ps-proxy.go

package main

import (
	"bytes"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"time"

	"path/filepath"

	"github.com/elazarl/goproxy"
	"github.com/fzerorubigd/expand"
)

type respWriter struct {
	buf    bytes.Buffer
	Result *http.Response
}

func (rw *respWriter) Header() http.Header {
	return rw.Result.Header
}

func (rw *respWriter) Write(p []byte) (int, error) {
	i, err := rw.buf.Write(p)
	rw.Result.Body = ioutil.NopCloser(&rw.buf)
	return i, err
}

func (rw *respWriter) WriteHeader(s int) {
	rw.Result.StatusCode = s
}

func NewRespWriter(r *http.Request) *respWriter {
	resp := &http.Response{}
	resp.Request = r
	resp.TransferEncoding = r.TransferEncoding
	resp.Header = make(http.Header)

	return &respWriter{
		Result: resp,
	}
}

func main() {
	pwd, err := expand.Pwd()
	if err != nil {
		panic(err)
	}
	cc := filepath.Join(pwd, "cache")
	proxy := goproxy.NewProxyHttpServer()
	proxy.Verbose = false
	proxy.OnRequest().DoFunc(
		func(r *http.Request, ctx *goproxy.ProxyCtx) (*http.Request, *http.Response) {
			log.Println("=>", r.URL.String())
			if filepath.Ext(r.URL.Path) == ".pkg" {
				log.Println(r.URL.Path)
				// ok time to hack!
				f := filepath.Join(cc, filepath.Base(r.URL.Path))
				if _, err := os.Stat(f); os.IsNotExist(err) {
					log.Println(err)
					return r, nil
				}
				log.Println("OK!")
				handle, err := os.Open(f)
				if err != nil {
					return r, nil
				}
				defer handle.Close()

				w := NewRespWriter(r)
				http.ServeContent(w, r, f, time.Time{}, handle)

				return r, w.Result

			}
			return r, nil
		})
	log.Fatal(http.ListenAndServe(":8080", proxy))
}