init

wp-content/plugins/mailpoet/lib/Newsletter/Renderer/PostProcess/OpenTracking.php

@@ -0,0 +1,51 @@
+<?php // phpcs:ignore SlevomatCodingStandard.TypeHints.DeclareStrictTypes.DeclareStrictTypesMissing
+
+namespace MailPoet\Newsletter\Renderer\PostProcess;
+
+if (!defined('ABSPATH')) exit;
+
+
+use MailPoet\Newsletter\Links\Links;
+use MailPoet\Newsletter\Renderer\Renderer;
+use MailPoet\Util\pQuery\pQuery;
+use MailPoet\WP\Functions as WPFunctions;
+
+class OpenTracking {
+  public static function process($template) {
+    $DOM = new pQuery();
+    $DOM = $DOM->parseStr($template);
+    $template = $DOM->select('body');
+    // url is a temporary data tag that will be further replaced with
+    // the proper track API URL during sending
+    $url = Links::DATA_TAG_OPEN;
+    $openTrackingImage = sprintf(
+      '<img alt="" class="" src="%s"/>',
+      $url
+    );
+    self::appendToDomNodes($template, $openTrackingImage);
+    return $DOM->__toString();
+  }
+
+  public static function addTrackingImage() {
+    WPFunctions::get()->addFilter(Renderer::FILTER_POST_PROCESS, function ($template) {
+      return OpenTracking::process($template);
+    });
+    return true;
+  }
+
+  private static function appendToDomNodes($template, $openTrackingImage): void {
+    // Preserve backward compatibility with pQuery::html()
+    // by processing an array of DomNodes
+    if (!empty($template)) {
+      $template = is_array($template) ? $template : [$template];
+      array_map(
+        function ($item) use ($openTrackingImage) {
+          $itemHtml = $item->toString(true, true, 1);
+          $item->html($itemHtml . $openTrackingImage);
+          return $item;
+        },
+        $template
+      );
+    }
+  }
+}

wp-content/plugins/mailpoet/lib/Newsletter/Renderer/PostProcess/index.php

@@ -0,0 +1 @@
+<?php