//
// WRP - Web Rendering Proxy
//
// Copyright (c) 2013-2018 Antoni Sawicki
// Copyright (c) 2019 Google LLC
//
package main
import (
"bytes"
"context"
"flag"
"fmt"
"image"
"image/color/palette"
"image/draw"
"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/cdproto/cdp"
"github.com/chromedp/cdproto/dom"
"github.com/chromedp/chromedp"
)
// Ismap for server side processing
type Ismap struct {
xmin int64
ymin int64
xmax int64
ymax int64
url string
}
var (
version = "3.0"
ctx context.Context
cancel context.CancelFunc
gifmap = make(map[string]bytes.Buffer)
ismap = make(map[string][]Ismap)
)
func pageServer(out http.ResponseWriter, req *http.Request) {
req.ParseForm()
u := req.FormValue("url")
var istr string
var ion string
var i bool
if req.FormValue("i") == "on" {
istr = "CHECKED"
i = true
ion = "&i=on"
} else {
istr = ""
i = false
}
p, _ := strconv.ParseInt(req.FormValue("p"), 10, 64)
if req.FormValue("pg") == "Dn" {
p++
} else if req.FormValue("pg") == "Up" {
p--
} else {
p = 0
}
w, _ := strconv.ParseInt(req.FormValue("w"), 10, 64)
if w < 10 {
w = 1024
}
h, _ := strconv.ParseInt(req.FormValue("h"), 10, 64)
if h < 10 {
h = 768
}
s, _ := strconv.ParseFloat(req.FormValue("s"), 64)
if s < 0.1 {
s = 1.0
}
c, _ := strconv.ParseInt(req.FormValue("c"), 10, 64)
if c < 2 || c > 256 {
c = 256
}
log.Printf("%s Page Reqest for url=\"%s\" [%s]\n", req.RemoteAddr, u, req.URL.Path)
out.Header().Set("Content-Type", "text/html")
fmt.Fprintf(out, "\n", version)
fmt.Fprintf(out, "\nWRP %s\n\n", u)
fmt.Fprintf(out, "
\n")
if len(u) > 1 {
if strings.HasPrefix(u, "http") {
capture(u, w, h, s, int(c), p, i, req.RemoteAddr, out)
} else {
capture(fmt.Sprintf("http://www.google.com/search?q=%s", url.QueryEscape(u)), w, h, s, int(c), p, i, req.RemoteAddr, out)
}
} else {
fmt.Fprintf(out, "No URL or search query specified")
}
fmt.Fprintf(out, "\nWeb Rendering Proxy Version %s\n\n", w, h, s, c, ion, version)
}
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 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 loc string
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
}
is, ok := ismap[req.URL.Path]
if !ok || is == nil {
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)
for _, i := range is {
if x >= i.xmin && x <= i.xmax && y >= i.ymin && y <= i.ymax {
loc = i.url
}
}
if len(loc) < 1 {
loc = is[0].url
}
log.Printf("%s ISMAP Redirect to: http://%s%s\n", req.RemoteAddr, req.Context().Value(http.LocalAddrContextKey), loc)
http.Redirect(out, req, fmt.Sprintf("http://%s%s", req.Context().Value(http.LocalAddrContextKey), loc), 301)
}
func capture(gourl string, w int64, h int64, s float64, co int, p int64, i bool, c string, out http.ResponseWriter) {
var nodes []*cdp.Node
ctxx := chromedp.FromContext(ctx)
var pngbuf []byte
var gifbuf bytes.Buffer
var loc string
var res *runtime.RemoteObject
is := make([]Ismap, 0)
var ion string
log.Printf("%s Processing Caputure Request for %s\n", c, gourl)
// Run ChromeDP Magic
err := chromedp.Run(ctx,
emulation.SetDeviceMetricsOverride(int64(float64(w)/s), int64(float64(h)/s), s, false),
chromedp.Navigate(gourl),
chromedp.Evaluate(fmt.Sprintf("window.scrollTo(0, %d);", p*int64(float64(h)*float64(0.9))), &res),
chromedp.Sleep(time.Second*1),
chromedp.CaptureScreenshot(&pngbuf),
chromedp.Location(&loc),
chromedp.Nodes("a", &nodes, chromedp.ByQueryAll))
if err != nil {
log.Printf("%s %s", c, err)
fmt.Fprintf(out, "
%s
", err)
return
}
log.Printf("%s Landed on: %s, Nodes: %d\n", c, loc, len(nodes))
// Process Screenshot Image
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
}
pm := image.NewPaletted(img.Bounds(), palette.WebSafe)
draw.FloydSteinberg.Draw(pm, img.Bounds(), img, image.ZP)
gifbuf.Reset()
err = gif.Encode(&gifbuf, img, nil)
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
}
seq := rand.Intn(9999)
imgpath := fmt.Sprintf("/img/%04d.gif", seq)
mappath := fmt.Sprintf("/map/%04d.map", seq)
log.Printf("%s Encoded GIF image: %s, Size: %dKB\n", c, imgpath, len(gifbuf.Bytes())/1024)
gifmap[imgpath] = gifbuf
// Process Nodes
base, _ := url.Parse(loc)
if i {
fmt.Fprintf(out, "![\"wrp\"](\"%s\")
", mappath, imgpath)
is = append(is, Ismap{xmin: -1, xmax: -1, ymin: -1, ymax: -1, url: fmt.Sprintf("/?url=%s&w=%d&h=%d&s=%1.2f&c=%d&i=on", loc, w, h, s, co)})
ion = "&i=on"
} else {
fmt.Fprintf(out, "\n\n")
}
ismap[mappath] = is
out.(http.Flusher).Flush()
log.Printf("%s Done with caputure for %s\n", c, gourl)
}
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("/img/", imgServer)
http.HandleFunc("/map/", mapServer)
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)
http.ListenAndServe(addr, nil)
}