{project_name} comes with a client-side JavaScript library called `keycloak-js` that can be used to secure web applications. The adapter also comes with built-in support for Cordova applications.
One important thing to consider about using client-side applications is that the client has to be a public client as there is no secure way to store client credentials in a client-side application. This consideration makes it very important to make sure the redirect URIs you have configured for the client are correct and as specific as possible.
To use the adapter, create a client for your application in the {project_name} Admin Console. Make the client public by toggling *Client authentication* to *Off* on the *Capability config* page.
You also need to configure `Valid Redirect URIs` and `Web Origins`. Be as specific as possible as failing to do so may result in a security vulnerability.
The following example shows how to initialize the adapter. Make sure that you replace the options passed to the `Keycloak` constructor with those of the client you have configured.
To authenticate, you call the `login` function. Two options exist to make the adapter automatically authenticate. You can pass `login-required` or `check-sso` to the `init()` function.
* `login-required` authenticates the client if the user is logged in to {project_name} or displays the login page if the user is not logged in.
* `check-sso` only authenticates the client if the user is already logged in. If the user is not logged in, the browser is redirected back to the application and remains unauthenticated.
You can configure a _silent_ `check-sso` option. With this feature enabled, your browser will not perform a full redirect to the {project_name} server and back to your application, but this action will be performed in a hidden iframe. Therefore, your application resources are only loaded and parsed once by the browser, namely when the application is initialized and not again after the redirect back from {project_name} to your application. This approach is particularly useful in case of SPAs (Single Page Applications).
To enable the _silent_ `check-sso`, you provide a `silentCheckSsoRedirectUri` attribute in the init method. Make sure this URI is a valid endpoint in the application; it must be configured as a valid redirect for the client in the {project_name} Admin Console:
The page at the silent check-sso redirect uri is loaded in the iframe after successfully checking your authentication state and retrieving the tokens from the {project_name} server.
It has no other task than sending the received tokens to the main application and should only look like this:
WARNING: _Silent_ `check-sso` functionality is limited in some modern browsers. Please see the <<_modern_browsers,Modern Browsers with Tracking Protection Section>>.
One thing to keep in mind is that the access token by default has a short life expiration so you may need to refresh the access token prior to sending the request. You refresh this token by calling the `updateToken()` method. This method returns a Promise, which makes it easy to invoke the service only if the token was successfully refreshed and displays an error to the user if it was not refreshed. For example:
Both access and refresh token are stored in memory and are not persisted in any kind of storage. Therefore, these tokens should never be persisted to prevent hijacking attacks.
By default, the adapter creates a hidden iframe that is used to detect if a Single-Sign Out has occurred. This iframe does not require any network traffic. Instead the status is retrieved by looking at a special status cookie. This feature can be disabled by setting `checkLoginIframe: false` in the options passed to the `init()` method.
WARNING: Session Status iframe functionality is limited in some modern browsers. Please see <<_modern_browsers,Modern Browsers with Tracking Protection Section>>.
With this flow, the {project_name} server returns an authorization code, not an authentication token, to the application. The JavaScript adapter exchanges the `code` for an access token and a refresh token after the browser is redirected back to the application.
{project_name} also supports the https://openid.net/specs/openid-connect-core-1_0.html#ImplicitFlowAuth[Implicit] flow where an access token is sent immediately after successful authentication with {project_name}. This flow may have better performance than the standard flow because no additional request exists to exchange the code for tokens, but it has implications when the access token expires.
However, sending the access token in the URL fragment can be a security vulnerability. For example the token could be leaked through web server logs and or
To enable implicit flow, you enable the *Implicit Flow Enabled* flag for the client in the {project_name} Admin Console. You also pass the parameter `flow` with the value `implicit` to `init` method:
Note that only an access token is provided and no refresh token exists. This situation means that once the access token has expired, the application has to redirect to {project_name} again to obtain a new access token.
This flow requires the client to have both the *Standard Flow* and *Implicit Flow* enabled in the Admin Console. The {project_name} server then sends both the code and tokens to your application. The access token can be used immediately while the code can be exchanged for access and refresh tokens. Similar to the implicit flow, the hybrid flow is good for performance because the access token is available immediately.
{project_name} supports hybrid mobile apps developed with https://cordova.apache.org/[Apache Cordova]. The adapter has two modes for this: `cordova` and `cordova-native`:
The default is `cordova`, which the adapter automatically selects if no adapter type has been explicitly configured and `window.cordova` is present. When logging in, it opens an https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-inappbrowser/[InApp Browser] that lets the user interact with {project_name} and afterwards returns to the app by redirecting to `http://localhost`. Because of this behavior, you whitelist this URL as a valid redirect-uri in the client configuration section of the Admin Console.
* The InApp-Browser is a browser embedded in the app and is not the phone's default browser. Therefore it will have different settings and stored credentials will not be available.
* The InApp-Browser might also be slower, especially when rendering more complex themes.
* There are security concerns to consider, before using this mode, such as that it is possible for the app to gain access to the credentials of the user, as it has full control of the browser rendering the login page, so do not allow its use in apps you do not trust.
The alternative mode is`cordova-native`, which takes a different approach. It opens the login page using the system's browser. After the user has authenticated, the browser redirects back into the application using a special URL. From there, the {project_name} adapter can finish the login by reading the code or token from the URL.
Please refer to the Android and iOS sections of the https://github.com/e-imaxina/cordova-plugin-deeplinks/blob/master/README.md[deeplinks plugin documentation] for further instructions.
While the former are easier to set up and tend to work more reliably, the latter offer extra security because they are unique and only the owner of a domain can register them. Custom-URLs are deprecated on iOS. For best reliability, we recommend that you use universal links combined with a fallback site that uses a custom-url link.
In some situations, you may need to run the adapter in environments that are not supported by default, such as Capacitor. To use the JavasScript client in these environments, you can pass a custom adapter. For example, a third-party library could provide such an adapter to make it possible to reliably run the adapter:
It's also possible to make your own adapter, to do so you will have to implement the methods described in the `KeycloakAdapter` interface. For example the following TypeScript code ensures that all the methods are properly implemented:
import Keycloak, { KeycloakAdapter } from 'keycloak-js';
// Implement the 'KeycloakAdapter' interface so that all required methods are guaranteed to be present.
const MyCustomAdapter: KeycloakAdapter = {
login(options) {
// Write your own implementation here.
}
// The other methods go here...
};
const keycloak = new Keycloak();
keycloak.init({
adapter: MyCustomAdapter,
});
----
Naturally you can also do this without TypeScript by omitting the type information, but ensuring implementing the interface properly will then be left entirely up to you.
In the latest versions of some browsers, various cookies policies are applied to prevent tracking of the users by third parties, such as SameSite in Chrome or completely blocked third-party cookies. Those policies are likely to become more restrictive and adopted by other browsers over time. Eventually cookies in third-party contexts may become completely unsupported and blocked by the browsers. As a result, the affected adapter features might ultimately be deprecated.
The adapter relies on third-party cookies for Session Status iframe, _silent_ `check-sso` and partially also for regular (non-silent) `check-sso`. Those features have limited functionality or are completely disabled based on how restrictive the browser is regarding cookies. The adapter tries to detect this setting and reacts accordingly.
All features are supported if SSL / TLS connection is configured on the {project_name} side as well as on the application side. For example, Chrome is affected starting with version 84.
Session Status iframe is not supported and is automatically disabled if such browser behavior is detected by the adapter. This means the adapter cannot use a session cookie for Single Sign-Out detection and must rely purely on tokens. As a result, when a user logs out in another window, the application using the adapter will not be logged out until the application tries to refresh the Access Token. Therefore, consider setting the Access Token Lifespan to a relatively short time, so that the logout is detected as soon as possible. For more details, see link:{adminguide_link}#_timeouts[Session and Token Timeouts].
_Silent_ `check-sso` is not supported and falls back to regular (non-silent) `check-sso` by default. This behavior can be changed by setting `silentCheckSsoFallback: false` in the options passed to the `init` method. In this case, `check-sso` will be completely disabled if restrictive browser behavior is detected.
Regular `check-sso` is affected as well. Since Session Status iframe is unsupported, an additional redirect to {project_name} has to be made when the adapter is initialized to check the user's login status. This check is different from the standard behavior when the iframe is used to tell whether the user is logged in, and the redirect is performed only when the user is logged out.
Allows you to override the way that redirects and other browser-related functions will be handled by the library.
Available options:
* "default" - the library uses the browser api for redirects (this is the default)
* "cordova" - the library will try to use the InAppBrowser cordova plugin to load keycloak login/registration pages (this is used automatically when the library is working in a cordova ecosystem)
* "cordova-native" - the library tries to open the login and registration page using the phone's system browser using the BrowserTabs cordova plugin. This requires extra setup for redirecting back to the app (see <<hybrid-apps-with-cordova>>).
Response type sent to {project_name} with login requests. This is determined based on the flow value used during initialization, but can be overridden by setting this value.
* scope - Set the default scope parameter to the {project_name} login endpoint. Use a space-delimited list of scopes. Those typically
reference link:{adminguide_link}#_client_scopes[Client scopes] defined on a particular client. Note that the scope `openid` will
always be added to the list of scopes by the adapter. For example, if you enter the scope options `address phone`, then the request
to {project_name} will contain the scope parameter `scope=openid address phone`. Note that the default scope specified here is overwritten if the `login()` options specify scope explicitly.
* responseMode - Set the OpenID Connect response mode send to {project_name} server at login request. Valid values are `query` or `fragment`. Default value is `fragment`, which means that after successful authentication will {project_name} redirect to JavaScript application with OpenID Connect parameters added in URL fragment. This is generally safer and recommended over `query`.
* flow - Set the OpenID Connect flow. Valid values are `standard`, `implicit` or `hybrid`.
* enableLogging - Enables logging messages from Keycloak to the console (default is `false`).
* pkceMethod - The method for Proof Key Code Exchange (https://datatracker.ietf.org/doc/html/rfc7636[PKCE]) to use. Configuring this value enables the PKCE mechanism. Available options:
* acrValues - Generates the `acr_values` parameter which refers to authentication context class reference and allows clients to declare the required assurance level requirements, e.g. authentication mechanisms. See https://openid.net/specs/openid-connect-modrna-authentication-1_0.html#acr_values[Section 4. acr_values request values and level of assurance in OpenID Connect MODRNA Authentication Profile 1.0].
* messageReceiveTimeout - Set a timeout in milliseconds for waiting for message responses from the Keycloak server. This is used, for example, when waiting for a message during 3rd party cookies check. The default value is 10000.
* locale - When onLoad is 'login-required', sets the 'ui_locales' query param in compliance with https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest[section 3.1.2.1 of the OIDC 1.0 specification].
For example, enforce displaying the login screen in case of value `login`. Or enforce displaying of consent screen for the value `consent` in case that client has `Consent Required`.
Finally it is possible use the value `none` to make sure that login screen is not displayed to the user, which is useful just to check SSO for the case when user was already
authenticated before (This is related to the `onLoad` check with value `check-sso` described above).
* maxAge - Used just if user is already authenticated. Specifies maximum time since the authentication of user happened. If user is already authenticated for longer time than `maxAge`, the SSO is ignored and he will need to re-authenticate again.
* acrValues - Generates the `acr_values` parameter which refers to authentication context class reference and allows clients to declare the required assurance level requirements, e.g. authentication mechanisms. See https://openid.net/specs/openid-connect-modrna-authentication-1_0.html#acr_values[Section 4. acr_values request values and level of assurance in OpenID Connect MODRNA Authentication Profile 1.0].
* action - If the value is `register`, the user is redirected to the registration page. See link:{adminguide_link}#_registration-rc-client-flows[Registration requested by client section] for more details.
If the value is `UPDATE_PASSWORD` or another supported required action, the user will be redirected to the reset password page or the other required action page. However, if the user is not authenticated, the user will be sent to the login page and redirected after authentication.
See link:{adminguide_link}#con-aia_server_administration_guide[Application Initiated Action section] for more details.
* locale - Sets the 'ui_locales' query param in compliance with https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest[section 3.1.2.1 of the OIDC 1.0 specification].
* cordovaOptions - Specifies the arguments that are passed to the Cordova in-app-browser (if applicable). Options `hidden` and `location` are not affected by these arguments. All available options are defined at https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-inappbrowser/. Example of use: `{ zoom: "no", hardwareback: "yes" }`;
* *onTokenExpired* - Called when the access token is expired. If a refresh token is available the token can be refreshed with updateToken, or in cases where it is not (that is, with implicit flow) you can redirect to the login screen to obtain a new access token.
