This is primarly an auto-generated client library for communicating with a Google Chrome Browser over their remote client debugger protocol. Note that their documentation is partially incorrect and does not contain a lot of the API calls that are actually available.
Because I'm lazy and there are hundereds of different custom types and API methods, this library has been automatically generated using their protocol.json.
The gcdapigen program was created to generate types, event types and commands for gcd.
June: Updated to the latest protocol.json, gcdapigen will download the js_protocol and browser_protocol json files from chromium repositories. It will also fix them up and merge them into a single file and output it. Note that several API endpoints have been removed and method calls have changed since the last update.
February: I created a new library for actual automation purposes. If you want something with more functionality and more usability I suggest checking out autogcd.
gcd requires the gcdapi and gcdmessage packages. gcdapi is the auto-generated API. gcdmessage is the glue between gcd and gcdapi so we can keep the packages clean.
The API consists of of synchronous requests, asynchronous requests / events. Synchronous requests are handled by using non-buffered channels and methods can be called and will return once the value is available. Events are handled by subscribing the response method type and calling the API's "Enable()" such as:
target, err := debugger.NewTab()
if err != nil {
log.Fatalf("error getting new tab: %s\n", err)
}
console := target.Console
target.Subscribe("Console.messageAdded", func(target *ChromeTarget, v []byte) {
msg := &gcdapi.ConsoleMessageAddedEvent{}
err := json.Unmarshal(v, msg)
if err != nil {
log.Fatalf("error unmarshalling event data: %v\n", err)
}
log.Printf("METHOD: %s\n", msg.Method)
eventData := msg.Params.Message
log.Printf("Got event: %s\n", eventData)
})
console.Enable()
// recv events
// console.Disable()For a full list of api methods, types, event types & godocs: Documentation
Loading a page using the Page API.
package main
import (
"github.com/wirepair/gcd"
"log"
"sync"
)
func main() {
var wg sync.WaitGroup
wg.Add(1)
debugger := gcd.NewChromeDebugger()
// start process, specify a tmp profile path so we get a fresh profiled browser
// set port 9222 as the debug port
debugger.StartProcess("C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe", "C:\\tmp\\", "9222")
defer debugger.ExitProcess() // exit when done
targets, err := debugger.GetTargets() // get the 'targets' or tabs/background processes
if err != nil {
log.Fatalf("error getting targets: %s\n", err)
}
target := targets[0] // take the first one
//subscribe to page load
target.Subscribe("Page.loadEventFired", func(targ *gcd.ChromeTarget, v []byte) {
wg.Done() // page loaded, we can exit now
// if you wanted to inspect the full response data, you could do that here
})
// get the Page API and enable it
if _, err := target.Page.Enable(); err != nil {
log.Fatalf("error getting page: %s\n", err)
}
ret, err := target.Page.Navigate("http://www.veracode.com") // navigate
if err != nil {
log.Fatalf("Error navigating: %s\n", err)
}
log.Printf("ret: %#v\n", ret)
wg.Wait() // wait for page load
}Getting a document from a target.
package main
import (
"github.com/wirepair/gcd"
"log"
)
func main() {
debugger := gcd.NewChromeDebugger()
debugger.StartProcess("C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe", "C:\\tmp\\", "9222")
defer debugger.ExitProcess()
target, err := debugger.NewTab()
if err != nil {
log.Fatalf("error getting new tab: %s\n", err)
}
dom := target.DOM
r, err := dom.GetDocument()
if err != nil {
log.Fatalf("error: %s\n", err)
}
log.Printf("NodeID: %d Node Name: %s, URL: %s\n", r.NodeId, r.NodeName, r.DocumentURL)
}Create 5 tabs, navigate to URLs, wait for them to load, take screen shot
package main
import (
"encoding/base64"
"fmt"
"github.com/wirepair/gcd"
"log"
"net/url"
"os"
"sync"
"time"
)
const (
numTabs = 5
)
var debugger *gcd.Gcd
var wg sync.WaitGroup
func main() {
var err error
urls := []string{"http://www.google.com", "http://www.veracode.com", "http://www.microsoft.com", "http://bbc.co.uk", "http://www.reddit.com/r/golang"}
debugger = gcd.NewChromeDebugger()
debugger.StartProcess("C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe", "C:\\tmp\\", "9222")
defer debugger.ExitProcess()
targets := make([]*gcd.ChromeTarget, numTabs)
for i := 0; i < numTabs; i++ {
wg.Add(1)
targets[i], err = debugger.NewTab()
if err != nil {
log.Fatalf("error getting targets")
}
page := targets[i].Page
page.Enable()
targets[i].Subscribe("Page.loadEventFired", PageLoaded)
page.Navigate(urls[i])
}
wg.Wait()
for i := 0; i < numTabs; i++ {
TakeScreenShot(targets[i])
}
}
func PageLoaded(target *gcd.ChromeTarget, event []byte) {
wg.Done()
}
func TakeScreenShot(target *gcd.ChromeTarget) {
dom := target.DOM
page := target.Page
doc, err := dom.GetDocument()
if err != nil {
fmt.Errorf("error getting doc: %s\n", err)
return
}
debugger.ActivateTab(target)
time.Sleep(1 * time.Second) // give it a sec to paint
u, urlErr := url.Parse(doc.DocumentURL)
if urlErr != nil {
fmt.Errorf("error parsing url: %s\n", urlErr)
return
}
fmt.Printf("Taking screen shot of: %s\n", u.Host)
img, errCap := page.CaptureScreenshot()
if errCap != nil {
fmt.Errorf("error getting doc: %s\n", errCap)
return
}
imgBytes, errDecode := base64.StdEncoding.DecodeString(img)
if errDecode != nil {
fmt.Errorf("error decoding image: %s\n", errDecode)
return
}
f, errFile := os.Create(u.Host + ".png")
defer f.Close()
if errFile != nil {
fmt.Errorf("error creating image file: %s\n", errFile)
return
}
f.Write(imgBytes)
}The MIT License (MIT)
Copyright (c) 2016 isaac dawson
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.