// // WRP - Web Rendering Proxy // // Copyright (c) 2013-2018 Antoni Sawicki // Copyright (c) 2019 Google LLC // package main import ( "bytes" "context" "flag" "fmt" "image/gif" "image/png" "log" "math/rand" "net/http" "net/url" "strconv" "strings" "time" "github.com/chromedp/cdproto/emulation" "github.com/chromedp/cdproto/runtime" "github.com/chromedp/chromedp" "github.com/ericpauley/go-quantize/quantize" ) var ( version = "3.0" srv http.Server ctx context.Context cancel context.CancelFunc gifmap = make(map[string]bytes.Buffer) ismap = make(map[string]Params) ) // Params - Page Configuration Parameters type Params struct { U string // url P int64 // page W int64 // width H int64 // height S float64 // scale C int64 // #colors } func (p *Params) parseForm(req *http.Request) { req.ParseForm() p.U = req.FormValue("url") if len(p.U) > 1 && !strings.HasPrefix(p.U, "http") { p.U = fmt.Sprintf("http://www.google.com/search?q=%s", url.QueryEscape(p.U)) } p.P, _ = strconv.ParseInt(req.FormValue("p"), 10, 64) if req.FormValue("pg") == "Dn" { p.P++ } else if req.FormValue("pg") == "Up" { p.P-- } else { p.P = 0 } p.W, _ = strconv.ParseInt(req.FormValue("w"), 10, 64) if p.W < 10 { p.W = 1024 } p.H, _ = strconv.ParseInt(req.FormValue("h"), 10, 64) if p.H < 10 { p.H = 768 } p.S, _ = strconv.ParseFloat(req.FormValue("s"), 64) if p.S < 0.1 { p.S = 1.0 } p.C, _ = strconv.ParseInt(req.FormValue("c"), 10, 64) if p.C < 2 || p.C > 256 { p.C = 256 } log.Printf("Params from Form: %+v\n", p) } func (p Params) printPage(out http.ResponseWriter) { out.Header().Set("Content-Type", "text/html") fmt.Fprintf(out, "\n", version) fmt.Fprintf(out, "\nWRP %s\n\n", p.U) fmt.Fprintf(out, "
", p.U) fmt.Fprintf(out, " \n") fmt.Fprintf(out, " \n") fmt.Fprintf(out, " \n", p.P) fmt.Fprintf(out, " \n") fmt.Fprintf(out, "W \n", p.W) fmt.Fprintf(out, "H \n", p.H) fmt.Fprintf(out, "S \n", p.S) fmt.Fprintf(out, "C \n", p.C) fmt.Fprintf(out, "

\n") } func (p Params) printFooter(out http.ResponseWriter) { fmt.Fprintf(out, "\n

"+ "Web Rendering Proxy Version %s | Shutdown WRP\n\n", p.W, p.H, p.S, p.C, version) } func pageServer(out http.ResponseWriter, req *http.Request) { log.Printf("%s Page Request for %s [%+v]\n", req.RemoteAddr, req.URL.Path, req.URL.RawQuery) var p Params p.parseForm(req) p.printPage(out) if len(p.U) > 4 { p.capture(req.RemoteAddr, out) } p.printFooter(out) } func mapServer(out http.ResponseWriter, req *http.Request) { log.Printf("%s ISMAP Request for %s [%+v]\n", req.RemoteAddr, req.URL.Path, req.URL.RawQuery) var x, y int64 n, err := fmt.Sscanf(req.URL.RawQuery, "%d,%d", &x, &y) if err != nil || n != 2 { fmt.Fprintf(out, "n=%d, err=%s\n", n, err) log.Printf("%s ISMAP n=%d, err=%s\n", req.RemoteAddr, n, err) return } p, ok := ismap[req.URL.Path] if !ok { fmt.Fprintf(out, "Unable to find map %s\n", req.URL.Path) log.Printf("Unable to find map %s\n", req.URL.Path) return } defer delete(ismap, req.URL.Path) log.Printf("%s Params from ISMAP: %+v\n", req.RemoteAddr, p) p.printPage(out) if len(p.U) > 4 { p.capture(req.RemoteAddr, out) } p.printFooter(out) } func imgServer(out http.ResponseWriter, req *http.Request) { log.Printf("%s IMG Request for %s\n", req.RemoteAddr, req.URL.Path) gifbuf, ok := gifmap[req.URL.Path] if !ok || gifbuf.Bytes() == nil { fmt.Fprintf(out, "Unable to find image %s\n", req.URL.Path) log.Printf("Unable to find image %s\n", req.URL.Path) return } defer delete(gifmap, req.URL.Path) out.Header().Set("Content-Type", "image/gif") out.Header().Set("Content-Length", strconv.Itoa(len(gifbuf.Bytes()))) out.Write(gifbuf.Bytes()) out.(http.Flusher).Flush() } func (p Params) capture(c string, out http.ResponseWriter) { var pngbuf []byte var gifbuf bytes.Buffer var loc string var res *runtime.RemoteObject log.Printf("%s Processing Capture Request for %s\n", c, p.U) // Run ChromeDP Magic err := chromedp.Run(ctx, emulation.SetDeviceMetricsOverride(int64(float64(p.W)/p.S), int64(float64(p.H)/p.S), p.S, false), chromedp.Navigate(p.U), chromedp.Evaluate(fmt.Sprintf("window.scrollTo(0, %d);", p.P*int64(float64(p.H)*float64(0.9))), &res), chromedp.Sleep(time.Second*1), chromedp.Location(&loc)) if err != nil { if err.Error() == "context canceled" { log.Printf("%s Contex cancelled, try again", c) fmt.Fprintf(out, "
%s
-- restarting, try again", err) ctx, cancel = chromedp.NewContext(context.Background()) } else { log.Printf("%s %s", c, err) fmt.Fprintf(out, "
%s
", err) } return } log.Printf("%s Landed on: %s\n", c, loc) p.U = loc // Process Screenshot Image err = chromedp.Run(ctx, chromedp.CaptureScreenshot(&pngbuf)) if err != nil { log.Printf("%s Failed to capture screenshot: %s\n", c, err) fmt.Fprintf(out, "
Unable to capture screenshot:
%s
\n", err) return } bytes.NewReader(pngbuf).Seek(0, 0) img, err := png.Decode(bytes.NewReader(pngbuf)) if err != nil { log.Printf("%s Failed to decode screenshot: %s\n", c, err) fmt.Fprintf(out, "
Unable to decode page screenshot:
%s
\n", err) return } gifbuf.Reset() err = gif.Encode(&gifbuf, img, &gif.Options{NumColors: int(p.C), Quantizer: quantize.MedianCutQuantizer{}}) if err != nil { log.Printf("%s Failed to encode GIF: %s\n", c, err) fmt.Fprintf(out, "
Unable to encode GIF:
%s
\n", err) return } // Compose map and gif seq := rand.Intn(9999) imgpath := fmt.Sprintf("/img/%04d.gif", seq) mappath := fmt.Sprintf("/map/%04d.map", seq) gifmap[imgpath] = gifbuf ismap[mappath] = p log.Printf("%s Encoded GIF image: %s, Size: %dKB, Colors: %d\n", c, imgpath, len(gifbuf.Bytes())/1024, p.C) fmt.Fprintf(out, "\"wrp\"", mappath, imgpath) log.Printf("%s Done with caputure for %s\n", c, p.U) } func haltServer(out http.ResponseWriter, req *http.Request) { log.Printf("%s Shutdown Request for %s\n", req.RemoteAddr, req.URL.Path) defer cancel() srv.Shutdown(context.Background()) } func main() { var addr string var head, headless bool var debug bool flag.StringVar(&addr, "l", ":8080", "Listen address:port, default :8080") flag.BoolVar(&head, "h", false, "Headed mode - display browser window") flag.BoolVar(&debug, "d", false, "Debug ChromeDP") flag.Parse() if head { headless = false } else { headless = true } opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Flag("headless", headless), ) actx, cancel := chromedp.NewExecAllocator(context.Background(), opts...) defer cancel() if debug { ctx, cancel = chromedp.NewContext(actx, chromedp.WithDebugf(log.Printf)) } else { ctx, cancel = chromedp.NewContext(actx) } defer cancel() rand.Seed(time.Now().UnixNano()) http.HandleFunc("/", pageServer) http.HandleFunc("/map/", mapServer) http.HandleFunc("/img/", imgServer) http.HandleFunc("/shutdown/", haltServer) http.HandleFunc("/favicon.ico", http.NotFound) log.Printf("Web Rendering Proxy Version %s\n", version) log.Printf("Starting WRP http server on %s\n", addr) srv.Addr = addr err := srv.ListenAndServe() if err != nil { log.Fatal(err) } }