Log in a citizen¶

This how-to guides you through the steps required to ensure that only citizens authenticated with ID-porten can access your application.

Prerequisites¶

• Your application is exposed to the appropriate audience.

Configure your application¶

Enable the login proxy for ID-porten in your application configuration:

spec:
  idporten:
    enabled: true
    sidecar:
      enabled: true

See the NAIS application reference for the complete specifications with all possible options.

Now that your application is configured, you will need to handle inbound requests in your application code.

Handle inbound requests¶

As long as the citizen is authenticated, the Authorization header includes their access_token as a Bearer token.

Your application is responsible for verifying that this token is present and valid. To do so, follow these steps:

Handle missing or empty Authorization header¶

If the Authorization header is missing or empty, the citizen is unauthenticated.

Return an appropriate HTTP status code to the frontend, and redirect the citizen's user agent to the login endpoint:

https://<ingress>/oauth2/login

Validate token in Authorization header¶

If the Authorization header is present, validate the JWT Bearer token within. If invalid, redirect the citizen to the login endpoint:

https://<ingress>/oauth2/login

To validate a token, you can either:

• validate tokens with Texas, or
• validate JWTs manually in your application

Validate with Texas¶

Send a HTTP POST request to the endpoint found in the NAIS_TOKEN_INTROSPECTION_ENDPOINT environment variable. The request must have a Content-Type header set to either:

• application/json or
• application/x-www-form-urlencoded

The body of the request should contain the following parameters:

POST ${NAIS_TOKEN_INTROSPECTION_ENDPOINT} HTTP/1.1
Content-Type: application/json

{
    "identity_provider": "idporten",
    "token": "eyJra..."
}

POST ${NAIS_TOKEN_INTROSPECTION_ENDPOINT} HTTP/1.1
Content-Type: application/x-www-form-urlencoded

identity_provider=idporten&
token=eyJra...

The response is always a HTTP 200 OK response with a JSON body.

It always contains the active field, which is a boolean value that indicates whether the token is valid or not.

Success response¶

If the token is valid, the response will additionally contain all the token's claims:

{
    "active": true,
    "exp": 1730980893,
    "iat": 1730977293,
    ...
}

Claims are copied verbatim from the token to the response.

Error response¶

If the token is invalid, the only additional field in the response is the error field:

{
    "active": false,
    "error": "token is expired"
}

The error field contains a human-readable error message that describes why the token is invalid.

Validate JWT manually¶

Validating a JWT involves a number of steps. These steps are outlined and described below in a language- and framework-agnostic way.

To validate the token, start by validating the signature and standard time-related claims.

Additionally, perform the following validations:

Issuer Validation

Validate that the iss claim has a value that is equal to either:

1. the IDPORTEN_ISSUER environment variable, or
2. the issuer property from the metadata discovery document. The document is found at the endpoint pointed to by the IDPORTEN_WELL_KNOWN_URL environment variable.

Audience Validation

Validate that the aud claim is equal to the IDPORTEN_AUDIENCE environment variable.

Signature Validation

Validate that the token is signed with a public key published at the JWKS endpoint. This endpoint URI can be found in one of two ways:

1. the IDPORTEN_JWKS_URI environment variable, or
2. the jwks_uri property from the metadata discovery document. The document is found at the endpoint pointed to by the IDPORTEN_WELL_KNOWN_URL environment variable.

Claims Validation

Other claims may be present in the token. Validation of these claims is optional.

Next steps¶

The citizen is now authenticated and can access your application. However, the subject token found in the Authorization header is only valid for your application.

To consume other APIs on behalf of the citizen, exchange the token for a new token that targets a specific API.

Related pages¶

Learn how to consume other APIs on behalf of a citizen

ID-porten reference

Login proxy reference