Prepare for content rewrites

camo-image-proxy.php

@@ -56,11 +56,14 @@ require_once PLUGIN_PATH . '/inc/functions.php';
  */
 function init() {
 	Options::instance();
+	URL::instance();
 
+	// Don't rewrite in the admin!
 	if ( is_admin() ) {
 		Options_Page::instance();
+	} else {
+		Rewrite_URLs::instance();
+		Rewrite_Content::instance();
 	}
-
-	Rewrite_URLs::instance();
 }
 add_action( 'init', __NAMESPACE__ . '\init' );

inc/class-rewrite-content.php

+<?php
+/**
+ * Rewrite images in content
+ *
+ * @package Camo_Image_Proxy
+ */
+
+namespace Camo_Image_Proxy;
+
+/**
+ * Class Rewrite_Content
+ */
+class Rewrite_Content {
+	use Singleton;
+
+	/**
+	 * Filter priority
+	 *
+	 * @var int
+	 */
+	private $priority;
+
+	/**
+	 * Hooks
+	 */
+	public function setup() {
+		$priority       = apply_filters( 'camo_image_proxy_rewrite_content_priority', PHP_INT_MAX - 1 );
+		$this->priority = absint( $priority );
+
+		add_filter( 'the_content', [ $this, 'filter_the_content' ], $this->priority );
+	}
+
+	/**
+	 * Rewrite image URLs in content
+	 *
+	 * @param string $content Post content.
+	 * @return string
+	 */
+	public function filter_the_content( string $content ) : string {
+		// TODO: only deal with image srcs, use DOM Document.
+		return $content;
+	}
+}