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 the `extraInfoSpec` parameter
* in the listener, 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, the browser attempts to log in with the 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 resolves with an object containing an `authCredentials` property, set to the credentials to supply

**Note:** 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 Chrome Manifest V3 extensions, the `"webRequestBlocking"` permission is no longer available (except for policy-installed extensions). Instead, the `"webRequest"` and `"webRequestAuthProvider"` permissions enable you to supply credentials asynchronously.

**Note:** Firefox does not support `"webRequestAuthProvider"`, but support is planned. See bug 1820569.

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
------


```js
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. Returns `true` 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.

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 `authCredentials` properties set.
 This behavior is the same for Firefox and Chrome. However, synchronous handling is only appropriate for the simplest of extensions.
* To handle the request asynchronously:
    + in Firefox, the `extraInfoSpec` array must include `"blocking"`, and the event handler function can return a Promise that resolves to a `BlockingResponse` object, with its `cancel` or `authCredentials` properties set. This is basically the same as handling the event synchronously.
    + in Chrome, the `extraInfoSpec` array must include `"asyncBlocking"` (without `"blocking"`). The event handler function is passed a function as a second parameter (called `asyncCallback`) that should be invoked with the `BlockingResponse` result, with its `cancel` or `authCredentials` properties set.

`filter`

`webRequest.RequestFilter`. A filter that restricts the events that are sent to this listener.

`extraInfoSpec` Optional

`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. To handle the request asynchronously in Chrome, use `"asyncBlocking"` instead.
* `"responseHeaders"`: include `responseHeaders` in the `details` object passed to the listener

Additional objects
------------------

### details

`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.


`cookieStoreId`

`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 is `0` 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` is `main_frame` or `sub_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` for `Proxy-Authenticate`, `false` for `WWW-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 the following properties:

`firstParty`

`array` of `strings`. Classification flags for the request's first party.

`thirdParty`

`array` of `strings`. Classification flags for the request or its window hierarchy's third parties.

The classification flags include:

* `fingerprinting` and `fingerprinting_content`: indicates the request is involved in fingerprinting. `fingerprinting_content` indicates the request is loaded from an origin found to fingerprint but is not considered to participate in tracking, such as a payment provider.
* `cryptomining` and `cryptomining_content`: similar to the fingerprinting category but for cryptomining resources.
* `tracking`, `tracking_ad`, `tracking_analytics`, `tracking_social`, and `tracking_content`: indicates the request is involved in tracking. `tracking` is any generic tracking request. The `ad`, `analytics`, `social`, and `content` suffixes identify the type of tracker.
* `any_basic_tracking`: a meta flag that combines tracking and fingerprinting flags, excluding `tracking_content` and `fingerprinting_content`.
* `any_strict_tracking`: a meta flag that combines tracking and fingerprinting flags, including `tracking_content` and `fingerprinting_content`.
* `any_social_tracking`: a meta flag that combines any social tracking flags.

Examples
--------

This code observes authentication requests for the target URL:


```js
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:


```js
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:


```js
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:


```js
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

* stored-credentials
Browser compatibility
---------------------

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

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