Official Go implementation of the Ethereum protocol
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go-ethereum/rpc/http.go

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// 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"
"math"
"mime"
"net/http"
"net/url"
"strconv"
"sync"
"time"
)
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
url string
closeOnce sync.Once
closeCh chan interface{}
mu sync.Mutex // protects headers
headers http.Header
auth HTTPAuth
}
// httpConn implements ServerCodec, but it is treated specially by Client
// and some methods don't work. The panic() stubs here exist to ensure
// this special treatment is correct.
func (hc *httpConn) writeJSON(context.Context, interface{}, bool) error {
panic("writeJSON called on httpConn")
}
func (hc *httpConn) peerInfo() PeerInfo {
panic("peerInfo called on httpConn")
}
func (hc *httpConn) remoteAddr() string {
return hc.url
}
func (hc *httpConn) readBatch() ([]*jsonrpcMessage, bool, error) {
<-hc.closeCh
return nil, false, io.EOF
}
func (hc *httpConn) close() {
hc.closeOnce.Do(func() { close(hc.closeCh) })
}
func (hc *httpConn) closed() <-chan interface{} {
return hc.closeCh
}
// 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
// ReadHeaderTimeout is the amount of time allowed to read
// request headers. The connection's read deadline is reset
// after reading the headers and the Handler can decide what
// is considered too slow for the body. If ReadHeaderTimeout
// is zero, the value of ReadTimeout is used. If both are
// zero, there is no timeout.
ReadHeaderTimeout 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,
ReadHeaderTimeout: 30 * time.Second,
WriteTimeout: 30 * time.Second,
IdleTimeout: 120 * time.Second,
}
// 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))
}
// DialHTTPWithClient creates a new RPC client that connects to an RPC server over HTTP
// using the provided HTTP Client.
//
// Deprecated: use DialOptions and the WithHTTPClient option.
func DialHTTPWithClient(endpoint string, client *http.Client) (*Client, error) {
// Sanity check URL so we don't end up with a client that will fail every request.
_, err := url.Parse(endpoint)
if err != nil {
return nil, err
}
var cfg clientConfig
cfg.httpClient = client
fn := newClientTransportHTTP(endpoint, &cfg)
return newClient(context.Background(), fn)
}
func newClientTransportHTTP(endpoint string, cfg *clientConfig) reconnectFunc {
headers := make(http.Header, 2+len(cfg.httpHeaders))
headers.Set("accept", contentType)
headers.Set("content-type", contentType)
for key, values := range cfg.httpHeaders {
headers[key] = values
}
client := cfg.httpClient
if client == nil {
client = new(http.Client)
}
hc := &httpConn{
client: client,
headers: headers,
url: endpoint,
auth: cfg.httpAuth,
closeCh: make(chan interface{}),
}
return func(ctx context.Context) (ServerCodec, error) {
return hc, nil
}
}
func (c *Client) sendHTTP(ctx context.Context, op *requestOp, msg interface{}) error {
hc := c.writeConn.(*httpConn)
respBody, err := hc.doRequest(ctx, msg)
if err != nil {
return err
}
defer respBody.Close()
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
}
if len(respmsgs) != len(msgs) {
return fmt.Errorf("batch has %d requests but response has %d: %w", len(msgs), len(respmsgs), ErrBadResult)
}
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, err := http.NewRequestWithContext(ctx, "POST", hc.url, io.NopCloser(bytes.NewReader(body)))
if err != nil {
return nil, err
}
req.ContentLength = int64(len(body))
req.GetBody = func() (io.ReadCloser, error) { return io.NopCloser(bytes.NewReader(body)), nil }
// set headers
hc.mu.Lock()
req.Header = hc.headers.Clone()
hc.mu.Unlock()
setHeaders(req.Header, headersFromContext(ctx))
if hc.auth != nil {
if err := hc.auth(req.Header); err != nil {
return nil, err
}
}
// do request
resp, err := hc.client.Do(req)
if err != nil {
return nil, err
}
if resp.StatusCode < 200 || resp.StatusCode >= 300 {
var buf bytes.Buffer
var body []byte
if _, err := buf.ReadFrom(resp.Body); err == nil {
body = buf.Bytes()
}
return nil, HTTPError{
Status: resp.Status,
StatusCode: resp.StatusCode,
Body: body,
}
}
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}
encoder := func(v any, isErrorResponse bool) error {
if !isErrorResponse {
return json.NewEncoder(conn).Encode(v)
}
// It's an error response and requires special treatment.
//
// In case of a timeout error, the response must be written before the HTTP
// server's write timeout occurs. So we need to flush the response. The
// Content-Length header also needs to be set to ensure the client knows
// when it has the full response.
encdata, err := json.Marshal(v)
if err != nil {
return err
}
w.Header().Set("content-length", strconv.Itoa(len(encdata)))
// If this request is wrapped in a handler that might remove Content-Length (such
// as the automatic gzip we do in package node), we need to ensure the HTTP server
// doesn't perform chunked encoding. In case WriteTimeout is reached, the chunked
// encoding might not be finished correctly, and some clients do not like it when
// the final chunk is missing.
w.Header().Set("transfer-encoding", "identity")
_, err = w.Write(encdata)
if f, ok := w.(http.Flusher); ok {
f.Flush()
}
return err
}
dec := json.NewDecoder(conn)
dec.UseNumber()
return NewFuncCodec(conn, encoder, dec.Decode)
}
// 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 }
// 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 == "" {
w.WriteHeader(http.StatusOK)
return
}
if code, err := validateRequest(r); err != nil {
http.Error(w, err.Error(), code)
return
}
// Create request-scoped context.
connInfo := PeerInfo{Transport: "http", RemoteAddr: r.RemoteAddr}
connInfo.HTTP.Version = r.Proto
connInfo.HTTP.Host = r.Host
connInfo.HTTP.Origin = r.Header.Get("Origin")
connInfo.HTTP.UserAgent = r.Header.Get("User-Agent")
ctx := r.Context()
ctx = context.WithValue(ctx, peerInfoContextKey{}, connInfo)
// All checks passed, create a codec that reads directly from the request body
// until EOF, writes the response to w, and orders the server to process a
// single request.
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
}
// ContextRequestTimeout returns the request timeout derived from the given context.
func ContextRequestTimeout(ctx context.Context) (time.Duration, bool) {
timeout := time.Duration(math.MaxInt64)
hasTimeout := false
setTimeout := func(d time.Duration) {
if d < timeout {
timeout = d
hasTimeout = true
}
}
if deadline, ok := ctx.Deadline(); ok {
setTimeout(time.Until(deadline))
}
// If the context is an HTTP request context, use the server's WriteTimeout.
httpSrv, ok := ctx.Value(http.ServerContextKey).(*http.Server)
if ok && httpSrv.WriteTimeout > 0 {
wt := httpSrv.WriteTimeout
// When a write timeout is configured, we need to send the response message before
// the HTTP server cuts connection. So our internal timeout must be earlier than
// the server's true timeout.
//
// Note: Timeouts are sanitized to be a minimum of 1 second.
// Also see issue: https://github.com/golang/go/issues/47229
wt -= 100 * time.Millisecond
setTimeout(wt)
}
return timeout, hasTimeout
}