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PSR-7 and PSR-15 Basic Auth Middleware

This middleware implements HTTP Basic Authentication. It was originally developed for Slim but can be used with all frameworks using PSR-7 or PSR-15 style middlewares. It has been tested with Slim Framework and Zend Expressive.

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Heads up! You are reading documentation for 3.x branch which is PHP 7.1 and up only. If you are using older version of PHP see the 2.x branch. These two branches are not backwards compatible, see UPGRADING for instructions how to upgrade.

Install

Install latest version using composer.

$ composer require tuupola/slim-basic-auth

Usage

Configuration options are passed as an array. Only mandatory parameter is users. This is an array where you pass one or more "username" => "password" combinations. Username is the key and password is the value.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ]
]));

Same with Zend Expressive.

$app = Zend\Expressive\AppFactory::create();

$app->pipe(new Tuupola\Middleware\HttpBasicAuthentication([
    "users" => [
        "root" => "t00r",
        "user" => "passw0rd"
    ]
]));

Rest of the examples assume you are using Slim Framework.

Cleartext passwords are only good for quick testing. You probably want to use hashed passwords. Hashed password can be generated with htpasswd command line tool or password_hash() PHP function

$ htpasswd -nbBC 10 root t00r
root:$2y$10$1lwCIlqktFZwEBIppL4ak.I1AHxjoKy9stLnbedwVMrt92aGz82.O
$ htpasswd -nbBC 10 somebody passw0rd
somebody:$2y$10$6/vGXuMUoRlJUeDN.bUWduge4GhQbgPkm6pfyGxwgEWT0vEkHKBUW

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "users" => [
        "root" => '$2y$10$1lwCIlqktFZwEBIppL4ak.I1AHxjoKy9stLnbedwVMrt92aGz82.O',
        "somebody" => '$2y$10$6/vGXuMUoRlJUeDN.bUWduge4GhQbgPkm6pfyGxwgEWT0vEkHKBUW'
    ]
]));

Even if you are using hashed passwords it is not the best idea to store credentials in the code. Instead you could store them in environment or external file which is not committed to GitHub.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "users" => [
        "admin" => getenv("ADMIN_PASSWORD")
    ]
]));

Optional parameters

Path

The optional path parameter allows you to specify the protected part of your website. It can be either a string or an array. You do not need to specify each URL. Instead think of path setting as a folder. In the example below everything starting with /api will be authenticated.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/api", /* or ["/admin", "/api"] */
    "realm" => "Protected",
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ]
]));

Ignore

With optional ignore parameter you can make exceptions to path parameter. In the example below everything starting with /api and /admin will be authenticated with the exception of /api/token and /admin/ping which will not be authenticated.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => ["/api", "/admin"],
    "ignore" => ["/api/token", "/admin/ping"],
    "realm" => "Protected",
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ]
]));

Before

Before function is called only when authentication succeeds but before the next incoming middleware is called. You can use this to alter the request before passing it to the next incoming middleware in the stack. If it returns anything else than \Psr\Http\Message\RequestInterface the return value will be ignored.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/admin",
    "realm" => "Protected",
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ],
    "before" => function ($request, $arguments) {
        return $request->withAttribute("user", $arguments["user"]);
    }
]));

After

After function is called only when authentication succeeds and after the incoming middleware stack has been called. You can use this to alter the response before passing it next outgoing middleware in the stack. If it returns anything else than \Psr\Http\Message\ResponseInterface the return value will be ignored.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/admin",
    "realm" => "Protected",
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ],
    "after" => function ($response, $arguments) {
        return $response->withHeader("X-Brawndo", "plants crave");
    }
]));

Security

Basic authentication transmits credentials in clear text. For this reason HTTPS should always be used together with basic authentication. If the middleware detects insecure usage over HTTP it will throw a RuntimeException with the following message: Insecure use of middleware over HTTP denied by configuration.

By default, localhost is allowed to use HTTP. The security behavior of HttpBasicAuthentication can also be configured to allow:

How to configure a whitelist:

You can list hosts to allow access insecurely. For example, to allow HTTP traffic to your development host dev.example.com, add the hostname to the relaxed config key.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/admin",
    "secure" => true,
    "relaxed" => ["localhost", "dev.example.com"],
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ]
]));

Allow HTTPS termination and forwarding

If public traffic terminates SSL on a load balancer or proxy and forwards to the application host insecurely, HttpBasicAuthentication can inspect request headers to ensure that the original client request was initiated securely. To enable, add the string headers to the relaxed config key.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/admin",
    "secure" => true,
    "relaxed" => ["localhost", "headers"],
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ]
]));

Allow all unencrypted traffic

To allow insecure usage by any host, you must enable it manually by setting secure to false. This is generally a bad idea. Use only if you know what you are doing.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/admin",
    "secure" => false,
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ]
]));

Custom authentication methods

Sometimes passing users in an array is not enough. To authenticate against custom datasource you can pass a callable as authenticator parameter. This can be either a class which implements AuthenticatorInterface or anonymous function. Callable receives an array containing user and password as argument. In both cases authenticator must return either true or false.

If you are creating an Enterprise™ software which randomly lets people log in you could use the following.

use Tuupola\Middleware\HttpBasicAuthentication\AuthenticatorInterface;
use Tuupola\Middleware\HttpBasicAuthentication;

class RandomAuthenticator implements AuthenticatorInterface {
    public function __invoke(array $arguments): bool {
        return (bool)rand(0,1);
    }
}

$app = new Slim\App;

$app->add(new HttpBasicAuthentication([
    "path" => "/admin",
    "realm" => "Protected",
    "authenticator" => new RandomAuthenticator
]));

Same thing can also be accomplished with anonymous function.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/admin",
    "realm" => "Protected",
    "authenticator" => function ($arguments) {
        return (bool)rand(0,1);
    }
]));

Setting response body when authentication fails

By default plugin returns an empty response body with 401 response. You can return custom body using by providing an error handler. This is useful for example when you need additional information why authentication failed.

$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/api",
    "realm" => "Protected",
    "users" => [
        "root" => "t00r",
        "somebody" => "passw0rd"
    ],
    "error" => function ($response, $arguments) {
        $data = [];
        $data["status"] = "error";
        $data["message"] = $arguments["message"];

        $body = $response->getBody();
        $body->write(json_encode($data, JSON_UNESCAPED_SLASHES));

        return $response->withBody($body);
    }
]));

Usage with PDO

For those in hurry there is a ready made PDO authenticator. It covers most of the use cases. You probably end up implementing your own though.

use Tuupola\Middleware\HttpBasicAuthentication\PdoAuthenticator;

$pdo = new PDO("sqlite:/tmp/users.sqlite");
$app = new Slim\App;

$app->add(new Tuupola\Middleware\HttpBasicAuthentication([
    "path" => "/admin",
    "realm" => "Protected",
    "authenticator" => new PdoAuthenticator([
        "pdo" => $pdo
    ])
]));

For better explanation see Basic Authentication from Database blog post.

Usage with FastCGI

By default Apache does not pass credentials to FastCGI process. If you are using mod_fcgi you can configure authorization headers with:

FastCgiExternalServer /usr/lib/cgi-bin/php5-fcgi -host 127.0.0.1:9000 -pass-header Authorization

Testing

You can run tests either manually or automatically on every code change. Automatic tests require entr to work.

$ make test

$ brew install entr
$ make watch

Contributing

Please see CONTRIBUTING for details.

Security

If you discover any security related issues, please email tuupola@appelsiini.net instead of using the issue tracker.

License

The MIT License (MIT). Please see LICENSE for more information.