wrp/wrp.go
2019-05-30 02:03:17 -07:00

156 lines
4.2 KiB
Go

//
// WRP - Web Rendering Proxy
//
// Copyright (c) 2013-2018 Antoni Sawicki
// Copyright (c) 2019 Google LLC
//
package main
import (
"bytes"
"context"
"flag"
"fmt"
_ "image"
"image/gif"
"image/png"
"log"
"math/rand"
"net/http"
"net/url"
"os"
"strconv"
"time"
"github.com/chromedp/cdproto/emulation"
"github.com/chromedp/cdproto/cdp"
"github.com/chromedp/cdproto/dom"
"github.com/chromedp/chromedp"
)
var (
ctx context.Context
cancel context.CancelFunc
gifmap = make(map[string]bytes.Buffer)
)
func pageServer(out http.ResponseWriter, req *http.Request) {
req.ParseForm()
furl := req.Form["url"]
var gourl string
if len(furl) >= 1 && len(furl[0]) > 4 {
gourl = furl[0]
} else {
gourl = "https://www.bbc.com/news"
}
log.Printf("%s Page Reqest for %s [%s]\n", req.RemoteAddr, gourl, req.URL.Path)
out.Header().Set("Content-Type", "text/html")
fmt.Fprintf(out, "<HTML>\n<HEAD><TITLE>WRP %s</TITLE>\n<BODY BGCOLOR=\"#F0F0F0\">", gourl)
fmt.Fprintf(out, "<FORM ACTION=\"/\">URL: <INPUT TYPE=\"TEXT\" NAME=\"url\" VALUE=\"%s\">", gourl)
fmt.Fprintf(out, "<INPUT TYPE=\"SUBMIT\" VALUE=\"Go\"></FORM><P>\n")
if len(gourl) > 4 {
capture(gourl, out)
}
fmt.Fprintf(out, "</BODY>\n</HTML>\n")
}
func imgServer(out http.ResponseWriter, req *http.Request) {
log.Printf("%s Img Request for %s\n", req.RemoteAddr, req.URL.Path)
gifbuf := gifmap[req.URL.Path]
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 haltServer(out http.ResponseWriter, req *http.Request) {
log.Printf("%s Shutdown request received [%s]\n", req.RemoteAddr, req.URL.Path)
out.Header().Set("Content-Type", "text/plain")
fmt.Fprintf(out, "WRP Shutdown")
out.(http.Flusher).Flush()
cancel()
os.Exit(0)
}
func capture(gourl string, out http.ResponseWriter) {
var nodes []*cdp.Node
ctxx := chromedp.FromContext(ctx)
var pngbuf []byte
var gifbuf bytes.Buffer
var loc string
log.Printf("Processing Caputure Request for %s\n", gourl)
// Run ChromeDP Magic
chromedp.Run(ctx,
emulation.SetDeviceMetricsOverride(1024, 768, 1.0, false),
chromedp.Navigate(gourl),
chromedp.Sleep(time.Second*2),
chromedp.CaptureScreenshot(&pngbuf),
chromedp.Location(&loc),
chromedp.Nodes("a", &nodes, chromedp.ByQueryAll))
log.Printf("Landed on: %s, Got %d nodes\n", loc, len(nodes))
// Process Screenshot Image
img, err := png.Decode(bytes.NewReader(pngbuf))
if err != nil {
log.Printf("Failed to decode screenshot: %s\n", err)
fmt.Fprintf(out, "<BR>Unable to decode page screenshot:<BR>%s<BR>\n", err)
return
}
gifbuf.Reset()
err = gif.Encode(&gifbuf, img, nil)
if err != nil {
log.Printf("Failed to encode GIF: %s\n", err)
fmt.Fprintf(out, "<BR>Unable to encode GIF:<BR>%s<BR>\n", err)
return
}
imgpath := fmt.Sprintf("/img/%04d.gif", rand.Intn(9999))
gifmap[imgpath] = gifbuf
// Process Nodes
base, _ := url.Parse(loc)
fmt.Fprintf(out, "<IMG SRC=\"%s\" ALT=\"wrp\" USEMAP=\"#map\">\n<MAP NAME=\"map\">\n", imgpath)
log.Printf("Image path will be: %s", imgpath)
for _, n := range nodes {
b, err := dom.GetBoxModel().WithNodeID(n.NodeID).Do(cdp.WithExecutor(ctx, ctxx.Target))
if err != nil {
continue
}
tgt, err := base.Parse(n.AttributeValue("href"))
if err != nil {
continue
}
target := fmt.Sprintf("/?url=%s", tgt)
if len(b.Content) > 6 && len(target) > 7 {
fmt.Fprintf(out, "<AREA SHAPE=\"RECT\" COORDS=\"%.f,%.f,%.f,%.f\" ALT=\"%s\" TITLE=\"%s\" HREF=\"%s\">\n",
b.Content[0], b.Content[1], b.Content[4], b.Content[5], n.AttributeValue("href"), n.AttributeValue("href"), target)
}
}
fmt.Fprintf(out, "</MAP>\n")
out.(http.Flusher).Flush()
log.Printf("Done with caputure for %s\n", gourl)
}
func main() {
ctx, cancel = chromedp.NewContext(context.Background())
defer cancel()
var addr string
flag.StringVar(&addr, "l", ":8080", "Listen address:port, default :8080")
flag.Parse()
rand.Seed(time.Now().UnixNano())
http.HandleFunc("/", pageServer)
http.HandleFunc("/img/", imgServer)
http.HandleFunc("/favicon.ico", http.NotFound)
http.HandleFunc("/halt", haltServer)
log.Printf("Starting http server on %s\n", addr)
http.ListenAndServe(addr, nil)
}