electron/docs/api/session.md

session

Manage browser sessions, cookies, cache, proxy settings, etc.

The session module can be used to create new Session objects.

You can also access the session of existing pages by using the session property of WebContents, or from the session module.

const {BrowserWindow} = require('electron')

let win = new BrowserWindow({width: 800, height: 600})
win.loadURL('http://github.com')

const ses = win.webContents.session
console.log(ses.getUserAgent())

Methods

The session module has the following methods:

session.fromPartition(partition[, options])

• partition String
• options Object
  • cache Boolean - Whether to enable cache.

Returns Session - A session instance from partition string. When there is an existing Session with the same partition, it will be returned; othewise a new Session instance will be created with options.

If partition starts with persist:, the page will use a persistent session available to all pages in the app with the same partition. if there is no persist: prefix, the page will use an in-memory session. If the partition is empty then default session of the app will be returned.

To create a Session with options, you have to ensure the Session with the partition has never been used before. There is no way to change the options of an existing Session object.

Properties

The session module has the following properties:

session.defaultSession

A Session object, the default session object of the app.

Class: Session

Get and set properties of a session.

You can create a Session object in the session module:

const {session} = require('electron')
const ses = session.fromPartition('persist:name')
console.log(ses.getUserAgent())

Instance Events

The following events are available on instances of Session:

Event: 'will-download'

• event Event
• item DownloadItem
• webContents WebContents

Emitted when Electron is about to download item in webContents.

Calling event.preventDefault() will cancel the download and item will not be available from next tick of the process.

const {session} = require('electron')
session.defaultSession.on('will-download', (event, item, webContents) => {
  event.preventDefault()
  require('request')(item.getURL(), (data) => {
    require('fs').writeFileSync('/somewhere', data)
  })
})

Instance Methods

The following methods are available on instances of Session:

ses.getCacheSize(callback)

• callback Function
  • size Integer - Cache size used in bytes.

Returns the session's current cache size.

ses.clearCache(callback)

• callback Function - Called when operation is done

Clears the session’s HTTP cache.

ses.clearStorageData([options, callback])

• options Object (optional)
  • origin String - Should follow window.location.origin’s representation scheme://host:port.
  • storages String[] - The types of storages to clear, can contain: appcache, cookies, filesystem, indexdb, local storage, shadercache, websql, serviceworkers
  • quotas String[] - The types of quotas to clear, can contain: temporary, persistent, syncable.
• callback Function (optional) - Called when operation is done.

Clears the data of web storages.

ses.flushStorageData()

Writes any unwritten DOMStorage data to disk.

ses.setProxy(config, callback)

• config Object
  • pacScript String - The URL associated with the PAC file.
  • proxyRules String - Rules indicating which proxies to use.
  • proxyBypassRules String - Rules indicating which URLs should bypass the proxy settings.
• callback Function - Called when operation is done.

Sets the proxy settings.

When pacScript and proxyRules are provided together, the proxyRules option is ignored and pacScript configuration is applied.

The proxyRules has to follow the rules below:

proxyRules = schemeProxies[";"<schemeProxies>]
schemeProxies = [<urlScheme>"="]<proxyURIList>
urlScheme = "http" | "https" | "ftp" | "socks"
proxyURIList = <proxyURL>[","<proxyURIList>]
proxyURL = [<proxyScheme>"://"]<proxyHost>[":"<proxyPort>]

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.

The proxyBypassRules is a comma separated list of rules described below:

• [ URL_SCHEME "://" ] HOSTNAME_PATTERN [ ":" <port> ]

  Match all hostnames that match the pattern HOSTNAME_PATTERN.

  Examples: "foobar.com", "foobar.com", ".foobar.com", "foobar.com:99", "https://x..y.com:99"

• "." HOSTNAME_SUFFIX_PATTERN [ ":" PORT ]

  Match a particular domain suffix.

  Examples: ".google.com", ".com", "http://.google.com"

• [ SCHEME "://" ] IP_LITERAL [ ":" PORT ]

  Match URLs which are IP address literals.

  Examples: "127.0.1", "[0:0::1]", "[::1]", "http://[::1]:99"

• IP_LITERAL "/" PREFIX_LENGHT_IN_BITS

  Match any URL that is to an IP literal that falls between the given range. IP range is specified using CIDR notation.

  Examples: "192.168.1.1/16", "fefe:13::abc/33".

• <local>

  Match local addresses. The meaning of <local> is whether the host matches one of: "127.0.0.1", "::1", "localhost".

ses.resolveProxy(url, callback)

• url URL
• callback Function

Resolves the proxy information for url. The callback will be called with callback(proxy) when the request is performed.

ses.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.

ses.enableNetworkEmulation(options)

• options Object
  • offline Boolean (optional) - Whether to emulate network outage. Defaults to false.
  • latency Double (optional) - RTT in ms. Defaults to 0 which will disable latency throttling.
  • downloadThroughput Double (optional) - Download rate in Bps. Defaults to 0 which will disable download throttling.
  • uploadThroughput Double (optional) - Upload rate in Bps. Defaults to 0 which will disable upload throttling.

Emulates network with the given configuration for the session.

// 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})

ses.disableNetworkEmulation()

Disables any network emulation already active for the session. Resets to the original network configuration.

ses.setCertificateVerifyProc(proc)

• proc Function

Sets the certificate verify proc for session, the proc will be called with proc(hostname, certificate, callback) whenever a server certificate verification is requested. Calling callback(true) accepts the certificate, calling callback(false) rejects it.

Calling setCertificateVerifyProc(null) will revert back to default certificate verify proc.

const {BrowserWindow} = require('electron')
let win = new BrowserWindow()

win.webContents.session.setCertificateVerifyProc((hostname, cert, callback) => {
  callback(hostname === 'github.com')
})

ses.setPermissionRequestHandler(handler)

• handler Function
  • webContents Object - WebContents requesting the permission.
  • permission String - Enum of 'media', 'geolocation', 'notifications', 'midiSysex', 'pointerLock', 'fullscreen', 'openExternal'.
  • callback Function - Allow or deny the permission.

Sets the handler which can be used to respond to permission requests for the session. Calling callback(true) will allow the permission and callback(false) will reject it.

const {session} = require('electron')
session.fromPartition('some-partition').setPermissionRequestHandler((webContents, permission, callback) => {
  if (webContents.getURL() === 'some-host' && permission === 'notifications') {
    return callback(false) // denied.
  }

  callback(true)
})

ses.clearHostResolverCache([callback])

• callback Function (optional) - Called when operation is done.

Clears the host resolver cache.

ses.allowNTLMCredentialsForDomains(domains)

• domains String - A comma-seperated list of servers for which integrated authentication is enabled.

Dynamically sets whether to always send credentials for HTTP NTLM or Negotiate authentication.

const {session} = require('electron')
// consider any url ending with `example.com`, `foobar.com`, `baz`
// for integrated authentication.
session.defaultSession.allowNTLMCredentialsForDomains('*example.com, *foobar.com, *baz')

// consider all urls for integrated authentication.
session.defaultSession.allowNTLMCredentialsForDomains('*')

ses.setUserAgent(userAgent[, acceptLanguages])

• userAgent String
• acceptLanguages String (optional)

Overrides the userAgent and acceptLanguages for this session.

The acceptLanguages must a comma separated ordered list of language codes, for example "en-US,fr,de,ko,zh-CN,ja".

This doesn't affect existing WebContents, and each WebContents can use webContents.setUserAgent to override the session-wide user agent.

ses.getUserAgent()

Returns String - The user agent for this session.

ses.getBlobData(identifier, callback)

• identifier String - Valid UUID.
• callback Function
  • result Buffer - Blob data.

Returns Blob - The blob data associated with the identifier.

Instance Properties

The following properties are available on instances of Session:

ses.cookies

A Cookies object for this session.

ses.webRequest

A WebRequest object for this session.

ses.protocol

A Protocol object (an instance of protocol module) for this session.

const {app, session} = require('electron')
const path = require('path')

app.on('ready', function () {
  const protocol = session.fromPartition('some-partition').protocol
  protocol.registerFileProtocol('atom', function (request, callback) {
    var url = request.url.substr(7)
    callback({path: path.normalize(`${__dirname}/${url}`)})
  }, function (error) {
    if (error) console.error('Failed to register protocol')
  })
})

Class: Cookies

Query and modify a session's cookies.

Instances of the Cookies class are accessed by using cookies property of a Session.

For example:

const {session} = require('electron')

// Query all cookies.
session.defaultSession.cookies.get({}, (error, cookies) => {
  console.log(error, cookies)
})

// Query all cookies associated with a specific url.
session.defaultSession.cookies.get({url: 'http://www.github.com'}, (error, cookies) => {
  console.log(error, cookies)
})

// Set a cookie with the given cookie data;
// may overwrite equivalent cookies if they exist.
const cookie = {url: 'http://www.github.com', name: 'dummy_name', value: 'dummy'}
session.defaultSession.cookies.set(cookie, (error) => {
  if (error) console.error(error)
})

Instance Events

The following events are available on instances of Cookies:

Event: 'changed'

• event Event
• cookie Object - The cookie that was changed
• cause String - The cause of the change with one of the following values:
  • explicit - The cookie was changed directly by a consumer's action.
  • overwrite - The cookie was automatically removed due to an insert operation that overwrote it.
  • expired - The cookie was automatically removed as it expired.
  • evicted - The cookie was automatically evicted during garbage collection.
  • expired-overwrite - The cookie was overwritten with an already-expired expiration date.
• removed Boolean - true if the cookie was removed, false otherwise.

Emitted when a cookie is changed because it was added, edited, removed, or expired.

Instance Methods

The following methods are available on instances of Cookies:

cookies.get(filter, callback)

• filter Object
  • url String (optional) - Retrieves cookies which are associated with url. Empty implies retrieving cookies of all urls.
  • name String (optional) - Filters cookies by name.
  • domain String (optional) - Retrieves cookies whose domains match or are subdomains of domains
  • path String (optional) - Retrieves cookies whose path matches path.
  • secure Boolean (optional) - Filters cookies by their Secure property.
  • session Boolean (optional) - Filters out session or persistent cookies.
• callback Function

Sends a request to get all cookies matching details, callback will be called with callback(error, cookies) on complete.

cookies is an Array of cookie objects.

• cookie Object
  • name String - The name of the cookie.
  • value String - The value of the cookie.
  • domain String - The domain of the cookie.
  • hostOnly 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.
  • httpOnly Boolean - Whether the cookie is marked as HTTP only.
  • session Boolean - Whether the cookie is a session cookie or a persistent cookie with an expiration date.
  • expirationDate Double (optional) - The expiration date of the cookie as the number of seconds since the UNIX epoch. Not provided for session cookies.

cookies.set(details, callback)

• details Object
  • url String - The url to associate the cookie with.
  • 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.
  • httpOnly Boolean - Whether the cookie should be marked as HTTP only. Defaults to false.
  • expirationDate Double - The expiration date of the cookie as the number of seconds since the UNIX epoch. If omitted then the cookie becomes a session cookie and will not be retained between sessions.
• callback Function

Sets a cookie with details, callback will be called with callback(error) on complete.

cookies.remove(url, name, callback)

• url String - The URL associated with the cookie.
• name String - The name of cookie to remove.
• callback Function

Removes the cookies matching url and name, callback will called with callback() on complete.

Class: WebRequest

Intercept and modify the contents of a request at various stages of its lifetime.

Instances of the WebRequest class are accessed by using the webRequest property of a Session.

The methods of WebRequest accept an optional filter and a listener. The listener will be called with listener(details) when the API's event has happened. The details object describes the request. Passing null as listener will unsubscribe from the event.

The filter object has a urls property which is an Array of URL patterns that will be used to filter out the requests that do not match the URL patterns. If the filter is omitted then all requests will be matched.

For certain events the listener is passed with a callback, which should be called with a response object when listener has done its work.

An example of adding User-Agent header for requests:

const {session} = require('electron')

// Modify the user agent for all requests to the following urls.
const filter = {
  urls: ['https://*.github.com/*', '*://electron.github.io']
}

session.defaultSession.webRequest.onBeforeSendHeaders(filter, (details, callback) => {
  details.requestHeaders['User-Agent'] = 'MyAgent'
  callback({cancel: false, requestHeaders: details.requestHeaders})
})

Instance Methods

The following methods are available on instances of WebRequest:

webRequest.onBeforeRequest([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details, callback) when a request is about to occur.

• details Object
  • id Integer
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • uploadData Array (optional)
• callback Function

The uploadData is an array of data objects:

• data Object
  • bytes Buffer - Content being sent.
  • file String - Path of file being uploaded.
  • blobUUID String - UUID of blob data. Use ses.getBlobData method to retrieve the data.

The callback has to be called with an response object:

• response Object
  • cancel Boolean (optional)
  • redirectURL String (optional) - The original request is prevented from being sent or completed, and is instead redirected to the given URL.

webRequest.onBeforeSendHeaders([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details, callback) before sending an HTTP request, once the request headers are available. This may occur after a TCP connection is made to the server, but before any http data is sent.

• details Object
  • id Integer
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • requestHeaders Object
• callback Function

The callback has to be called with an response object:

• response Object
  • cancel Boolean (optional)
  • requestHeaders Object (optional) - When provided, request will be made with these headers.

webRequest.onSendHeaders([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details) just before a request is going to be sent to the server, modifications of previous onBeforeSendHeaders response are visible by the time this listener is fired.

• details Object
  • id Integer
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • requestHeaders Object

webRequest.onHeadersReceived([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details, callback) when HTTP response headers of a request have been received.

• details Object
  • id String
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • statusLine String
  • statusCode Integer
  • responseHeaders Object
• callback Function

The callback has to be called with an response object:

• response Object
  • cancel Boolean
  • responseHeaders Object (optional) - When provided, the server is assumed to have responded with these headers.
  • statusLine String (optional) - Should be provided when overriding responseHeaders to change header status otherwise original response header's status will be used.

webRequest.onResponseStarted([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details) when first byte of the response body is received. For HTTP requests, this means that the status line and response headers are available.

• details Object
  • id Integer
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • responseHeaders Object
  • fromCache Boolean - Indicates whether the response was fetched from disk cache.
  • statusCode Integer
  • statusLine String

webRequest.onBeforeRedirect([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details) when a server initiated redirect is about to occur.

• details Object
  • id String
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • redirectURL String
  • statusCode Integer
  • ip String (optional) - The server IP address that the request was actually sent to.
  • fromCache Boolean
  • responseHeaders Object

webRequest.onCompleted([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details) when a request is completed.

• details Object
  • id Integer
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • responseHeaders Object
  • fromCache Boolean
  • statusCode Integer
  • statusLine String

webRequest.onErrorOccurred([filter, ]listener)

• filter Object
• listener Function

The listener will be called with listener(details) when an error occurs.

• details Object
  • id Integer
  • url String
  • method String
  • resourceType String
  • timestamp Double
  • fromCache Boolean
  • error String - The error description.