsonrpcMessage, 1)}
+
+ if c.isHTTP {
+ err = c.sendHTTP(ctx, op, msg)
+ } else {
+ err = c.send(ctx, op, msg)
+ }
+ if err != nil {
+ return err
+ }
+
+ // dispatch has accepted the request and will close the channel when it quits.
+ switch resp, err := op.wait(ctx, c); {
+ case err != nil:
+ return err
+ case resp.Error != nil:
+ return resp.Error
+ case len(resp.Result) == 0:
+ return ErrNoResult
+ default:
+ return json.Unmarshal(resp.Result, &result)
+ }
+}
+
+// BatchCall sends all given requests as a single batch and waits for the server
+// to return a response for all of them.
+//
+// In contrast to Call, BatchCall only returns I/O errors. Any error specific to
+// a request is reported through the Error field of the corresponding BatchElem.
+//
+// Note that batch calls may not be executed atomically on the server side.
+func (c *Client) BatchCall(b []BatchElem) error {
+ ctx := context.Background()
+ return c.BatchCallContext(ctx, b)
+}
+
+// BatchCall sends all given requests as a single batch and waits for the server
+// to return a response for all of them. The wait duration is bounded by the
+// context's deadline.
+//
+// In contrast to CallContext, BatchCallContext only returns errors that have occurred
+// while sending the request. Any error specific to a request is reported through the
+// Error field of the corresponding BatchElem.
+//
+// Note that batch calls may not be executed atomically on the server side.
+func (c *Client) BatchCallContext(ctx context.Context, b []BatchElem) error {
+ msgs := make([]*jsonrpcMessage, len(b))
+ op := &requestOp{
+ ids: make([]json.RawMessage, len(b)),
+ resp: make(chan *jsonrpcMessage, len(b)),
+ }
+ for i, elem := range b {
+ msg, err := c.newMessage(elem.Method, elem.Args...)
+ if err != nil {
+ return err
+ }
+ msgs[i] = msg
+ op.ids[i] = msg.ID
+ }
+
+ var err error
+ if c.isHTTP {
+ err = c.sendBatchHTTP(ctx, op, msgs)
+ } else {
+ err = c.send(ctx, op, msgs)
+ }
+
+ // Wait for all responses to come back.
+ for n := 0; n < len(b) && err == nil; n++ {
+ var resp *jsonrpcMessage
+ resp, err = op.wait(ctx, c)
+ if err != nil {
+ break
+ }
+ // Find the element corresponding to this response.
+ // The element is guaranteed to be present because dispatch
+ // only sends valid IDs to our channel.
+ var elem *BatchElem
+ for i := range msgs {
+ if bytes.Equal(msgs[i].ID, resp.ID) {
+ elem = &b[i]
+ break
+ }
+ }
+ if resp.Error != nil {
+ elem.Error = resp.Error
+ continue
+ }
+ if len(resp.Result) == 0 {
+ elem.Error = ErrNoResult
+ continue
+ }
+ elem.Error = json.Unmarshal(resp.Result, elem.Result)
+ }
+ return err
+}
+
+// Notify sends a notification, i.e. a method call that doesn't expect a response.
+func (c *Client) Notify(ctx context.Context, method string, args ...interface{}) error {
+ op := new(requestOp)
+ msg, err := c.newMessage(method, args...)
+ if err != nil {
+ return err
+ }
+ msg.ID = nil
+
+ if c.isHTTP {
+ return c.sendHTTP(ctx, op, msg)
+ } else {
+ return c.send(ctx, op, msg)
+ }
+}
+
+// EthSubscribe registers a subscripion under the "eth" namespace.
+func (c *Client) EthSubscribe(ctx context.Context, channel interface{}, args ...interface{}) (*ClientSubscription, error) {
+ return c.Subscribe(ctx, "eth", channel, args...)
+}
+
+// ShhSubscribe registers a subscripion under the "shh" namespace.
+func (c *Client) ShhSubscribe(ctx context.Context, channel interface{}, args ...interface{}) (*ClientSubscription, error) {
+ return c.Subscribe(ctx, "shh", channel, args...)
+}
+
+// Subscribe calls the "<namespace>_subscribe" method with the given arguments,
+// registering a subscription. Server notifications for the subscription are
+// sent to the given channel. The element type of the channel must match the
+// expected type of content returned by the subscription.
+//
+// The context argument cancels the RPC request that sets up the subscription but has no
+// effect on the subscription after Subscribe has returned.
+//
+// Slow subscribers will be dropped eventually. Client buffers up to 20000 notifications
+// before considering the subscriber dead. The subscription Err channel will receive
+// ErrSubscriptionQueueOverflow. Use a sufficiently large buffer on the channel or ensure
+// that the channel usually has at least one reader to prevent this issue.
+func (c *Client) Subscribe(ctx context.Context, namespace string, channel interface{}, args ...interface{}) (*ClientSubscription, error) {
+ // Check type of channel first.
+ chanVal := reflect.ValueOf(channel)
+ if chanVal.Kind() != reflect.Chan || chanVal.Type().ChanDir()&reflect.SendDir == 0 {
+ panic("first argument to Subscribe must be a writable channel")
+ }
+ if chanVal.IsNil() {
+ panic("channel given to Subscribe must not be nil")
+ }
+ if c.isHTTP {
+ return nil, ErrNotificationsUnsupported
+ }
+
+ msg, err := c.newMessage(namespace+subscribeMethodSuffix, args...)
+ if err != nil {
+ return nil, err
+ }
+ op := &requestOp{
+ ids: []json.RawMessage{msg.ID},
+ resp: make(chan *jsonrpcMessage),
+ sub: newClientSubscription(c, namespace, chanVal),
+ }
+
+ // Send the subscription request.
+ // The arrival and validity of the response is signaled on sub.quit.
+ if err := c.send(ctx, op, msg); err != nil {
+ return nil, err
+ }
+ if _, err := op.wait(ctx, c); err != nil {
+ return nil, err
+ }
+ return op.sub, nil
+}
+
+func (c *Client) newMessage(method string, paramsIn ...interface{}) (*jsonrpcMessage, error) {
+ msg := &jsonrpcMessage{Version: vsn, ID: c.nextID(), Method: method}
+ if paramsIn != nil { // prevent sending "params":null
+ var err error
+ if msg.Params, err = json.Marshal(paramsIn); err != nil {
+ return nil, err
+ }
+ }
+ return msg, nil
+}
+
+// send registers op with the dispatch loop, then sends msg on the connection.
+// if sending fails, op is deregistered.
+func (c *Client) send(ctx context.Context, op *requestOp, msg interface{}) error {
+ select {
+ case c.reqInit <- op:
+ err := c.write(ctx, msg)
+ c.reqSent <- err
+ return err
+ case <-ctx.Done():
+ // This can happen if the client is overloaded or unable to keep up with
+ // subscription notifications.
+ return ctx.Err()
+ case <-c.closing:
+ return ErrClientQuit
+ }
+}
+
+func (c *Client) write(ctx context.Context, msg interface{}) error {
+ // The previous write failed. Try to establish a new connection.
+ if c.writeConn == nil {
+ if err := c.reconnect(ctx); err != nil {
+ return err
+ }
+ }
+ err := c.writeConn.Write(ctx, msg)
+ if err != nil {
+ c.writeConn = nil
+ }
+ return err
+}
+
+func (c *Client) reconnect(ctx context.Context) error {
+ if c.reconnectFunc == nil {
+ return errDead
+ }
+
+ if _, ok := ctx.Deadline(); !ok {
+ var cancel func()
+ ctx, cancel = context.WithTimeout(ctx, defaultDialTimeout)
+ defer cancel()
+ }
+ newconn, err := c.reconnectFunc(ctx)
+ if err != nil {
+ log.Trace("RPC client reconnect failed", "err", err)
+ return err
+ }
+ select {
+ case c.reconnected <- newconn:
+ c.writeConn = newconn
+ return nil
+ case <-c.didClose:
+ newconn.Close()
+ return ErrClientQuit
+ }
+}
+
+// dispatch is the main loop of the client.
+// It sends read messages to waiting calls to Call and BatchCall
+// and subscription notifications to registered subscriptions.
+func (c *Client) dispatch(codec ServerCodec) {
+ var (
+ lastOp *requestOp // tracks last send operation
+ reqInitLock = c.reqInit // nil while the send lock is held
+ conn = c.newClientConn(codec)
+ reading = true
+ )
+ defer func() {
+ close(c.closing)
+ if reading {
+ conn.close(ErrClientQuit, nil)
+ c.drainRead()
+ }
+ close(c.didClose)
+ }()
+
+ // Spawn the initial read loop.
+ go c.read(codec)
+
+ for {
+ select {
+ case <-c.close:
+ return
+
+ // Read path:
+ case op := <-c.readOp:
+ if op.batch {
+ conn.handler.handleBatch(op.msgs)
+ } else {
+ conn.handler.handleMsg(op.msgs[0])
+ }
+
+ case err := <-c.readErr:
+ conn.handler.log.Debug("RPC connection read error", "err", err)
+ conn.close(err, lastOp)
+ reading = false
+
+ // Reconnect:
+ case newcodec := <-c.reconnected:
+ log.Debug("RPC client reconnected", "reading", reading, "conn", newcodec.RemoteAddr())
+ if reading {
+ // Wait for the previous read loop to exit. This is a rare case which
+ // happens if this loop isn't notified in time after the connection breaks.
+ // In those cases the caller will notice first and reconnect. Closing the
+ // handler terminates all waiting requests (closing op.resp) except for
+ // lastOp, which will be transferred to the new handler.
+ conn.close(errClientReconnected, lastOp)
+ c.drainRead()
+ }
+ go c.read(newcodec)
+ reading = true
+ conn = c.newClientConn(newcodec)
+ // Re-register the in-flight request on the new handler
+ // because that's where it will be sent.
+ conn.handler.addRequestOp(lastOp)
+
+ // Send path:
+ case op := <-reqInitLock:
+ // Stop listening for further requests until the current one has been sent.
+ reqInitLock = nil
+ lastOp = op
+ conn.handler.addRequestOp(op)
+
+ case err := <-c.reqSent:
+ if err != nil {
+ // Remove response handlers for the last send. When the read loop
+ // goes down, it will signal all other current operations.
+ conn.handler.removeRequestOp(lastOp)
+ }
+ // Let the next request in.
+ reqInitLock = c.reqInit
+ lastOp = nil
+
+ case op := <-c.reqTimeout:
+ conn.handler.removeRequestOp(op)
+ }
+ }
+}
+
+// drainRead drops read messages until an error occurs.
+func (c *Client) drainRead() {
+ for {
+ select {
+ case <-c.readOp:
+ case <-c.readErr:
+ return
+ }
+ }
+}
+
+// read decodes RPC messages from a codec, feeding them into dispatch.
+func (c *Client) read(codec ServerCodec) {
+ for {
+ msgs, batch, err := codec.Read()
+ if _, ok := err.(*json.SyntaxError); ok {
+ codec.Write(context.Background(), errorMessage(&parseError{err.Error()}))
+ }
+ if err != nil {
+ c.readErr <- err
+ return
+ }
+ c.readOp <- readOp{msgs, batch}
+ }
+}
diff --git a/rpc/constants_unix_nocgo.go b/rpc/constants_unix_nocgo.go
new file mode 100644
index 0000000..ecb231f
--- /dev/null
+++ b/rpc/constants_unix_nocgo.go
@@ -0,0 +1,25 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build !cgo,!windows
+
+package rpc
+
+var (
+ // On Linux, sun_path is 108 bytes in size
+ // see http://man7.org/linux/man-pages/man7/unix.7.html
+ max_path_size = 108
+)
diff --git a/rpc/doc.go b/rpc/doc.go
new file mode 100644
index 0000000..e5840c3
--- /dev/null
+++ b/rpc/doc.go
@@ -0,0 +1,118 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+/*
+
+Package rpc implements bi-directional JSON-RPC 2.0 on multiple transports.
+
+It provides access to the exported methods of an object across a network or other I/O
+connection. After creating a server or client instance, objects can be registered to make
+them visible as 'services'. Exported methods that follow specific conventions can be
+called remotely. It also has support for the publish/subscribe pattern.
+
+RPC Methods
+
+Methods that satisfy the following criteria are made available for remote access:
+
+ - method must be exported
+ - method returns 0, 1 (response or error) or 2 (response and error) values
+ - method argument(s) must be exported or builtin types
+ - method returned value(s) must be exported or builtin types
+
+An example method:
+
+ func (s *CalcService) Add(a, b int) (int, error)
+
+When the returned error isn't nil the returned integer is ignored and the error is sent
+back to the client. Otherwise the returned integer is sent back to the client.
+
+Optional arguments are supported by accepting pointer values as arguments. E.g. if we want
+to do the addition in an optional finite field we can accept a mod argument as pointer
+value.
+
+ func (s *CalcService) Add(a, b int, mod *int) (int, error)
+
+This RPC method can be called with 2 integers and a null value as third argument. In that
+case the mod argument will be nil. Or it can be called with 3 integers, in that case mod
+will be pointing to the given third argument. Since the optional argument is the last
+argument the RPC package will also accept 2 integers as arguments. It will pass the mod
+argument as nil to the RPC method.
+
+The server offers the ServeCodec method which accepts a ServerCodec instance. It will read
+requests from the codec, process the request and sends the response back to the client
+using the codec. The server can execute requests concurrently. Responses can be sent back
+to the client out of order.
+
+An example server which uses the JSON codec:
+
+ type CalculatorService struct {}
+
+ func (s *CalculatorService) Add(a, b int) int {
+ return a + b
+ }
+
+ func (s *CalculatorService) Div(a, b int) (int, error) {
+ if b == 0 {
+ return 0, errors.New("divide by zero")
+ }
+ return a/b, nil
+ }
+
+ calculator := new(CalculatorService)
+ server := NewServer()
+ server.RegisterName("calculator", calculator")
+
+ l, _ := net.ListenUnix("unix", &net.UnixAddr{Net: "unix", Name: "/tmp/calculator.sock"})
+ for {
+ c, _ := l.AcceptUnix()
+ codec := v2.NewJSONCodec(c)
+ go server.ServeCodec(codec, 0)
+ }
+
+Subscriptions
+
+The package also supports the publish subscribe pattern through the use of subscriptions.
+A method that is considered eligible for notifications must satisfy the following
+criteria:
+
+ - method must be exported
+ - first method argument type must be context.Context
+ - method argument(s) must be exported or builtin types
+ - method must have return types (rpc.Subscription, error)
+
+An example method:
+
+ func (s *BlockChainService) NewBlocks(ctx context.Context) (rpc.Subscription, error) {
+ ...
+ }
+
+When the service containing the subscription method is registered to the server, for
+example under the "blockchain" namespace, a subscription is created by calling the
+"blockchain_subscribe" method.
+
+Subscriptions are deleted when the user sends an unsubscribe request or when the
+connection which was used to create the subscription is closed. This can be initiated by
+the client and server. The server will close the connection for any write error.
+
+For more information about subscriptions, see https://github.com/ethereum/go-ethereum/wiki/RPC-PUB-SUB.
+
+Reverse Calls
+
+In any method handler, an instance of rpc.Client can be accessed through the
+ClientFromContext method. Using this client instance, server-to-client method calls can be
+performed on the RPC connection.
+*/
+package rpc
diff --git a/rpc/errors.go b/rpc/errors.go
new file mode 100644
index 0000000..c3aa826
--- /dev/null
+++ b/rpc/errors.go
@@ -0,0 +1,65 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import "fmt"
+
+const defaultErrorCode = -32000
+
+type methodNotFoundError struct{ method string }
+
+func (e *methodNotFoundError) ErrorCode() int { return -32601 }
+
+func (e *methodNotFoundError) Error() string {
+ return fmt.Sprintf("the method %s does not exist/is not available", e.method)
+}
+
+type subscriptionNotFoundError struct{ namespace, subscription string }
+
+func (e *subscriptionNotFoundError) ErrorCode() int { return -32601 }
+
+func (e *subscriptionNotFoundError) Error() string {
+ return fmt.Sprintf("no %q subscription in %s namespace", e.subscription, e.namespace)
+}
+
+// Invalid JSON was received by the server.
+type parseError struct{ message string }
+
+func (e *parseError) ErrorCode() int { return -32700 }
+
+func (e *parseError) Error() string { return e.message }
+
+// received message isn't a valid request
+type invalidRequestError struct{ message string }
+
+func (e *invalidRequestError) ErrorCode() int { return -32600 }
+
+func (e *invalidRequestError) Error() string { return e.message }
+
+// received message is invalid
+type invalidMessageError struct{ message string }
+
+func (e *invalidMessageError) ErrorCode() int { return -32700 }
+
+func (e *invalidMessageError) Error() string { return e.message }
+
+// unable to decode supplied params, or an invalid number of parameters
+type invalidParamsError struct{ message string }
+
+func (e *invalidParamsError) ErrorCode() int { return -32602 }
+
+func (e *invalidParamsError) Error() string { return e.message }
diff --git a/rpc/gzip.go b/rpc/gzip.go
new file mode 100644
index 0000000..a14fd09
--- /dev/null
+++ b/rpc/gzip.go
@@ -0,0 +1,66 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "compress/gzip"
+ "io"
+ "io/ioutil"
+ "net/http"
+ "strings"
+ "sync"
+)
+
+var gzPool = sync.Pool{
+ New: func() interface{} {
+ w := gzip.NewWriter(ioutil.Discard)
+ return w
+ },
+}
+
+type gzipResponseWriter struct {
+ io.Writer
+ http.ResponseWriter
+}
+
+func (w *gzipResponseWriter) WriteHeader(status int) {
+ w.Header().Del("Content-Length")
+ w.ResponseWriter.WriteHeader(status)
+}
+
+func (w *gzipResponseWriter) Write(b []byte) (int, error) {
+ return w.Writer.Write(b)
+}
+
+func newGzipHandler(next http.Handler) http.Handler {
+ return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+ next.ServeHTTP(w, r)
+ return
+ }
+
+ w.Header().Set("Content-Encoding", "gzip")
+
+ gz := gzPool.Get().(*gzip.Writer)
+ defer gzPool.Put(gz)
+
+ gz.Reset(w)
+ defer gz.Close()
+
+ next.ServeHTTP(&gzipResponseWriter{ResponseWriter: w, Writer: gz}, r)
+ })
+}
diff --git a/rpc/handler.go b/rpc/handler.go
new file mode 100644
index 0000000..187d0f8
--- /dev/null
+++ b/rpc/handler.go
@@ -0,0 +1,397 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "context"
+ "encoding/json"
+ "reflect"
+ "strconv"
+ "strings"
+ "sync"
+ "time"
+
+ "github.com/ava-labs/go-ethereum/log"
+)
+
+// handler handles JSON-RPC messages. There is one handler per connection. Note that
+// handler is not safe for concurrent use. Message handling never blocks indefinitely
+// because RPCs are processed on background goroutines launched by handler.
+//
+// The entry points for incoming messages are:
+//
+// h.handleMsg(message)
+// h.handleBatch(message)
+//
+// Outgoing calls use the requestOp struct. Register the request before sending it
+// on the connection:
+//
+// op := &requestOp{ids: ...}
+// h.addRequestOp(op)
+//
+// Now send the request, then wait for the reply to be delivered through handleMsg:
+//
+// if err := op.wait(...); err != nil {
+// h.removeRequestOp(op) // timeout, etc.
+// }
+//
+type handler struct {
+ reg *serviceRegistry
+ unsubscribeCb *callback
+ idgen func() ID // subscription ID generator
+ respWait map[string]*requestOp // active client requests
+ clientSubs map[string]*ClientSubscription // active client subscriptions
+ callWG sync.WaitGroup // pending call goroutines
+ rootCtx context.Context // canceled by close()
+ cancelRoot func() // cancel function for rootCtx
+ conn jsonWriter // where responses will be sent
+ log log.Logger
+ allowSubscribe bool
+
+ subLock sync.Mutex
+ serverSubs map[ID]*Subscription
+}
+
+type callProc struct {
+ ctx context.Context
+ notifiers []*Notifier
+}
+
+func newHandler(connCtx context.Context, conn jsonWriter, idgen func() ID, reg *serviceRegistry) *handler {
+ rootCtx, cancelRoot := context.WithCancel(connCtx)
+ h := &handler{
+ reg: reg,
+ idgen: idgen,
+ conn: conn,
+ respWait: make(map[string]*requestOp),
+ clientSubs: make(map[string]*ClientSubscription),
+ rootCtx: rootCtx,
+ cancelRoot: cancelRoot,
+ allowSubscribe: true,
+ serverSubs: make(map[ID]*Subscription),
+ log: log.Root(),
+ }
+ if conn.RemoteAddr() != "" {
+ h.log = h.log.New("conn", conn.RemoteAddr())
+ }
+ h.unsubscribeCb = newCallback(reflect.Value{}, reflect.ValueOf(h.unsubscribe))
+ return h
+}
+
+// handleBatch executes all messages in a batch and returns the responses.
+func (h *handler) handleBatch(msgs []*jsonrpcMessage) {
+ // Emit error response for empty batches:
+ if len(msgs) == 0 {
+ h.startCallProc(func(cp *callProc) {
+ h.conn.Write(cp.ctx, errorMessage(&invalidRequestError{"empty batch"}))
+ })
+ return
+ }
+
+ // Handle non-call messages first:
+ calls := make([]*jsonrpcMessage, 0, len(msgs))
+ for _, msg := range msgs {
+ if handled := h.handleImmediate(msg); !handled {
+ calls = append(calls, msg)
+ }
+ }
+ if len(calls) == 0 {
+ return
+ }
+ // Process calls on a goroutine because they may block indefinitely:
+ h.startCallProc(func(cp *callProc) {
+ answers := make([]*jsonrpcMessage, 0, len(msgs))
+ for _, msg := range calls {
+ if answer := h.handleCallMsg(cp, msg); answer != nil {
+ answers = append(answers, answer)
+ }
+ }
+ h.addSubscriptions(cp.notifiers)
+ if len(answers) > 0 {
+ h.conn.Write(cp.ctx, answers)
+ }
+ for _, n := range cp.notifiers {
+ n.activate()
+ }
+ })
+}
+
+// handleMsg handles a single message.
+func (h *handler) handleMsg(msg *jsonrpcMessage) {
+ if ok := h.handleImmediate(msg); ok {
+ return
+ }
+ h.startCallProc(func(cp *callProc) {
+ answer := h.handleCallMsg(cp, msg)
+ h.addSubscriptions(cp.notifiers)
+ if answer != nil {
+ h.conn.Write(cp.ctx, answer)
+ }
+ for _, n := range cp.notifiers {
+ n.activate()
+ }
+ })
+}
+
+// close cancels all requests except for inflightReq and waits for
+// call goroutines to shut down.
+func (h *handler) close(err error, inflightReq *requestOp) {
+ h.cancelAllRequests(err, inflightReq)
+ h.callWG.Wait()
+ h.cancelRoot()
+ h.cancelServerSubscriptions(err)
+}
+
+// addRequestOp registers a request operation.
+func (h *handler) addRequestOp(op *requestOp) {
+ for _, id := range op.ids {
+ h.respWait[string(id)] = op
+ }
+}
+
+// removeRequestOps stops waiting for the given request IDs.
+func (h *handler) removeRequestOp(op *requestOp) {
+ for _, id := range op.ids {
+ delete(h.respWait, string(id))
+ }
+}
+
+// cancelAllRequests unblocks and removes pending requests and active subscriptions.
+func (h *handler) cancelAllRequests(err error, inflightReq *requestOp) {
+ didClose := make(map[*requestOp]bool)
+ if inflightReq != nil {
+ didClose[inflightReq] = true
+ }
+
+ for id, op := range h.respWait {
+ // Remove the op so that later calls will not close op.resp again.
+ delete(h.respWait, id)
+
+ if !didClose[op] {
+ op.err = err
+ close(op.resp)
+ didClose[op] = true
+ }
+ }
+ for id, sub := range h.clientSubs {
+ delete(h.clientSubs, id)
+ sub.quitWithError(err, false)
+ }
+}
+
+func (h *handler) addSubscriptions(nn []*Notifier) {
+ h.subLock.Lock()
+ defer h.subLock.Unlock()
+
+ for _, n := range nn {
+ if sub := n.takeSubscription(); sub != nil {
+ h.serverSubs[sub.ID] = sub
+ }
+ }
+}
+
+// cancelServerSubscriptions removes all subscriptions and closes their error channels.
+func (h *handler) cancelServerSubscriptions(err error) {
+ h.subLock.Lock()
+ defer h.subLock.Unlock()
+
+ for id, s := range h.serverSubs {
+ s.err <- err
+ close(s.err)
+ delete(h.serverSubs, id)
+ }
+}
+
+// startCallProc runs fn in a new goroutine and starts tracking it in the h.calls wait group.
+func (h *handler) startCallProc(fn func(*callProc)) {
+ h.callWG.Add(1)
+ go func() {
+ ctx, cancel := context.WithCancel(h.rootCtx)
+ defer h.callWG.Done()
+ defer cancel()
+ fn(&callProc{ctx: ctx})
+ }()
+}
+
+// handleImmediate executes non-call messages. It returns false if the message is a
+// call or requires a reply.
+func (h *handler) handleImmediate(msg *jsonrpcMessage) bool {
+ start := time.Now()
+ switch {
+ case msg.isNotification():
+ if strings.HasSuffix(msg.Method, notificationMethodSuffix) {
+ h.handleSubscriptionResult(msg)
+ return true
+ }
+ return false
+ case msg.isResponse():
+ h.handleResponse(msg)
+ h.log.Trace("Handled RPC response", "reqid", idForLog{msg.ID}, "t", time.Since(start))
+ return true
+ default:
+ return false
+ }
+}
+
+// handleSubscriptionResult processes subscription notifications.
+func (h *handler) handleSubscriptionResult(msg *jsonrpcMessage) {
+ var result subscriptionResult
+ if err := json.Unmarshal(msg.Params, &result); err != nil {
+ h.log.Debug("Dropping invalid subscription message")
+ return
+ }
+ if h.clientSubs[result.ID] != nil {
+ h.clientSubs[result.ID].deliver(result.Result)
+ }
+}
+
+// handleResponse processes method call responses.
+func (h *handler) handleResponse(msg *jsonrpcMessage) {
+ op := h.respWait[string(msg.ID)]
+ if op == nil {
+ h.log.Debug("Unsolicited RPC response", "reqid", idForLog{msg.ID})
+ return
+ }
+ delete(h.respWait, string(msg.ID))
+ // For normal responses, just forward the reply to Call/BatchCall.
+ if op.sub == nil {
+ op.resp <- msg
+ return
+ }
+ // For subscription responses, start the subscription if the server
+ // indicates success. EthSubscribe gets unblocked in either case through
+ // the op.resp channel.
+ defer close(op.resp)
+ if msg.Error != nil {
+ op.err = msg.Error
+ return
+ }
+ if op.err = json.Unmarshal(msg.Result, &op.sub.subid); op.err == nil {
+ go op.sub.start()
+ h.clientSubs[op.sub.subid] = op.sub
+ }
+}
+
+// handleCallMsg executes a call message and returns the answer.
+func (h *handler) handleCallMsg(ctx *callProc, msg *jsonrpcMessage) *jsonrpcMessage {
+ start := time.Now()
+ switch {
+ case msg.isNotification():
+ h.handleCall(ctx, msg)
+ h.log.Debug("Served "+msg.Method, "t", time.Since(start))
+ return nil
+ case msg.isCall():
+ resp := h.handleCall(ctx, msg)
+ if resp.Error != nil {
+ h.log.Warn("Served "+msg.Method, "reqid", idForLog{msg.ID}, "t", time.Since(start), "err", resp.Error.Message)
+ } else {
+ h.log.Debug("Served "+msg.Method, "reqid", idForLog{msg.ID}, "t", time.Since(start))
+ }
+ return resp
+ case msg.hasValidID():
+ return msg.errorResponse(&invalidRequestError{"invalid request"})
+ default:
+ return errorMessage(&invalidRequestError{"invalid request"})
+ }
+}
+
+// handleCall processes method calls.
+func (h *handler) handleCall(cp *callProc, msg *jsonrpcMessage) *jsonrpcMessage {
+ if msg.isSubscribe() {
+ return h.handleSubscribe(cp, msg)
+ }
+ var callb *callback
+ if msg.isUnsubscribe() {
+ callb = h.unsubscribeCb
+ } else {
+ callb = h.reg.callback(msg.Method)
+ }
+ if callb == nil {
+ return msg.errorResponse(&methodNotFoundError{method: msg.Method})
+ }
+ args, err := parsePositionalArguments(msg.Params, callb.argTypes)
+ if err != nil {
+ return msg.errorResponse(&invalidParamsError{err.Error()})
+ }
+
+ return h.runMethod(cp.ctx, msg, callb, args)
+}
+
+// handleSubscribe processes *_subscribe method calls.
+func (h *handler) handleSubscribe(cp *callProc, msg *jsonrpcMessage) *jsonrpcMessage {
+ if !h.allowSubscribe {
+ return msg.errorResponse(ErrNotificationsUnsupported)
+ }
+
+ // Subscription method name is first argument.
+ name, err := parseSubscriptionName(msg.Params)
+ if err != nil {
+ return msg.errorResponse(&invalidParamsError{err.Error()})
+ }
+ namespace := msg.namespace()
+ callb := h.reg.subscription(namespace, name)
+ if callb == nil {
+ return msg.errorResponse(&subscriptionNotFoundError{namespace, name})
+ }
+
+ // Parse subscription name arg too, but remove it before calling the callback.
+ argTypes := append([]reflect.Type{stringType}, callb.argTypes...)
+ args, err := parsePositionalArguments(msg.Params, argTypes)
+ if err != nil {
+ return msg.errorResponse(&invalidParamsError{err.Error()})
+ }
+ args = args[1:]
+
+ // Install notifier in context so the subscription handler can find it.
+ n := &Notifier{h: h, namespace: namespace}
+ cp.notifiers = append(cp.notifiers, n)
+ ctx := context.WithValue(cp.ctx, notifierKey{}, n)
+
+ return h.runMethod(ctx, msg, callb, args)
+}
+
+// runMethod runs the Go callback for an RPC method.
+func (h *handler) runMethod(ctx context.Context, msg *jsonrpcMessage, callb *callback, args []reflect.Value) *jsonrpcMessage {
+ result, err := callb.call(ctx, msg.Method, args)
+ if err != nil {
+ return msg.errorResponse(err)
+ }
+ return msg.response(result)
+}
+
+// unsubscribe is the callback function for all *_unsubscribe calls.
+func (h *handler) unsubscribe(ctx context.Context, id ID) (bool, error) {
+ h.subLock.Lock()
+ defer h.subLock.Unlock()
+
+ s := h.serverSubs[id]
+ if s == nil {
+ return false, ErrSubscriptionNotFound
+ }
+ close(s.err)
+ delete(h.serverSubs, id)
+ return true, nil
+}
+
+type idForLog struct{ json.RawMessage }
+
+func (id idForLog) String() string {
+ if s, err := strconv.Unquote(string(id.RawMessage)); err == nil {
+ return s
+ }
+ return string(id.RawMessage)
+}
diff --git a/rpc/http.go b/rpc/http.go
new file mode 100644
index 0000000..2dffc5d
--- /dev/null
+++ b/rpc/http.go
@@ -0,0 +1,359 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "bytes"
+ "context"
+ "encoding/json"
+ "errors"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "mime"
+ "net"
+ "net/http"
+ "strings"
+ "sync"
+ "time"
+
+ "github.com/ava-labs/go-ethereum/log"
+ "github.com/rs/cors"
+)
+
+const (
+ maxRequestContentLength = 1024 * 1024 * 5
+ contentType = "application/json"
+)
+
+// https://www.jsonrpc.org/historical/json-rpc-over-http.html#id13
+var acceptedContentTypes = []string{contentType, "application/json-rpc", "application/jsonrequest"}
+
+type httpConn struct {
+ client *http.Client
+ req *http.Request
+ closeOnce sync.Once
+ closed chan interface{}
+}
+
+// httpConn is treated specially by Client.
+func (hc *httpConn) Write(context.Context, interface{}) error {
+ panic("Write called on httpConn")
+}
+
+func (hc *httpConn) RemoteAddr() string {
+ return hc.req.URL.String()
+}
+
+func (hc *httpConn) Read() ([]*jsonrpcMessage, bool, error) {
+ <-hc.closed
+ return nil, false, io.EOF
+}
+
+func (hc *httpConn) Close() {
+ hc.closeOnce.Do(func() { close(hc.closed) })
+}
+
+func (hc *httpConn) Closed() <-chan interface{} {
+ return hc.closed
+}
+
+// HTTPTimeouts represents the configuration params for the HTTP RPC server.
+type HTTPTimeouts struct {
+ // ReadTimeout is the maximum duration for reading the entire
+ // request, including the body.
+ //
+ // Because ReadTimeout does not let Handlers make per-request
+ // decisions on each request body's acceptable deadline or
+ // upload rate, most users will prefer to use
+ // ReadHeaderTimeout. It is valid to use them both.
+ ReadTimeout time.Duration
+
+ // WriteTimeout is the maximum duration before timing out
+ // writes of the response. It is reset whenever a new
+ // request's header is read. Like ReadTimeout, it does not
+ // let Handlers make decisions on a per-request basis.
+ WriteTimeout time.Duration
+
+ // IdleTimeout is the maximum amount of time to wait for the
+ // next request when keep-alives are enabled. If IdleTimeout
+ // is zero, the value of ReadTimeout is used. If both are
+ // zero, ReadHeaderTimeout is used.
+ IdleTimeout time.Duration
+}
+
+// DefaultHTTPTimeouts represents the default timeout values used if further
+// configuration is not provided.
+var DefaultHTTPTimeouts = HTTPTimeouts{
+ ReadTimeout: 30 * time.Second,
+ WriteTimeout: 30 * time.Second,
+ IdleTimeout: 120 * time.Second,
+}
+
+// DialHTTPWithClient creates a new RPC client that connects to an RPC server over HTTP
+// using the provided HTTP Client.
+func DialHTTPWithClient(endpoint string, client *http.Client) (*Client, error) {
+ req, err := http.NewRequest(http.MethodPost, endpoint, nil)
+ if err != nil {
+ return nil, err
+ }
+ req.Header.Set("Content-Type", contentType)
+ req.Header.Set("Accept", contentType)
+
+ initctx := context.Background()
+ return newClient(initctx, func(context.Context) (ServerCodec, error) {
+ return &httpConn{client: client, req: req, closed: make(chan interface{})}, nil
+ })
+}
+
+// DialHTTP creates a new RPC client that connects to an RPC server over HTTP.
+func DialHTTP(endpoint string) (*Client, error) {
+ return DialHTTPWithClient(endpoint, new(http.Client))
+}
+
+func (c *Client) sendHTTP(ctx context.Context, op *requestOp, msg interface{}) error {
+ hc := c.writeConn.(*httpConn)
+ respBody, err := hc.doRequest(ctx, msg)
+ if respBody != nil {
+ defer respBody.Close()
+ }
+
+ if err != nil {
+ if respBody != nil {
+ buf := new(bytes.Buffer)
+ if _, err2 := buf.ReadFrom(respBody); err2 == nil {
+ return fmt.Errorf("%v %v", err, buf.String())
+ }
+ }
+ return err
+ }
+ var respmsg jsonrpcMessage
+ if err := json.NewDecoder(respBody).Decode(&respmsg); err != nil {
+ return err
+ }
+ op.resp <- &respmsg
+ return nil
+}
+
+func (c *Client) sendBatchHTTP(ctx context.Context, op *requestOp, msgs []*jsonrpcMessage) error {
+ hc := c.writeConn.(*httpConn)
+ respBody, err := hc.doRequest(ctx, msgs)
+ if err != nil {
+ return err
+ }
+ defer respBody.Close()
+ var respmsgs []jsonrpcMessage
+ if err := json.NewDecoder(respBody).Decode(&respmsgs); err != nil {
+ return err
+ }
+ for i := 0; i < len(respmsgs); i++ {
+ op.resp <- &respmsgs[i]
+ }
+ return nil
+}
+
+func (hc *httpConn) doRequest(ctx context.Context, msg interface{}) (io.ReadCloser, error) {
+ body, err := json.Marshal(msg)
+ if err != nil {
+ return nil, err
+ }
+ req := hc.req.WithContext(ctx)
+ req.Body = ioutil.NopCloser(bytes.NewReader(body))
+ req.ContentLength = int64(len(body))
+
+ resp, err := hc.client.Do(req)
+ if err != nil {
+ return nil, err
+ }
+ if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+ return resp.Body, errors.New(resp.Status)
+ }
+ return resp.Body, nil
+}
+
+// httpServerConn turns a HTTP connection into a Conn.
+type httpServerConn struct {
+ io.Reader
+ io.Writer
+ r *http.Request
+}
+
+func newHTTPServerConn(r *http.Request, w http.ResponseWriter) ServerCodec {
+ body := io.LimitReader(r.Body, maxRequestContentLength)
+ conn := &httpServerConn{Reader: body, Writer: w, r: r}
+ return NewJSONCodec(conn)
+}
+
+// Close does nothing and always returns nil.
+func (t *httpServerConn) Close() error { return nil }
+
+// RemoteAddr returns the peer address of the underlying connection.
+func (t *httpServerConn) RemoteAddr() string {
+ return t.r.RemoteAddr
+}
+
+// SetWriteDeadline does nothing and always returns nil.
+func (t *httpServerConn) SetWriteDeadline(time.Time) error { return nil }
+
+// NewHTTPServer creates a new HTTP RPC server around an API provider.
+//
+// Deprecated: Server implements http.Handler
+func NewHTTPServer(cors []string, vhosts []string, timeouts HTTPTimeouts, srv http.Handler) *http.Server {
+ // Wrap the CORS-handler within a host-handler
+ handler := newCorsHandler(srv, cors)
+ handler = newVHostHandler(vhosts, handler)
+ handler = newGzipHandler(handler)
+
+ // Make sure timeout values are meaningful
+ if timeouts.ReadTimeout < time.Second {
+ log.Warn("Sanitizing invalid HTTP read timeout", "provided", timeouts.ReadTimeout, "updated", DefaultHTTPTimeouts.ReadTimeout)
+ timeouts.ReadTimeout = DefaultHTTPTimeouts.ReadTimeout
+ }
+ if timeouts.WriteTimeout < time.Second {
+ log.Warn("Sanitizing invalid HTTP write timeout", "provided", timeouts.WriteTimeout, "updated", DefaultHTTPTimeouts.WriteTimeout)
+ timeouts.WriteTimeout = DefaultHTTPTimeouts.WriteTimeout
+ }
+ if timeouts.IdleTimeout < time.Second {
+ log.Warn("Sanitizing invalid HTTP idle timeout", "provided", timeouts.IdleTimeout, "updated", DefaultHTTPTimeouts.IdleTimeout)
+ timeouts.IdleTimeout = DefaultHTTPTimeouts.IdleTimeout
+ }
+ // Bundle and start the HTTP server
+ return &http.Server{
+ Handler: handler,
+ ReadTimeout: timeouts.ReadTimeout,
+ WriteTimeout: timeouts.WriteTimeout,
+ IdleTimeout: timeouts.IdleTimeout,
+ }
+}
+
+// ServeHTTP serves JSON-RPC requests over HTTP.
+func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+ // Permit dumb empty requests for remote health-checks (AWS)
+ if r.Method == http.MethodGet && r.ContentLength == 0 && r.URL.RawQuery == "" {
+ return
+ }
+ if code, err := validateRequest(r); err != nil {
+ http.Error(w, err.Error(), code)
+ return
+ }
+ // All checks passed, create a codec that reads direct from the request body
+ // untilEOF and writes the response to w and order the server to process a
+ // single request.
+ ctx := r.Context()
+ ctx = context.WithValue(ctx, "remote", r.RemoteAddr)
+ ctx = context.WithValue(ctx, "scheme", r.Proto)
+ ctx = context.WithValue(ctx, "local", r.Host)
+ if ua := r.Header.Get("User-Agent"); ua != "" {
+ ctx = context.WithValue(ctx, "User-Agent", ua)
+ }
+ if origin := r.Header.Get("Origin"); origin != "" {
+ ctx = context.WithValue(ctx, "Origin", origin)
+ }
+
+ w.Header().Set("content-type", contentType)
+ codec := newHTTPServerConn(r, w)
+ defer codec.Close()
+ s.serveSingleRequest(ctx, codec)
+}
+
+// validateRequest returns a non-zero response code and error message if the
+// request is invalid.
+func validateRequest(r *http.Request) (int, error) {
+ if r.Method == http.MethodPut || r.Method == http.MethodDelete {
+ return http.StatusMethodNotAllowed, errors.New("method not allowed")
+ }
+ if r.ContentLength > maxRequestContentLength {
+ err := fmt.Errorf("content length too large (%d>%d)", r.ContentLength, maxRequestContentLength)
+ return http.StatusRequestEntityTooLarge, err
+ }
+ // Allow OPTIONS (regardless of content-type)
+ if r.Method == http.MethodOptions {
+ return 0, nil
+ }
+ // Check content-type
+ if mt, _, err := mime.ParseMediaType(r.Header.Get("content-type")); err == nil {
+ for _, accepted := range acceptedContentTypes {
+ if accepted == mt {
+ return 0, nil
+ }
+ }
+ }
+ // Invalid content-type
+ err := fmt.Errorf("invalid content type, only %s is supported", contentType)
+ return http.StatusUnsupportedMediaType, err
+}
+
+func newCorsHandler(srv http.Handler, allowedOrigins []string) http.Handler {
+ // disable CORS support if user has not specified a custom CORS configuration
+ if len(allowedOrigins) == 0 {
+ return srv
+ }
+ c := cors.New(cors.Options{
+ AllowedOrigins: allowedOrigins,
+ AllowedMethods: []string{http.MethodPost, http.MethodGet},
+ MaxAge: 600,
+ AllowedHeaders: []string{"*"},
+ })
+ return c.Handler(srv)
+}
+
+// virtualHostHandler is a handler which validates the Host-header of incoming requests.
+// The virtualHostHandler can prevent DNS rebinding attacks, which do not utilize CORS-headers,
+// since they do in-domain requests against the RPC api. Instead, we can see on the Host-header
+// which domain was used, and validate that against a whitelist.
+type virtualHostHandler struct {
+ vhosts map[string]struct{}
+ next http.Handler
+}
+
+// ServeHTTP serves JSON-RPC requests over HTTP, implements http.Handler
+func (h *virtualHostHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+ // if r.Host is not set, we can continue serving since a browser would set the Host header
+ if r.Host == "" {
+ h.next.ServeHTTP(w, r)
+ return
+ }
+ host, _, err := net.SplitHostPort(r.Host)
+ if err != nil {
+ // Either invalid (too many colons) or no port specified
+ host = r.Host
+ }
+ if ipAddr := net.ParseIP(host); ipAddr != nil {
+ // It's an IP address, we can serve that
+ h.next.ServeHTTP(w, r)
+ return
+
+ }
+ // Not an ip address, but a hostname. Need to validate
+ if _, exist := h.vhosts["*"]; exist {
+ h.next.ServeHTTP(w, r)
+ return
+ }
+ if _, exist := h.vhosts[host]; exist {
+ h.next.ServeHTTP(w, r)
+ return
+ }
+ http.Error(w, "invalid host specified", http.StatusForbidden)
+}
+
+func newVHostHandler(vhosts []string, next http.Handler) http.Handler {
+ vhostMap := make(map[string]struct{})
+ for _, allowedHost := range vhosts {
+ vhostMap[strings.ToLower(allowedHost)] = struct{}{}
+ }
+ return &virtualHostHandler{vhostMap, next}
+}
diff --git a/rpc/ipc_js.go b/rpc/ipc_js.go
new file mode 100644
index 0000000..7e7554a
--- /dev/null
+++ b/rpc/ipc_js.go
@@ -0,0 +1,37 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build js
+
+package rpc
+
+import (
+ "context"
+ "errors"
+ "net"
+)
+
+var errNotSupported = errors.New("rpc: not supported")
+
+// ipcListen will create a named pipe on the given endpoint.
+func ipcListen(endpoint string) (net.Listener, error) {
+ return nil, errNotSupported
+}
+
+// newIPCConnection will connect to a named pipe with the given endpoint as name.
+func newIPCConnection(ctx context.Context, endpoint string) (net.Conn, error) {
+ return nil, errNotSupported
+}
diff --git a/rpc/json.go b/rpc/json.go
new file mode 100644
index 0000000..75c2210
--- /dev/null
+++ b/rpc/json.go
@@ -0,0 +1,335 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "bytes"
+ "context"
+ "encoding/json"
+ "errors"
+ "fmt"
+ "io"
+ "reflect"
+ "strings"
+ "sync"
+ "time"
+)
+
+const (
+ vsn = "2.0"
+ serviceMethodSeparator = "_"
+ subscribeMethodSuffix = "_subscribe"
+ unsubscribeMethodSuffix = "_unsubscribe"
+ notificationMethodSuffix = "_subscription"
+
+ defaultWriteTimeout = 10 * time.Second // used if context has no deadline
+)
+
+var null = json.RawMessage("null")
+
+type subscriptionResult struct {
+ ID string `json:"subscription"`
+ Result json.RawMessage `json:"result,omitempty"`
+}
+
+// A value of this type can a JSON-RPC request, notification, successful response or
+// error response. Which one it is depends on the fields.
+type jsonrpcMessage struct {
+ Version string `json:"jsonrpc,omitempty"`
+ ID json.RawMessage `json:"id,omitempty"`
+ Method string `json:"method,omitempty"`
+ Params json.RawMessage `json:"params,omitempty"`
+ Error *jsonError `json:"error,omitempty"`
+ Result json.RawMessage `json:"result,omitempty"`
+}
+
+func (msg *jsonrpcMessage) isNotification() bool {
+ return msg.ID == nil && msg.Method != ""
+}
+
+func (msg *jsonrpcMessage) isCall() bool {
+ return msg.hasValidID() && msg.Method != ""
+}
+
+func (msg *jsonrpcMessage) isResponse() bool {
+ return msg.hasValidID() && msg.Method == "" && msg.Params == nil && (msg.Result != nil || msg.Error != nil)
+}
+
+func (msg *jsonrpcMessage) hasValidID() bool {
+ return len(msg.ID) > 0 && msg.ID[0] != '{' && msg.ID[0] != '['
+}
+
+func (msg *jsonrpcMessage) isSubscribe() bool {
+ return strings.HasSuffix(msg.Method, subscribeMethodSuffix)
+}
+
+func (msg *jsonrpcMessage) isUnsubscribe() bool {
+ return strings.HasSuffix(msg.Method, unsubscribeMethodSuffix)
+}
+
+func (msg *jsonrpcMessage) namespace() string {
+ elem := strings.SplitN(msg.Method, serviceMethodSeparator, 2)
+ return elem[0]
+}
+
+func (msg *jsonrpcMessage) String() string {
+ b, _ := json.Marshal(msg)
+ return string(b)
+}
+
+func (msg *jsonrpcMessage) errorResponse(err error) *jsonrpcMessage {
+ resp := errorMessage(err)
+ resp.ID = msg.ID
+ return resp
+}
+
+func (msg *jsonrpcMessage) response(result interface{}) *jsonrpcMessage {
+ enc, err := json.Marshal(result)
+ if err != nil {
+ // TODO: wrap with 'internal server error'
+ return msg.errorResponse(err)
+ }
+ return &jsonrpcMessage{Version: vsn, ID: msg.ID, Result: enc}
+}
+
+func errorMessage(err error) *jsonrpcMessage {
+ msg := &jsonrpcMessage{Version: vsn, ID: null, Error: &jsonError{
+ Code: defaultErrorCode,
+ Message: err.Error(),
+ }}
+ ec, ok := err.(Error)
+ if ok {
+ msg.Error.Code = ec.ErrorCode()
+ }
+ return msg
+}
+
+type jsonError struct {
+ Code int `json:"code"`
+ Message string `json:"message"`
+ Data interface{} `json:"data,omitempty"`
+}
+
+func (err *jsonError) Error() string {
+ if err.Message == "" {
+ return fmt.Sprintf("json-rpc error %d", err.Code)
+ }
+ return err.Message
+}
+
+func (err *jsonError) ErrorCode() int {
+ return err.Code
+}
+
+// Conn is a subset of the methods of net.Conn which are sufficient for ServerCodec.
+type Conn interface {
+ io.ReadWriteCloser
+ SetWriteDeadline(time.Time) error
+}
+
+type deadlineCloser interface {
+ io.Closer
+ SetWriteDeadline(time.Time) error
+}
+
+// ConnRemoteAddr wraps the RemoteAddr operation, which returns a description
+// of the peer address of a connection. If a Conn also implements ConnRemoteAddr, this
+// description is used in log messages.
+type ConnRemoteAddr interface {
+ RemoteAddr() string
+}
+
+// connWithRemoteAddr overrides the remote address of a connection.
+type connWithRemoteAddr struct {
+ Conn
+ addr string
+}
+
+func (c connWithRemoteAddr) RemoteAddr() string { return c.addr }
+
+// jsonCodec reads and writes JSON-RPC messages to the underlying connection. It also has
+// support for parsing arguments and serializing (result) objects.
+type jsonCodec struct {
+ remoteAddr string
+ closer sync.Once // close closed channel once
+ closed chan interface{} // closed on Close
+ decode func(v interface{}) error // decoder to allow multiple transports
+ encMu sync.Mutex // guards the encoder
+ encode func(v interface{}) error // encoder to allow multiple transports
+ conn deadlineCloser
+}
+
+func newCodec(conn deadlineCloser, encode, decode func(v interface{}) error) ServerCodec {
+ codec := &jsonCodec{
+ closed: make(chan interface{}),
+ encode: encode,
+ decode: decode,
+ conn: conn,
+ }
+ if ra, ok := conn.(ConnRemoteAddr); ok {
+ codec.remoteAddr = ra.RemoteAddr()
+ }
+ return codec
+}
+
+// NewJSONCodec creates a codec that reads from the given connection. If conn implements
+// ConnRemoteAddr, log messages will use it to include the remote address of the
+// connection.
+func NewJSONCodec(conn Conn) ServerCodec {
+ enc := json.NewEncoder(conn)
+ dec := json.NewDecoder(conn)
+ dec.UseNumber()
+ return newCodec(conn, enc.Encode, dec.Decode)
+}
+
+func (c *jsonCodec) RemoteAddr() string {
+ return c.remoteAddr
+}
+
+func (c *jsonCodec) Read() (msg []*jsonrpcMessage, batch bool, err error) {
+ // Decode the next JSON object in the input stream.
+ // This verifies basic syntax, etc.
+ var rawmsg json.RawMessage
+ if err := c.decode(&rawmsg); err != nil {
+ return nil, false, err
+ }
+ msg, batch = parseMessage(rawmsg)
+ return msg, batch, nil
+}
+
+// Write sends a message to client.
+func (c *jsonCodec) Write(ctx context.Context, v interface{}) error {
+ c.encMu.Lock()
+ defer c.encMu.Unlock()
+
+ deadline, ok := ctx.Deadline()
+ if !ok {
+ deadline = time.Now().Add(defaultWriteTimeout)
+ }
+ c.conn.SetWriteDeadline(deadline)
+ return c.encode(v)
+}
+
+// Close the underlying connection
+func (c *jsonCodec) Close() {
+ c.closer.Do(func() {
+ close(c.closed)
+ c.conn.Close()
+ })
+}
+
+// Closed returns a channel which will be closed when Close is called
+func (c *jsonCodec) Closed() <-chan interface{} {
+ return c.closed
+}
+
+// parseMessage parses raw bytes as a (batch of) JSON-RPC message(s). There are no error
+// checks in this function because the raw message has already been syntax-checked when it
+// is called. Any non-JSON-RPC messages in the input return the zero value of
+// jsonrpcMessage.
+func parseMessage(raw json.RawMessage) ([]*jsonrpcMessage, bool) {
+ if !isBatch(raw) {
+ msgs := []*jsonrpcMessage{{}}
+ json.Unmarshal(raw, &msgs[0])
+ return msgs, false
+ }
+ dec := json.NewDecoder(bytes.NewReader(raw))
+ dec.Token() // skip '['
+ var msgs []*jsonrpcMessage
+ for dec.More() {
+ msgs = append(msgs, new(jsonrpcMessage))
+ dec.Decode(&msgs[len(msgs)-1])
+ }
+ return msgs, true
+}
+
+// isBatch returns true when the first non-whitespace characters is '['
+func isBatch(raw json.RawMessage) bool {
+ for _, c := range raw {
+ // skip insignificant whitespace (http://www.ietf.org/rfc/rfc4627.txt)
+ if c == 0x20 || c == 0x09 || c == 0x0a || c == 0x0d {
+ continue
+ }
+ return c == '['
+ }
+ return false
+}
+
+// parsePositionalArguments tries to parse the given args to an array of values with the
+// given types. It returns the parsed values or an error when the args could not be
+// parsed. Missing optional arguments are returned as reflect.Zero values.
+func parsePositionalArguments(rawArgs json.RawMessage, types []reflect.Type) ([]reflect.Value, error) {
+ dec := json.NewDecoder(bytes.NewReader(rawArgs))
+ var args []reflect.Value
+ tok, err := dec.Token()
+ switch {
+ case err == io.EOF || tok == nil && err == nil:
+ // "params" is optional and may be empty. Also allow "params":null even though it's
+ // not in the spec because our own client used to send it.
+ case err != nil:
+ return nil, err
+ case tok == json.Delim('['):
+ // Read argument array.
+ if args, err = parseArgumentArray(dec, types); err != nil {
+ return nil, err
+ }
+ default:
+ return nil, errors.New("non-array args")
+ }
+ // Set any missing args to nil.
+ for i := len(args); i < len(types); i++ {
+ if types[i].Kind() != reflect.Ptr {
+ return nil, fmt.Errorf("missing value for required argument %d", i)
+ }
+ args = append(args, reflect.Zero(types[i]))
+ }
+ return args, nil
+}
+
+func parseArgumentArray(dec *json.Decoder, types []reflect.Type) ([]reflect.Value, error) {
+ args := make([]reflect.Value, 0, len(types))
+ for i := 0; dec.More(); i++ {
+ if i >= len(types) {
+ return args, fmt.Errorf("too many arguments, want at most %d", len(types))
+ }
+ argval := reflect.New(types[i])
+ if err := dec.Decode(argval.Interface()); err != nil {
+ return args, fmt.Errorf("invalid argument %d: %v", i, err)
+ }
+ if argval.IsNil() && types[i].Kind() != reflect.Ptr {
+ return args, fmt.Errorf("missing value for required argument %d", i)
+ }
+ args = append(args, argval.Elem())
+ }
+ // Read end of args array.
+ _, err := dec.Token()
+ return args, err
+}
+
+// parseSubscriptionName extracts the subscription name from an encoded argument array.
+func parseSubscriptionName(rawArgs json.RawMessage) (string, error) {
+ dec := json.NewDecoder(bytes.NewReader(rawArgs))
+ if tok, _ := dec.Token(); tok != json.Delim('[') {
+ return "", errors.New("non-array args")
+ }
+ v, _ := dec.Token()
+ method, ok := v.(string)
+ if !ok {
+ return "", errors.New("expected subscription name as first argument")
+ }
+ return method, nil
+}
diff --git a/rpc/server.go b/rpc/server.go
new file mode 100644
index 0000000..bf5d93e
--- /dev/null
+++ b/rpc/server.go
@@ -0,0 +1,147 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "context"
+ "io"
+ "sync/atomic"
+
+ mapset "github.com/deckarep/golang-set"
+ "github.com/ava-labs/go-ethereum/log"
+)
+
+const MetadataApi = "rpc"
+
+// CodecOption specifies which type of messages a codec supports.
+//
+// Deprecated: this option is no longer honored by Server.
+type CodecOption int
+
+const (
+ // OptionMethodInvocation is an indication that the codec supports RPC method calls
+ OptionMethodInvocation CodecOption = 1 << iota
+
+ // OptionSubscriptions is an indication that the codec suports RPC notifications
+ OptionSubscriptions = 1 << iota // support pub sub
+)
+
+// Server is an RPC server.
+type Server struct {
+ services serviceRegistry
+ idgen func() ID
+ run int32
+ codecs mapset.Set
+}
+
+// NewServer creates a new server instance with no registered handlers.
+func NewServer() *Server {
+ server := &Server{idgen: randomIDGenerator(), codecs: mapset.NewSet(), run: 1}
+ // Register the default service providing meta information about the RPC service such
+ // as the services and methods it offers.
+ rpcService := &RPCService{server}
+ server.RegisterName(MetadataApi, rpcService)
+ return server
+}
+
+// RegisterName creates a service for the given receiver type under the given name. When no
+// methods on the given receiver match the criteria to be either a RPC method or a
+// subscription an error is returned. Otherwise a new service is created and added to the
+// service collection this server provides to clients.
+func (s *Server) RegisterName(name string, receiver interface{}) error {
+ return s.services.registerName(name, receiver)
+}
+
+// ServeCodec reads incoming requests from codec, calls the appropriate callback and writes
+// the response back using the given codec. It will block until the codec is closed or the
+// server is stopped. In either case the codec is closed.
+//
+// Note that codec options are no longer supported.
+func (s *Server) ServeCodec(codec ServerCodec, options CodecOption) {
+ defer codec.Close()
+
+ // Don't serve if server is stopped.
+ if atomic.LoadInt32(&s.run) == 0 {
+ return
+ }
+
+ // Add the codec to the set so it can be closed by Stop.
+ s.codecs.Add(codec)
+ defer s.codecs.Remove(codec)
+
+ c := initClient(codec, s.idgen, &s.services)
+ <-codec.Closed()
+ c.Close()
+}
+
+// serveSingleRequest reads and processes a single RPC request from the given codec. This
+// is used to serve HTTP connections. Subscriptions and reverse calls are not allowed in
+// this mode.
+func (s *Server) serveSingleRequest(ctx context.Context, codec ServerCodec) {
+ // Don't serve if server is stopped.
+ if atomic.LoadInt32(&s.run) == 0 {
+ return
+ }
+
+ h := newHandler(ctx, codec, s.idgen, &s.services)
+ h.allowSubscribe = false
+ defer h.close(io.EOF, nil)
+
+ reqs, batch, err := codec.Read()
+ if err != nil {
+ if err != io.EOF {
+ codec.Write(ctx, errorMessage(&invalidMessageError{"parse error"}))
+ }
+ return
+ }
+ if batch {
+ h.handleBatch(reqs)
+ } else {
+ h.handleMsg(reqs[0])
+ }
+}
+
+// Stop stops reading new requests, waits for stopPendingRequestTimeout to allow pending
+// requests to finish, then closes all codecs which will cancel pending requests and
+// subscriptions.
+func (s *Server) Stop() {
+ if atomic.CompareAndSwapInt32(&s.run, 1, 0) {
+ log.Debug("RPC server shutting down")
+ s.codecs.Each(func(c interface{}) bool {
+ c.(ServerCodec).Close()
+ return true
+ })
+ }
+}
+
+// RPCService gives meta information about the server.
+// e.g. gives information about the loaded modules.
+type RPCService struct {
+ server *Server
+}
+
+// Modules returns the list of RPC services with their version number
+func (s *RPCService) Modules() map[string]string {
+ s.server.services.mu.Lock()
+ defer s.server.services.mu.Unlock()
+
+ modules := make(map[string]string)
+ for name := range s.server.services.services {
+ modules[name] = "1.0"
+ }
+ return modules
+}
diff --git a/rpc/service.go b/rpc/service.go
new file mode 100644
index 0000000..ead6fb6
--- /dev/null
+++ b/rpc/service.go
@@ -0,0 +1,285 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "context"
+ "errors"
+ "fmt"
+ "reflect"
+ "runtime"
+ "strings"
+ "sync"
+ "unicode"
+ "unicode/utf8"
+
+ "github.com/ava-labs/go-ethereum/log"
+)
+
+var (
+ contextType = reflect.TypeOf((*context.Context)(nil)).Elem()
+ errorType = reflect.TypeOf((*error)(nil)).Elem()
+ subscriptionType = reflect.TypeOf(Subscription{})
+ stringType = reflect.TypeOf("")
+)
+
+type serviceRegistry struct {
+ mu sync.Mutex
+ services map[string]service
+}
+
+// service represents a registered object.
+type service struct {
+ name string // name for service
+ callbacks map[string]*callback // registered handlers
+ subscriptions map[string]*callback // available subscriptions/notifications
+}
+
+// callback is a method callback which was registered in the server
+type callback struct {
+ fn reflect.Value // the function
+ rcvr reflect.Value // receiver object of method, set if fn is method
+ argTypes []reflect.Type // input argument types
+ hasCtx bool // method's first argument is a context (not included in argTypes)
+ errPos int // err return idx, of -1 when method cannot return error
+ isSubscribe bool // true if this is a subscription callback
+}
+
+func (r *serviceRegistry) registerName(name string, rcvr interface{}) error {
+ rcvrVal := reflect.ValueOf(rcvr)
+ if name == "" {
+ return fmt.Errorf("no service name for type %s", rcvrVal.Type().String())
+ }
+ callbacks := suitableCallbacks(rcvrVal)
+ if len(callbacks) == 0 {
+ return fmt.Errorf("service %T doesn't have any suitable methods/subscriptions to expose", rcvr)
+ }
+
+ r.mu.Lock()
+ defer r.mu.Unlock()
+ if r.services == nil {
+ r.services = make(map[string]service)
+ }
+ svc, ok := r.services[name]
+ if !ok {
+ svc = service{
+ name: name,
+ callbacks: make(map[string]*callback),
+ subscriptions: make(map[string]*callback),
+ }
+ r.services[name] = svc
+ }
+ for name, cb := range callbacks {
+ if cb.isSubscribe {
+ svc.subscriptions[name] = cb
+ } else {
+ svc.callbacks[name] = cb
+ }
+ }
+ return nil
+}
+
+// callback returns the callback corresponding to the given RPC method name.
+func (r *serviceRegistry) callback(method string) *callback {
+ elem := strings.SplitN(method, serviceMethodSeparator, 2)
+ if len(elem) != 2 {
+ return nil
+ }
+ r.mu.Lock()
+ defer r.mu.Unlock()
+ return r.services[elem[0]].callbacks[elem[1]]
+}
+
+// subscription returns a subscription callback in the given service.
+func (r *serviceRegistry) subscription(service, name string) *callback {
+ r.mu.Lock()
+ defer r.mu.Unlock()
+ return r.services[service].subscriptions[name]
+}
+
+// suitableCallbacks iterates over the methods of the given type. It determines if a method
+// satisfies the criteria for a RPC callback or a subscription callback and adds it to the
+// collection of callbacks. See server documentation for a summary of these criteria.
+func suitableCallbacks(receiver reflect.Value) map[string]*callback {
+ typ := receiver.Type()
+ callbacks := make(map[string]*callback)
+ for m := 0; m < typ.NumMethod(); m++ {
+ method := typ.Method(m)
+ if method.PkgPath != "" {
+ continue // method not exported
+ }
+ cb := newCallback(receiver, method.Func)
+ if cb == nil {
+ continue // function invalid
+ }
+ name := formatName(method.Name)
+ callbacks[name] = cb
+ }
+ return callbacks
+}
+
+// newCallback turns fn (a function) into a callback object. It returns nil if the function
+// is unsuitable as an RPC callback.
+func newCallback(receiver, fn reflect.Value) *callback {
+ fntype := fn.Type()
+ c := &callback{fn: fn, rcvr: receiver, errPos: -1, isSubscribe: isPubSub(fntype)}
+ // Determine parameter types. They must all be exported or builtin types.
+ c.makeArgTypes()
+ if !allExportedOrBuiltin(c.argTypes) {
+ return nil
+ }
+ // Verify return types. The function must return at most one error
+ // and/or one other non-error value.
+ outs := make([]reflect.Type, fntype.NumOut())
+ for i := 0; i < fntype.NumOut(); i++ {
+ outs[i] = fntype.Out(i)
+ }
+ if len(outs) > 2 || !allExportedOrBuiltin(outs) {
+ return nil
+ }
+ // If an error is returned, it must be the last returned value.
+ switch {
+ case len(outs) == 1 && isErrorType(outs[0]):
+ c.errPos = 0
+ case len(outs) == 2:
+ if isErrorType(outs[0]) || !isErrorType(outs[1]) {
+ return nil
+ }
+ c.errPos = 1
+ }
+ return c
+}
+
+// makeArgTypes composes the argTypes list.
+func (c *callback) makeArgTypes() {
+ fntype := c.fn.Type()
+ // Skip receiver and context.Context parameter (if present).
+ firstArg := 0
+ if c.rcvr.IsValid() {
+ firstArg++
+ }
+ if fntype.NumIn() > firstArg && fntype.In(firstArg) == contextType {
+ c.hasCtx = true
+ firstArg++
+ }
+ // Add all remaining parameters.
+ c.argTypes = make([]reflect.Type, fntype.NumIn()-firstArg)
+ for i := firstArg; i < fntype.NumIn(); i++ {
+ c.argTypes[i-firstArg] = fntype.In(i)
+ }
+}
+
+// call invokes the callback.
+func (c *callback) call(ctx context.Context, method string, args []reflect.Value) (res interface{}, errRes error) {
+ // Create the argument slice.
+ fullargs := make([]reflect.Value, 0, 2+len(args))
+ if c.rcvr.IsValid() {
+ fullargs = append(fullargs, c.rcvr)
+ }
+ if c.hasCtx {
+ fullargs = append(fullargs, reflect.ValueOf(ctx))
+ }
+ fullargs = append(fullargs, args...)
+
+ // Catch panic while running the callback.
+ defer func() {
+ if err := recover(); err != nil {
+ const size = 64 << 10
+ buf := make([]byte, size)
+ buf = buf[:runtime.Stack(buf, false)]
+ log.Error("RPC method " + method + " crashed: " + fmt.Sprintf("%v\n%s", err, buf))
+ errRes = errors.New("method handler crashed")
+ }
+ }()
+ // Run the callback.
+ results := c.fn.Call(fullargs)
+ if len(results) == 0 {
+ return nil, nil
+ }
+ if c.errPos >= 0 && !results[c.errPos].IsNil() {
+ // Method has returned non-nil error value.
+ err := results[c.errPos].Interface().(error)
+ return reflect.Value{}, err
+ }
+ return results[0].Interface(), nil
+}
+
+// Is this an exported - upper case - name?
+func isExported(name string) bool {
+ rune, _ := utf8.DecodeRuneInString(name)
+ return unicode.IsUpper(rune)
+}
+
+// Are all those types exported or built-in?
+func allExportedOrBuiltin(types []reflect.Type) bool {
+ for _, typ := range types {
+ for typ.Kind() == reflect.Ptr {
+ typ = typ.Elem()
+ }
+ // PkgPath will be non-empty even for an exported type,
+ // so we need to check the type name as well.
+ if !isExported(typ.Name()) && typ.PkgPath() != "" {
+ return false
+ }
+ }
+ return true
+}
+
+// Is t context.Context or *context.Context?
+func isContextType(t reflect.Type) bool {
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ return t == contextType
+}
+
+// Does t satisfy the error interface?
+func isErrorType(t reflect.Type) bool {
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ return t.Implements(errorType)
+}
+
+// Is t Subscription or *Subscription?
+func isSubscriptionType(t reflect.Type) bool {
+ for t.Kind() == reflect.Ptr {
+ t = t.Elem()
+ }
+ return t == subscriptionType
+}
+
+// isPubSub tests whether the given method has as as first argument a context.Context and
+// returns the pair (Subscription, error).
+func isPubSub(methodType reflect.Type) bool {
+ // numIn(0) is the receiver type
+ if methodType.NumIn() < 2 || methodType.NumOut() != 2 {
+ return false
+ }
+ return isContextType(methodType.In(1)) &&
+ isSubscriptionType(methodType.Out(0)) &&
+ isErrorType(methodType.Out(1))
+}
+
+// formatName converts to first character of name to lowercase.
+func formatName(name string) string {
+ ret := []rune(name)
+ if len(ret) > 0 {
+ ret[0] = unicode.ToLower(ret[0])
+ }
+ return string(ret)
+}
diff --git a/rpc/subscription.go b/rpc/subscription.go
new file mode 100644
index 0000000..c1e869b
--- /dev/null
+++ b/rpc/subscription.go
@@ -0,0 +1,327 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "bufio"
+ "container/list"
+ "context"
+ crand "crypto/rand"
+ "encoding/binary"
+ "encoding/hex"
+ "encoding/json"
+ "errors"
+ "math/rand"
+ "reflect"
+ "strings"
+ "sync"
+ "time"
+)
+
+var (
+ // ErrNotificationsUnsupported is returned when the connection doesn't support notifications
+ ErrNotificationsUnsupported = errors.New("notifications not supported")
+ // ErrNotificationNotFound is returned when the notification for the given id is not found
+ ErrSubscriptionNotFound = errors.New("subscription not found")
+)
+
+var globalGen = randomIDGenerator()
+
+// ID defines a pseudo random number that is used to identify RPC subscriptions.
+type ID string
+
+// NewID returns a new, random ID.
+func NewID() ID {
+ return globalGen()
+}
+
+// randomIDGenerator returns a function generates a random IDs.
+func randomIDGenerator() func() ID {
+ seed, err := binary.ReadVarint(bufio.NewReader(crand.Reader))
+ if err != nil {
+ seed = int64(time.Now().Nanosecond())
+ }
+ var (
+ mu sync.Mutex
+ rng = rand.New(rand.NewSource(seed))
+ )
+ return func() ID {
+ mu.Lock()
+ defer mu.Unlock()
+ id := make([]byte, 16)
+ rng.Read(id)
+ return encodeID(id)
+ }
+}
+
+func encodeID(b []byte) ID {
+ id := hex.EncodeToString(b)
+ id = strings.TrimLeft(id, "0")
+ if id == "" {
+ id = "0" // ID's are RPC quantities, no leading zero's and 0 is 0x0.
+ }
+ return ID("0x" + id)
+}
+
+type notifierKey struct{}
+
+// NotifierFromContext returns the Notifier value stored in ctx, if any.
+func NotifierFromContext(ctx context.Context) (*Notifier, bool) {
+ n, ok := ctx.Value(notifierKey{}).(*Notifier)
+ return n, ok
+}
+
+// Notifier is tied to a RPC connection that supports subscriptions.
+// Server callbacks use the notifier to send notifications.
+type Notifier struct {
+ h *handler
+ namespace string
+
+ mu sync.Mutex
+ sub *Subscription
+ buffer []json.RawMessage
+ callReturned bool
+ activated bool
+}
+
+// CreateSubscription returns a new subscription that is coupled to the
+// RPC connection. By default subscriptions are inactive and notifications
+// are dropped until the subscription is marked as active. This is done
+// by the RPC server after the subscription ID is send to the client.
+func (n *Notifier) CreateSubscription() *Subscription {
+ n.mu.Lock()
+ defer n.mu.Unlock()
+
+ if n.sub != nil {
+ panic("can't create multiple subscriptions with Notifier")
+ } else if n.callReturned {
+ panic("can't create subscription after subscribe call has returned")
+ }
+ n.sub = &Subscription{ID: n.h.idgen(), namespace: n.namespace, err: make(chan error, 1)}
+ return n.sub
+}
+
+// Notify sends a notification to the client with the given data as payload.
+// If an error occurs the RPC connection is closed and the error is returned.
+func (n *Notifier) Notify(id ID, data interface{}) error {
+ enc, err := json.Marshal(data)
+ if err != nil {
+ return err
+ }
+
+ n.mu.Lock()
+ defer n.mu.Unlock()
+
+ if n.sub == nil {
+ panic("can't Notify before subscription is created")
+ } else if n.sub.ID != id {
+ panic("Notify with wrong ID")
+ }
+ if n.activated {
+ return n.send(n.sub, enc)
+ }
+ n.buffer = append(n.buffer, enc)
+ return nil
+}
+
+// Closed returns a channel that is closed when the RPC connection is closed.
+// Deprecated: use subscription error channel
+func (n *Notifier) Closed() <-chan interface{} {
+ return n.h.conn.Closed()
+}
+
+// takeSubscription returns the subscription (if one has been created). No subscription can
+// be created after this call.
+func (n *Notifier) takeSubscription() *Subscription {
+ n.mu.Lock()
+ defer n.mu.Unlock()
+ n.callReturned = true
+ return n.sub
+}
+
+// acticate is called after the subscription ID was sent to client. Notifications are
+// buffered before activation. This prevents notifications being sent to the client before
+// the subscription ID is sent to the client.
+func (n *Notifier) activate() error {
+ n.mu.Lock()
+ defer n.mu.Unlock()
+
+ for _, data := range n.buffer {
+ if err := n.send(n.sub, data); err != nil {
+ return err
+ }
+ }
+ n.activated = true
+ return nil
+}
+
+func (n *Notifier) send(sub *Subscription, data json.RawMessage) error {
+ params, _ := json.Marshal(&subscriptionResult{ID: string(sub.ID), Result: data})
+ ctx := context.Background()
+ return n.h.conn.Write(ctx, &jsonrpcMessage{
+ Version: vsn,
+ Method: n.namespace + notificationMethodSuffix,
+ Params: params,
+ })
+}
+
+// A Subscription is created by a notifier and tight to that notifier. The client can use
+// this subscription to wait for an unsubscribe request for the client, see Err().
+type Subscription struct {
+ ID ID
+ namespace string
+ err chan error // closed on unsubscribe
+}
+
+// Err returns a channel that is closed when the client send an unsubscribe request.
+func (s *Subscription) Err() <-chan error {
+ return s.err
+}
+
+// MarshalJSON marshals a subscription as its ID.
+func (s *Subscription) MarshalJSON() ([]byte, error) {
+ return json.Marshal(s.ID)
+}
+
+// ClientSubscription is a subscription established through the Client's Subscribe or
+// EthSubscribe methods.
+type ClientSubscription struct {
+ client *Client
+ etype reflect.Type
+ channel reflect.Value
+ namespace string
+ subid string
+ in chan json.RawMessage
+
+ quitOnce sync.Once // ensures quit is closed once
+ quit chan struct{} // quit is closed when the subscription exits
+ errOnce sync.Once // ensures err is closed once
+ err chan error
+}
+
+func newClientSubscription(c *Client, namespace string, channel reflect.Value) *ClientSubscription {
+ sub := &ClientSubscription{
+ client: c,
+ namespace: namespace,
+ etype: channel.Type().Elem(),
+ channel: channel,
+ quit: make(chan struct{}),
+ err: make(chan error, 1),
+ in: make(chan json.RawMessage),
+ }
+ return sub
+}
+
+// Err returns the subscription error channel. The intended use of Err is to schedule
+// resubscription when the client connection is closed unexpectedly.
+//
+// The error channel receives a value when the subscription has ended due
+// to an error. The received error is nil if Close has been called
+// on the underlying client and no other error has occurred.
+//
+// The error channel is closed when Unsubscribe is called on the subscription.
+func (sub *ClientSubscription) Err() <-chan error {
+ return sub.err
+}
+
+// Unsubscribe unsubscribes the notification and closes the error channel.
+// It can safely be called more than once.
+func (sub *ClientSubscription) Unsubscribe() {
+ sub.quitWithError(nil, true)
+ sub.errOnce.Do(func() { close(sub.err) })
+}
+
+func (sub *ClientSubscription) quitWithError(err error, unsubscribeServer bool) {
+ sub.quitOnce.Do(func() {
+ // The dispatch loop won't be able to execute the unsubscribe call
+ // if it is blocked on deliver. Close sub.quit first because it
+ // unblocks deliver.
+ close(sub.quit)
+ if unsubscribeServer {
+ sub.requestUnsubscribe()
+ }
+ if err != nil {
+ if err == ErrClientQuit {
+ err = nil // Adhere to subscription semantics.
+ }
+ sub.err <- err
+ }
+ })
+}
+
+func (sub *ClientSubscription) deliver(result json.RawMessage) (ok bool) {
+ select {
+ case sub.in <- result:
+ return true
+ case <-sub.quit:
+ return false
+ }
+}
+
+func (sub *ClientSubscription) start() {
+ sub.quitWithError(sub.forward())
+}
+
+func (sub *ClientSubscription) forward() (err error, unsubscribeServer bool) {
+ cases := []reflect.SelectCase{
+ {Dir: reflect.SelectRecv, Chan: reflect.ValueOf(sub.quit)},
+ {Dir: reflect.SelectRecv, Chan: reflect.ValueOf(sub.in)},
+ {Dir: reflect.SelectSend, Chan: sub.channel},
+ }
+ buffer := list.New()
+ defer buffer.Init()
+ for {
+ var chosen int
+ var recv reflect.Value
+ if buffer.Len() == 0 {
+ // Idle, omit send case.
+ chosen, recv, _ = reflect.Select(cases[:2])
+ } else {
+ // Non-empty buffer, send the first queued item.
+ cases[2].Send = reflect.ValueOf(buffer.Front().Value)
+ chosen, recv, _ = reflect.Select(cases)
+ }
+
+ switch chosen {
+ case 0: // <-sub.quit
+ return nil, false
+ case 1: // <-sub.in
+ val, err := sub.unmarshal(recv.Interface().(json.RawMessage))
+ if err != nil {
+ return err, true
+ }
+ if buffer.Len() == maxClientSubscriptionBuffer {
+ return ErrSubscriptionQueueOverflow, true
+ }
+ buffer.PushBack(val)
+ case 2: // sub.channel<-
+ cases[2].Send = reflect.Value{} // Don't hold onto the value.
+ buffer.Remove(buffer.Front())
+ }
+ }
+}
+
+func (sub *ClientSubscription) unmarshal(result json.RawMessage) (interface{}, error) {
+ val := reflect.New(sub.etype)
+ err := json.Unmarshal(result, val.Interface())
+ return val.Elem().Interface(), err
+}
+
+func (sub *ClientSubscription) requestUnsubscribe() error {
+ var result interface{}
+ return sub.client.Call(&result, sub.namespace+unsubscribeMethodSuffix, sub.subid)
+}
diff --git a/rpc/types.go b/rpc/types.go
index 7312397..202dd79 100644
--- a/rpc/types.go
+++ b/rpc/types.go
@@ -17,6 +17,7 @@
 package rpc
 
 import (
+ "context"
 "fmt"
 "math"
 "strings"
@@ -24,6 +25,39 @@ import (
 "github.com/ava-labs/go-ethereum/common/hexutil"
 )
 
+// API describes the set of methods offered over the RPC interface
+type API struct {
+ Namespace string // namespace under which the rpc methods of Service are exposed
+ Version string // api version for DApp's
+ Service interface{} // receiver instance which holds the methods
+ Public bool // indication if the methods must be considered safe for public use
+}
+
+// Error wraps RPC errors, which contain an error code in addition to the message.
+type Error interface {
+ Error() string // returns the message
+ ErrorCode() int // returns the code
+}
+
+// ServerCodec implements reading, parsing and writing RPC messages for the server side of
+// a RPC session. Implementations must be go-routine safe since the codec can be called in
+// multiple go-routines concurrently.
+type ServerCodec interface {
+ Read() (msgs []*jsonrpcMessage, isBatch bool, err error)
+ Close()
+ jsonWriter
+}
+
+// jsonWriter can write JSON messages to its underlying connection.
+// Implementations must be safe for concurrent use.
+type jsonWriter interface {
+ Write(context.Context, interface{}) error
+ // Closed returns a channel which is closed when the connection is closed.
+ Closed() <-chan interface{}
+ // RemoteAddr returns the peer address of the connection.
+ RemoteAddr() string
+}
+
 type BlockNumber int64
 
 const (
diff --git a/rpc/websocket.go b/rpc/websocket.go
new file mode 100644
index 0000000..d87e8a5
--- /dev/null
+++ b/rpc/websocket.go
@@ -0,0 +1,175 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package rpc
+
+import (
+ "context"
+ "encoding/base64"
+ "fmt"
+ "net/http"
+ "net/url"
+ "os"
+ "strings"
+ "sync"
+
+ mapset "github.com/deckarep/golang-set"
+ "github.com/ava-labs/go-ethereum/log"
+ "github.com/gorilla/websocket"
+)
+
+const (
+ wsReadBuffer = 1024
+ wsWriteBuffer = 1024
+)
+
+var wsBufferPool = new(sync.Pool)
+
+// NewWSServer creates a new websocket RPC server around an API provider.
+//
+// Deprecated: use Server.WebsocketHandler
+func NewWSServer(allowedOrigins []string, srv *Server) *http.Server {
+ return &http.Server{Handler: srv.WebsocketHandler(allowedOrigins)}
+}
+
+// WebsocketHandler returns a handler that serves JSON-RPC to WebSocket connections.
+//
+// allowedOrigins should be a comma-separated list of allowed origin URLs.
+// To allow connections with any origin, pass "*".
+func (s *Server) WebsocketHandler(allowedOrigins []string) http.Handler {
+ var upgrader = websocket.Upgrader{
+ ReadBufferSize: wsReadBuffer,
+ WriteBufferSize: wsWriteBuffer,
+ WriteBufferPool: wsBufferPool,
+ CheckOrigin: wsHandshakeValidator(allowedOrigins),
+ }
+ return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ conn, err := upgrader.Upgrade(w, r, nil)
+ if err != nil {
+ log.Debug("WebSocket upgrade failed", "err", err)
+ return
+ }
+ codec := newWebsocketCodec(conn)
+ s.ServeCodec(codec, OptionMethodInvocation|OptionSubscriptions)
+ })
+}
+
+// wsHandshakeValidator returns a handler that verifies the origin during the
+// websocket upgrade process. When a '*' is specified as an allowed origins all
+// connections are accepted.
+func wsHandshakeValidator(allowedOrigins []string) func(*http.Request) bool {
+ origins := mapset.NewSet()
+ allowAllOrigins := false
+
+ for _, origin := range allowedOrigins {
+ if origin == "*" {
+ allowAllOrigins = true
+ }
+ if origin != "" {
+ origins.Add(strings.ToLower(origin))
+ }
+ }
+ // allow localhost if no allowedOrigins are specified.
+ if len(origins.ToSlice()) == 0 {
+ origins.Add("http://localhost")
+ if hostname, err := os.Hostname(); err == nil {
+ origins.Add("http://" + strings.ToLower(hostname))
+ }
+ }
+ log.Debug(fmt.Sprintf("Allowed origin(s) for WS RPC interface %v", origins.ToSlice()))
+
+ f := func(req *http.Request) bool {
+ // Skip origin verification if no Origin header is present. The origin check
+ // is supposed to protect against browser based attacks. Browsers always set
+ // Origin. Non-browser software can put anything in origin and checking it doesn't
+ // provide additional security.
+ if _, ok := req.Header["Origin"]; !ok {
+ return true
+ }
+ // Verify origin against whitelist.
+ origin := strings.ToLower(req.Header.Get("Origin"))
+ if allowAllOrigins || origins.Contains(origin) {
+ return true
+ }
+ log.Warn("Rejected WebSocket connection", "origin", origin)
+ return false
+ }
+
+ return f
+}
+
+type wsHandshakeError struct {
+ err error
+ status string
+}
+
+func (e wsHandshakeError) Error() string {
+ s := e.err.Error()
+ if e.status != "" {
+ s += " (HTTP status " + e.status + ")"
+ }
+ return s
+}
+
+// DialWebsocket creates a new RPC client that communicates with a JSON-RPC server
+// that is listening on the given endpoint.
+//
+// The context is used for the initial connection establishment. It does not
+// affect subsequent interactions with the client.
+func DialWebsocket(ctx context.Context, endpoint, origin string) (*Client, error) {
+ endpoint, header, err := wsClientHeaders(endpoint, origin)
+ if err != nil {
+ return nil, err
+ }
+ dialer := websocket.Dialer{
+ ReadBufferSize: wsReadBuffer,
+ WriteBufferSize: wsWriteBuffer,
+ WriteBufferPool: wsBufferPool,
+ }
+ return newClient(ctx, func(ctx context.Context) (ServerCodec, error) {
+ conn, resp, err := dialer.DialContext(ctx, endpoint, header)
+ if err != nil {
+ hErr := wsHandshakeError{err: err}
+ if resp != nil {
+ hErr.status = resp.Status
+ }
+ return nil, hErr
+ }
+ return newWebsocketCodec(conn), nil
+ })
+}
+
+func wsClientHeaders(endpoint, origin string) (string, http.Header, error) {
+ endpointURL, err := url.Parse(endpoint)
+ if err != nil {
+ return endpoint, nil, err
+ }
+ header := make(http.Header)
+ if origin != "" {
+ header.Add("origin", origin)
+ }
+ if endpointURL.User != nil {
+ b64auth := base64.StdEncoding.EncodeToString([]byte(endpointURL.User.String()))
+ header.Add("authorization", "Basic "+b64auth)
+ endpointURL.User = nil
+ }
+ return endpointURL.String(), header, nil
+}
+
+func newWebsocketCodec(conn *websocket.Conn) ServerCodec {
+ conn.SetReadLimit(maxRequestContentLength)
+ return newCodec(conn, conn.WriteJSON, conn.ReadJSON)
+}
author	Determinant <[email protected]>	2020-07-30 14:18:44 -0400
committer	Determinant <[email protected]>	2020-07-30 14:18:44 -0400
commit	0444e66f640999c15496066637841efcc0433934 (patch)
tree	c19aec2dced2e9129c880c19c52ca0f87b3d62f6 /rpc
parent	cffa0954bbdb43821d1b71d00f99fb705cecd25b (diff)
parent	1f49826de2bb8bb4f5f99f69fd2beb039b1172d9 (diff)