hrcproxy，简单的可修改http返回内容的反向代理

hrcproxy.go

package main

import (
	"bufio"
	"bytes"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"net/http/httputil"
	"net/url"
	"os"
	"strconv"
	"strings"
)

type proxyConfig struct {
	TargetHost     string
	TargetUrl      string
	SourceStr      string
	DestinationStr string
}

var listenIpPort string
var backendServer string

var configMap = make(map[string][]proxyConfig)

type transport struct {
	http.RoundTripper
}

func (t *transport) RoundTrip(req *http.Request) (resp *http.Response, err error) {
	resp, err = t.RoundTripper.RoundTrip(req)
	if err != nil {
		return nil, err
	}
	thisUrl := req.URL.Path
	thisHost := req.Host
	// log.Println("Input request :[HOST]" + thisHost + "[URL]" + thisUrl)
	if v, ok := configMap[(thisHost + "|@|" + thisUrl)]; ok {
		log.Println("Start Processing...")
		b, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return nil, err
		}
		err = resp.Body.Close()
		if err != nil {
			return nil, err
		}
		for i := 0; i < len(v); i++ {
			var config proxyConfig = v[i]
			b = bytes.Replace(b, []byte(config.SourceStr), []byte(config.DestinationStr), -1)
		}

		body := ioutil.NopCloser(bytes.NewReader(b))
		resp.Body = body
		resp.ContentLength = int64(len(b))
		resp.Header.Set("Content-Length", strconv.Itoa(len(b)))
		log.Println("Process end...")

	}
	return resp, nil
}

func main() {
	// Override the default usage
	flag.Usage = GoproxyUsage
	handleArgs()

	target, _ := url.Parse("http://" + backendServer)
	proxy := httputil.NewSingleHostReverseProxy(target)
	// proxy.ModifyResponse = rewriteBody
	proxy.Transport = &transport{http.DefaultTransport}

	http.Handle("/", proxy)
	log.Fatal(http.ListenAndServe(listenIpPort, nil))
}

func handleArgs() {
	configFileNamePoint := flag.String("f", "hrcproxy.conf", "config file")
	listenIpPortPoint := flag.String("l", "localhost:9090", "server listen port")
	backendServerPoint := flag.String("s", "", "backend server ip and port")
	flag.Parse()

	configFileName := *configFileNamePoint
	listenIpPort, backendServer = *listenIpPortPoint, *backendServerPoint
	if configFileName == "" || listenIpPort == "" || backendServer == "" {
		fmt.Println("\nPlease Input enough infos!\n")
		flag.Usage()
		os.Exit(1)
	}
	readConfigFile(configFileName)
}

func readConfigFile(configFileName string) {
	file, err := os.Open(configFileName)
	if err != nil {
		log.Fatal(err)
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		var line = strings.TrimSpace(scanner.Text())
		//跳过空行和注释行
		if line != "" || line[0] != '#' {
			var parts = strings.Split(line, "|@|")
			//仅处理4个参数的，否则报错
			if len(parts) != 4 {
				log.Fatal("config error : " + line)
			}
			var config proxyConfig
			config.TargetHost = parts[0]
			config.TargetUrl = parts[1]
			config.SourceStr = parts[2]
			config.DestinationStr = parts[3]

			var key = config.TargetHost + "|@|" + config.TargetUrl
			configMap[key] = append(configMap[key], config)
		}
	}

	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}
}

func GoproxyUsage() {
	fmt.Fprintf(os.Stderr, "Usage:  ./hrcproxy -l=0.0.0.0:9090 -s=xx.xx.xx.xx:80 -f=my.conf\n\n")
	flag.PrintDefaults()
}

my.conf

#目标的域名|@|目标url|@|要替换的源字符串|@|目标字符串
test.dev.com|@|/online/main|@|192.168.1.26:8008|@|out.test.site