webRequest.onAuthRequired

Fired when the server sends a 401 or 407 status code: that is, when the server is asking the client to provide authentication credentials such as a username and password.

The listener can respond in one of four different ways:

Take no action: the listener can do nothing, just observing the request. If this happens, it will have no effect on the handling of the request, and the browser will probably just ask the user to log in.

Cancel the request: the listener can cancel the request. If they do this, then authentication will fail, and the user will not be asked to log in. Extensions can cancel requests as follows:

in addListener, pass "blocking" in the extraInfoSpec parameter
in the listener itself, return an object with a cancel property set to true

Provide credentials synchronously: if credentials are available synchronously, the extension can supply them synchronously. If the extension does this, then the browser will attempt to log in with the given credentials. The listener can provide credentials synchronously as follows:

in addListener, pass "blocking" in the extraInfoSpec parameter
in the listener, return an object with an authCredentials property set to the credentials to supply

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 "blocking" in the extraInfoSpec parameter
in the listener, return a Promise that is resolved with an object containing an authCredentials property, set to the credentials to supply

See Examples.

If you use "blocking" you must have the "webRequestBlocking" API permission in your manifest.json.

If your extension provides bad credentials, then the listener will be called again. For this reason, take care not to enter an infinite loop by repeatedly providing bad credentials.

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(callback, 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. Returns true if it is listening, false otherwise.

addListener syntax

Parameters

callback

A function that will be called when this event occurs. The function will be passed the following arguments:

details: object. Details about the request. See details below.

Returns: webRequest.BlockingResponse or a Promise.

To handle the request synchronously, include "blocking" in the extraInfoSpec parameter and return a BlockingResponse object, with its cancel or its authCredentials properties set.
To handle the request asynchronously, include "blocking" in the extraInfoSpec parameter and return a Promise that is resolved with a BlockingResponse object, with its cancel or its authCredentials properties set.

filter

webRequest.RequestFilter. A filter that restricts the events that will be sent to this listener.

extraInfoSpecOptional

array of string. Extra options for the event. You can pass any of the following values:

"blocking": make the request block, so you can cancel the request or supply authentication credentials
"responseHeaders": include responseHeaders in the details object passed to the listener

Additional objects

details

requestId

string. The ID of the request. Request IDs are unique within a browser session, so you can use them to relate different events associated with the same request.

url

string. Target of the request.

method

string. Standard HTTP method: for example, "GET" or "POST".

frameId

integer. Zero if the request happens in the main frame; a positive value is the ID of a subframe in which the request happens. If the document of a (sub-)frame is loaded (type is main_frame or sub_frame), frameId indicates the ID of this frame, not the ID of the outer frame. Frame IDs are unique within a tab.

parentFrameId

integer. ID of the frame that contains the frame which sent the request. Set to -1 if no parent frame exists.

tabId

integer. ID of the tab in which the request takes place. Set to -1 if the request isn't related to a tab.

type

webRequest.ResourceType. The type of resource being requested: for example, "image", "script", "stylesheet".

timeStamp

number. The time when this event fired, in milliseconds since the epoch.

scheme

string. The authentication scheme: "basic" or "digest".

realmOptional

string. The authentication realm provided by the server, if there is one.

challenger

object. The server requesting authentication. This is an object with the following properties:

host: string. The server's hostname.
port: integer. The server's port number.

isProxy

boolean. true for Proxy-Authenticate, false for WWW-Authenticate. Note: webRequest.onAuthRequired is only called for HTTP and HTTPS/SSL proxy servers requiring authentication, and not for SOCKS proxy servers requiring authenticaiton.

responseHeadersOptional

webRequest.HttpHeaders. The HTTP response headers that were received along with this response.

statusLine

string. HTTP status line of the response or 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.

statusCode

integer. Standard HTTP status code returned by the server.

Browser compatibility

	Chrome	Edge	Firefox	Firefox for Android	Opera
Basic support	Yes	Yes	54 ¹	54 ¹	Yes
`asyncBlocking`	Yes	Yes	No	No	Yes

1. To handle a request asynchronously, return a Promise from the listener.

Examples

This code just observes authentication requests for the target URL:

var 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:

var 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 has to keep track of outstanding requests, to ensure that it doesn't repeatedly try to submit bad credentials:

var target = "https://intranet.company.com/";
var myCredentials = {
  username: "me@company.com",
  password: "zDR$ERHGDFy"
}
var pendingRequests = [];
// A request has completed.
// We can stop worrying about it.
function completed(requestDetails) {
  console.log("completed: " + requestDetails.requestId);
  var 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.indexOf(requestDetails.requestId) != -1) {
    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 has to keep track of outstanding requests, to ensure that it doesn't repeatedly try to submit bad credentials:

var target = "https://httpbin.org/basic-auth/*";
var pendingRequests = [];
/*
A request has completed. We can stop worrying about it.
*/
function completed(requestDetails) {
  console.log("completed: " + requestDetails.requestId);
  var 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.indexOf(requestDetails.requestId) != -1) {
    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

stored-credentials

Acknowledgements

This API is based on Chromium's chrome.webRequest API. This documentation is derived from web_request.json in the Chromium code.

Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.

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