PHP OpenID Connect Basic Client

A simple library that allows an application to authenticate a user through the basic OpenID Connect flow. This library hopes to encourage OpenID Connect use by making it simple enough for a developer with little knowledge of the OpenID Connect protocol to setup authentication.

Supported Specifications

• OpenID Connect Core 1.0
• OpenID Connect Discovery 1.0 (finding the issuer is missing)
• OpenID Connect RP-Initiated Logout 1.0 - draft 01
• OpenID Connect Dynamic Client Registration 1.0
• RFC 6749: The OAuth 2.0 Authorization Framework
• RFC 7009: OAuth 2.0 Token Revocation
• RFC 7636: Proof Key for Code Exchange by OAuth Public Clients
• RFC 7662: OAuth 2.0 Token Introspection
• Draft: OAuth 2.0 Authorization Server Issuer Identifier in Authorization Response

Tested providers

Note: This list is not exhaustive. Other generic OIDC providers should work as well. If you have tested this library with a provider not listed here, please open a PR to add it to the list and add a test configuration (.run directory).

Provider	Is tested?	Notes
Keycloak	✅	Client authenticator must be set to "Client id and secret"
Casdoor	✅	Code challenge must be set to S256 or PKCE should be disabled

Requirements

1. PHP 8.1+
2. JSON extension
3. MBString extension
4. (Optional) One between GMP or BCMath extension to allow faster cipher key operations (for JWT; see here for more information)

Install

Install using composer:

composer require maicol07/oidc-client

Examples

Example 1: Basic Client

This example uses the Authorization Code flow and will also use PKCE if the OpenID Provider announces it in his Discovery document. If you are not sure, which flow you should choose: This one is the way to go. It is the most secure and versatile.

use Maicol07\OpenIDConnect\Client;

$oidc = new Client(
    provider_url: 'https://id.example.com',
    client_id: 'ClientIDHere',
    client_secret: 'ClientSecretHere',
    redirect_uri: 'https://example.com/callback.php',
);
$oidc->authenticate();
$name = $oidc->getUserInfo()->given_name;

See OpenID Connect spec for available user attributes

Example 2: Dynamic Registration

use Maicol07\OpenIDConnect\Client;

$oidc = new Client(
    provider_url: 'https://id.example.com',
    redirect_uri: 'https://example.com/callback.php',
    client_name: 'My Client',
);

$oidc->register();
[$client_id, $client_secret] = $oidc->getClientCredentials();

// Be sure to add logic to store the client id and client secret

Example 3: Network and Security

You should always use HTTPS for your application. If you are using a self-signed certificate, you can disable the SSL verification by setting the verify_ssl property on the client and, if you have it, set a custom certificate in the cert_path property (this works only if verifySsl is set to false).

You can also setup a proxy via the http_proxy.

use Maicol07\OpenIDConnect\Client;

$oidc = new Client(
    provider_url: 'https://id.example.com',
    client_id: 'ClientIDHere',
    client_secret: 'ClientSecretHere',
    redirect_uri: 'https://example.com/callback.php',
    http_proxy: 'http://proxy.example.com:8080',
    cert_path: 'path/to/cert.pem',
    verify_ssl: false
);

Example 4: Implicit flow

Reference: https://openid.net/specs/openid-connect-core-1_0.html#ImplicitFlowAuth

The implicit flow should be considered a legacy flow and not used if authorization code grant can be used. Due to its disadvantages and poor security, the implicit flow will be obsoleted with the upcoming OAuth 2.1 standard. See Example 1 for alternatives.

use Maicol07\OpenIDConnect\Client;
use Maicol07\OpenIDConnect\ResponseType;

$oidc = new Client(
    provider_url: 'https://id.example.com',
    client_id: 'ClientIDHere',
    client_secret: 'ClientSecretHere',
    redirect_uri: 'https://example.com/callback.php',
    response_type: ResponseType::ID_TOKEN,
    allow_implicit_flow: true,
);
$oidc->authenticate();
$sub = $oidc->getUserInfo()->sub;

Example 5: Introspection of an access token

Reference: https://tools.ietf.org/html/rfc7662

use Maicol07\OpenIDConnect\Client;

$oidc = new Client(
    provider_url: 'https://id.example.com',
    client_id: 'ClientIDHere',
    client_secret: 'ClientSecretHere',
    redirect_uri: 'https://example.com/callback.php'
);

$data = $oidc->introspectToken('an.access-token.as.given');
if (!$data->get('active')) {
    // the token is no longer usable
}

Example 6: PKCE Client

PKCE is already configured and used in most scenarios in Example 1. This example shows you how to explicitly set the Code Challenge Method in the initial config. This enables PKCE in case your OpenID Provider doesn’t announce support for it in the discovery document, but supports it anyway.

use Maicol07\OpenIDConnect\Client;
use Maicol07\OpenIDConnect\CodeChallengeMethod;

$oidc = new Client(
    provider_url: 'https://id.example.com',
    client_id: 'ClientIDHere',
    client_secret: 'ClientSecretHere',
    redirect_uri: 'https://example.com/callback.php',
    // for some reason we want to set S256 explicitly as Code Challenge Method
    // maybe your OP doesn’t announce support for PKCE in its discovery document.
    code_challenge_method: CodeChallengeMethod::S256
);

$oidc->authenticate();
$name = $oidc->getUserInfo()->given_name;

Example 7: Token endpoint authentication method

By default, only client_secret_basic is enabled on client side which was the only supported for a long time. Recently client_secret_jwt and private_key_jwt have been added, but they remain disabled until explicitly enabled.

use Maicol07\OpenIDConnect\Client;
use Maicol07\OpenIDConnect\TokenEndpointAuthMethod;

$oidc = new Client(
    provider_url: 'https://id.example.com',
    client_id: 'ClientIDHere',
    client_secret: 'ClientSecretHere',
    redirect_uri: 'https://example.com/callback.php',
    token_endpoint_auth_methods_supported: [
        TokenEndpointAuthMethod::CLIENT_SECRET_BASIC,
        TokenEndpointAuthMethod::CLIENT_SECRET_JWT,
        TokenEndpointAuthMethod::PRIVATE_KEY_JWT,
    ]
);

Note: A JWT generator is not included in this library yet.

Development Environments

Sometimes you may need to disable SSL security on your development systems. You can do it by calling the verify method with the false parameter. Note: This is not recommended on production systems.

use Maicol07\OpenIDConnect\Client;

$oidc new Client(
    provider_url: 'https://id.example.com',
    client_id: 'ClientIDHere',
    client_secret: 'ClientSecretHere',
    redirect_uri: 'https://example.com/callback.php',
    verify_ssl: false      
);

Testing

To run the tests, you need to have a running OpenID Connect provider

Keycloak

1. Run a Keycloak docker container

docker run -p 8080:8080 -e KEYCLOAK_ADMIN=admin -e KEYCLOAK_ADMIN_PASSWORD=admin quay.io/keycloak/keycloak:25.0.5 start-dev

2. Create a realm named test
3. Create a client named test-client with confidential access type
4. Set the Valid Redirect URIs to http://localhost:8080/callback
5. Set the Web Origins to http://localhost:8080
6. Set the Access Type to Bearer-only
7. Set the Client Authenticator to Client id and secret
8. Set the Client ID to test-client
9. Set the Client Secret to test-client-secret
10. Set the Root URL to http://localhost:8080

Todo

• Dynamic registration does not support registration auth tokens and endpoints

Contributing

• Issues and pull requests are welcome.