JWT Authentication for WP REST API

Extends the WP REST API using JSON Web Tokens Authentication as an authentication method.

JSON Web Tokens are an open, industry standard RFC 7519 method for representing claims securely between two parties.

Support and Requests please in Github: https://github.com/Tmeister/wp-api-jwt-auth

REQUIREMENTS

WP REST API V2

This plugin was conceived to extend the WP REST API V2 plugin features and, of course, was built on top of it.

So, to use the wp-api-jwt-auth you need to install and activate WP REST API.

PHP

Minimum PHP version: 7.4.0

PHP HTTP Authorization Header enable

Most of the shared hosting has disabled the HTTP Authorization Header by default.

To enable this option you’ll need to edit your .htaccess file adding the follow

RewriteEngine on
RewriteCond %{HTTP:Authorization} ^(.*)
RewriteRule ^(.*) - [E=HTTP_AUTHORIZATION:%1]

WPENGINE

To enable this option you’ll need to edit your .htaccess file adding the follow

See https://github.com/Tmeister/wp-api-jwt-auth/issues/1

SetEnvIf Authorization "(.*)" HTTP_AUTHORIZATION=$1

CONFIGURATION

Configurate the Secret Key

The JWT needs a secret key to sign the token this secret key must be unique and never revealed.

To add the secret key edit your wp-config.php file and add a new constant called JWT_AUTH_SECRET_KEY

define('JWT_AUTH_SECRET_KEY', 'your-top-secret-key');

You can use a string from here https://api.wordpress.org/secret-key/1.1/salt/

Configurate CORs Support

The wp-api-jwt-auth plugin has the option to activate CORs support.

To enable the CORs Support edit your wp-config.php file and add a new constant called JWT_AUTH_CORS_ENABLE

define('JWT_AUTH_CORS_ENABLE', true);

Finally activate the plugin within your wp-admin.

Namespace and Endpoints

When the plugin is activated, a new namespace is added

/jwt-auth/v1

Also, two new endpoints are added to this namespace

Endpoint | HTTP Verb
/wp-json/jwt-auth/v1/token | POST
/wp-json/jwt-auth/v1/token/validate | POST

USAGE

/wp-json/jwt-auth/v1/token

This is the entry point for the JWT Authentication.

Validates the user credentials, username and password, and returns a token to use in a future request to the API if the authentication is correct or error if the authentication fails.

Sample request using AngularJS

( function() {

  var app = angular.module( 'jwtAuth', [] );

  app.controller( 'MainController', function( $scope, $http ) {

    var apiHost = 'http://yourdomain.com/wp-json';

    $http.post( apiHost + '/jwt-auth/v1/token', {
        username: 'admin',
        password: 'password'
      } )

      .then( function( response ) {
        console.log( response.data )
      } )

      .catch( function( error ) {
        console.error( 'Error', error.data[0] );
      } );

  } );

} )();

Success response from the server

{
    "token": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJodHRwOlwvXC9qd3QuZGV2IiwiaWF0IjoxNDM4NTcxMDUwLCJuYmYiOjE0Mzg1NzEwNTAsImV4cCI6MTQzOTE3NTg1MCwiZGF0YSI6eyJ1c2VyIjp7ImlkIjoiMSJ9fX0.YNe6AyWW4B7ZwfFE5wJ0O6qQ8QFcYizimDmBy6hCH_8",
    "user_display_name": "admin",
    "user_email": "[email protected]",
    "user_nicename": "admin"
}

Error response from the server

{
    "code": "jwt_auth_failed",
    "data": {
        "status": 403
    },
    "message": "Invalid Credentials."
}

Once you get the token, you must store it somewhere in your application, ex. in a cookie or using localstorage.

From this point, you should pass this token to every API call

Sample call using the Authorization header using AngularJS

app.config( function( $httpProvider ) {
  $httpProvider.interceptors.push( [ '$q', '$location', '$cookies', function( $q, $location, $cookies ) {
    return {
      'request': function( config ) {
        config.headers = config.headers || {};
        //Assume that you store the token in a cookie.
        var globals = $cookies.getObject( 'globals' ) || {};
        //If the cookie has the CurrentUser and the token
        //add the Authorization header in each request
        if ( globals.currentUser && globals.currentUser.token ) {
          config.headers.Authorization = 'Bearer ' + globals.currentUser.token;
        }
        return config;
      }
    };
  } ] );
} );

The wp-api-jwt-auth will intercept every call to the server and will look for the Authorization Header, if the Authorization header is present will try to decode the token and will set the user according with the data stored in it.

If the token is valid, the API call flow will continue as always.

Sample Headers

POST /resource HTTP/1.1
Host: server.example.com
Authorization: Bearer mF_s9.B5f-4.1JqM

ERRORS

If the token is invalid an error will be returned, here are some samples of errors.

Invalid Credentials

[
  {
    "code": "jwt_auth_failed",
    "message": "Invalid Credentials.",
    "data": {
      "status": 403
    }
  }
]

Invalid Signature

[
  {
    "code": "jwt_auth_invalid_token",
    "message": "Signature verification failed",
    "data": {
      "status": 403
    }
  }
]

Expired Token

[
  {
    "code": "jwt_auth_invalid_token",
    "message": "Expired token",
    "data": {
      "status": 403
    }
  }
]

/wp-json/jwt-auth/v1/token/validate

This is a simple helper endpoint to validate a token; you only will need to make a POST request sending the Authorization header.

Valid Token Response

{
  "code": "jwt_auth_valid_token",
  "data": {
    "status": 200
  }
}

AVAILABLE HOOKS

The wp-api-jwt-auth is dev friendly and has five filters available to override the default settings.

jwt_auth_cors_allow_headers

The jwt_auth_cors_allow_headers allows you to modify the available headers when the CORs support is enabled.

Default Value:

'Access-Control-Allow-Headers, Content-Type, Authorization'

jwt_auth_not_before

The jwt_auth_not_before allows you to change the nbf value before the token is created.

Default Value:

Creation time - time()

jwt_auth_expire

The jwt_auth_expire allows you to change the value exp before the token is created.

Default Value:

time() + (DAY_IN_SECONDS * 7)

jwt_auth_token_before_sign

The jwt_auth_token_before_sign allows you to modify all the token data before to be encoded and signed.

Default Value

<?php
$token = array(
    'iss' => get_bloginfo('url'),
    'iat' => $issuedAt,
    'nbf' => $notBefore,
    'exp' => $expire,
    'data' => array(
        'user' => array(
            'id' => $user->data->ID,
        )
    )
);

jwt_auth_token_before_dispatch

The jwt_auth_token_before_dispatch allows you to modify all the response array before to dispatch it to the client.

Default Value:

<?php
$data = array(
    'token' => $token,
    'user_email' => $user->data->user_email,
    'user_nicename' => $user->data->user_nicename,
    'user_display_name' => $user->data->display_name,
);

jwt_auth_algorithm

The jwt_auth_algorithm allows you to modify the signing algorithm.

Default value:

<?php
$token = JWT::encode(
    apply_filters('jwt_auth_token_before_sign', $token, $user),
    $secret_key,
    apply_filters('jwt_auth_algorithm', 'HS256')
);

// ...

$token = JWT::decode(
    $token,
    new Key($secret_key, apply_filters('jwt_auth_algorithm', 'HS256'))
);

Testing

I’ve created a small app to test the basic functionality of the plugin; you can get the app and read all the details on the JWT-Client Repo