//
// 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
}
type wrpReq struct {
U string // url
W int64 // width
H int64 // height
S float64 // scale
C int64 // #colors
X int64 // mouseX
Y int64 // mouseY
K string // keys to send
F string // Fn buttons
T string // imgtype
}
func (w *wrpReq) parseForm(req *http.Request) {
req.ParseForm()
w.U = req.FormValue("url")
if len(w.U) > 1 && !strings.HasPrefix(w.U, "http") {
w.U = fmt.Sprintf("http://www.google.com/search?q=%s", url.QueryEscape(w.U))
}
w.W, _ = strconv.ParseInt(req.FormValue("w"), 10, 64)
w.H, _ = strconv.ParseInt(req.FormValue("h"), 10, 64)
if w.W < 10 && w.H < 10 {
w.W = defgeom.w
w.H = defgeom.h
}
w.S, _ = strconv.ParseFloat(req.FormValue("s"), 64)
if w.S < 0.1 {
w.S = 1.0
}
w.C, _ = strconv.ParseInt(req.FormValue("c"), 10, 64)
if w.C < 2 || w.C > 256 {
w.C = defgeom.c
}
w.K = req.FormValue("k")
w.F = req.FormValue("Fn")
w.T = req.FormValue("t")
if w.T != "gif" && w.T != "png" {
w.T = deftype
}
log.Printf("%s WrpReq from Form: %+v\n", req.RemoteAddr, w)
}
func (w wrpReq) printPage(out http.ResponseWriter, bgcolor string) {
var s string
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/html")
fmt.Fprintf(out, "\n", version)
fmt.Fprintf(out, "\nWRP %s\n\n", w.U, bgcolor)
fmt.Fprintf(out, "
\n")
}
func (w wrpReq) printFooter(out http.ResponseWriter, h string, s string) {
fmt.Fprintf(out, "\n"+
"Web Rendering Proxy Version %s | Shutdown WRP | "+
"Page Height: %s | Img Size: %s\n\n", w.W, w.H, w.S, w.C, w.T, version, h, s)
}
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.parseForm(req)
if len(w.U) > 4 {
w.capture(req.RemoteAddr, out)
} else {
w.printPage(out, "#FFFFFF")
w.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)
w, 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
}
if !nodel {
defer delete(ismap, req.URL.Path)
}
n, err := fmt.Sscanf(req.URL.RawQuery, "%d,%d", &w.X, &w.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
}
log.Printf("%s WrpReq from ISMAP: %+v\n", req.RemoteAddr, w)
if len(w.U) > 4 {
w.capture(req.RemoteAddr, out)
} else {
w.printPage(out, "#FFFFFF")
w.printFooter(out, "", "")
}
}
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()
}
func (w wrpReq) capture(c string, out http.ResponseWriter) {
var err error
if w.X > 0 && w.Y > 0 {
log.Printf("%s Mouse Click %d,%d\n", c, w.X, w.Y)
err = chromedp.Run(ctx, chromedp.MouseClickXY(float64(w.X)/float64(w.S), float64(w.Y)/float64(w.S)))
} else if len(w.F) > 0 {
log.Printf("%s Button %v\n", c, w.F)
switch w.F {
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"))
}
} else if len(w.K) > 0 {
log.Printf("%s Sending Keys: %#v\n", c, w.K)
err = chromedp.Run(ctx, chromedp.KeyEvent(w.K))
} else {
log.Printf("%s Processing Capture Request for %s\n", c, w.U)
err = chromedp.Run(ctx, chromedp.Navigate(w.U))
}
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
}
var styles []*css.ComputedStyleProperty
var r, g, b int
var h int64
var pngcap []byte
chromedp.Run(ctx,
emulation.SetDeviceMetricsOverride(int64(float64(w.W)/w.S), 10, w.S, false),
chromedp.Sleep(time.Second*2),
chromedp.Location(&w.U),
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", c, w.U, h)
w.printPage(out, fmt.Sprintf("#%02X%02X%02X", r, g, b))
if w.H == 0 && h > 0 {
chromedp.Run(ctx, emulation.SetDeviceMetricsOverride(int64(float64(w.W)/w.S), h+30, w.S, false))
} else {
chromedp.Run(ctx, emulation.SetDeviceMetricsOverride(int64(float64(w.W)/w.S), int64(float64(w.H)/w.S), w.S, false))
}
err = chromedp.Run(ctx, chromedp.CaptureScreenshot(&pngcap))
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
}
seq := rand.Intn(9999)
imgpath := fmt.Sprintf("/img/%04d.%s", seq, w.T)
mappath := fmt.Sprintf("/map/%04d.map", seq)
ismap[mappath] = w
var ssize string
var sw, sh int
if w.T == "gif" {
i, err := png.Decode(bytes.NewReader(pngcap))
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
}
var gifbuf bytes.Buffer
err = gif.Encode(&gifbuf, i, &gif.Options{NumColors: int(w.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
}
img[imgpath] = gifbuf
ssize = fmt.Sprintf("%.1f MB", float32(len(gifbuf.Bytes()))/1024.0/1024.0)
sw = i.Bounds().Max.X
sh = i.Bounds().Max.Y
log.Printf("%s Encoded GIF image: %s, Size: %s, Colors: %d, %dx%d\n", c, imgpath, ssize, w.C, sw, sh)
} else if w.T == "png" {
pngbuf := bytes.NewBuffer(pngcap)
img[imgpath] = *pngbuf
cfg, _, _ := image.DecodeConfig(pngbuf)
ssize = fmt.Sprintf("%.1f MB", float32(len(pngbuf.Bytes()))/1024.0/1024.0)
sw = cfg.Width
sh = cfg.Height
log.Printf("%s Got PNG image: %s, Size: %s, %dx%d\n", c, imgpath, ssize, sw, sh)
}
fmt.Fprintf(out, "![\"Url:](\"%s\")
", mappath, imgpath, w.U, ssize, sw, sh)
w.printFooter(out, fmt.Sprintf("%d PX", h), ssize)
log.Printf("%s Done with caputure for %s\n", c, w.U)
}
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)
}
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
}
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("Starting WRP http server on %s\n", addr)
srv.Addr = addr
err = srv.ListenAndServe()
if err != nil {
log.Fatal(err)
}
}