67 KiB
title | description | slug | hide_title |
---|---|---|---|
session | Manage browser sessions, cookies, cache, proxy settings, etc. | session | false |
session
Manage browser sessions, cookies, cache, proxy settings, etc.
Process: Main
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')
const win = new BrowserWindow({ width: 800, height: 600 })
win.loadURL('https://github.com')
const ses = win.webContents.session
console.log(ses.getUserAgent())
Methods
The session
module has the following methods:
session.fromPartition(partition[, options])
partition
stringoptions
Object (optional)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; otherwise 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.
session.fromPath(path[, options])
path
stringoptions
Object (optional)cache
boolean - Whether to enable cache.
Returns Session
- A session instance from the absolute path as specified by the path
string. When there is an existing Session
with the same absolute path, it
will be returned; otherwise a new Session
instance will be created with options
. The
call will throw an error if the path is not an absolute path. Additionally, an error will
be thrown if an empty string is provided.
To create a Session
with options
, you have to ensure the Session
with the
path
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.
Process: Main
This class is not exported from the 'electron'
module. It is only available as a return value of other methods in the Electron API.
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'
Returns:
event
Eventitem
DownloadItemwebContents
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('got')(item.getURL()).then((response) => {
require('node:fs').writeFileSync('/somewhere', response.body)
})
})
Event: 'extension-loaded'
Returns:
event
Eventextension
Extension
Emitted after an extension is loaded. This occurs whenever an extension is added to the "enabled" set of extensions. This includes:
- Extensions being loaded from
Session.loadExtension
. - Extensions being reloaded:
- from a crash.
- if the extension requested it (
chrome.runtime.reload()
).
Event: 'extension-unloaded'
Returns:
event
Eventextension
Extension
Emitted after an extension is unloaded. This occurs when
Session.removeExtension
is called.
Event: 'extension-ready'
Returns:
event
Eventextension
Extension
Emitted after an extension is loaded and all necessary browser state is initialized to support the start of the extension's background page.
Event: 'file-system-access-restricted'
Returns:
event
Eventdetails
Objectorigin
string - The origin that initiated access to the blocked path.isDirectory
boolean - Whether or not the path is a directory.path
string - The blocked path attempting to be accessed.
callback
Functionaction
string - The action to take as a result of the restricted path access attempt.allow
- This will allowpath
to be accessed despite restricted status.deny
- This will block the access request and trigger anAbortError
.tryAgain
- This will open a new file picker and allow the user to choose another path.
const { app, dialog, BrowserWindow, session } = require('electron')
async function createWindow () {
const mainWindow = new BrowserWindow()
await mainWindow.loadURL('https://buzzfeed.com')
session.defaultSession.on('file-system-access-restricted', async (e, details, callback) => {
const { origin, path } = details
const { response } = await dialog.showMessageBox({
message: `Are you sure you want ${origin} to open restricted path ${path}?`,
title: 'File System Access Restricted',
buttons: ['Choose a different folder', 'Allow', 'Cancel'],
cancelId: 2
})
if (response === 0) {
callback('tryAgain')
} else if (response === 1) {
callback('allow')
} else {
callback('deny')
}
})
mainWindow.webContents.executeJavaScript(`
window.showDirectoryPicker({
id: 'electron-demo',
mode: 'readwrite',
startIn: 'downloads',
}).catch(e => {
console.log(e)
})`, true
)
}
app.whenReady().then(() => {
createWindow()
app.on('activate', () => {
if (BrowserWindow.getAllWindows().length === 0) createWindow()
})
})
app.on('window-all-closed', function () {
if (process.platform !== 'darwin') app.quit()
})
Event: 'preconnect'
Returns:
event
EventpreconnectUrl
string - The URL being requested for preconnection by the renderer.allowCredentials
boolean - True if the renderer is requesting that the connection include credentials (see the spec for more details.)
Emitted when a render process requests preconnection to a URL, generally due to a resource hint.
Event: 'spellcheck-dictionary-initialized'
Returns:
event
EventlanguageCode
string - The language code of the dictionary file
Emitted when a hunspell dictionary file has been successfully initialized. This occurs after the file has been downloaded.
Event: 'spellcheck-dictionary-download-begin'
Returns:
event
EventlanguageCode
string - The language code of the dictionary file
Emitted when a hunspell dictionary file starts downloading
Event: 'spellcheck-dictionary-download-success'
Returns:
event
EventlanguageCode
string - The language code of the dictionary file
Emitted when a hunspell dictionary file has been successfully downloaded
Event: 'spellcheck-dictionary-download-failure'
Returns:
event
EventlanguageCode
string - The language code of the dictionary file
Emitted when a hunspell dictionary file download fails. For details on the failure you should collect a netlog and inspect the download request.
Event: 'select-hid-device'
Returns:
event
Eventdetails
ObjectdeviceList
HIDDevice[]frame
WebFrameMain | null - The frame initiating this event. May benull
if accessed after the frame has either navigated or been destroyed.
callback
FunctiondeviceId
string | null (optional)
Emitted when a HID device needs to be selected when a call to
navigator.hid.requestDevice
is made. callback
should be called with
deviceId
to be selected; passing no arguments to callback
will
cancel the request. Additionally, permissioning on navigator.hid
can
be further managed by using ses.setPermissionCheckHandler(handler)
and ses.setDevicePermissionHandler(handler)
.
const { app, BrowserWindow } = require('electron')
let win = null
app.whenReady().then(() => {
win = new BrowserWindow()
win.webContents.session.setPermissionCheckHandler((webContents, permission, requestingOrigin, details) => {
if (permission === 'hid') {
// Add logic here to determine if permission should be given to allow HID selection
return true
}
return false
})
// Optionally, retrieve previously persisted devices from a persistent store
const grantedDevices = fetchGrantedDevices()
win.webContents.session.setDevicePermissionHandler((details) => {
if (new URL(details.origin).hostname === 'some-host' && details.deviceType === 'hid') {
if (details.device.vendorId === 123 && details.device.productId === 345) {
// Always allow this type of device (this allows skipping the call to `navigator.hid.requestDevice` first)
return true
}
// Search through the list of devices that have previously been granted permission
return grantedDevices.some((grantedDevice) => {
return grantedDevice.vendorId === details.device.vendorId &&
grantedDevice.productId === details.device.productId &&
grantedDevice.serialNumber && grantedDevice.serialNumber === details.device.serialNumber
})
}
return false
})
win.webContents.session.on('select-hid-device', (event, details, callback) => {
event.preventDefault()
const selectedDevice = details.deviceList.find((device) => {
return device.vendorId === 9025 && device.productId === 67
})
callback(selectedDevice?.deviceId)
})
})
Event: 'hid-device-added'
Returns:
event
Eventdetails
Objectdevice
HIDDeviceframe
WebFrameMain | null - The frame initiating this event. May benull
if accessed after the frame has either navigated or been destroyed.
Emitted after navigator.hid.requestDevice
has been called and
select-hid-device
has fired if a new device becomes available before
the callback from select-hid-device
is called. This event is intended for
use when using a UI to ask users to pick a device so that the UI can be updated
with the newly added device.
Event: 'hid-device-removed'
Returns:
event
Eventdetails
Objectdevice
HIDDeviceframe
WebFrameMain | null - The frame initiating this event. May benull
if accessed after the frame has either navigated or been destroyed.
Emitted after navigator.hid.requestDevice
has been called and
select-hid-device
has fired if a device has been removed before the callback
from select-hid-device
is called. This event is intended for use when using
a UI to ask users to pick a device so that the UI can be updated to remove the
specified device.
Event: 'hid-device-revoked'
Returns:
event
Eventdetails
Objectdevice
HIDDeviceorigin
string (optional) - The origin that the device has been revoked from.
Emitted after HIDDevice.forget()
has been called. This event can be used
to help maintain persistent storage of permissions when
setDevicePermissionHandler
is used.
Event: 'select-serial-port'
Returns:
event
EventportList
SerialPort[]webContents
WebContentscallback
FunctionportId
string
Emitted when a serial port needs to be selected when a call to
navigator.serial.requestPort
is made. callback
should be called with
portId
to be selected, passing an empty string to callback
will
cancel the request. Additionally, permissioning on navigator.serial
can
be managed by using ses.setPermissionCheckHandler(handler)
with the serial
permission.
const { app, BrowserWindow } = require('electron')
let win = null
app.whenReady().then(() => {
win = new BrowserWindow({
width: 800,
height: 600
})
win.webContents.session.setPermissionCheckHandler((webContents, permission, requestingOrigin, details) => {
if (permission === 'serial') {
// Add logic here to determine if permission should be given to allow serial selection
return true
}
return false
})
// Optionally, retrieve previously persisted devices from a persistent store
const grantedDevices = fetchGrantedDevices()
win.webContents.session.setDevicePermissionHandler((details) => {
if (new URL(details.origin).hostname === 'some-host' && details.deviceType === 'serial') {
if (details.device.vendorId === 123 && details.device.productId === 345) {
// Always allow this type of device (this allows skipping the call to `navigator.serial.requestPort` first)
return true
}
// Search through the list of devices that have previously been granted permission
return grantedDevices.some((grantedDevice) => {
return grantedDevice.vendorId === details.device.vendorId &&
grantedDevice.productId === details.device.productId &&
grantedDevice.serialNumber && grantedDevice.serialNumber === details.device.serialNumber
})
}
return false
})
win.webContents.session.on('select-serial-port', (event, portList, webContents, callback) => {
event.preventDefault()
const selectedPort = portList.find((device) => {
return device.vendorId === '9025' && device.productId === '67'
})
if (!selectedPort) {
callback('')
} else {
callback(selectedPort.portId)
}
})
})
Event: 'serial-port-added'
Returns:
event
Eventport
SerialPortwebContents
WebContents
Emitted after navigator.serial.requestPort
has been called and
select-serial-port
has fired if a new serial port becomes available before
the callback from select-serial-port
is called. This event is intended for
use when using a UI to ask users to pick a port so that the UI can be updated
with the newly added port.
Event: 'serial-port-removed'
Returns:
event
Eventport
SerialPortwebContents
WebContents
Emitted after navigator.serial.requestPort
has been called and
select-serial-port
has fired if a serial port has been removed before the
callback from select-serial-port
is called. This event is intended for use
when using a UI to ask users to pick a port so that the UI can be updated
to remove the specified port.
Event: 'serial-port-revoked'
Returns:
event
Eventdetails
Objectport
SerialPortframe
WebFrameMain | null - The frame initiating this event. May benull
if accessed after the frame has either navigated or been destroyed.origin
string - The origin that the device has been revoked from.
Emitted after SerialPort.forget()
has been called. This event can be used
to help maintain persistent storage of permissions when setDevicePermissionHandler
is used.
// Browser Process
const { app, BrowserWindow } = require('electron')
app.whenReady().then(() => {
const win = new BrowserWindow({
width: 800,
height: 600
})
win.webContents.session.on('serial-port-revoked', (event, details) => {
console.log(`Access revoked for serial device from origin ${details.origin}`)
})
})
// Renderer Process
const portConnect = async () => {
// Request a port.
const port = await navigator.serial.requestPort()
// Wait for the serial port to open.
await port.open({ baudRate: 9600 })
// ...later, revoke access to the serial port.
await port.forget()
}
Event: 'select-usb-device'
Returns:
event
Eventdetails
ObjectdeviceList
USBDevice[]frame
WebFrameMain | null - The frame initiating this event. May benull
if accessed after the frame has either navigated or been destroyed.
callback
FunctiondeviceId
string (optional)
Emitted when a USB device needs to be selected when a call to
navigator.usb.requestDevice
is made. callback
should be called with
deviceId
to be selected; passing no arguments to callback
will
cancel the request. Additionally, permissioning on navigator.usb
can
be further managed by using ses.setPermissionCheckHandler(handler)
and ses.setDevicePermissionHandler(handler)
.
const { app, BrowserWindow } = require('electron')
let win = null
app.whenReady().then(() => {
win = new BrowserWindow()
win.webContents.session.setPermissionCheckHandler((webContents, permission, requestingOrigin, details) => {
if (permission === 'usb') {
// Add logic here to determine if permission should be given to allow USB selection
return true
}
return false
})
// Optionally, retrieve previously persisted devices from a persistent store (fetchGrantedDevices needs to be implemented by developer to fetch persisted permissions)
const grantedDevices = fetchGrantedDevices()
win.webContents.session.setDevicePermissionHandler((details) => {
if (new URL(details.origin).hostname === 'some-host' && details.deviceType === 'usb') {
if (details.device.vendorId === 123 && details.device.productId === 345) {
// Always allow this type of device (this allows skipping the call to `navigator.usb.requestDevice` first)
return true
}
// Search through the list of devices that have previously been granted permission
return grantedDevices.some((grantedDevice) => {
return grantedDevice.vendorId === details.device.vendorId &&
grantedDevice.productId === details.device.productId &&
grantedDevice.serialNumber && grantedDevice.serialNumber === details.device.serialNumber
})
}
return false
})
win.webContents.session.on('select-usb-device', (event, details, callback) => {
event.preventDefault()
const selectedDevice = details.deviceList.find((device) => {
return device.vendorId === 9025 && device.productId === 67
})
if (selectedDevice) {
// Optionally, add this to the persisted devices (updateGrantedDevices needs to be implemented by developer to persist permissions)
grantedDevices.push(selectedDevice)
updateGrantedDevices(grantedDevices)
}
callback(selectedDevice?.deviceId)
})
})
Event: 'usb-device-added'
Returns:
event
Eventdevice
USBDevicewebContents
WebContents
Emitted after navigator.usb.requestDevice
has been called and
select-usb-device
has fired if a new device becomes available before
the callback from select-usb-device
is called. This event is intended for
use when using a UI to ask users to pick a device so that the UI can be updated
with the newly added device.
Event: 'usb-device-removed'
Returns:
event
Eventdevice
USBDevicewebContents
WebContents
Emitted after navigator.usb.requestDevice
has been called and
select-usb-device
has fired if a device has been removed before the callback
from select-usb-device
is called. This event is intended for use when using
a UI to ask users to pick a device so that the UI can be updated to remove the
specified device.
Event: 'usb-device-revoked'
Returns:
event
Eventdetails
Objectdevice
USBDeviceorigin
string (optional) - The origin that the device has been revoked from.
Emitted after USBDevice.forget()
has been called. This event can be used
to help maintain persistent storage of permissions when
setDevicePermissionHandler
is used.
Instance Methods
The following methods are available on instances of Session
:
ses.getCacheSize()
Returns Promise<Integer>
- the session's current cache size, in bytes.
ses.clearCache()
Returns Promise<void>
- resolves when the cache clear operation is complete.
Clears the session’s HTTP cache.
ses.clearStorageData([options])
options
Object (optional)origin
string (optional) - Should followwindow.location.origin
’s representationscheme://host:port
.storages
string[] (optional) - The types of storages to clear, can becookies
,filesystem
,indexdb
,localstorage
,shadercache
,websql
,serviceworkers
,cachestorage
. If not specified, clear all storage types.quotas
string[] (optional) - The types of quotas to clear, can betemporary
,syncable
. If not specified, clear all quotas.
Returns Promise<void>
- resolves when the storage data has been cleared.
ses.flushStorageData()
Writes any unwritten DOMStorage data to disk.
ses.setProxy(config)
config
ProxyConfig
Returns Promise<void>
- Resolves when the proxy setting process is complete.
Sets the proxy settings.
You may need ses.closeAllConnections
to close currently in flight connections to prevent
pooled sockets using previous proxy from being reused by future requests.
ses.resolveHost(host, [options])
host
string - Hostname to resolve.options
Object (optional)queryType
string (optional) - Requested DNS query type. If unspecified, resolver will pick A or AAAA (or both) based on IPv4/IPv6 settings:A
- Fetch only A recordsAAAA
- Fetch only AAAA records.
source
string (optional) - The source to use for resolved addresses. Default allows the resolver to pick an appropriate source. Only affects use of big external sources (e.g. calling the system for resolution or using DNS). Even if a source is specified, results can still come from cache, resolving "localhost" or IP literals, etc. One of the following values:any
(default) - Resolver will pick an appropriate source. Results could come from DNS, MulticastDNS, HOSTS file, etcsystem
- Results will only be retrieved from the system or OS, e.g. via thegetaddrinfo()
system calldns
- Results will only come from DNS queriesmdns
- Results will only come from Multicast DNS querieslocalOnly
- No external sources will be used. Results will only come from fast local sources that are available no matter the source setting, e.g. cache, hosts file, IP literal resolution, etc.
cacheUsage
string (optional) - Indicates what DNS cache entries, if any, can be used to provide a response. One of the following values:allowed
(default) - Results may come from the host cache if non-stalestaleAllowed
- Results may come from the host cache even if stale (by expiration or network changes)disallowed
- Results will not come from the host cache.
secureDnsPolicy
string (optional) - Controls the resolver's Secure DNS behavior for this request. One of the following values:allow
(default)disable
Returns Promise<ResolvedHost>
- Resolves with the resolved IP addresses for the host
.
ses.resolveProxy(url)
url
URL
Returns Promise<string>
- Resolves with the proxy information for url
.
ses.forceReloadProxyConfig()
Returns Promise<void>
- Resolves when the all internal states of proxy service is reset and the latest proxy configuration is reapplied if it's already available. The pac script will be fetched from pacScript
again if the proxy mode is pac_script
.
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
Objectoffline
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
.
const win = new BrowserWindow()
// To emulate a GPRS connection with 50kbps throughput and 500 ms latency.
win.webContents.session.enableNetworkEmulation({
latency: 500,
downloadThroughput: 6400,
uploadThroughput: 6400
})
// To emulate a network outage.
win.webContents.session.enableNetworkEmulation({ offline: true })
ses.preconnect(options)
options
Objecturl
string - URL for preconnect. Only the origin is relevant for opening the socket.numSockets
number (optional) - number of sockets to preconnect. Must be between 1 and 6. Defaults to 1.
Preconnects the given number of sockets to an origin.
ses.closeAllConnections()
Returns Promise<void>
- Resolves when all connections are closed.
Note: It will terminate / fail all requests currently in flight.
ses.fetch(input[, init])
input
string | GlobalRequestinit
RequestInit & { bypassCustomProtocolHandlers?: boolean } (optional)
Returns Promise<GlobalResponse>
- see Response.
Sends a request, similarly to how fetch()
works in the renderer, using
Chrome's network stack. This differs from Node's fetch()
, which uses
Node.js's HTTP stack.
Example:
async function example () {
const response = await net.fetch('https://my.app')
if (response.ok) {
const body = await response.json()
// ... use the result.
}
}
See also net.fetch()
, a convenience method which
issues requests from the default session.
See the MDN documentation for
fetch()
for more
details.
Limitations:
net.fetch()
does not support thedata:
orblob:
schemes.- The value of the
integrity
option is ignored. - The
.type
and.url
values of the returnedResponse
object are incorrect.
By default, requests made with net.fetch
can be made to custom protocols
as well as file:
, and will trigger webRequest handlers if present.
When the non-standard bypassCustomProtocolHandlers
option is set in RequestInit,
custom protocol handlers will not be called for this request. This allows forwarding an
intercepted request to the built-in handler. webRequest
handlers will still be triggered when bypassing custom protocols.
protocol.handle('https', (req) => {
if (req.url === 'https://my-app.com') {
return new Response('<body>my app</body>')
} else {
return net.fetch(req, { bypassCustomProtocolHandlers: true })
}
})
ses.disableNetworkEmulation()
Disables any network emulation already active for the session
. Resets to
the original network configuration.
ses.setCertificateVerifyProc(proc)
proc
Function | nullrequest
Objecthostname
stringcertificate
CertificatevalidatedCertificate
CertificateisIssuedByKnownRoot
boolean -true
if Chromium recognises the root CA as a standard root. If it isn't then it's probably the case that this certificate was generated by a MITM proxy whose root has been installed locally (for example, by a corporate proxy). This should not be trusted if theverificationResult
is notOK
.verificationResult
string -OK
if the certificate is trusted, otherwise an error likeCERT_REVOKED
.errorCode
Integer - Error code.
callback
FunctionverificationResult
Integer - Value can be one of certificate error codes from here. Apart from the certificate error codes, the following special codes can be used.0
- Indicates success and disables Certificate Transparency verification.-2
- Indicates failure.-3
- Uses the verification result from chromium.
Sets the certificate verify proc for session
, the proc
will be called with
proc(request, callback)
whenever a server certificate
verification is requested. Calling callback(0)
accepts the certificate,
calling callback(-2)
rejects it.
Calling setCertificateVerifyProc(null)
will revert back to default certificate
verify proc.
const { BrowserWindow } = require('electron')
const win = new BrowserWindow()
win.webContents.session.setCertificateVerifyProc((request, callback) => {
const { hostname } = request
if (hostname === 'github.com') {
callback(0)
} else {
callback(-2)
}
})
NOTE: The result of this procedure is cached by the network service.
ses.setPermissionRequestHandler(handler)
handler
Function | nullwebContents
WebContents - WebContents requesting the permission. Please note that if the request comes from a subframe you should userequestingUrl
to check the request origin.permission
string - The type of requested permission.clipboard-read
- Request access to read from the clipboard.clipboard-sanitized-write
- Request access to write to the clipboard.display-capture
- Request access to capture the screen via the Screen Capture API.fullscreen
- Request control of the app's fullscreen state via the Fullscreen API.geolocation
- Request access to the user's location via the Geolocation APIidle-detection
- Request access to the user's idle state via the IdleDetector API.media
- Request access to media devices such as camera, microphone and speakers.mediaKeySystem
- Request access to DRM protected content.midi
- Request MIDI access in the Web MIDI API.midiSysex
- Request the use of system exclusive messages in the Web MIDI API.notifications
- Request notification creation and the ability to display them in the user's system tray using the Notifications APIpointerLock
- Request to directly interpret mouse movements as an input method via the Pointer Lock API. These requests always appear to originate from the main frame.keyboardLock
- Request capture of keypresses for any or all of the keys on the physical keyboard via the Keyboard Lock API. These requests always appear to originate from the main frame.openExternal
- Request to open links in external applications.speaker-selection
- Request to enumerate and select audio output devices via the speaker-selection permissions policy.storage-access
- Allows content loaded in a third-party context to request access to third-party cookies using the Storage Access API.top-level-storage-access
- Allow top-level sites to request third-party cookie access on behalf of embedded content originating from another site in the same related website set using the Storage Access API.window-management
- Request access to enumerate screens using thegetScreenDetails
API.unknown
- An unrecognized permission request.fileSystem
- Request access to read, write, and file management capabilities using the File System API.
callback
FunctionpermissionGranted
boolean - Allow or deny the permission.
details
PermissionRequest | FilesystemPermissionRequest | MediaAccessPermissionRequest | OpenExternalPermissionRequest - Additional information about the permission being requested.
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.
To clear the handler, call setPermissionRequestHandler(null)
. Please note that
you must also implement setPermissionCheckHandler
to get complete permission handling.
Most web APIs do a permission check and then make a permission request if the check is denied.
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.setPermissionCheckHandler(handler)
handler
Function<boolean> | nullwebContents
(WebContents | null) - WebContents checking the permission. Please note that if the request comes from a subframe you should userequestingUrl
to check the request origin. All cross origin sub frames making permission checks will pass anull
webContents to this handler, while certain other permission checks such asnotifications
checks will always passnull
. You should useembeddingOrigin
andrequestingOrigin
to determine what origin the owning frame and the requesting frame are on respectively.permission
string - Type of permission check.clipboard-read
- Request access to read from the clipboard.clipboard-sanitized-write
- Request access to write to the clipboard.geolocation
- Access the user's geolocation data via the Geolocation APIfullscreen
- Control of the app's fullscreen state via the Fullscreen API.hid
- Access the HID protocol to manipulate HID devices via the WebHID API.idle-detection
- Access the user's idle state via the IdleDetector API.media
- Access to media devices such as camera, microphone and speakers.mediaKeySystem
- Access to DRM protected content.midi
- Enable MIDI access in the Web MIDI API.midiSysex
- Use system exclusive messages in the Web MIDI API.notifications
- Configure and display desktop notifications to the user with the Notifications API.openExternal
- Open links in external applications.pointerLock
- Directly interpret mouse movements as an input method via the Pointer Lock API. These requests always appear to originate from the main frame.serial
- Read from and write to serial devices with the Web Serial API.storage-access
- Allows content loaded in a third-party context to request access to third-party cookies using the Storage Access API.top-level-storage-access
- Allow top-level sites to request third-party cookie access on behalf of embedded content originating from another site in the same related website set using the Storage Access API.usb
- Expose non-standard Universal Serial Bus (USB) compatible devices services to the web with the WebUSB API.
requestingOrigin
string - The origin URL of the permission checkdetails
Object - Some properties are only available on certain permission types.embeddingOrigin
string (optional) - The origin of the frame embedding the frame that made the permission check. Only set for cross-origin sub frames making permission checks.securityOrigin
string (optional) - The security origin of themedia
check.mediaType
string (optional) - The type of media access being requested, can bevideo
,audio
orunknown
requestingUrl
string (optional) - The last URL the requesting frame loaded. This is not provided for cross-origin sub frames making permission checks.isMainFrame
boolean - Whether the frame making the request is the main frame
Sets the handler which can be used to respond to permission checks for the session
.
Returning true
will allow the permission and false
will reject it. Please note that
you must also implement setPermissionRequestHandler
to get complete permission handling.
Most web APIs do a permission check and then make a permission request if the check is denied.
To clear the handler, call setPermissionCheckHandler(null)
.
const { session } = require('electron')
const url = require('url')
session.fromPartition('some-partition').setPermissionCheckHandler((webContents, permission, requestingOrigin) => {
if (new URL(requestingOrigin).hostname === 'some-host' && permission === 'notifications') {
return true // granted
}
return false // denied
})
ses.setDisplayMediaRequestHandler(handler[, opts])
handler
Function | nullrequest
Objectframe
WebFrameMain | null - Frame that is requesting access to media. May benull
if accessed after the frame has either navigated or been destroyed.securityOrigin
String - Origin of the page making the request.videoRequested
Boolean - true if the web content requested a video stream.audioRequested
Boolean - true if the web content requested an audio stream.userGesture
Boolean - Whether a user gesture was active when this request was triggered.
callback
Functionstreams
Objectvideo
Object | WebFrameMain (optional)id
String - The id of the stream being granted. This will usually come from a DesktopCapturerSource object.name
String - The name of the stream being granted. This will usually come from a DesktopCapturerSource object.
audio
String | WebFrameMain (optional) - If a string is specified, can beloopback
orloopbackWithMute
. Specifying a loopback device will capture system audio, and is currently only supported on Windows. If a WebFrameMain is specified, will capture audio from that frame.enableLocalEcho
Boolean (optional) - Ifaudio
is a WebFrameMain and this is set totrue
, then local playback of audio will not be muted (e.g. usingMediaRecorder
to recordWebFrameMain
with this flag set totrue
will allow audio to pass through to the speakers while recording). Default isfalse
.
opts
Object (optional) macOS ExperimentaluseSystemPicker
Boolean - true if the available native system picker should be used. Default isfalse
. macOS Experimental
This handler will be called when web content requests access to display media
via the navigator.mediaDevices.getDisplayMedia
API. Use the
desktopCapturer API to choose which stream(s) to grant
access to.
useSystemPicker
allows an application to use the system picker instead of providing a specific video source from getSources
.
This option is experimental, and currently available for MacOS 15+ only. If the system picker is available and useSystemPicker
is set to true
, the handler will not be invoked.
const { session, desktopCapturer } = require('electron')
session.defaultSession.setDisplayMediaRequestHandler((request, callback) => {
desktopCapturer.getSources({ types: ['screen'] }).then((sources) => {
// Grant access to the first screen found.
callback({ video: sources[0] })
})
// Use the system picker if available.
// Note: this is currently experimental. If the system picker
// is available, it will be used and the media request handler
// will not be invoked.
}, { useSystemPicker: true })
Passing a WebFrameMain object as a video or audio stream will capture the video or audio stream from that frame.
const { session } = require('electron')
session.defaultSession.setDisplayMediaRequestHandler((request, callback) => {
// Allow the tab to capture itself.
callback({ video: request.frame })
})
Passing null
instead of a function resets the handler to its default state.
ses.setDevicePermissionHandler(handler)
handler
Function<boolean> | nulldetails
ObjectdeviceType
string - The type of device that permission is being requested on, can behid
,serial
, orusb
.origin
string - The origin URL of the device permission check.device
HIDDevice | SerialPort | USBDevice - the device that permission is being requested for.
Sets the handler which can be used to respond to device permission checks for the session
.
Returning true
will allow the device to be permitted and false
will reject it.
To clear the handler, call setDevicePermissionHandler(null)
.
This handler can be used to provide default permissioning to devices without first calling for permission
to devices (eg via navigator.hid.requestDevice
). If this handler is not defined, the default device
permissions as granted through device selection (eg via navigator.hid.requestDevice
) will be used.
Additionally, the default behavior of Electron is to store granted device permission in memory.
If longer term storage is needed, a developer can store granted device
permissions (eg when handling the select-hid-device
event) and then read from that storage with setDevicePermissionHandler
.
const { app, BrowserWindow } = require('electron')
let win = null
app.whenReady().then(() => {
win = new BrowserWindow()
win.webContents.session.setPermissionCheckHandler((webContents, permission, requestingOrigin, details) => {
if (permission === 'hid') {
// Add logic here to determine if permission should be given to allow HID selection
return true
} else if (permission === 'serial') {
// Add logic here to determine if permission should be given to allow serial port selection
} else if (permission === 'usb') {
// Add logic here to determine if permission should be given to allow USB device selection
}
return false
})
// Optionally, retrieve previously persisted devices from a persistent store
const grantedDevices = fetchGrantedDevices()
win.webContents.session.setDevicePermissionHandler((details) => {
if (new URL(details.origin).hostname === 'some-host' && details.deviceType === 'hid') {
if (details.device.vendorId === 123 && details.device.productId === 345) {
// Always allow this type of device (this allows skipping the call to `navigator.hid.requestDevice` first)
return true
}
// Search through the list of devices that have previously been granted permission
return grantedDevices.some((grantedDevice) => {
return grantedDevice.vendorId === details.device.vendorId &&
grantedDevice.productId === details.device.productId &&
grantedDevice.serialNumber && grantedDevice.serialNumber === details.device.serialNumber
})
} else if (details.deviceType === 'serial') {
if (details.device.vendorId === 123 && details.device.productId === 345) {
// Always allow this type of device (this allows skipping the call to `navigator.hid.requestDevice` first)
return true
}
}
return false
})
win.webContents.session.on('select-hid-device', (event, details, callback) => {
event.preventDefault()
const selectedDevice = details.deviceList.find((device) => {
return device.vendorId === 9025 && device.productId === 67
})
callback(selectedDevice?.deviceId)
})
})
ses.setUSBProtectedClassesHandler(handler)
handler
Function<string[]> | nulldetails
ObjectprotectedClasses
string[] - The current list of protected USB classes. Possible class values include:audio
audio-video
hid
mass-storage
smart-card
video
wireless
Sets the handler which can be used to override which USB classes are protected. The return value for the handler is a string array of USB classes which should be considered protected (eg not available in the renderer). Valid values for the array are:
audio
audio-video
hid
mass-storage
smart-card
video
wireless
Returning an empty string array from the handler will allow all USB classes; returning the passed in array will maintain the default list of protected USB classes (this is also the default behavior if a handler is not defined).
To clear the handler, call setUSBProtectedClassesHandler(null)
.
const { app, BrowserWindow } = require('electron')
let win = null
app.whenReady().then(() => {
win = new BrowserWindow()
win.webContents.session.setUSBProtectedClassesHandler((details) => {
// Allow all classes:
// return []
// Keep the current set of protected classes:
// return details.protectedClasses
// Selectively remove classes:
return details.protectedClasses.filter((usbClass) => {
// Exclude classes except for audio classes
return usbClass.indexOf('audio') === -1
})
})
})
ses.setBluetoothPairingHandler(handler)
Windows Linux
handler
Function | nulldetails
ObjectdeviceId
stringpairingKind
string - The type of pairing prompt being requested. One of the following values:confirm
This prompt is requesting confirmation that the Bluetooth device should be paired.confirmPin
This prompt is requesting confirmation that the provided PIN matches the pin displayed on the device.providePin
This prompt is requesting that a pin be provided for the device.
frame
WebFrameMain | null - The frame initiating this handler. May benull
if accessed after the frame has either navigated or been destroyed.pin
string (optional) - The pin value to verify ifpairingKind
isconfirmPin
.
callback
Functionresponse
Objectconfirmed
boolean -false
should be passed in if the dialog is canceled. If thepairingKind
isconfirm
orconfirmPin
, this value should indicate if the pairing is confirmed. If thepairingKind
isprovidePin
the value should betrue
when a value is provided.pin
string | null (optional) - When thepairingKind
isprovidePin
this value should be the required pin for the Bluetooth device.
Sets a handler to respond to Bluetooth pairing requests. This handler
allows developers to handle devices that require additional validation
before pairing. When a handler is not defined, any pairing on Linux or Windows
that requires additional validation will be automatically cancelled.
macOS does not require a handler because macOS handles the pairing
automatically. To clear the handler, call setBluetoothPairingHandler(null)
.
const { app, BrowserWindow, session } = require('electron')
const path = require('node:path')
function createWindow () {
let bluetoothPinCallback = null
const mainWindow = new BrowserWindow({
webPreferences: {
preload: path.join(__dirname, 'preload.js')
}
})
mainWindow.webContents.session.setBluetoothPairingHandler((details, callback) => {
bluetoothPinCallback = callback
// Send a IPC message to the renderer to prompt the user to confirm the pairing.
// Note that this will require logic in the renderer to handle this message and
// display a prompt to the user.
mainWindow.webContents.send('bluetooth-pairing-request', details)
})
// Listen for an IPC message from the renderer to get the response for the Bluetooth pairing.
mainWindow.webContents.ipc.on('bluetooth-pairing-response', (event, response) => {
bluetoothPinCallback(response)
})
}
app.whenReady().then(() => {
createWindow()
})
ses.clearHostResolverCache()
Returns Promise<void>
- Resolves when the operation is complete.
Clears the host resolver cache.
ses.allowNTLMCredentialsForDomains(domains)
domains
string - A comma-separated 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
stringacceptLanguages
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.isPersistent()
Returns boolean
- Whether or not this session is a persistent one. The default
webContents
session of a BrowserWindow
is persistent. When creating a session
from a partition, session prefixed with persist:
will be persistent, while others
will be temporary.
ses.getUserAgent()
Returns string
- The user agent for this session.
ses.setSSLConfig(config)
config
ObjectminVersion
string (optional) - Can betls1
,tls1.1
,tls1.2
ortls1.3
. The minimum SSL version to allow when connecting to remote servers. Defaults totls1
.maxVersion
string (optional) - Can betls1.2
ortls1.3
. The maximum SSL version to allow when connecting to remote servers. Defaults totls1.3
.disabledCipherSuites
Integer[] (optional) - List of cipher suites which should be explicitly prevented from being used in addition to those disabled by the net built-in policy. Supported literal forms: 0xAABB, where AA iscipher_suite[0]
and BB iscipher_suite[1]
, as defined in RFC 2246, Section 7.4.1.2. Unrecognized but parsable cipher suites in this form will not return an error. Ex: To disable TLS_RSA_WITH_RC4_128_MD5, specify 0x0004, while to disable TLS_ECDH_ECDSA_WITH_RC4_128_SHA, specify 0xC002. Note that TLSv1.3 ciphers cannot be disabled using this mechanism.
Sets the SSL configuration for the session. All subsequent network requests will use the new configuration. Existing network connections (such as WebSocket connections) will not be terminated, but old sockets in the pool will not be reused for new connections.
ses.getBlobData(identifier)
identifier
string - Valid UUID.
Returns Promise<Buffer>
- resolves with blob data.
ses.downloadURL(url[, options])
url
stringoptions
Object (optional)headers
Record<string, string> (optional) - HTTP request headers.
Initiates a download of the resource at url
.
The API will generate a DownloadItem that can be accessed
with the will-download event.
Note: This does not perform any security checks that relate to a page's origin,
unlike webContents.downloadURL
.
ses.createInterruptedDownload(options)
options
Objectpath
string - Absolute path of the download.urlChain
string[] - Complete URL chain for the download.mimeType
string (optional)offset
Integer - Start range for the download.length
Integer - Total length of the download.lastModified
string (optional) - Last-Modified header value.eTag
string (optional) - ETag header value.startTime
Double (optional) - Time when download was started in number of seconds since UNIX epoch.
Allows resuming cancelled
or interrupted
downloads from previous Session
.
The API will generate a DownloadItem that can be accessed with the will-download
event. The DownloadItem will not have any WebContents
associated with it and
the initial state will be interrupted
. The download will start only when the
resume
API is called on the DownloadItem.
ses.clearAuthCache()
Returns Promise<void>
- resolves when the session’s HTTP authentication cache has been cleared.
ses.setPreloads(preloads)
preloads
string[] - An array of absolute path to preload scripts
Adds scripts that will be executed on ALL web contents that are associated with
this session just before normal preload
scripts run.
ses.getPreloads()
Returns string[]
an array of paths to preload scripts that have been
registered.
ses.setCodeCachePath(path)
path
String - Absolute path to store the v8 generated JS code cache from the renderer.
Sets the directory to store the generated JS code cache for this session. The directory is not required to be created by the user before this call, the runtime will create if it does not exist otherwise will use the existing directory. If directory cannot be created, then code cache will not be used and all operations related to code cache will fail silently inside the runtime. By default, the directory will be Code Cache
under the
respective user data folder.
Note that by default code cache is only enabled for http(s) URLs, to enable code
cache for custom protocols, codeCache: true
and standard: true
must be
specified when registering the protocol.
ses.clearCodeCaches(options)
options
Objecturls
String[] (optional) - An array of url corresponding to the resource whose generated code cache needs to be removed. If the list is empty then all entries in the cache directory will be removed.
Returns Promise<void>
- resolves when the code cache clear operation is complete.
ses.setSpellCheckerEnabled(enable)
enable
boolean
Sets whether to enable the builtin spell checker.
ses.isSpellCheckerEnabled()
Returns boolean
- Whether the builtin spell checker is enabled.
ses.setSpellCheckerLanguages(languages)
languages
string[] - An array of language codes to enable the spellchecker for.
The built in spellchecker does not automatically detect what language a user is typing in. In order for the
spell checker to correctly check their words you must call this API with an array of language codes. You can
get the list of supported language codes with the ses.availableSpellCheckerLanguages
property.
Note: On macOS the OS spellchecker is used and will detect your language automatically. This API is a no-op on macOS.
ses.getSpellCheckerLanguages()
Returns string[]
- An array of language codes the spellchecker is enabled for. If this list is empty the spellchecker
will fallback to using en-US
. By default on launch if this setting is an empty list Electron will try to populate this
setting with the current OS locale. This setting is persisted across restarts.
Note: On macOS the OS spellchecker is used and has its own list of languages. On macOS, this API will return whichever languages have been configured by the OS.
ses.setSpellCheckerDictionaryDownloadURL(url)
url
string - A base URL for Electron to download hunspell dictionaries from.
By default Electron will download hunspell dictionaries from the Chromium CDN. If you want to override this
behavior you can use this API to point the dictionary downloader at your own hosted version of the hunspell
dictionaries. We publish a hunspell_dictionaries.zip
file with each release which contains the files you need
to host here.
The file server must be case insensitive. If you cannot do this, you must upload each file twice: once with the case it has in the ZIP file and once with the filename as all lowercase.
If the files present in hunspell_dictionaries.zip
are available at https://example.com/dictionaries/language-code.bdic
then you should call this api with ses.setSpellCheckerDictionaryDownloadURL('https://example.com/dictionaries/')
. Please
note the trailing slash. The URL to the dictionaries is formed as ${url}${filename}
.
Note: On macOS the OS spellchecker is used and therefore we do not download any dictionary files. This API is a no-op on macOS.
ses.listWordsInSpellCheckerDictionary()
Returns Promise<string[]>
- An array of all words in app's custom dictionary.
Resolves when the full dictionary is loaded from disk.
ses.addWordToSpellCheckerDictionary(word)
word
string - The word you want to add to the dictionary
Returns boolean
- Whether the word was successfully written to the custom dictionary. This API
will not work on non-persistent (in-memory) sessions.
Note: On macOS and Windows 10 this word will be written to the OS custom dictionary as well
ses.removeWordFromSpellCheckerDictionary(word)
word
string - The word you want to remove from the dictionary
Returns boolean
- Whether the word was successfully removed from the custom dictionary. This API
will not work on non-persistent (in-memory) sessions.
Note: On macOS and Windows 10 this word will be removed from the OS custom dictionary as well
ses.loadExtension(path[, options])
path
string - Path to a directory containing an unpacked Chrome extensionoptions
Object (optional)allowFileAccess
boolean - Whether to allow the extension to read local files overfile://
protocol and inject content scripts intofile://
pages. This is required e.g. for loading devtools extensions onfile://
URLs. Defaults to false.
Returns Promise<Extension>
- resolves when the extension is loaded.
This method will raise an exception if the extension could not be loaded. If there are warnings when installing the extension (e.g. if the extension requests an API that Electron does not support) then they will be logged to the console.
Note that Electron does not support the full range of Chrome extensions APIs. See Supported Extensions APIs for more details on what is supported.
Note that in previous versions of Electron, extensions that were loaded would
be remembered for future runs of the application. This is no longer the case:
loadExtension
must be called on every boot of your app if you want the
extension to be loaded.
const { app, session } = require('electron')
const path = require('node:path')
app.whenReady().then(async () => {
await session.defaultSession.loadExtension(
path.join(__dirname, 'react-devtools'),
// allowFileAccess is required to load the devtools extension on file:// URLs.
{ allowFileAccess: true }
)
// Note that in order to use the React DevTools extension, you'll need to
// download and unzip a copy of the extension.
})
This API does not support loading packed (.crx) extensions.
Note: This API cannot be called before the ready
event of the app
module
is emitted.
Note: Loading extensions into in-memory (non-persistent) sessions is not supported and will throw an error.
ses.removeExtension(extensionId)
extensionId
string - ID of extension to remove
Unloads an extension.
Note: This API cannot be called before the ready
event of the app
module
is emitted.
ses.getExtension(extensionId)
extensionId
string - ID of extension to query
Returns Extension | null
- The loaded extension with the given ID.
Note: This API cannot be called before the ready
event of the app
module
is emitted.
ses.getAllExtensions()
Returns Extension[]
- A list of all loaded extensions.
Note: This API cannot be called before the ready
event of the app
module
is emitted.
ses.getStoragePath()
Returns string | null
- The absolute file system path where data for this
session is persisted on disk. For in memory sessions this returns null
.
ses.clearData([options])
options
Object (optional)dataTypes
String[] (optional) - The types of data to clear. By default, this will clear all types of data.backgroundFetch
- Background Fetchcache
- Cachecookies
- Cookiesdownloads
- DownloadsfileSystems
- File SystemsindexedDB
- IndexedDBlocalStorage
- Local StorageserviceWorkers
- Service WorkerswebSQL
- WebSQL
origins
String[] (optional) - Clear data for only these origins. Cannot be used withexcludeOrigins
.excludeOrigins
String[] (optional) - Clear data for all origins except these ones. Cannot be used withorigins
.avoidClosingConnections
boolean (optional) - Skips deleting cookies that would close current network connections. (Default:false
)originMatchingMode
String (optional) - The behavior for matching data to origins.third-parties-included
(default) - Storage is matched on origin in first-party contexts and top-level-site in third-party contexts.origin-in-all-contexts
- Storage is matched on origin only in all contexts.
Returns Promise<void>
- resolves when all data has been cleared.
Clears various different types of data.
This method clears more types of data and is more thorough than the
clearStorageData
method.
Note: Cookies are stored at a broader scope than origins. When removing cookies and filtering by origins
(or excludeOrigins
), the cookies will be removed at the registrable domain level. For example, clearing cookies for the origin https://really.specific.origin.example.com/
will end up clearing all cookies for example.com
. Clearing cookies for the origin https://my.website.example.co.uk/
will end up clearing all cookies for example.co.uk
.
For more information, refer to Chromium's BrowsingDataRemover
interface.
Instance Properties
The following properties are available on instances of Session
:
ses.availableSpellCheckerLanguages
Readonly
A string[]
array which consists of all the known available spell checker languages. Providing a language
code to the setSpellCheckerLanguages
API that isn't in this array will result in an error.
ses.spellCheckerEnabled
A boolean
indicating whether builtin spell checker is enabled.
ses.storagePath
Readonly
A string | null
indicating the absolute file system path where data for this
session is persisted on disk. For in memory sessions this returns null
.
ses.cookies
Readonly
A Cookies
object for this session.
ses.serviceWorkers
Readonly
A ServiceWorkers
object for this session.
ses.webRequest
Readonly
A WebRequest
object for this session.
ses.protocol
Readonly
A Protocol
object for this session.
const { app, session } = require('electron')
const path = require('node:path')
app.whenReady().then(() => {
const protocol = session.fromPartition('some-partition').protocol
if (!protocol.registerFileProtocol('atom', (request, callback) => {
const url = request.url.substr(7)
callback({ path: path.normalize(path.join(__dirname, url)) })
})) {
console.error('Failed to register protocol')
}
})
ses.netLog
Readonly
A NetLog
object for this session.
const { app, session } = require('electron')
app.whenReady().then(async () => {
const netLog = session.fromPartition('some-partition').netLog
netLog.startLogging('/path/to/net-log')
// After some network events
const path = await netLog.stopLogging()
console.log('Net-logs written to', path)
})