Introduced hotlink prevention & hotlink management

CHANGELOG.md

@@ -1,5 +1,17 @@
 # Changelog
 
+## Unreleased
+
+> [!WARNING]
+> [Hotlinking](https://plugins.doublesecretagency.com/digital-download/hotlinking/) from other websites is **prevented by default** for all new links. Hotlinking can be enabled either on the "Settings" page, or when configuring an individual token.
+
+### Added
+- Introduced hotlink prevention (and enabled it by default).
+- Made it possible to [allow hotlinks](https://plugins.doublesecretagency.com/digital-download/hotlinking/#allowing-hotlinks) from other websites.
+
+### Changed
+- [Hotlinking](https://plugins.doublesecretagency.com/digital-download/hotlinking/) is now prevented by default.
+
 ## 2.2.1 - 2022-08-02
 
 ### Fixed

docs/.vuepress/config.js

@@ -37,6 +37,7 @@ module.exports = {
                     {text: 'Storing a Token', link: '/storing-a-token/'},
                     {text: 'Short Download Links', link: '/short-download-links/'},
                     {text: 'Get Link Data from a Token', link: '/get-link-data-from-a-token/'},
+                    {text: 'Hotlinking', link: '/hotlinking/'},
                 ]
             },
             {
@@ -55,6 +56,7 @@ module.exports = {
                 'storing-a-token',
                 'short-download-links',
                 'get-link-data-from-a-token',
+                'hotlinking',
             ],
         }
     }

docs/creating-a-token.md

@@ -47,12 +47,15 @@ $token = DigitalDownload::$plugin->digitalDownload->createToken($asset, [
  - **asset** - The downloadable Asset.
  - **options** - A key-value set of options.
 
-| Option       | Default  | Description
-|:-------------|:---------|:------------------
-| expires      | `'P14D'` | Time until asset key expires. Accepts any valid PHP interval specification.
-| maxDownloads | `0`      | Maximum number of downloads allowed. (0 = unlimited)
-| requireUser  | _null_   | If downloads are restricted to specific users and/or user groups.
-| headers      | `{}`     | Associative array of optional HTTP headers to send during download.
+| Option                          | Default  | Description                                                                 |
+|:--------------------------------|:---------|:----------------------------------------------------------------------------|
+| expires                         | `'P14D'` | Time until asset key expires. Accepts any valid PHP interval specification. |
+| maxDownloads                    | `0`      | Maximum number of downloads allowed. (0 = unlimited)                        |
+| [requireUser](#requireuser)     | _null_   | If downloads are restricted to specific users and/or user groups.           |
+| [allowHotlinks](#allowhotlinks) | `'none'` | Whether to allow [hotlinking](/hotlinking/) of download link.               |
+| headers                         | `{}`     | Associative array of optional HTTP headers to send during download.         |
+
+### `requireUser`
 
 The `requireUser` option can take on a variety of forms:
 
@@ -68,3 +71,25 @@ null                      // Anyone can download (default)
 
 ['mygroup', 467]          // Mix & match users and groups
 ```
+
+### `allowHotlinks`
+
+There are three ways to use the `allowHotlinks` option:
+
+#### Prevent hotlinking from all other websites. (default)
+```twig
+'allowHotlinks': 'none'
+```
+
+#### Allow hotlinking from all other websites.
+```twig
+'allowHotlinks': 'all'
+```
+
+#### Allow hotlinking from specified sites (an array of domains).
+```twig
+'allowHotlinks': [
+    'friendlysite.com',
+    'anotherfriendlysite.com'
+]
+```

docs/hotlinking.md

@@ -0,0 +1,31 @@
+---
+description: Protect your download links by preventing downloads from other domains.
+---
+
+# Hotlinking
+
+Hotlinking (also known as leeching) is when another website links directly to your downloadable content. For a variety of reasons, you probably don't want your content to be downloadable from other websites.
+
+:::warning Prevented by default since v2.3 (in Craft 4) and v3.1 (in Craft 5)
+Once hotlink prevention was introduced, prevention became the default behavior for all new links.
+:::
+
+## Allowing Hotlinks
+
+Hotlinking from other websites is **forbidden by default.** When necessary, there are two ways to configure hotlinking:
+
+### Option 1 - Configure availability per each link
+
+For maximum control, configure the availability of individual links when [creating each token](/creating-a-token/#createtoken-asset-options).
+
+Use the `allowHotlinks` option to configure exactly how hotlinks should be allowed.
+
+### Option 2 - Configure availability globally via plugin's Settings
+
+For global control, edit the plugin's Settings page. Set the "Allow Hotlinks" field to manage the availability of all links in the system.
+
+<img width="520" :src="$withBase('/images/allow-hotlinks.png')" class="dropshadow" alt="">
+
+If the option to "only hotlink from specified sites" is selected, you'll then be prompted to specify a whitelist of friendly domains.
+
+<img width="520" :src="$withBase('/images/hotlink-domain-whitelist.png')" class="dropshadow" alt="">

src/DigitalDownload.php

@@ -50,7 +50,7 @@ class DigitalDownload extends Plugin
     /**
      * @inheritdoc
      */
-    public string $schemaVersion = '2.1.0';
+    public string $schemaVersion = '3.1.0';
 
     /**
      * @inheritdoc

src/migrations/Install.php

@@ -48,6 +48,7 @@ protected function createTables(): void
             'id'             => $this->primaryKey(),
             'assetId'        => $this->integer()->notNull(),
             'token'          => $this->string(),
+            'allowHotlinks'  => $this->string(),
             'headers'        => $this->text(),
             'enabled'        => $this->boolean()->defaultValue(true),
             'expires'        => $this->dateTime(),

src/migrations/m240408_000000_digitalDownload_addAllowHotlinksColumn.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * Digital Download plugin for Craft CMS
+ *
+ * Provide secure digital download links to your files.
+ *
+ * @author    Double Secret Agency
+ * @link      https://www.doublesecretagency.com/
+ * @copyright Copyright (c) 2016 Double Secret Agency
+ */
+
+namespace doublesecretagency\digitaldownload\migrations;
+
+use craft\db\Migration;
+use yii\base\NotSupportedException;
+
+/**
+ * Migration: Add allowHotlinks column
+ * @since 3.1.0
+ */
+class m240408_000000_digitalDownload_addAllowHotlinksColumn extends Migration
+{
+
+    /**
+     * @inheritdoc
+     * @throws NotSupportedException
+     */
+    public function safeUp(): void
+    {
+        $table = '{{%digitaldownload_tokens}}';
+        if (!$this->db->columnExists($table, 'allowHotlinks')) {
+            $this->addColumn($table, 'allowHotlinks', $this->string()->after('token'));
+        }
+        $this->update($table, ['allowHotlinks' => 'all']);
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function safeDown(): bool
+    {
+        echo "m240408_000000_digitalDownload_addAllowHotlinksColumn cannot be reverted.\n";
+
+        return false;
+    }
+
+}

src/models/Link.php

@@ -42,6 +42,11 @@ class Link extends Model
      */
     public string $token;
 
+    /**
+     * @var string|array Which domains (besides this one) can download linked files.
+     */
+    public string|array $allowHotlinks = 'none';
+
     /**
      * @var string Optionally append or replace download headers.
      */

src/models/Settings.php

@@ -25,6 +25,16 @@ class Settings extends Model
      */
     public string $shortPath = 'download';
 
+    /**
+     * @var string Which domains (besides this one) can download linked files.
+     */
+    public string $allowHotlinks = 'none';
+
+    /**
+     * @var array List of domains allowed to hotlink downloadable files.
+     */
+    public array $hotlinksWhitelist = [];
+
     /**
      * @var bool Whether to keep a detailed log of all downloads.
      */

src/records/Token.php

@@ -23,6 +23,7 @@
  * @property int $id
  * @property int $assetId
  * @property string $token
+ * @property string|array $allowHotlinks
  * @property string $headers
  * @property int $enabled
  * @property DateTime $expires
@@ -54,7 +55,7 @@ public static function tableName(): string
      */
     public function getAsset(): ActiveQueryInterface
     {
-        return $this->hasOne(Asset::class, ['id' => 'assetId']);
+        return self::hasOne(Asset::class, ['id' => 'assetId']);
     }
 
 }

src/resources/js/settings.js

@@ -25,7 +25,7 @@ function updateDemoPath() {
     $demoPath.html(demoPath);
 }
 
-// =========================================================================
+// ========================================================================= //
 
 // Update path while typing
 $shortPath.on('keyup', function() {

src/services/DigitalDownloadService.php

@@ -56,7 +56,7 @@ public function createToken(Asset $file, array $options = []): string
         return DigitalDownload::$plugin->digitalDownload_token->createToken($file, $options);
     }
 
-    // =========================================================================
+    // ========================================================================= //
 
     /**
      * Generates a URL to download the file.
@@ -122,7 +122,7 @@ public function link(Asset|string $token, array|string $options = [], string $la
         return Template::raw("<a href=\"{$url}\">{$label}</a>");
     }
 
-    // =========================================================================
+    // ========================================================================= //
 
     /**
      * Get the link data from an existing token.
@@ -183,7 +183,7 @@ public function cleanup(): void
         $this->disableExpiredLinks();
     }
 
-    // =========================================================================
+    // ========================================================================= //
 
     /**
      * Ensures that we're working with a proper token