webRequest.onAuthRequired
Fired when the server sends a 401
or 407
status code and a WWW-Authenticate
header using the Basic
scheme (that is, when the server asks the client to provide authentication credentials, such as a username and password).
The listener can respond in one of four ways:
- Take no action
-
The listener can do nothing, just observing the request. If this happens, it does not affect the handling of the request, and the browser asks the user to log in, if appropriate.
- Cancel the request
-
The listener can cancel the request. If it does this, authentication fails, and the user is not asked to log in. Extensions can cancel requests as follows:
- in addListener, pass
"blocking"
in theextraInfoSpec
parameter - in the listener, return an object with a
cancel
property set totrue
- in addListener, pass
- Provide credentials synchronously
-
If credentials are available synchronously, the extension can supply them synchronously. If the extension does this, the browser attempts to log in with the credentials. The listener can provide credentials synchronously as follows:
- in addListener, pass
"blocking"
in theextraInfoSpec
parameter - in the listener, return an object with an
authCredentials
property set to the credentials to supply
- in addListener, pass
- Provide credentials asynchronously
-
The extension might need to fetch credentials asynchronously. For example, the extension might need to fetch credentials from storage or ask the user. In this case, the listener can supply credentials asynchronously as follows:
-
in addListener, pass
"asyncBlocking"
in Chrome and Firefox or"blocking"
in Firefox in theextraInfoSpec
parameter -
If
"blocking"
is provided, the extension can return awebRequest.BlockingResponse
object or a Promise that resolves to awebRequest.BlockingResponse
object -
If
"asyncBlocking"
is provided, the event listener function receives aasyncCallback
function as its second parameter.asyncCallback
can be called asynchronously and takes awebRequest.BlockingResponse
object as its only parameterNote: Chrome does not support a Promise as a return value (Chromium issue 1510405). For alternatives, see the return value of the
listener
.
-
See Examples.
If your extension provides bad credentials, then the listener is called again. For this reason, take care to avoid entering an infinite loop by repeatedly providing bad credentials.
Permissions
In Firefox and Chrome Manifest V2 extensions, you must add the "webRequest"
and "webRequestBlocking"
API permissions to your manifest.json
.
For Manifest V3 extensions, Chrome no longer supports the "webRequestBlocking"
permission (except for policy-installed extensions). Instead, the "webRequest"
and "webRequestAuthProvider"
permissions enable you to supply credentials asynchronously. Firefox continues to support "webRequestBlocking"
in Manifest V3 and provides "webRequestAuthProvider"
to offer cross-browser compatibility.
Proxy authorization
Firefox does not generally fire webRequest
events for system requests, such as browser or extension upgrades or search engine queries. To enable proxy authorization to work smoothly for system requests, from version 57, Firefox supports an exception to this.
If an extension has the "webRequest"
, "webRequestBlocking"
, "proxy"
, and "<all_urls>"
permissions, then it can use onAuthRequired
to supply credentials for proxy authorization (but not for normal web authorization). The listener cannot cancel system requests or make any other modifications to any system requests.
Syntax
browser.webRequest.onAuthRequired.addListener(
listener, // function
filter, // object
extraInfoSpec // optional array of strings
)
browser.webRequest.onAuthRequired.removeListener(listener)
browser.webRequest.onAuthRequired.hasListener(listener)
Events have three functions:
addListener(listener, filter, extraInfoSpec)
-
Adds a listener to this event.
removeListener(listener)
-
Stop listening to this event. The
listener
argument is the listener to remove. hasListener(listener)
-
Check whether
listener
is registered for this event. Returnstrue
if it is listening,false
otherwise.
addListener syntax
Parameters
listener
-
The function called when this event occurs. The function is passed these arguments:
details
-
object
. Details about the request. See the details section for more information. asyncCallback
Optional-
A function to call, at most once, to asynchronously modify the request object. This parameter is only present if the event listener is registered with
"asyncBlocking"
in theextraInfoSpec
array.asyncCallback
is undefined ifextraInfoSpec
is not provided or contains"blocking"
.
Returns:
webRequest.BlockingResponse
or aPromise
depending on the settings inextraInfoSpec
. filter
-
webRequest.RequestFilter
. A filter that restricts the events sent to this listener. extraInfoSpec
Optional-
array
ofstring
. Extra options for the event. You can pass any of these values:-
"blocking"
: make the request block so you can cancel the request or supply authentication credentials. Return aBlockingResponse
object with itscancel
orauthCredentials
properties set.- In Chrome, the event listener must respond synchronously.
- In Firefox, the event listener can respond synchronously or return a promise that resolves to a
BlockingResponse
object to respond asynchronously.
-
"asyncBlocking"
: handle the request asynchronously. The return value of the event listener is ignored. To resolve the event, pass theasyncCallback
parameter aBlockingResponse
object.- Supported from Chrome 120 and Firefox 128.
- Not supported in Safari.
-
Additional objects
details
challenger
-
object
. The server requesting authentication. This is an object with the following properties: -
string
. If the request is from a tab open in a contextual identity, the cookie store ID of the contextual identity. See Work with contextual identities for more information. frameId
-
integer
. This is0
if the request occurs in the main frame; a positive value is the ID of a subframe where the request happens. If the document of a (sub-)frame is loaded (type
ismain_frame
orsub_frame
),frameId
indicates this frame's ID, not the outer frame's ID. Frame IDs are unique within a tab. incognito
-
boolean
. Whether the request is from a private browsing window. isProxy
-
boolean
.true
forProxy-Authenticate
,false
forWWW-Authenticate
.Note:
webRequest.onAuthRequired
is only called for HTTP and HTTPS/TLS proxy servers requiring authentication, not for SOCKS proxy servers requiring authentication. method
-
string
. Standard HTTP method (For example,"GET"
or"POST"
). parentFrameId
-
integer
. ID of the frame that contains the frame that sent the request. Set to-1
if no parent frame exists. proxyInfo
-
object
. This property is present only if the request is being proxied. It contains the following properties:host
-
string
. The hostname of the proxy server. port
-
integer
. The port number of the proxy server. type
-
string
. The type of proxy server. One of:"http"
: HTTP proxy (or SSL CONNECT for HTTPS)"https"
: HTTP proxying over TLS connection to proxy"socks"
: SOCKS v5 proxy"socks4"
: SOCKS v4 proxy"direct"
: no proxy"unknown"
: unknown proxy
username
-
string
. Username for the proxy service. proxyDNS
-
boolean
. True if the proxy performs domain name resolution based on the hostname supplied, meaning that the client should not do its own DNS lookup. failoverTimeout
-
integer
. Failover timeout in seconds. If the connection fails to connect the proxy server after this number of seconds, the next proxy server in the array returned from FindProxyForURL() is used.
realm
Optional-
string
. The authentication realm provided by the server, if there is one. requestId
-
string
. The ID of the request. Request IDs are unique within a browser session, so you can relate different events associated with the same request. responseHeaders
Optional-
webRequest.HttpHeaders
. The HTTP response headers received with this response. scheme
-
string
. The authentication scheme:"basic"
or"digest
". statusCode
-
integer
. Standard HTTP status code returned by the server. statusLine
-
string
. HTTP status line of the response, the'HTTP/0.9 200 OK'
string for HTTP/0.9 responses (i.e., responses that lack a status line), or an empty string if there are no headers. tabId
-
integer
. ID of the tab where the request takes place. Set to-1
if the request isn't related to a tab. thirdParty
-
boolean
. Indicates whether the request and its content window hierarchy are third-party. timeStamp
-
number
. The time when this event fired, in milliseconds since the epoch. type
-
webRequest.ResourceType
. The type of resource being requested: for example,"image"
,"script"
, or"stylesheet"
. url
-
string
. Target of the request. urlClassification
-
object
. The type of tracking associated with the request, if the request is classified by Firefox Tracking Protection. This is an object with these properties:firstParty
-
array
ofstrings
. Classification flags for the request's first party. thirdParty
-
array
ofstrings
. Classification flags for the request or its window hierarchy's third parties.
The classification flags include:
fingerprinting
andfingerprinting_content
: indicates the request is involved in fingerprinting ("an origin found to fingerprint").fingerprinting
indicates the domain is in the fingerprinting and tracking category. Examples of this type of domain include advertisers who want to associate a profile with the visiting user.fingerprinting_content
indicates the domain is in the fingerprinting category but not the tracking category. Examples of this type of domain include payment providers who use fingerprinting techniques to identify the visiting user for anti-fraud purposes.
cryptomining
andcryptomining_content
: similar to the fingerprinting category but for cryptomining resources.tracking
,tracking_ad
,tracking_analytics
,tracking_social
, andtracking_content
: indicates the request is involved in tracking.tracking
is any generic tracking request. Thead
,analytics
,social
, andcontent
suffixes identify the type of tracker.emailtracking
andemailtracking_content
: indicates the request is involved in tracking emails.any_basic_tracking
: a meta flag that combines tracking and fingerprinting flags, excludingtracking_content
andfingerprinting_content
.any_strict_tracking
: a meta flag that combines all tracking and fingerprinting flags.any_social_tracking
: a meta flag that combines all social tracking flags.
You can find more information on tracker types on the disconnect.me website. The
content
suffix indicates trackers that track and serve content. Blocking them protects users but can lead to sites breaking or elements not being displayed.
Examples
This code observes authentication requests for the target URL:
const target = "https://intranet.company.com/";
function observe(requestDetails) {
console.log(`observing: ${requestDetails.requestId}`);
}
browser.webRequest.onAuthRequired.addListener(observe, { urls: [target] });
This code cancels authentication requests for the target URL:
const target = "https://intranet.company.com/";
function cancel(requestDetails) {
console.log(`canceling: ${requestDetails.requestId}`);
return { cancel: true };
}
browser.webRequest.onAuthRequired.addListener(cancel, { urls: [target] }, [
"blocking",
]);
This code supplies credentials synchronously. It keeps track of outstanding requests to ensure that it doesn't repeatedly try to submit bad credentials:
const target = "https://intranet.company.com/";
const myCredentials = {
username: "me@company.com",
password: "zDR$ERHGDFy",
};
const pendingRequests = [];
// A request has completed.
// We can stop worrying about it.
function completed(requestDetails) {
console.log(`completed: ${requestDetails.requestId}`);
let index = pendingRequests.indexOf(requestDetails.requestId);
if (index > -1) {
pendingRequests.splice(index, 1);
}
}
function provideCredentialsSync(requestDetails) {
// If we have seen this request before, then
// assume our credentials were bad, and give up.
if (pendingRequests.includes(requestDetails.requestId)) {
console.log(`bad credentials for: ${requestDetails.requestId}`);
return { cancel: true };
}
pendingRequests.push(requestDetails.requestId);
console.log(`providing credentials for: ${requestDetails.requestId}`);
return { authCredentials: myCredentials };
}
browser.webRequest.onAuthRequired.addListener(
provideCredentialsSync,
{ urls: [target] },
["blocking"],
);
browser.webRequest.onCompleted.addListener(completed, { urls: [target] });
browser.webRequest.onErrorOccurred.addListener(completed, { urls: [target] });
This code supplies credentials asynchronously, fetching them from storage. It also keeps track of outstanding requests to ensure that it doesn't repeatedly try to submit bad credentials:
const target = "https://httpbin.org/basic-auth/*";
const pendingRequests = [];
/*
* A request has completed. We can stop worrying about it.
*/
function completed(requestDetails) {
console.log(`completed: ${requestDetails.requestId}`);
let index = pendingRequests.indexOf(requestDetails.requestId);
if (index > -1) {
pendingRequests.splice(index, 1);
}
}
function provideCredentialsAsync(requestDetails) {
// If we have seen this request before,
// then assume our credentials were bad,
// and give up.
if (pendingRequests.includes(requestDetails.requestId)) {
console.log(`bad credentials for: ${requestDetails.requestId}`);
return { cancel: true };
} else {
pendingRequests.push(requestDetails.requestId);
console.log(`providing credentials for: ${requestDetails.requestId}`);
// we can return a promise that will be resolved
// with the stored credentials
return browser.storage.local.get(null);
}
}
browser.webRequest.onAuthRequired.addListener(
provideCredentialsAsync,
{ urls: [target] },
["blocking"],
);
browser.webRequest.onCompleted.addListener(completed, { urls: [target] });
browser.webRequest.onErrorOccurred.addListener(completed, { urls: [target] });
Example extensions
Browser compatibility
BCD tables only load in the browser
Note:
This API is based on Chromium's chrome.webRequest
API. This documentation is derived from web_request.json
in the Chromium code.