diff --git a/composer.json b/composer.json
index 287bee0..2176b1d 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
   "name": "codeinc/assets-middleware",
-  "version": "2.0.2",
+  "version": "2.0.3",
   "description": "A PSR-15 middleware to server static assets (CSS, JS, images, etc.)",
   "homepage": "https://github.com/CodeIncHQ/AssetsMiddleware",
   "type": "library",
diff --git a/src/AssetsMiddleware.php b/src/AssetsMiddleware.php
index 875cfc9..b356053 100644
--- a/src/AssetsMiddleware.php
+++ b/src/AssetsMiddleware.php
@@ -243,8 +243,27 @@ public function getAssetUri(string $assetPath):?string
         }
         foreach ($this->getAssetsDirectories() as $directoryKey => $directoryPath) {
             if (substr($assetPath, 0, strlen($directoryPath)) == $directoryPath) {
-                return $this->assetsUriPrefix.urlencode($directoryKey)
-                    .str_replace('\\', '/', substr($assetPath, strlen($directoryPath)));
+                return $this->assetsUriPrefix.urlencode($directoryKey).'/'
+                    .str_replace('\\', '/', substr($assetPath, strlen($directoryPath) + 1));
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Returns the URI of an assets directory.
+     *
+     * @param string $dirPath
+     * @return null|string
+     */
+    public function getAssetsDirectoryUri(string $dirPath):?string
+    {
+        if (($realDirPath = realpath($dirPath)) === false) {
+            throw new InvalidAssetPathException($dirPath);
+        }
+        foreach ($this->getAssetsDirectories() as $directoryKey => $directoryPath) {
+            if ($realDirPath = $directoryPath) {
+                return $this->assetsUriPrefix.urlencode($directoryKey).'/';
             }
         }
         return null;
diff --git a/src/Exceptions/InvalidAssetDirectoryPathException.php b/src/Exceptions/InvalidAssetDirectoryPathException.php
new file mode 100644
index 0000000..8ba0ed1
--- /dev/null
+++ b/src/Exceptions/InvalidAssetDirectoryPathException.php
@@ -0,0 +1,63 @@
+<?php
+//
+// +---------------------------------------------------------------------+
+// | CODE INC. SOURCE CODE                                               |
+// +---------------------------------------------------------------------+
+// | Copyright (c) 2018 - Code Inc. SAS - All Rights Reserved.           |
+// | Visit https://www.codeinc.fr for more information about licensing.  |
+// +---------------------------------------------------------------------+
+// | NOTICE:  All information contained herein is, and remains the       |
+// | property of Code Inc. SAS. The intellectual and technical concepts  |
+// | contained herein are proprietary to Code Inc. SAS are protected by  |
+// | trade secret or copyright law. Dissemination of this information or |
+// | reproduction of this material is strictly forbidden unless prior    |
+// | written permission is obtained from Code Inc. SAS.                  |
+// +---------------------------------------------------------------------+
+//
+// Author:   Joan Fabrégat <joan@codeinc.fr>
+// Date:     28/09/2018
+// Project:  AssetsMiddleware
+//
+declare(strict_types=1);
+namespace CodeInc\AssetsMiddleware\Exceptions;
+use Throwable;
+
+
+/**
+ * Class InvalidAssetDirectoryPathException
+ *
+ * @package CodeInc\AssetsMiddleware\Exceptions
+ * @author Joan Fabrégat <joan@codeinc.fr>
+ */
+class InvalidAssetDirectoryPathException extends \RuntimeException implements AssetsMiddlewareException
+{
+    /**
+     * @var string
+     */
+    private $dirPath;
+
+    /**
+     * InvalidAssetDirectoryPathException constructor.
+     *
+     * @param string $dirPath
+     * @param int $code
+     * @param Throwable|null $previous
+     */
+    public function __construct(string $dirPath, int $code = 0, Throwable $previous = null)
+    {
+        $this->dirPath = $dirPath;
+        parent::__construct(
+            sprintf("The assets directory path '%s' is not valid.", $dirPath),
+            $code,
+            $previous
+        );
+    }
+
+    /**
+     * @return string
+     */
+    public function getDirPath():string
+    {
+        return $this->dirPath;
+    }
+}
\ No newline at end of file