Authenticate an end-user.

This method is called only when Resource Owner Password Credentials Grant was used. Therefore, if you have no mind to support Resource Owner Password Credentials, always return null. In typical cases, you don't have to support Resource Owner Password Credentials Grant.

FYI: RFC 6749 says "The authorization server should take special care when enabling this grant type and only allow it when other flows are not viable."

Get extra properties to associate with an access token.

This method is expected to return an array of extra properties. The following is an example that returns an array containing one extra property.

public getProperties(): Property[] | null
{
    return [
        new Property('example_parameter', 'example_value')
    ];
}

Extra properties returned from this method will appear as top-level entries in a JSON response from an authorization server as shown in 5.1. Successful Response in RFC 6749.

Keys listed below should not be used and they would be ignored on the server side even if they were used. It's because they are reserved in RFC 6749 and OpenID Connect Core 1.0.

• access_token
• token_type
• expires_in
• refresh_token
• scope
• error
• error_description
• error_uri
• id_token

Note that there is an upper limit on the total size of extra properties. On the server side, the properties will be (1) converted to a multidimensional string array, (2) converted to JSON, (3) encrypted by AES/CBC/PKCS5Padding, (4) encoded by base64url, and then stored into the database. The length of the resultant string must not exceed 65,535 in bytes. This is the upper limit, but we think it is big enough.

When the value of grant_type parameter contained in the token request from the client application is authorization_code or refresh_token, extra properties are merged. Rules are as described below.

Rules for grant_type=authorization_code

If the authorization code presented by the client application already has extra properties (this happens if AuthorizationDecisionHandlerSpi.getProperties() returned extra properties when the authorization code was issued), extra properties returned by this method will be merged into the existing extra properties. Note that the existing extra properties will be overwritten if extra properties returned by this method have the same keys. For example, if an authorization code has two extra properties, a=1 and b=2, and if this method returns two extra properties, a=A and c=3, the resultant access token will have three extra properties, a=A, b=2 and c=3.

Rules for grant_type=refresh_token

If the access token associated with the refresh token presented by the client application already has extra properties, extra properties returned by this method will be merged into the existing extra properties. Note that the existing extra properties will be overwritten if extra properties returned by this method have the same keys.