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// Copyright (C) 2019-2024 Algorand, Inc.
// This file is part of go-algorand
//
// go-algorand is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// go-algorand 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with go-algorand. If not, see <https://www.gnu.org/licenses/>.
package fixtures
import (
"net"
"net/http"
"strings"
"github.com/algorand/go-algorand/logging"
)
// WebProxyInterceptFunc expose the web proxy intercept function
type WebProxyInterceptFunc func(http.ResponseWriter, *http.Request, http.HandlerFunc)
// WebProxy is the web proxy instance
type WebProxy struct {
server *http.Server
listener net.Listener
destination string
intercept WebProxyInterceptFunc
log logging.Logger
}
// MakeWebProxy creates an instance of the web proxy
func MakeWebProxy(destination string, log logging.Logger, intercept WebProxyInterceptFunc) (wp *WebProxy, err error) {
destination = strings.TrimPrefix(destination, "http://")
wp = &WebProxy{
destination: destination,
intercept: intercept,
log: log,
}
wp.server = &http.Server{
Handler: wp,
}
wp.listener, err = net.Listen("tcp", "localhost:")
if err != nil {
return nil, err
}
go func() {
wp.server.Serve(wp.listener)
}()
return wp, nil
}
// GetListenAddress retrieves the listening address of the web proxy
func (wp *WebProxy) GetListenAddress() string {
return wp.listener.Addr().String()
}
// Close release the web proxy resources
func (wp *WebProxy) Close() {
wp.log.Debugln("webproxy: quiting")
// we can't use shutdown, since we have tunneled websocket, which is a hijacked connection
// that http.Server doens't know how to handle.
wp.server.Close()
}
// ServeHTTP serves a single HTTP request
func (wp *WebProxy) ServeHTTP(response http.ResponseWriter, request *http.Request) {
wp.log.Debugf("webproxy: incoming request for %v", request.URL)
if wp.intercept == nil {
wp.Passthrough(response, request)
return
}
wp.intercept(response, request, wp.Passthrough)
}
// Passthrough is the default web proxy implemented function for passing a requests through without modifying it.
func (wp *WebProxy) Passthrough(response http.ResponseWriter, request *http.Request) {
client := http.Client{}
clientRequestURL := *request.URL
clientRequestURL.Scheme = "http"
clientRequestURL.Host = wp.destination
clientRequest, err := http.NewRequest(request.Method, clientRequestURL.String(), request.Body)
if err != nil {
wp.log.Debugf("Passthrough request assembly error %v (%#v)", err, clientRequestURL)
response.WriteHeader(http.StatusInternalServerError)
return
}
if request.Header != nil {
for headerKey, headerValues := range request.Header {
for _, headerValue := range headerValues {
clientRequest.Header.Add(headerKey, headerValue)
}
}
}
clientResponse, err := client.Do(clientRequest)
if err != nil {
wp.log.Debugf("Passthrough request error %v (%v)", err, request.URL.String())
response.WriteHeader(http.StatusInternalServerError)
return
}
if clientResponse.Header != nil {
for headerKey, headerValues := range clientResponse.Header {
for _, headerValue := range headerValues {
response.Header().Add(headerKey, headerValue)
}
}
}
response.WriteHeader(clientResponse.StatusCode)
ch := make(chan []byte, 10)
go func(outCh chan []byte) {
defer close(outCh)
if clientResponse.Body == nil {
return
}
defer clientResponse.Body.Close()
for {
buf := make([]byte, 4096)
n, err := clientResponse.Body.Read(buf)
if n > 0 {
outCh <- buf[:n]
}
if err != nil {
break
}
}
}(ch)
for bytes := range ch {
response.Write(bytes)
if flusher, has := response.(http.Flusher); has {
flusher.Flush()
}
}
}
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