# session The `session` object is a property of [`webContents`](web-contents.md) which is a property of [`BrowserWindow`](browser-window.md). You can access it through an instance of `BrowserWindow`. For example: ```javascript var BrowserWindow = require('browser-window'); var win = new BrowserWindow({ width: 800, height: 600 }); win.loadUrl("http://github.com"); var session = win.webContents.session ``` ## Events ### Event: 'will-download' * `event` Event * `item` [DownloadItem](download-item.md) * `webContents` [WebContents](web-contents.md) Fired when Electron is about to download `item` in `webContents`. Calling `event.preventDefault()` will cancel the download. ```javascript session.on('will-download', function(event, item, webContents) { event.preventDefault(); require('request')(item.getUrl(), function(data) { require('fs').writeFileSync('/somewhere', data); }); }); ``` ## Methods The `session` object has the following methods: ### `session.cookies` The `cookies` gives you ability to query and modify cookies. For example: ```javascript var BrowserWindow = require('browser-window'); var win = new BrowserWindow({ width: 800, height: 600 }); win.loadUrl('https://github.com'); win.webContents.on('did-finish-load', function() { // Query all cookies. win.webContents.session.cookies.get({}, function(error, cookies) { if (error) throw error; console.log(cookies); }); // Query all cookies associated with a specific url. win.webContents.session.cookies.get({ url : "http://www.github.com" }, function(error, cookies) { if (error) throw error; console.log(cookies); }); // Set a cookie with the given cookie data; // may overwrite equivalent cookies if they exist. win.webContents.session.cookies.set( { url : "http://www.github.com", name : "dummy_name", value : "dummy"}, function(error, cookies) { if (error) throw error; console.log(cookies); }); }); ``` ### `session.cookies.get(details, callback)` `details` Object, properties: * `url` String - Retrieves cookies which are associated with `url`. Empty implies retrieving cookies of all urls. * `name` String - Filters cookies by name * `domain` String - Retrieves cookies whose domains match or are subdomains of `domains` * `path` String - Retrieves cookies whose path matches `path` * `secure` Boolean - Filters cookies by their Secure property * `session` Boolean - Filters out session or persistent cookies. * `callback` Function - function(error, cookies) * `error` Error * `cookies` Array - array of `cookie` objects, properties: * `name` String - The name of the cookie. * `value` String - The value of the cookie. * `domain` String - The domain of the cookie. * `host_only` String - Whether the cookie is a host-only cookie. * `path` String - The path of the cookie. * `secure` Boolean - Whether the cookie is marked as Secure (typically HTTPS). * `http_only` Boolean - Whether the cookie is marked as HttpOnly. * `session` Boolean - Whether the cookie is a session cookie or a persistent cookie with an expiration date. * `expirationDate` Double - (Option) The expiration date of the cookie as the number of seconds since the UNIX epoch. Not provided for session cookies. ### `session.cookies.set(details, callback)` `details` Object, properties: * `url` String - Retrieves cookies which are associated with `url` * `name` String - The name of the cookie. Empty by default if omitted. * `value` String - The value of the cookie. Empty by default if omitted. * `domain` String - The domain of the cookie. Empty by default if omitted. * `path` String - The path of the cookie. Empty by default if omitted. * `secure` Boolean - Whether the cookie should be marked as Secure. Defaults to false. * `session` Boolean - Whether the cookie should be marked as HttpOnly. Defaults to false. * `expirationDate` Double - The expiration date of the cookie as the number of seconds since the UNIX epoch. If omitted, the cookie becomes a session cookie. * `callback` Function - function(error) * `error` Error ### `session.cookies.remove(details, callback)` * `details` Object, proprties: * `url` String - The URL associated with the cookie * `name` String - The name of cookie to remove * `callback` Function - function(error) * `error` Error ### `session.clearCache(callback)` * `callback` Function - Called when operation is done Clears the session’s HTTP cache. ### `session.clearStorageData([options, ]callback)` * `options` Object (optional), proprties: * `origin` String - Should follow `window.location.origin`’s representation `scheme://host:port`. * `storages` Array - The types of storages to clear, can contain: `appcache`, `cookies`, `filesystem`, `indexdb`, `local storage`, `shadercache`, `websql`, `serviceworkers` * `quotas` Array - The types of quotas to clear, can contain: `temporary`, `persistent`, `syncable`. * `callback` Function - Called when operation is done. Clears the data of web storages. ### `session.setProxy(config, callback)` * `config` String * `callback` Function - Called when operation is done. If `config` is a PAC url, it is used directly otherwise `config` is parsed based on the following rules indicating which proxies to use for the session. ``` config = scheme-proxies[";"] scheme-proxies = ["="] url-scheme = "http" | "https" | "ftp" | "socks" proxy-uri-list = [","] proxy-uri = ["://"][":"] For example: "http=foopy:80;ftp=foopy2" -- use HTTP proxy "foopy:80" for http:// URLs, and HTTP proxy "foopy2:80" for ftp:// URLs. "foopy:80" -- use HTTP proxy "foopy:80" for all URLs. "foopy:80,bar,direct://" -- use HTTP proxy "foopy:80" for all URLs, failing over to "bar" if "foopy:80" is unavailable, and after that using no proxy. "socks4://foopy" -- use SOCKS v4 proxy "foopy:1080" for all URLs. "http=foopy,socks5://bar.com -- use HTTP proxy "foopy" for http URLs, and fail over to the SOCKS5 proxy "bar.com" if "foopy" is unavailable. "http=foopy,direct:// -- use HTTP proxy "foopy" for http URLs, and use no proxy if "foopy" is unavailable. "http=foopy;socks=foopy2 -- use HTTP proxy "foopy" for http URLs, and use socks4://foopy2 for all other URLs. ``` ### `session.setDownloadPath(path)` * `path` String - The download location Sets download saving directory. By default, the download directory will be the `Downloads` under the respective app folder. ### `session.enableNetworkEmulation(options)` * `options` Object * `offline` Boolean - Whether to emulate network outage. * `latency` Double - RTT in ms * `downloadThroughput` Double - Download rate in Bps * `uploadThroughput` Double - Upload rate in Bps Emulates network with the given configuration for the `session`. ```javascript // To emulate a GPRS connection with 50kbps throughput and 500 ms latency. window.webContents.session.enableNetworkEmulation({ latency: 500, downloadThroughput: 6400, uploadThroughput: 6400 }); // To emulate a network outage. window.webContents.session.enableNetworkEmulation({offline: true}); ``` ### `session.disableNetworkEmulation` Disables any network emulation already active for the `session`. Resets to the original network configuration. ### `session.setCertificateVerifier(handler)` * `handler` Function * `hostname` String * `certificate` Object * `data` Buffer - PEM encoded data * `issuerName` String * `callback` Function Sets the certificate verifier for the `session`, will be called whenever a server certificate verification is requested by the network layer with `hostname`, `certificate` and `callback`. `callback` should be called with a boolean response to indicate continuation or cancellation of the request. ```js var handler = function(hostname, certificate, callback) { if (hostname == "github.com") { // verification logic callback(true) } callback(false) } window.webContents.session.setCertificateVerifier(handler) ``` ### `session.removeCertificateVerifier()` Removes the certificate verifier provided for the `session`.