// // WRP - Web Rendering Proxy // // Copyright (c) 2013-2018 Antoni Sawicki // Copyright (c) 2019-2021 Google LLC // package main import ( "bytes" "context" "embed" "flag" "fmt" "html/template" "image" "image/gif" "image/png" "io/ioutil" "log" "math" "math/rand" "net/http" "net/url" "os" "os/signal" "strconv" "strings" "syscall" "time" "github.com/MaxHalford/halfgone" "github.com/chromedp/cdproto/css" "github.com/chromedp/cdproto/emulation" "github.com/chromedp/cdproto/page" "github.com/chromedp/chromedp" "github.com/ericpauley/go-quantize/quantize" ) var ( version = "4.5.2" srv http.Server ctx context.Context cancel context.CancelFunc img = make(map[string]bytes.Buffer) ismap = make(map[string]wrpReq) noDel bool defType string defGeom geom htmlTmpl *template.Template ) // go:embed *.html var fs embed.FS type geom struct { w int64 h int64 c int64 } // Data for html template type uiData struct { Version string URL string BgColor string NColors int64 Width int64 Height int64 Zoom float64 ImgType string ImgURL string ImgSize string ImgWidth int ImgHeight int MapURL string PageHeight string } // Parameters for HTML print function type printParams struct { bgColor string pageHeight string imgSize string imgURL string mapURL string imgWidth int imgHeight int } // WRP Request type wrpReq struct { url string // url width int64 // width height int64 // height zoom float64 // zoom/scale colors int64 // #colors mouseX int64 // mouseX mouseY int64 // mouseY keys string // keys to send buttons string // Fn buttons imgType string // imgtype out http.ResponseWriter req *http.Request } // Parse HTML Form, Process Input Boxes, Etc. func parseForm(w *wrpReq) { w.req.ParseForm() w.url = w.req.FormValue("url") if len(w.url) > 1 && !strings.HasPrefix(w.url, "http") { w.url = fmt.Sprintf("http://www.google.com/search?q=%s", url.QueryEscape(w.url)) } w.width, _ = strconv.ParseInt(w.req.FormValue("w"), 10, 64) w.height, _ = strconv.ParseInt(w.req.FormValue("h"), 10, 64) if w.width < 10 && w.height < 10 { w.width = defGeom.w w.height = defGeom.h } w.zoom, _ = strconv.ParseFloat(w.req.FormValue("z"), 64) if w.zoom < 0.1 { w.zoom = 1.0 } w.colors, _ = strconv.ParseInt(w.req.FormValue("c"), 10, 64) if w.colors < 2 || w.colors > 256 { w.colors = defGeom.c } w.keys = w.req.FormValue("k") w.buttons = w.req.FormValue("Fn") w.imgType = w.req.FormValue("t") if w.imgType != "gif" && w.imgType != "png" { w.imgType = defType } log.Printf("%s WrpReq from UI Form: %+v\n", w.req.RemoteAddr, w) } // Display WP UI func printHTML(w wrpReq, p printParams) { w.out.Header().Set("Cache-Control", "max-age=0") w.out.Header().Set("Expires", "-1") w.out.Header().Set("Pragma", "no-cache") w.out.Header().Set("Content-Type", "text/html") data := uiData{ Version: version, URL: w.url, BgColor: p.bgColor, Width: w.width, Height: w.height, NColors: w.colors, Zoom: w.zoom, ImgType: w.imgType, ImgSize: p.imgSize, ImgWidth: p.imgWidth, ImgHeight: p.imgHeight, ImgURL: p.imgURL, MapURL: p.mapURL, PageHeight: p.pageHeight, } err := htmlTmpl.Execute(w.out, data) if err != nil { log.Fatal(err) } } // Determine what action to take func action(w wrpReq) chromedp.Action { // Mouse Click if w.mouseX > 0 && w.mouseY > 0 { log.Printf("%s Mouse Click %d,%d\n", w.req.RemoteAddr, w.mouseX, w.mouseY) return chromedp.MouseClickXY(float64(w.mouseX)/float64(w.zoom), float64(w.mouseY)/float64(w.zoom)) } // Buttons if len(w.buttons) > 0 { log.Printf("%s Button %v\n", w.req.RemoteAddr, w.buttons) switch w.buttons { case "Bk": return chromedp.NavigateBack() case "St": return chromedp.Stop() case "Re": return chromedp.Reload() case "Bs": return chromedp.KeyEvent("\b") case "Rt": return chromedp.KeyEvent("\r") case "<": return chromedp.KeyEvent("\u0302") case "^": return chromedp.KeyEvent("\u0304") case "v": return chromedp.KeyEvent("\u0301") case ">": return chromedp.KeyEvent("\u0303") } } // Keys if len(w.keys) > 0 { log.Printf("%s Sending Keys: %#v\n", w.req.RemoteAddr, w.keys) return chromedp.KeyEvent(w.keys) } // Navigate to URL log.Printf("%s Processing Capture Request for %s\n", w.req.RemoteAddr, w.url) return chromedp.Navigate(w.url) } // Process Keyboard and Mouse events or Navigate to the desired URL. func navigate(w wrpReq) { err := chromedp.Run(ctx, action(w)) if err != nil { if err.Error() == "context canceled" { log.Printf("%s Contex cancelled, try again", w.req.RemoteAddr) fmt.Fprintf(w.out, "
%s
-- restarting, try again", err) ctx, cancel = chromedp.NewContext(context.Background()) return } log.Printf("%s %s", w.req.RemoteAddr, err) fmt.Fprintf(w.out, "
%s
", err) } } // Capture currently rendered web page to an image and fake ISMAP func capture(w wrpReq) { var err error var styles []*css.ComputedStyleProperty var r, g, b int var h int64 var pngcap []byte chromedp.Run(ctx, emulation.SetDeviceMetricsOverride(int64(float64(w.width)/w.zoom), 10, w.zoom, false), chromedp.Location(&w.url), chromedp.ComputedStyle("body", &styles, chromedp.ByQuery), chromedp.ActionFunc(func(ctx context.Context) error { _, _, s, err := page.GetLayoutMetrics().Do(ctx) if err == nil { h = int64(math.Ceil(s.Height)) } return nil }), ) for _, style := range styles { if style.Name == "background-color" { fmt.Sscanf(style.Value, "rgb(%d,%d,%d)", &r, &g, &b) } } log.Printf("%s Landed on: %s, Height: %v\n", w.req.RemoteAddr, w.url, h) height := int64(float64(w.height) / w.zoom) if w.height == 0 && h > 0 { height = h + 30 } chromedp.Run(ctx, emulation.SetDeviceMetricsOverride(int64(float64(w.width)/w.zoom), height, w.zoom, false)) // Capture screenshot... err = chromedp.Run(ctx, chromedp.Sleep(time.Second*2), chromedp.CaptureScreenshot(&pngcap), ) if err != nil { if err.Error() == "context canceled" { log.Printf("%s Contex cancelled, try again", w.req.RemoteAddr) fmt.Fprintf(w.out, "
%s
-- restarting, try again", err) ctx, cancel = chromedp.NewContext(context.Background()) return } log.Printf("%s Failed to capture screenshot: %s\n", w.req.RemoteAddr, err) fmt.Fprintf(w.out, "
Unable to capture screenshot:
%s
\n", err) return } seq := rand.Intn(9999) imgpath := fmt.Sprintf("/img/%04d.%s", seq, w.imgType) mappath := fmt.Sprintf("/map/%04d.map", seq) ismap[mappath] = w var ssize string var iw, ih int switch w.imgType { case "gif": i, err := png.Decode(bytes.NewReader(pngcap)) if err != nil { log.Printf("%s Failed to decode screenshot: %s\n", w.req.RemoteAddr, err) fmt.Fprintf(w.out, "
Unable to decode page screenshot:
%s
\n", err) return } if w.colors == 2 { gray := halfgone.ImageToGray(i) i = halfgone.FloydSteinbergDitherer{}.Apply(gray) } var gifbuf bytes.Buffer err = gif.Encode(&gifbuf, i, &gif.Options{NumColors: int(w.colors), Quantizer: quantize.MedianCutQuantizer{}}) if err != nil { log.Printf("%s Failed to encode GIF: %s\n", w.req.RemoteAddr, err) fmt.Fprintf(w.out, "
Unable to encode GIF:
%s
\n", err) return } img[imgpath] = gifbuf ssize = fmt.Sprintf("%.0f KB", float32(len(gifbuf.Bytes()))/1024.0) iw = i.Bounds().Max.X ih = i.Bounds().Max.Y log.Printf("%s Encoded GIF image: %s, Size: %s, Colors: %d, %dx%d\n", w.req.RemoteAddr, imgpath, ssize, w.colors, iw, ih) case "png": pngbuf := bytes.NewBuffer(pngcap) img[imgpath] = *pngbuf cfg, _, _ := image.DecodeConfig(pngbuf) ssize = fmt.Sprintf("%.0f KB", float32(len(pngbuf.Bytes()))/1024.0) iw = cfg.Width ih = cfg.Height log.Printf("%s Got PNG image: %s, Size: %s, %dx%d\n", w.req.RemoteAddr, imgpath, ssize, iw, ih) } printHTML(w, printParams{ bgColor: fmt.Sprintf("#%02X%02X%02X", r, g, b), pageHeight: fmt.Sprintf("%d PX", h), imgSize: ssize, imgURL: imgpath, mapURL: mappath, imgWidth: iw, imgHeight: ih, }) log.Printf("%s Done with capture for %s\n", w.req.RemoteAddr, w.url) } // Process HTTP requests to WRP '/' url 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 w wrpReq w.req = req w.out = out parseForm(&w) if len(w.url) < 4 { printHTML(w, printParams{bgColor: "#FFFFFF"}) return } navigate(w) capture(w) } // Process HTTP requests to ISMAP '/map/' url 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) w, ok := ismap[req.URL.Path] w.req = req w.out = out 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 } if !noDel { defer delete(ismap, req.URL.Path) } n, err := fmt.Sscanf(req.URL.RawQuery, "%d,%d", &w.mouseX, &w.mouseY) 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 } log.Printf("%s WrpReq from ISMAP: %+v\n", req.RemoteAddr, w) if len(w.url) < 4 { printHTML(w, printParams{bgColor: "#FFFFFF"}) return } navigate(w) capture(w) } // Process HTTP requests for images '/img/' url func imgServer(out http.ResponseWriter, req *http.Request) { log.Printf("%s IMG Request for %s\n", req.RemoteAddr, req.URL.Path) imgbuf, ok := img[req.URL.Path] if !ok || imgbuf.Bytes() == nil { fmt.Fprintf(out, "Unable to find image %s\n", req.URL.Path) log.Printf("%s Unable to find image %s\n", req.RemoteAddr, req.URL.Path) return } if !noDel { defer delete(img, req.URL.Path) } switch { case strings.HasPrefix(req.URL.Path, ".gif"): out.Header().Set("Content-Type", "image/gif") case strings.HasPrefix(req.URL.Path, ".png"): out.Header().Set("Content-Type", "image/png") } out.Header().Set("Content-Length", strconv.Itoa(len(imgbuf.Bytes()))) out.Header().Set("Cache-Control", "max-age=0") out.Header().Set("Expires", "-1") out.Header().Set("Pragma", "no-cache") out.Write(imgbuf.Bytes()) out.(http.Flusher).Flush() } // Process HTTP requests for Shutdown via '/shutdown/' url func haltServer(out http.ResponseWriter, req *http.Request) { log.Printf("%s Shutdown Request for %s\n", req.RemoteAddr, req.URL.Path) out.Header().Set("Cache-Control", "max-age=0") out.Header().Set("Expires", "-1") out.Header().Set("Pragma", "no-cache") out.Header().Set("Content-Type", "text/plain") fmt.Fprintf(out, "Shutting down WRP...\n") out.(http.Flusher).Flush() time.Sleep(time.Second * 2) cancel() srv.Shutdown(context.Background()) os.Exit(1) } // returns html template, either from html file or built-in func tmpl(t string) string { var tmpl []byte fh, err := os.Open(t) if err != nil { goto statik } tmpl, err = ioutil.ReadAll(fh) if err != nil { goto statik } log.Printf("Got UI template from %v file\n", t) return string(tmpl) statik: fhs, err := fs.Open("/wrp.html") if err != nil { log.Fatal(err) } tmpl, err = ioutil.ReadAll(fhs) if err != nil { log.Fatal(err) } log.Printf("Got UI template from built-in\n") return string(tmpl) } // Main... func main() { var addr, fgeom, tHTML string var headless bool var debug bool var err error flag.StringVar(&addr, "l", ":8080", "Listen address:port, default :8080") flag.BoolVar(&headless, "h", true, "Headless mode - hide browser window") flag.BoolVar(&debug, "d", false, "Debug ChromeDP") flag.BoolVar(&noDel, "n", false, "Do not free maps and images after use") flag.StringVar(&defType, "t", "gif", "Image type: gif|png") flag.StringVar(&fgeom, "g", "1152x600x256", "Geometry: width x height x colors, height can be 0 for unlimited") flag.StringVar(&tHTML, "ui", "wrp.html", "HTML template file for the UI") flag.Parse() if len(os.Getenv("PORT")) > 0 { addr = ":" + os.Getenv(("PORT")) } n, err := fmt.Sscanf(fgeom, "%dx%dx%d", &defGeom.w, &defGeom.h, &defGeom.c) if err != nil || n != 3 { log.Fatalf("Unable to parse -g geometry flag / %s", err) } opts := append(chromedp.DefaultExecAllocatorOptions[:], chromedp.Flag("headless", headless), chromedp.Flag("hide-scrollbars", false), ) actx, acancel := chromedp.NewExecAllocator(context.Background(), opts...) defer acancel() if debug { ctx, cancel = chromedp.NewContext(actx, chromedp.WithDebugf(log.Printf)) } else { ctx, cancel = chromedp.NewContext(actx) } defer cancel() rand.Seed(time.Now().UnixNano()) c := make(chan os.Signal) signal.Notify(c, os.Interrupt, syscall.SIGTERM) go func() { <-c log.Printf("Interrupt - shutting down.") cancel() srv.Shutdown(context.Background()) os.Exit(1) }() 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("Args: %q", os.Args) log.Printf("Default Img Type: %v, Geometry: %+v", defType, defGeom) htmlTmpl, err = template.New("wrp.html").Parse(tmpl(tHTML)) if err != nil { log.Fatal(err) } log.Printf("Starting WRP http server on %s\n", addr) srv.Addr = addr err = srv.ListenAndServe() if err != nil { log.Fatal(err) } }