REST API structure using Slim framework

  * REST API routes are handle by Slim.
  * Every API controller go through ApiMiddleware which handles security.
  * First service implemented `/info`, for tests purpose.

1 files changed, 132 insertions, 0 deletions

diff --git a/application/api/ApiMiddleware.php b/application/api/ApiMiddleware.php
new file mode 100644
index 00000000..162e88e0
--- /dev/null
+++ b/application/api/ApiMiddleware.php
@@ -0,0 +1,132 @@
+<?php
+
+namespace Shaarli\Api;
+
+use Shaarli\Api\Exceptions\ApiException;
+use Shaarli\Api\Exceptions\ApiAuthorizationException;
+use Slim\Container;
+use Slim\Http\Request;
+use Slim\Http\Response;
+
+/**
+ * Class ApiMiddleware
+ *
+ * This will be called before accessing any API Controller.
+ * Its role is to make sure that the API is enabled, configured, and to validate the JWT token.
+ *
+ * If the request is validated, the controller is called, otherwise a JSON error response is returned.
+ *
+ * @package Api
+ */
+class ApiMiddleware
+{
+    /**
+     * @var int JWT token validity in seconds (9 min).
+     */
+    public static $TOKEN_DURATION = 540;
+
+    /**
+     * @var Container: contains conf, plugins, etc.
+     */
+    protected $container;
+
+    /**
+     * @var \ConfigManager instance.
+     */
+    protected $conf;
+
+    /**
+     * ApiMiddleware constructor.
+     *
+     * @param Container $container instance.
+     */
+    public function __construct($container)
+    {
+        $this->container = $container;
+        $this->conf = $this->container->get('conf');
+        $this->setLinkDb($this->conf);
+    }
+
+    /**
+     * Middleware execution:
+     *   - check the API request
+     *   - execute the controller
+     *   - return the response
+     *
+     * @param  Request  $request  Slim request
+     * @param  Response $response Slim response
+     * @param  callable $next     Next action
+     *
+     * @return Response response.
+     */
+    public function __invoke($request, $response, $next)
+    {
+        try {
+            $this->checkRequest($request);
+            $response = $next($request, $response);
+        } catch(ApiException $e) {
+            $e->setResponse($response);
+            $e->setDebug($this->conf->get('dev.debug', false));
+            $response = $e->getApiResponse();
+        }
+
+        return $response;
+    }
+
+    /**
+     * Check the request validity (HTTP method, request value, etc.),
+     * that the API is enabled, and the JWT token validity.
+     *
+     * @param  Request $request  Slim request
+     *
+     * @throws ApiAuthorizationException The API is disabled or the token is invalid.
+     */
+    protected function checkRequest($request)
+    {
+        if (! $this->conf->get('api.enabled', true)) {
+            throw new ApiAuthorizationException('API is disabled');
+        }
+        $this->checkToken($request);
+    }
+
+    /**
+     * Check that the JWT token is set and valid.
+     * The API secret setting must be set.
+     *
+     * @param  Request $request  Slim request
+     *
+     * @throws ApiAuthorizationException The token couldn't be validated.
+     */
+    protected function checkToken($request) {
+        $jwt = $request->getHeaderLine('jwt');
+        if (empty($jwt)) {
+            throw new ApiAuthorizationException('JWT token not provided');
+        }
+
+        if (empty($this->conf->get('api.secret'))) {
+            throw new ApiAuthorizationException('Token secret must be set in Shaarli\'s administration');
+        }
+
+        ApiUtils::validateJwtToken($jwt, $this->conf->get('api.secret'));
+    }
+
+    /**
+     * Instantiate a new LinkDB including private links,
+     * and load in the Slim container.
+     *
+     * FIXME! LinkDB could use a refactoring to avoid this trick.
+     *
+     * @param \ConfigManager $conf instance.
+     */
+    protected function setLinkDb($conf)
+    {
+        $linkDb = new \LinkDB(
+            $conf->get('resource.datastore'),
+            true,
+            $conf->get('privacy.hide_public_links'),
+            $conf->get('redirector.url'),
+            $conf->get('redirector.encode_url')
+        );
+        $this->container['db'] = $linkDb;
+    }
+}