vk-auth/lib/scrapper/index.js

authorization in VK social network as standalone application. Uses PhantomJS for opening VK auth form and entering credentials

//script that is executed by phantomjs to get VK access token
//uses system stdout and stderr for returning of execution result

var
    system = require('system'),
    args = system.args,
    stderr = system.stderr,
    stdout = system.stdout,
    page = require('webpage').create(),

//reading variables passed as parameters for phantomjs
    login = decodeURIComponent(args[1]),
    password = decodeURIComponent(args[2]),
    clientId = decodeURIComponent(args[3]),
    scope = decodeURIComponent(args[4]);

var output = {
    error: function () {
        stderr.write(Array.prototype.join.call(arguments, ' '));
    },
    success: function () {
        stdout.write(Array.prototype.join.call(arguments, ' '));
    }
}

var exitWithError = function (errorMessage) {
    page.onUrlChanged = null;
    if (!errorMessage) {
        errorMessage = 'Request timeout error';
    }

    //writing error message to stderr
    output.error(errorMessage);

    //end callback execution and close phantomjs
    setTimeout(phantom.exit, 1);
};


//that enters user's credentials on VK login page
var submitLoginForm = function (login, pass) {
    try {
        document.getElementsByName("email")[0].value = login;
        document.getElementsByName("pass")[0].value = pass;
        document.getElementById("login_submit").submit();
    } catch (e) {
    }
};

//presses "allow access" button on VK permissions page
var confirmPermissions = function () {
    try {
        var allowButton = document.querySelector(".flat_button.fl_r.button_indent");
        allowButton.click();
    } catch (e) {
    }
};

//check url with regexp of permissions page url
var isPermissionsPage = function (url) {
    var permissionsPageExp = /^https:\/\/oauth.vk.com\/authorize.*__q_hash=/;
    return permissionsPageExp.test(url);
};

//check url with regexp of access token page
var isAccessTokenPage = function (url) {
    var tokenPageExp = /https:\/\/oauth.vk.com\/blank.html#access_token/;
    return tokenPageExp.test(url);
};

//check url with regexp of page with incorrectly entered user credentials
var isIncorrectCredPage = function (url) {
    var incorrectCredExp = /^https:\/\/oauth.vk.com\/authorize.*&email=/;
    return incorrectCredExp.test(url);
};

//url of VK authorization page
var authUrl = 'https://oauth.vk.com/oauth/authorize?client_id=' + clientId + '&scope=' + scope + '&redirect_uri=https://oauth.vk.com/blank.html&response_type=token';

page.open(authUrl, function (status) {
    if (status !== 'success') {
        exitWithError('Unable to open authorization page');
    } else {

        var pageResponseTimeout;

        page.onUrlChanged = function (currentUrl) {
            clearTimeout(pageResponseTimeout);

            if (isPermissionsPage(currentUrl)) {

                setTimeout(function () {
                    page.evaluate(confirmPermissions);

                   pageResponseTimeout = setTimeout(exitWithError, 15000);
                }, 1500);
            } else {
                if (isAccessTokenPage(currentUrl)) {

                    output.success(currentUrl);
                    page.onUrlChanged = null;
                    setTimeout(phantom.exit, 1);
                } else {
                    if (isIncorrectCredPage(currentUrl)) {
                        exitWithError('Incorrect login or password');
                    } else {
                        exitWithError('Unexpected authorization error');
                    }
                }
            }
        };

        //executing login function on loaded page
        page.evaluate(submitLoginForm, login, password);

        pageResponseTimeout = setTimeout(exitWithError, 15000);
    }
});