|
| 1 | +..index:: |
| 2 | + single: Security; Access Token |
| 3 | + |
| 4 | +How to use Access Token Authentication |
| 5 | +====================================== |
| 6 | + |
| 7 | +Access tokens are commonly used in API contexts. The access token is obtained |
| 8 | +through an authorization server (or similar) whose role is to verify the user identity |
| 9 | +and receive consent before the token is issued. |
| 10 | + |
| 11 | +Access Tokens can be of any kind: opaque strings, Json Web Tokens (JWT) or SAML2 (XML structures). |
| 12 | +Please refer to the `RFC6750`_: *The OAuth 2.0 Authorization Framework: Bearer Token Usage*. |
| 13 | + |
| 14 | +Using the Access Token Authenticator |
| 15 | +------------------------------------ |
| 16 | + |
| 17 | +This guide assumes you have setup security and have created a user object |
| 18 | +in your application. Follow:doc:`the main security guide</security>` if |
| 19 | +this is not yet the case. |
| 20 | + |
| 21 | +1) Configure the Access Token Authenticator |
| 22 | +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| 23 | + |
| 24 | +To use the access token authenticator, you must configure a ``token_handler``. |
| 25 | +The token handler retrieves the user identifier from the token. |
| 26 | +In order to get the user identifier, implementations may need to load and validate |
| 27 | +the token (e.g. revocation, expiration time, digital signature...). |
| 28 | + |
| 29 | +..configuration-block:: |
| 30 | + |
| 31 | + ..code-block::yaml |
| 32 | +
|
| 33 | +# config/packages/security.yaml |
| 34 | +security: |
| 35 | +firewalls: |
| 36 | +main: |
| 37 | +access_token: |
| 38 | +token_handler:App\Security\AccessTokenHandler |
| 39 | +
|
| 40 | +This handler shall implement the interface |
| 41 | +:class:`Symfony\\Component\\Security\\Http\\AccessToken\\AccessTokenHandlerInterface`. |
| 42 | +In the following example, the handler will retrieve the token from a database |
| 43 | +using a fictive repository. |
| 44 | + |
| 45 | +..configuration-block:: |
| 46 | + |
| 47 | + ..code-block::php |
| 48 | +
|
| 49 | + // src/Security/AccessTokenHandler.php |
| 50 | + namespace App\Security; |
| 51 | +
|
| 52 | + use App\Repository\AccessTokenRepository; |
| 53 | + use Symfony\Component\Security\Http\AccessToken\AccessTokenHandlerInterface; |
| 54 | +
|
| 55 | + class AccessTokenHandler implements AccessTokenHandlerInterface |
| 56 | + { |
| 57 | + public function __construct( |
| 58 | + private readonly AccessTokenRepository $repository |
| 59 | + ) { |
| 60 | + } |
| 61 | +
|
| 62 | + public function getUserIdentifierFrom(string $token): string |
| 63 | + { |
| 64 | + $accessToken = $this->repository->findOneByValue($token); |
| 65 | + if ($accessToken === null || !$accessToken->isValid()) { |
| 66 | + throw new BadCredentialsException('Invalid credentials.'); |
| 67 | + } |
| 68 | +
|
| 69 | + return $accessToken->getUserId(); |
| 70 | + } |
| 71 | + } |
| 72 | +
|
| 73 | +..caution:: |
| 74 | + |
| 75 | + It is important to check the token is valid. |
| 76 | + For instance, in the example we verify the token has not expired. |
| 77 | + With self-contained access tokens such as JWT, the handler is required to |
| 78 | + verify the digital signature and understand all claims, |
| 79 | + especially ``sub``, ``iat``, ``nbf`` and ``exp``. |
| 80 | + |
| 81 | +Customizing the Authenticator |
| 82 | +----------------------------- |
| 83 | + |
| 84 | +1) Access Token Extractors |
| 85 | + |
| 86 | +By default, the access token is read from the request header parameter ``Authorization`` with the scheme ``Bearer``. |
| 87 | +You can change the behavior and send the access token through different ways. |
| 88 | + |
| 89 | +This authenticator provides services able to extract the access token as per the RFC6750: |
| 90 | + |
| 91 | +- ``header`` or ``security.access_token_extractor.header``: the token is sent through the request header. Usually ``Authorization`` with the ``Bearer`` scheme. |
| 92 | +- ``query_string`` or ``security.access_token_extractor.query_string``: the token is part of the query string. Usually ``access_token``. |
| 93 | +- ``request_body`` or ``security.access_token_extractor.request_body``: the token is part of the request body during a POST request. Usually ``access_token``. |
| 94 | + |
| 95 | +..caution:: |
| 96 | + |
| 97 | + Because of the security weaknesses associated with the URI method, |
| 98 | + including the high likelihood that the URL or the request body containing the access token will be logged, |
| 99 | + methods ``query_string`` and ``request_body`` **SHOULD NOT** be used unless it is impossible |
| 100 | + to transport the access token in the request header field. |
| 101 | + |
| 102 | +Also, you can also create a custom extractor. The class shall implement the interface |
| 103 | +:class:`Symfony\\Component\\Security\\Http\\AccessToken\\AccessTokenExtractorInterface`. |
| 104 | + |
| 105 | +..configuration-block:: |
| 106 | + |
| 107 | + ..code-block::yaml |
| 108 | +
|
| 109 | +# config/packages/security.yaml |
| 110 | +security: |
| 111 | +firewalls: |
| 112 | +main: |
| 113 | +access_token: |
| 114 | +token_handler:App\Security\AccessTokenHandler |
| 115 | +token_extractors:'my_custom_access_token_extractor' |
| 116 | +
|
| 117 | +It is possible to set multiple extractors. |
| 118 | +In this case, **the order is important**: the first in the list is called first. |
| 119 | + |
| 120 | +..configuration-block:: |
| 121 | + |
| 122 | + ..code-block::yaml |
| 123 | +
|
| 124 | +# config/packages/security.yaml |
| 125 | +security: |
| 126 | +firewalls: |
| 127 | +main: |
| 128 | +access_token: |
| 129 | +token_handler:App\Security\AccessTokenHandler |
| 130 | +token_extractors: |
| 131 | + -'header' |
| 132 | + -'request_body' |
| 133 | + -'query_string' |
| 134 | + -'my_custom_access_token_extractor' |
| 135 | +
|
| 136 | +2) Customizing the Success Handler |
| 137 | + |
| 138 | +Sometimes, the default success handling does not fit your use-case (e.g. |
| 139 | +when you need to generate and return additional response header parameters). |
| 140 | +To customize how the success handler behaves, create your own handler as a class that implements |
| 141 | +:class:`Symfony\\Component\\Security\\Http\\Authentication\\AuthenticationSuccessHandlerInterface`:: |
| 142 | + |
| 143 | + // src/Security/Authentication/AuthenticationSuccessHandler.php |
| 144 | + namespace App\Security\Authentication; |
| 145 | + |
| 146 | + use Symfony\Component\HttpFoundation\JsonResponse; |
| 147 | + use Symfony\Component\HttpFoundation\Request; |
| 148 | + use Symfony\Component\Security\Core\Authentication\Token\TokenInterface; |
| 149 | + use Symfony\Component\Security\Http\Authentication\AuthenticationSuccessHandlerInterface; |
| 150 | + |
| 151 | + class AuthenticationSuccessHandler implements AuthenticationSuccessHandlerInterface |
| 152 | + { |
| 153 | + public function onAuthenticationSuccess(Request $request, TokenInterface $token): JsonResponse |
| 154 | + { |
| 155 | + $user = $token->getUser(); |
| 156 | + $userApiToken = $user->getApiToken(); |
| 157 | + |
| 158 | + return new JsonResponse(['apiToken' => $userApiToken]); |
| 159 | + } |
| 160 | + } |
| 161 | + |
| 162 | +Then, configure this service ID as the ``success_handler``: |
| 163 | + |
| 164 | +..configuration-block:: |
| 165 | + |
| 166 | + ..code-block::yaml |
| 167 | +
|
| 168 | +# config/packages/security.yaml |
| 169 | +security: |
| 170 | +firewalls: |
| 171 | +main: |
| 172 | +access_token: |
| 173 | +token_handler:App\Security\AccessTokenHandler |
| 174 | +success_handler:App\Security\Authentication\AuthenticationSuccessHandler |
| 175 | +
|
| 176 | +..tip:: |
| 177 | + |
| 178 | + If you want to customize the default failure handling, use the |
| 179 | + ``failure_handler`` option and create a class that implements |
| 180 | +:class:`Symfony\\Component\\Security\\Http\\Authentication\\AuthenticationFailureHandlerInterface`. |
| 181 | + |
| 182 | +.. _`RFC6750`:https://datatracker.ietf.org/doc/html/rfc6750 |