//
// WRP - Web Rendering Proxy
//
// Copyright (c) 2013-2018 Antoni Sawicki
// Copyright (c) 2019-2020 Google LLC
//
package main
import (
"bytes"
"context"
"flag"
"fmt"
"image"
"image/gif"
"image/png"
"log"
"math"
"math/rand"
"net/http"
"net/url"
"os"
"os/signal"
"strconv"
"strings"
"syscall"
"time"
"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"
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
)
type geom struct {
w int64
h int64
c int64
}
// WRP Request
type wrpReq struct {
url string // url
width int64 // width
height int64 // height
scale float64 // 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 (w *wrpReq) parseForm() {
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.scale, _ = strconv.ParseFloat(w.req.FormValue("s"), 64)
if w.scale < 0.1 {
w.scale = 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
// TODO: make this in to an external template
func (w wrpReq) printPage(bgcolor string) {
var s string
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")
fmt.Fprintf(w.out, "\n", version)
fmt.Fprintf(w.out, "\nWRP %s\n\n", w.url, bgcolor)
fmt.Fprintf(w.out, "
\n")
}
// Status bar below captured image
func (w wrpReq) printFooter(h string, s string) {
fmt.Fprintf(w.out,
"\n"+
""+
"Web Rendering Proxy Version %s | "+
"Shutdown WRP | "+
"Page Height: %s |"+
"Img Size: %s "+
"\n\n",
w.width,
w.height,
w.scale,
w.colors,
w.imgType,
version,
h,
s)
}
// 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
w.parseForm()
if len(w.url) > 4 {
w.navigate()
w.capture()
} else {
w.printPage("#FFFFFF")
w.printFooter("", "")
}
}
// 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 {
w.navigate()
w.capture()
} else {
w.printPage("#FFFFFF")
w.printFooter("", "")
}
}
// 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)
}
if strings.HasPrefix(req.URL.Path, ".gif") {
out.Header().Set("Content-Type", "image/gif")
} else if 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)
}
// Process Keyboard and Mouse events or Navigate to the desired URL.
func (w wrpReq) navigate() {
var err error
// Mouse Click
if w.mouseX > 0 && w.mouseY > 0 {
log.Printf("%s Mouse Click %d,%d\n", w.req.RemoteAddr, w.mouseX, w.mouseY)
err = chromedp.Run(ctx, chromedp.MouseClickXY(float64(w.mouseX)/float64(w.scale), float64(w.mouseY)/float64(w.scale)))
// Buttons
} else if len(w.buttons) > 0 {
log.Printf("%s Button %v\n", w.req.RemoteAddr, w.buttons)
switch w.buttons {
case "Bk":
err = chromedp.Run(ctx, chromedp.NavigateBack())
case "Bs":
err = chromedp.Run(ctx, chromedp.KeyEvent("\b"))
case "Rt":
err = chromedp.Run(ctx, chromedp.KeyEvent("\r"))
case "<":
err = chromedp.Run(ctx, chromedp.KeyEvent("\u0302"))
case "^":
err = chromedp.Run(ctx, chromedp.KeyEvent("\u0304"))
case "v":
err = chromedp.Run(ctx, chromedp.KeyEvent("\u0301"))
case ">":
err = chromedp.Run(ctx, chromedp.KeyEvent("\u0303"))
}
// Keys
} else if len(w.keys) > 0 {
log.Printf("%s Sending Keys: %#v\n", w.req.RemoteAddr, w.keys)
err = chromedp.Run(ctx, chromedp.KeyEvent(w.keys))
// Navigate to URL
} else {
log.Printf("%s Processing Capture Request for %s\n", w.req.RemoteAddr, w.url)
err = chromedp.Run(ctx, chromedp.Navigate(w.url))
}
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())
} else {
log.Printf("%s %s", w.req.RemoteAddr, err)
fmt.Fprintf(w.out, "
%s
", err)
}
return
}
}
// Capture currently rendered web page to an image and fake ISMAP
func (w wrpReq) capture() {
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.scale), 10, w.scale, false),
chromedp.Sleep(time.Second*2),
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)
w.printPage(fmt.Sprintf("#%02X%02X%02X", r, g, b))
if w.height == 0 && h > 0 {
chromedp.Run(ctx, emulation.SetDeviceMetricsOverride(int64(float64(w.width)/w.scale), h+30, w.scale, false))
} else {
chromedp.Run(ctx, emulation.SetDeviceMetricsOverride(int64(float64(w.width)/w.scale), int64(float64(w.height)/w.scale), w.scale, false))
}
// Capture screenshot...
err = chromedp.Run(ctx, 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())
} else {
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 sw, sh int
if w.imgType == "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
}
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)
sw = i.Bounds().Max.X
sh = 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, sw, sh)
} else if w.imgType == "png" {
pngbuf := bytes.NewBuffer(pngcap)
img[imgpath] = *pngbuf
cfg, _, _ := image.DecodeConfig(pngbuf)
ssize = fmt.Sprintf("%.0f KB", float32(len(pngbuf.Bytes()))/1024.0)
sw = cfg.Width
sh = cfg.Height
log.Printf("%s Got PNG image: %s, Size: %s, %dx%d\n", w.req.RemoteAddr, imgpath, ssize, sw, sh)
}
fmt.Fprintf(w.out, "![\"Url:](\"%s\")
", mappath, imgpath, w.url, ssize, sw, sh)
w.printFooter(fmt.Sprintf("%d PX", h), ssize)
log.Printf("%s Done with caputure for %s\n", w.req.RemoteAddr, w.url)
}
// Main...
func main() {
var addr, fgeom string
var head, headless bool
var debug bool
var err error
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.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.Parse()
if head {
headless = false
} else {
headless = true
}
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.Print(os.Args)
log.Printf("Starting WRP http server on %s\n", addr)
srv.Addr = addr
err = srv.ListenAndServe()
if err != nil {
log.Fatal(err)
}
}