Add a text filter that converts supported plain URLs to <drupal-url> elements

src/Plugin/Filter/ConvertUrlToEmbedFilter.php

@@ -0,0 +1,191 @@
+<?php
+
+namespace Drupal\url_embed\Plugin\Filter;
+
+use Drupal\Component\Utility\Html;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\filter\FilterProcessResult;
+use Drupal\filter\Plugin\FilterBase;
+
+/**
+ * Provides a filter to display embedded entities based on data attributes.
+ *
+ * @Filter(
+ *   id = "url_embed_convert_links",
+ *   title = @Translation("Convert URLs to URL embeds"),
+ *   description = @Translation("Convert plain URLs to embed elements that can be rendered with the <em>Display embedded URLs</em> filter."),
+ *   type = Drupal\filter\Plugin\FilterInterface::TYPE_TRANSFORM_REVERSIBLE,
+ *   settings = {
+ *     "url_prefix" = "",
+ *   },
+ * )
+ */
+class ConvertUrlToEmbedFilter extends FilterBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function settingsForm(array $form, FormStateInterface $form_state) {
+    $form['url_prefix'] = [
+      '#type' => 'textfield',
+      '#title' => $this->t('URL prefix'),
+      '#default_value' => $this->settings['url_prefix'],
+      '#description' => $this->t('Optional prefix that will be used to indicate which URLs that apply. All URLs that are supported will be converted if empty. Example: EMBED-https://twitter.com/drupal/status/735873777683320832'),
+    ];
+    return $form;
+  }
+
+
+  /**
+   * {@inheritdoc}
+   */
+  public function process($text, $langcode) {
+    return new FilterProcessResult(static::convertUrls($text, $this->settings['url_prefix']));
+  }
+
+  /**
+   * Replaces appearances of supported URLs with <drupal-url> embed elements.
+   *
+   * Logic of this function is copied from _filter_url() and slightly adopted
+   * for our use case. _filter_url() is unfortunately not general enough to
+   * re-use it.
+   *
+   * @param string $text
+   *   Text to be processed.
+   * @param string $url_prefix
+   *   (Optional) Prefix that should be used to manually choose which URLs
+   *   should be converted.
+   *
+   * @return string
+   *   Processed text.
+   */
+  public static function convertUrls($text, $url_prefix = '') {
+    // Tags to skip and not recurse into.
+    $ignore_tags = 'a|script|style|code|pre';
+
+    // Create an array which contains the regexps for each type of link.
+    // The key to the regexp is the name of a function that is used as
+    // callback function to process matches of the regexp. The callback function
+    // is to return the replacement for the match. The array is used and
+    // matching/replacement done below inside some loops.
+    $tasks = [];
+
+    // Prepare protocols pattern for absolute URLs.
+    // \Drupal\Component\Utility\UrlHelper::stripDangerousProtocols() will replace
+    // any bad protocols with HTTP, so we need to support the identical list.
+    // While '//' is technically optional for MAILTO only, we cannot cleanly
+    // differ between protocols here without hard-coding MAILTO, so '//' is
+    // optional for all protocols.
+    // @see \Drupal\Component\Utility\UrlHelper::stripDangerousProtocols()
+    $protocols = \Drupal::getContainer()->getParameter('filter_protocols');
+    $protocols = implode(':(?://)?|', $protocols) . ':(?://)?';
+
+    $valid_url_path_characters = "[\p{L}\p{M}\p{N}!\*\';:=\+,\.\$\/%#\[\]\-_~@&]";
+
+    // Allow URL paths to contain balanced parens
+    // 1. Used in Wikipedia URLs like /Primer_(film)
+    // 2. Used in IIS sessions like /S(dfd346)/
+    $valid_url_balanced_parens = '\('. $valid_url_path_characters . '+\)';
+
+    // Valid end-of-path characters (so /foo. does not gobble the period).
+    // 1. Allow =&# for empty URL parameters and other URL-join artifacts
+    $valid_url_ending_characters = '[\p{L}\p{M}\p{N}:_+~#=/]|(?:' . $valid_url_balanced_parens . ')';
+
+    $valid_url_query_chars = '[a-zA-Z0-9!?\*\'@\(\);:&=\+\$\/%#\[\]\-_\.,~|]';
+    $valid_url_query_ending_chars = '[a-zA-Z0-9_&=#\/]';
+
+    //full path
+    //and allow @ in a url, but only in the middle. Catch things like http://example.com/@user/
+    $valid_url_path = '(?:(?:'.$valid_url_path_characters . '*(?:'.$valid_url_balanced_parens .$valid_url_path_characters . '*)*'. $valid_url_ending_characters . ')|(?:@' . $valid_url_path_characters . '+\/))';
+
+    // Prepare domain name pattern.
+    // The ICANN seems to be on track towards accepting more diverse top level
+    // domains, so this pattern has been "future-proofed" to allow for TLDs
+    // of length 2-64.
+    $domain = '(?:[\p{L}\p{M}\p{N}._+-]+\.)?[\p{L}\p{M}]{2,64}\b';
+    $ip = '(?:[0-9]{1,3}\.){3}[0-9]{1,3}';
+    $auth = '[\p{L}\p{M}\p{N}:%_+*~#?&=.,/;-]+@';
+    $trail = '('.$valid_url_path.'*)?(\\?'.$valid_url_query_chars .'*'.$valid_url_query_ending_chars.')?';
+
+    // Match absolute URLs.
+    $url_pattern = "(?:$auth)?(?:$domain|$ip)/?(?:$trail)?";
+    $pattern = "`$url_prefix((?:$protocols)(?:$url_pattern))`u";
+    $tasks['replaceFullLinks'] = $pattern;
+
+    // HTML comments need to be handled separately, as they may contain HTML
+    // markup, especially a '>'. Therefore, remove all comment contents and add
+    // them back later.
+    _filter_url_escape_comments('', TRUE);
+    $text = preg_replace_callback('`<!--(.*?)-->`s', '_filter_url_escape_comments', $text);
+
+    // Split at all tags; ensures that no tags or attributes are processed.
+    $chunks = preg_split('/(<.+?>)/is', $text, -1, PREG_SPLIT_DELIM_CAPTURE);
+    // PHP ensures that the array consists of alternating delimiters and
+    // literals, and begins and ends with a literal (inserting NULL as
+    // required). Therefore, the first chunk is always text:
+    $chunk_type = 'text';
+    // If a tag of $ignore_tags is found, it is stored in $open_tag and only
+    // removed when the closing tag is found. Until the closing tag is found,
+    // no replacements are made.
+    $open_tag = '';
+
+    for ($i = 0; $i < count($chunks); $i++) {
+      if ($chunk_type == 'text') {
+        // Only process this text if there are no unclosed $ignore_tags.
+        if ($open_tag == '') {
+          // If there is a match, inject a link into this chunk via the callback
+          // function contained in $task.
+          $chunks[$i] = preg_replace_callback(
+            $pattern,
+            function ($match) {
+              if (\Drupal::service('url_embed')->getEmbed(Html::decodeEntities($match[1]))) {
+                return '<drupal-url data-embed-url="' . $match[1] . '"></drupal-url>';
+              }
+              else {
+                return $match[1];
+              }
+            },
+            $chunks[$i]
+          );
+        }
+        // Text chunk is done, so next chunk must be a tag.
+        $chunk_type = 'tag';
+      }
+      else {
+        // Only process this tag if there are no unclosed $ignore_tags.
+        if ($open_tag == '') {
+          // Check whether this tag is contained in $ignore_tags.
+          if (preg_match("`<($ignore_tags)(?:\s|>)`i", $chunks[$i], $matches)) {
+            $open_tag = $matches[1];
+          }
+        }
+        // Otherwise, check whether this is the closing tag for $open_tag.
+        else {
+          if (preg_match("`<\/$open_tag>`i", $chunks[$i], $matches)) {
+            $open_tag = '';
+          }
+        }
+        // Tag chunk is done, so next chunk must be text.
+        $chunk_type = 'text';
+      }
+    }
+
+    $text = implode($chunks);
+    // Revert to the original comment contents
+    _filter_url_escape_comments('', FALSE);
+    return preg_replace_callback('`<!--(.*?)-->`', '_filter_url_escape_comments', $text);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function tips($long = FALSE) {
+    if ($long) {
+      return $this->t('<p>You can convert plain URLs to &lt;drupal-url&gt; HTML elements. Those elements are later converted to embeds using "Display embedded URLs" text filter.</p>');
+    }
+    else {
+      return $this->t('You can convert plain URLs to embed elements.');
+    }
+  }
+
+}

src/Tests/ConvertUrlToEmbedFilterTest.php

@@ -0,0 +1,134 @@
+<?php
+
+namespace Drupal\url_embed\Tests;
+
+use Drupal\editor\Entity\Editor;
+use Drupal\filter\Entity\FilterFormat;
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests the url_embed_convert_links filter.
+ *
+ * @group url_embed
+ */
+class ConvertUrlToEmbedFilterTest extends WebTestBase {
+
+  /**
+   * Modules to enable.
+   *
+   * @var array
+   */
+  public static $modules = ['url_embed', 'node', 'ckeditor'];
+
+  /**
+   * Set the configuration up.
+   */
+  protected function setUp() {
+    parent::setUp();
+    // Create a page content type.
+    $this->drupalCreateContentType(['type' => 'page', 'name' => 'Basic page']);
+
+    // Create a text format and enable the url_embed filter.
+    $format = FilterFormat::create([
+      'format' => 'custom_format',
+      'name' => 'Custom format',
+      'filters' => [
+        'url_embed_convert_links' => [
+          'status' => 1,
+          'settings' => ['url_prefix' => ''],
+        ],
+      ],
+    ]);
+    $format->save();
+
+    $editor_group = [
+      'name' => 'URL Embed',
+      'items' => [
+        'url',
+      ],
+    ];
+    $editor = Editor::create([
+      'format' => 'custom_format',
+      'editor' => 'ckeditor',
+      'settings' => [
+        'toolbar' => [
+          'rows' => [[$editor_group]],
+        ],
+      ],
+    ]);
+    $editor->save();
+
+    // Create a user with required permissions.
+    $this->webUser = $this->drupalCreateUser([
+      'access content',
+      'create page content',
+      'use text format custom_format',
+    ]);
+    $this->drupalLogin($this->webUser);
+  }
+
+  /**
+   * Tests the url_embed_convert_links filter.
+   *
+   * Ensures that iframes are getting rendered when valid urls
+   * are passed. Also tests situations when embed fails.
+   */
+  public function testFilter() {
+    $content = 'before https://twitter.com/drupal/status/735873777683320832 after';
+    $settings = [];
+    $settings['type'] = 'page';
+    $settings['title'] = 'Test convert url to embed with sample Twitter url';
+    $settings['body'] = [['value' => $content, 'format' => 'custom_format']];
+    $node = $this->drupalCreateNode($settings);
+    $this->drupalGet('node/' . $node->id());
+    $this->assertRaw('<drupal-url data-embed-url="https://twitter.com/drupal/status/735873777683320832"></drupal-url>');
+    $this->assertNoText(strip_tags($content), 'URL does not appear in the output when embed is successful.');
+
+    $content = 'before /not-valid/url after';
+    $settings = [];
+    $settings['type'] = 'page';
+    $settings['title'] = 'Test convert url to embed with non valid URL';
+    $settings['body'] = [['value' => $content, 'format' => 'custom_format']];
+    $node = $this->drupalCreateNode($settings);
+    $this->drupalGet('node/' . $node->id());
+    $this->assertRaw($content);
+
+    /** @var \Drupal\filter\FilterFormatInterface $format */
+    $format = FilterFormat::load('custom_format');
+    $configuration = $format->filters('url_embed_convert_links')->getConfiguration();
+    $configuration['settings']['url_prefix'] = 'EMBED ';
+    $format->setFilterConfig('url_embed_convert_links', $configuration);
+    $format->save();
+
+    $content = 'before https://twitter.com/drupal/status/735873777683320832 after';
+    $settings = [];
+    $settings['type'] = 'page';
+    $settings['title'] = 'Test convert url to embed with sample Twitter url and no prefix';
+    $settings['body'] = [['value' => $content, 'format' => 'custom_format']];
+    $node = $this->drupalCreateNode($settings);
+    $this->drupalGet('node/' . $node->id());
+    $this->assertRaw(strip_tags($content));
+    $this->assertNoRaw('<drupal-url data-embed-url="https://twitter.com/drupal/status/735873777683320832"></drupal-url>');
+
+    $content = 'before EMBED https://twitter.com/drupal/status/735873777683320832 after';
+    $settings = [];
+    $settings['type'] = 'page';
+    $settings['title'] = 'Test convert url to embed with sample Twitter url with the prefix';
+    $settings['body'] = [['value' => $content, 'format' => 'custom_format']];
+    $node = $this->drupalCreateNode($settings);
+    $this->drupalGet('node/' . $node->id());
+    $this->assertRaw('<drupal-url data-embed-url="https://twitter.com/drupal/status/735873777683320832"></drupal-url>');
+    $this->assertNoText(strip_tags($content), 'URL does not appear in the output when embed is successful.');
+
+    $content = 'before Embed https://twitter.com/drupal/status/735873777683320832 after';
+    $settings = [];
+    $settings['type'] = 'page';
+    $settings['title'] = 'Test convert url to embed with sample Twitter url with wrong prefix';
+    $settings['body'] = [['value' => $content, 'format' => 'custom_format']];
+    $node = $this->drupalCreateNode($settings);
+    $this->drupalGet('node/' . $node->id());
+    $this->assertRaw(strip_tags($content));
+    $this->assertNoRaw('<drupal-url data-embed-url="https://twitter.com/drupal/status/735873777683320832"></drupal-url>');
+  }
+
+}