Client Credentials Grant with OAuth 2.0 Playground

This page guides you through using a sample Playground application to try out authentication to an OAuth 2.0/OpenID Connect web application using the Client Credentials grant type.


Set up the sample application

Prerequisites

  • Download Apache Tomcat 8.x and install it. Tomcat server installation location will later be referred to as <TOMCAT_HOME> in this guide.

  • It is recommended that you use a hostname that is not localhost to avoid browser errors. Modify your machine's /etc/hosts entry to reflect this.

    Info

    Note that wso2is.local is used in this documentation as an example, but you must modify this when configuring the authenticators or connectors with this sample application.

Download the sample

To deploy a WSO2 Identity Server sample application, you need download the playground2.war file from the latest release assets.

Deploy the sample web app

To deploy the sample web app on a web container:

  1. Copy the downloaded playground2.war file into the <TOMCAT_HOME>/apache-tomcat-<version>/webapps folder.

  2. Start the Tomcat server.

  3. Access the applcation through this URL: http://wso2is.local:8080/playground2/oauth2.jsp

    Info

    By default, Tomcat runs on port 8080. If you have configured it to run on a different port, update the URL and access the playground application.

You will now be redirected to the landing page of the sample application.

Troubleshooting tip

If you are getting the following error, the sample applications do not have a keystore in them. Therefore, you may get this error after changing the tomcat hostname because the public key of the WSO2 Identity Server does not exist in the Java certificate store.

` java javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target


Register a service provider

  1. On WSO2 Identity Server Management Console, go to Main > Identity > Service Providers and click Add.

  2. Enter playground2 as the Service Provider Name text box, and click Register.

  3. Expand the Inbound Authentication Configuration > OAuth/OpenID Connect Configuration and click Configure.

  4. Fill in the form that appears. By default, all Allowed Grant Types are selected; you can disable the grant types that are not required.

    Note

    The custom grant type will only appear on the UI if you have configured the JWT grant type. The value specified as the name of the oauth.custom_grant_type in the deployment.toml file when creating the custom grant type is the value that will appear on the UI. For more information on writing a custom grant type, see Write a Custom OAuth 2.0 Grant Type.

  5. Enter the Callback Url as http://wso2is.local:8080/playground2/oauth2client.

    Tip

    For more information on other advanced configurations refer, Advanced OpenID Connect.

  6. Click Add. Note that client key and client secret are generated.

  7. Click Update.


Try Client Credentials grant

The following cURL command can be used to try this grant type.

Request Format

curl -v -X POST --basic -u <oauth_client_key>:<oauth_client_secret> -H "Content-Type:application/x-www-form-urlencoded;charset=UTF-8" -k -d "grant_type=client_credentials" <token_endpoint>


Sample Request

curl -v -X POST --basic -u 7wYeybBGCVfLxPmS0z66WNMffyMa:WYfwHUsbsEvwtqmDLuaxF_VCQJwa -H "Content-Type:application/x-www-form-urlencoded;charset=UTF-8" -k -d "grant_type=client_credentials" https://localhost:9443/oauth2/token

You will receive the following response with the access token.

{
    "access_token":"16ab408c-0f31-3321-8bed-313e836df373",
    "token_type":"Bearer",
    "expires_in":2986
}

Note

WSO2 Identity Server provides more control over issuing id tokens and user claims for client-credential grant type. To facilitate this, add the following configurations to the deployment.toml file found in the <IS_HOME>/repository/conf folder in order to register new ScopeHandlers and ScopeValidators .

[oauth.custom_scope_validator]
class = "org.fully.qualified.class.name.CustomScopeValidator"

Further, by configuring the <IdTokenAllowed> property to true or false along with the above configuration, you can turn on or turn off the process of issuing ID tokens for the grant types that have the openid scope. By default, IdTokenAllowed is set to true, you can allow it to issue id_tokens for all grant types that have the openid scope. By configuring it to false, you can stop issuing ID tokens.
Note: You can not turn off the process of issuing ID tokens for the authorization_code grant type.

By configuring the <IsRefreshTokenAllowed> property to true or false along with the above configuration, you can turn on or turn on the process of issuing refresh tokens. By default, IsRefreshTokenAllowed is set to true, and you can allow it to issue refresh tokens for all grant types. By configuring it to false, you can stop issuing refresh tokens.
Note: By default, issuing ID token for client_credentials grant type is disabled as it is logically invalid.

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