init

LICENSE

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+Copyright (c) 2019 Darren Hoo
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Readme.md

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+## pacroxy
+
+
+pacproxy is a proxy that parses pac file and start a simple http proxy which will forward http requests to proxies in pac
+
+
+## Install
+
+Ensure that `Go` enviroment has been properly setup.
+
+```bash
+go get -u -v github.com/darren/pacroxy
+```
+
+
+## Usage
+
+```
+pacroxy -p wpad.dat -l 127.0.0.1:9999
+curl -x 127.0.0.1:9999 https://example.com
+```
+
+## Note
+
+This is a simple tool still in development, use at your own risk.
+
+

go.mod

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+module github.com/darren/pacroxy
+
+require github.com/darren/gpac v0.0.0-20190201203621-687614ea7470

go.sum

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+github.com/darren/gpac v0.0.0-20190201203621-687614ea7470 h1:liq6Kzh6QchRPvsAKmIG/QPrHc0bSntrXFM2eBWkRxo=
+github.com/darren/gpac v0.0.0-20190201203621-687614ea7470/go.mod h1:fK76ZiaaM0f4rW2A3sTomlo/wlY9jRV07KJ66DbOAXs=
+github.com/robertkrimen/otto v0.0.0-20180617131154-15f95af6e78d h1:1VUlQbCfkoSGv7qP7Y+ro3ap1P1pPZxgdGVqiTVy5C4=
+github.com/robertkrimen/otto v0.0.0-20180617131154-15f95af6e78d/go.mod h1:xvqspoSXJTIpemEonrMDFq6XzwHYYgToXWj5eRX1OtY=
+gopkg.in/sourcemap.v1 v1.0.5 h1:inv58fC9f9J3TK2Y2R1NPntXEn3/wjWHkonhIUODNTI=
+gopkg.in/sourcemap.v1 v1.0.5/go.mod h1:2RlvNNSMglmRrcvhfuzp4hQHwOtjxlbjX7UPY/GXb78=

main.go

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+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+
+	"github.com/darren/gpac"
+)
+
+var scripts = `
+  function FindProxyForURL(url, host) {
+    if (host == "www.baidu.com") return "DIRECT";
+    if (isPlainHostName(host)) return "DIRECT";
+    else return "PROXY 10.0.1.254:8080; PROXY 127.0.0.1:8080; DIRECT";
+  }
+`
+
+var pacfile = flag.String("p", "wpad.dat", "pac file to load")
+var addr = flag.String("l", "127.0.0.1:8080", "Listening address")
+
+// Server the proxy server
+type Server struct {
+	http.Server
+	pac *gpac.Parser
+}
+
+func (s *Server) handle(w http.ResponseWriter, r *http.Request) {
+	if r.Method == http.MethodConnect {
+		s.handleTunneling(w, r)
+	} else {
+		s.handleHTTP(w, r)
+	}
+}
+
+type peekedConn struct {
+	net.Conn
+	r io.Reader
+}
+
+// concat combine conn and peeked buffer
+func combine(peeked io.Reader, conn net.Conn) *peekedConn {
+	r := io.MultiReader(peeked, conn)
+	return &peekedConn{conn, r}
+}
+
+func (p *peekedConn) Read(data []byte) (int, error) {
+	return p.r.Read(data)
+}
+
+func (s *Server) handleTunneling(w http.ResponseWriter, r *http.Request) {
+	host, _, _ := net.SplitHostPort(r.Host)
+	url := fmt.Sprintf("https://%s/", host)
+
+	proxies, err := s.pac.FindProxy(url)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusServiceUnavailable)
+		return
+	}
+
+	ctx := context.Background()
+
+	var dst net.Conn
+	var proxy *gpac.Proxy
+
+	for _, proxy = range proxies {
+		dialer := proxy.Dialer()
+		dst, err = dialer(ctx, "tcp", r.Host)
+		if err != nil {
+			log.Println("Dial failed:", err)
+			continue
+		} else {
+			break
+		}
+	}
+
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusServiceUnavailable)
+		return
+	}
+
+	if proxy == nil {
+		http.Error(w, "No Proxy Available", http.StatusServiceUnavailable)
+		return
+	}
+
+	if proxy.IsDirect() {
+		w.WriteHeader(http.StatusOK)
+	}
+
+	hijacker, ok := w.(http.Hijacker)
+	if !ok {
+		http.Error(w, "Hijacking not supported", http.StatusInternalServerError)
+		return
+	}
+	src, buf, err := hijacker.Hijack()
+
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusServiceUnavailable)
+	}
+
+	src = combine(buf, src)
+
+	go transfer(dst, src)
+	go transfer(src, dst)
+
+	log.Printf("[%s] %s %v [%v]", r.RemoteAddr, r.Method, url, proxy)
+}
+
+func transfer(destination io.WriteCloser, source io.ReadCloser) {
+	defer destination.Close()
+	defer source.Close()
+	io.Copy(destination, source)
+}
+
+func (s *Server) handleHTTP(w http.ResponseWriter, req *http.Request) {
+	proxies, err := s.pac.FindProxy(req.URL.String())
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusServiceUnavailable)
+		return
+	}
+
+	req.RequestURI = ""
+
+	for _, proxy := range proxies {
+		resp, err := proxy.Do(req)
+		if err != nil {
+			continue
+		}
+
+		defer resp.Body.Close()
+		cloneHeader(w.Header(), resp.Header)
+		w.WriteHeader(resp.StatusCode)
+		io.Copy(w, resp.Body)
+
+		log.Printf("[%s] %s %v [%v]", req.RemoteAddr, req.Method, req.URL, proxy)
+
+		if err == nil {
+			return
+		}
+	}
+
+	log.Printf("[%s] %s %v FAILED", req.RemoteAddr, req.Method, req.URL)
+	http.Error(w, "No Proxy Available", http.StatusServiceUnavailable)
+}
+
+func cloneHeader(dst, src http.Header) {
+	for k, vv := range src {
+		for _, v := range vv {
+			dst.Add(k, v)
+		}
+	}
+}
+
+func main() {
+	flag.Parse()
+
+	log.Printf("Loading pac from %s", *pacfile)
+	pac, err := gpac.From(*pacfile)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	log.Printf("Start proxy on %s", *addr)
+	server := Server{
+		Server: http.Server{
+			Addr: *addr,
+		},
+		pac: pac,
+	}
+
+	server.Handler = http.HandlerFunc(server.handle)
+	log.Fatal(server.ListenAndServe())
+}