WebLoop

Scriptable, headless WebKit with a Go API. Like PhantomJS, but for Go. Render static HTML versions of dynamic JavaScript applications, automate browsing, run arbitrary JavaScript in a browser window context, etc., all from Go or the command line.

• Documentation on Sourcegraph

Requirements

• Go >= 1.2rc1 (due to #3250)
• WebKitGTK+ >= 2.0.0
• go-webkit2

For instructions on installing these dependencies, see the go-webkit2 README.

To install WebLoop, run: go get github.com/sourcegraph/webloop/...

Usage

Static HTML rendering reverse proxy

The included command static-reverse-proxy proxies a dynamic JavaScript application and serves an equivalent statically rendered HTML website to clients. Run it with:

$ go install github.com/sourcegraph/webloop/...
$ static-reverse-proxy

For example, to proxy a dynamic application at http://example.com and serve an equivalent statically rendered HTML website on http://localhost:13000, run:

$ static-reverse-proxy -target=http://example.com -http=:13000

Run with -h to see more information.

Rendering static HTML from a dynamic, single-page AngularJS app

StaticRenderer is an HTTP handler that serves a static HTML version of a dynamic web application. Use it like:

staticHandler := &webloop.StaticRenderer{
        TargetBaseURL:         "http://dynamic-app.example.com",
        WaitTimeout:           time.Second * 3,
        ReturnUnfinishedPages: true
}
http.Handle("/", staticHandler)

See the examples/angular-static-seo/ directory for example code. Run the included binary with:

$ go run examples/angular-static-seo/server.go

Instructions will be printed for accessing the 2 local demo HTTP servers. Run with -h to see more information.

Operating a headless WebKit and running arbitrary JavaScript in the page

package webloop_test

import (
	"fmt"
	"os"
	"runtime"

	"github.com/gotk3/gotk3/gtk"
	"github.com/sourcegraph/webloop"
)

func Example() {
	gtk.Init(nil)
	go func() {
		runtime.LockOSThread()
		gtk.Main()
	}()

	ctx := webloop.New()
	view := ctx.NewView()
	defer view.Close()
	view.Open("http://google.com")
	err := view.Wait()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to load URL: %s", err)
		os.Exit(1)
	}
	res, err := view.EvaluateJavaScript("document.title")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to run JavaScript: %s", err)
		os.Exit(1)
	}
	fmt.Printf("JavaScript returned: %q\n", res)
	// output:
	// JavaScript returned: "Google"
}

See webloop_test.go for more examples.

TODO

• Set up CI testing. This is difficult because all of the popular CI services run older versions of Ubuntu that make it difficult to install WebKitGTK+ >= 2.0.0.
• Add the ability for JavaScript code to send messages to WebLoop, similar to [PhantomJS's callPhantom] (https://github.com/ariya/phantomjs/wiki/API-Reference-WebPage#oncallback) mechanism.

Users

• WebLoop is used to render static HTML pages on Sourcegraph for search engine crawlers

Contributors

See the AUTHORS file for a list of contributors.

Submit contributions via GitHub pull request. Patches should include tests and should pass golint.