steer

Use steer to control your chrome (the browser)

Installation

npm install steer

Dependencies

You will need to install google-chrome (not chromeium) on your machine first. You can find it here: https://www.google.com/intl/en/chrome/browser/

Example

This example starts a google-chrome browser navigates to http://google.com and then query the document.title value.

var steer = require('steer');
var path = require('path');
 
var chrome = steer({
  cache: path.resolve(__dirname, 'cache'),
  inspectorPort: 7510
});
 
chrome.once('open', function () {
  chrome.inspector.Page.enable(function (err) {
    chrome.inspector.Page.navigate('http://google.com', function(err) {
      chrome.inspector.Page.once('domContentEventFired', function () {
        chrome.inspector.Runtime.evaluate('(function () { return document.title; })();', function (err, res) {
          console.log(res.result.value); // Google
 
          chrome.close();
        });
      });
    });
  });
});

As you can see the API is quite complicated but you do pretty anything with it. This module supports two binding APIs:

• WebKit remote inspector http://developer.chrome.com/extensions/api_index.html
• Chrome Extension API http://developer.chrome.com/extensions/api_index.html

I would personally recomed using WebKit remote inspector API, this is what the "Chrome DevTools" uses, so you should be familiar with what's possible. However it can do more than just what the GUI allows but sometimes you have to use the Extension API as well.

Futhermore there are modules there abstacts the complicated API away, here are some:

• steer-screenshot
• steer-evaluate
• steer-loaded
• steer-reset

Documentation

When requireing this module you get a steer constructor.

var steer = require('steer');

When createing a new instance a google-chrome process is stared with it own private profile. This means it won't interfere with other google-chrome processes.

var chrome = steer(settings, [callback]);

The steer contructor takes a warity of settings where some are optional.

• cache (required). The directory where the cached files will be stored. This should be reused when your application craches.
• inspectorPort (required). A free port number for localhost used for the WebKit inspector protocol communication.
• userAgent (optional). This is the user-agent header chrome will be using. If not set this will just the long user-agent chrome will usually send.
• blocked (optional). An array of hostnames there will return a 404. This could be ad sites or other websites you don't which to spend time on.
• size (optional). This will be the inner size of the chrome frame. By default this is [800, 600] where 800 is the width and 600 is the height.
• permissions (optional). This is an array of the permissions there should be given to the chrome extension there binds this module to the extension API.

var chrome = steer({
  cache: path.resolve(__dirname, 'cache'),
  inspectorPort: 7510,
  userAgent: 'SteerBot/1.0',
  blocked: [
    'googleadservices.com',
    'google-analytics.com'
  ],
  size: [1280, 1024],
  permissions: [
    'browsingData'
  ]
});

chrome.inspector

An insterface for the WebKit remote inspector API, for documentation see the inspector module.

For example, to navigate to a page:

chrome.inspector.Page.navigate('http://google.com', function(err) {
  if (err) throw err;
 
  // chrome is now at google.com, but the page might stil be loading
});

Another example, to evaluate some javascript within the browser:

inspector.Runtime.evaluate(
  '(function () { return document.innerHTML.length; })();',
  function (err, response) {
    console.log(response.result.value);
  }
);

chrome.extension

A simple interface for the chrome extension API. For the full API see http://developer.chrome.com/extensions/api_index.html

For example, to take a screenshot do:

// Note this requires `taps` permissions
 
var BASE64_URL_PREFIX = 'data:image/jpeg;base64,';
 
chrome.extension.send('chrome.tabs.captureVisibleTab', null, { quality: 60 }, function(err, img) {
  var data = new Buffer(img.slice(BASE64_URL_PREFIX.length), 'base64');
  fs.writeFile('image.jpeg', data, function () {
    // screenshot saved
  });
});

Another example, to clear the cookies and all other sort of browser states do:

// Note this requires `browsingData` permissions
 
chrome.extension.send('chrome.browsingData.remove', {}, {
  'webSQL': true,
  'cookies': true,
  'indexedDB': true
}, function (err) {
  if (err) throw err;
 
  // stuff removed
});

chrome.process

The standard node process object for the google-chrome process.

chrome.once('open', function () {
  chrome.process.stdout.pipe(process.stdout);
  chrome.process.stderr.pipe(process.stderr);
});

chrome.close([callback])

Close the browser in a gracefull way, this will cleanup the temporary directories and shutdown the a server used for blocking requests and finally close the browser. The optional callback is just attached to the close event.

chrome.destory()

This will simply kill the browser. You should call process.exit() after this as there will still be active stuff running.

chrome.on('open')

Everything is ready, you can start navigating the browser now. Until this event fires you should expect inspector, extensions and process to be null.

chrome.on('close')

This event emits when the browser closes.

chrome.on('error')

An error occurred. As there are many things running in order to manage the remote connection (actually there are more) this can be caused by quite a lot.

License

The software is license under "MIT"

Copyright (c) 2014 Peter V. T. Schlegel

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.