{project_name} comes with a client-side JavaScript library that can be used to secure HTML5/JavaScript applications. The JavaScript adapter has built-in support for Cordova applications.
A best practice is to load the JavaScript adapter directly from {project_name} Server as it will automatically be updated when you upgrade the server. If you copy the adapter to your web application instead, make sure you upgrade the adapter only after you have upgraded the server.
One important thing to note 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 makes it very important to make sure the redirect URIs you have configured for the client are correct and as specific as possible.
You also need to configure valid redirect URIs and valid web origins. Be as specific as possible as failing to do so may result in a security vulnerability.
By default to authenticate you need to call the `login` function. However, there are two options available to make the adapter automatically authenticate. You
can pass `login-required` or `check-sso` to the init function. `login-required` will authenticate the client if the user is logged-in to {project_name}
or display the login page if not. `check-sso` will only authenticate the client if the user is already logged-in, if the user is not logged-in the browser will be
redirected back to the application and remain unauthenticated.
To enable `login-required` set `onLoad` to `login-required` and pass to the init method:
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 can do this by the `updateToken` method. The `updateToken` method returns a promise object which makes it easy to invoke the service only if the
token was successfully refreshed and for example display an error to the user if it wasn't. For example:
With this flow the {project_name} server returns an authorization code, not an authentication token, to the application. The JavaScript adapter exchanges
{project_name} also supports the http://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 may have better performance than standard flow, as there is no additional
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
One thing to note is that only an access token is provided and there is no refresh token. This means that once the access token has expired the application
Keycloaks support hybird mobile apps developed with https://cordova.apache.org/[Apache Cordova]. The Javascript adapter has two modes for this: `cordova` and `cordova-native`:
The default is `cordova`. The adapter will pick it automatically if no adapter type has been configured and `window.cordova` is present.
When logging in, it will open an https://cordova.apache.org/docs/en/latest/reference/cordova-plugin-inappbrowser/[InApp Browser] that lets the user interact with keycloak and afterwards returns to the app by redirecting to http://localhost.
Therefore this URL needs to be whitelisted as valid redirect-uri in the client configuration section of the Administration Console.
While this mode is very easy to setup, it also has a few disadvantages:
The InApp-Browser is a browser embedded in the app and not the phones default browser.
Therefore it will have different settings and stored credentials will not be available. It might be slower, especially when rendering more complex themes.
There are security concerns to consider, before using this mode:
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 dont trust.
The alternative mode `cordova-native` takes a different approach.
It opens the login page in the systems browser.
After the user has authenticated, the browser redirects back into the app by a special URL.
From there, the keycloak adapter can finish the login by reading the code or token from the URL.
You can activate the native mode by passing the adater type `cordova-native` to the ìnit` method:
[source,javascript]
----
keycloak.init({ adapter: 'cordova-native' })
----
This adapter required two additional plugins:
* https://github.com/google/cordova-plugin-browsertab[cordova-plugin-browsertab]: allows the app to open webpages in the systems browser
* https://github.com/e-imaxina/cordova-plugin-deeplinks[cordova-plugin-deeplinks]: allow the browser to redirect back to your app by special URLs
The technical details for linking to an app differ on each plattform and special setup is needed.
Please refer to the according sections of the deeplinks plugin for further instructions (https://github.com/e-imaxina/cordova-plugin-deeplinks#android-web-integration[Android] and [iOS https://github.com/e-imaxina/cordova-plugin-deeplinks#ios-web-integration[iOS]].
There are different kinds of links for opening apps: custom schemes (i.e. `myapp://login` or `android-app://com.example.myapp/https/example.com/login`) and https://developer.apple.com/ios/universal-links/[Universal Links (iOS]) / https://developer.android.com/training/app-indexing/deep-linking.html[Deep Links (Android)]. While the former are easier to setup and tend to work more reliable, the later offer extra security as they are unique and only the owner of a domain can register them. Custom-URLs are deprecated on iOS. We recommend that you use universal links, combined with a fallback site with a custom-url link on it for best reliability.
Furthermore, we recommend the following steps to improve compatibility with the Keycloak Adapter:
* Universal Links on iOS seem to work more reliable with `response-mode` set to `query`
* To prevent Android from opening a new instance of your app on redirect add the following snippet to `config.xml`:
If available, the JavaScript adapter will use native Promise instances as return values from functions documented as returning promises. To retain backwards compatibility, the `success()` and `error()` functions from previous versions of the adapter are retained. These remain available whether or not native Promises are provided by the browser. Promise API polyfills are available for browsers without support:
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 try to open the login andregistration page in the phones 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.
* 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.
* prompt - By default the login screen is displayed if the user is not logged-in to {project_name}. To only authenticate to the application if the user is already logged-in and not display the login page if the user is not logged-in, set this option to `none`. To always require re-authentication and ignore SSO, set this option to `login` .
* 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.
* locale - Sets the 'ui_locales' query param in compliance with section 3.1.2.1 of the OIDC 1.0 specification.
* kcLocale - Specifies the desired Keycloak locale for the UI. This differs from the locale param in that it tells the Keycloak server to set a cookie and update the user's profile to a new preferred locale.
* 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 login screen to obtain a new access token.
