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/wp-includes/ -> feed.php (source)

   1  <?php
   2  /**
   3   * WordPress Feed API
   4   *
   5   * Many of the functions used in here belong in The Loop, or The Loop for the
   6   * Feeds.
   7   *
   8   * @package WordPress
   9   * @subpackage Feed
  10   * @since 2.1.0
  11   */
  12  
  13  /**
  14   * RSS container for the bloginfo function.
  15   *
  16   * You can retrieve anything that you can using the get_bloginfo() function.
  17   * Everything will be stripped of tags and characters converted, when the values
  18   * are retrieved for use in the feeds.
  19   *
  20   * @since 1.5.1
  21   *
  22   * @see get_bloginfo() For the list of possible values to display.
  23   *
  24   * @param string $show See get_bloginfo() for possible values.
  25   * @return string
  26   */
  27  function get_bloginfo_rss( $show = '' ) {
  28      $info = strip_tags( get_bloginfo( $show ) );
  29      /**
  30       * Filters the bloginfo for use in RSS feeds.
  31       *
  32       * @since 2.2.0
  33       *
  34       * @see convert_chars()
  35       * @see get_bloginfo()
  36       *
  37       * @param string $info Converted string value of the blog information.
  38       * @param string $show The type of blog information to retrieve.
  39       */
  40      return apply_filters( 'get_bloginfo_rss', convert_chars( $info ), $show );
  41  }
  42  
  43  /**
  44   * Display RSS container for the bloginfo function.
  45   *
  46   * You can retrieve anything that you can using the get_bloginfo() function.
  47   * Everything will be stripped of tags and characters converted, when the values
  48   * are retrieved for use in the feeds.
  49   *
  50   * @since 0.71
  51   *
  52   * @see get_bloginfo() For the list of possible values to display.
  53   *
  54   * @param string $show See get_bloginfo() for possible values.
  55   */
  56  function bloginfo_rss( $show = '' ) {
  57      /**
  58       * Filters the bloginfo for display in RSS feeds.
  59       *
  60       * @since 2.1.0
  61       *
  62       * @see get_bloginfo()
  63       *
  64       * @param string $rss_container RSS container for the blog information.
  65       * @param string $show          The type of blog information to retrieve.
  66       */
  67      echo apply_filters( 'bloginfo_rss', get_bloginfo_rss( $show ), $show );
  68  }
  69  
  70  /**
  71   * Retrieve the default feed.
  72   *
  73   * The default feed is 'rss2', unless a plugin changes it through the
  74   * {@see 'default_feed'} filter.
  75   *
  76   * @since 2.5.0
  77   *
  78   * @return string Default feed, or for example 'rss2', 'atom', etc.
  79   */
  80  function get_default_feed() {
  81      /**
  82       * Filters the default feed type.
  83       *
  84       * @since 2.5.0
  85       *
  86       * @param string $feed_type Type of default feed. Possible values include 'rss2', 'atom'.
  87       *                          Default 'rss2'.
  88       */
  89      $default_feed = apply_filters( 'default_feed', 'rss2' );
  90  
  91      return ( 'rss' === $default_feed ) ? 'rss2' : $default_feed;
  92  }
  93  
  94  /**
  95   * Retrieve the blog title for the feed title.
  96   *
  97   * @since 2.2.0
  98   * @since 4.4.0 The optional `$sep` parameter was deprecated and renamed to `$deprecated`.
  99   *
 100   * @param string $deprecated Unused..
 101   * @return string The document title.
 102   */
 103  function get_wp_title_rss( $deprecated = '&#8211;' ) {
 104      if ( '&#8211;' !== $deprecated ) {
 105          /* translators: %s: 'document_title_separator' filter name. */
 106          _deprecated_argument( __FUNCTION__, '4.4.0', sprintf( __( 'Use the %s filter instead.' ), '<code>document_title_separator</code>' ) );
 107      }
 108  
 109      /**
 110       * Filters the blog title for use as the feed title.
 111       *
 112       * @since 2.2.0
 113       * @since 4.4.0 The `$sep` parameter was deprecated and renamed to `$deprecated`.
 114       *
 115       * @param string $title      The current blog title.
 116       * @param string $deprecated Unused.
 117       */
 118      return apply_filters( 'get_wp_title_rss', wp_get_document_title(), $deprecated );
 119  }
 120  
 121  /**
 122   * Display the blog title for display of the feed title.
 123   *
 124   * @since 2.2.0
 125   * @since 4.4.0 The optional `$sep` parameter was deprecated and renamed to `$deprecated`.
 126   *
 127   * @param string $deprecated Unused.
 128   */
 129  function wp_title_rss( $deprecated = '&#8211;' ) {
 130      if ( '&#8211;' !== $deprecated ) {
 131          /* translators: %s: 'document_title_separator' filter name. */
 132          _deprecated_argument( __FUNCTION__, '4.4.0', sprintf( __( 'Use the %s filter instead.' ), '<code>document_title_separator</code>' ) );
 133      }
 134  
 135      /**
 136       * Filters the blog title for display of the feed title.
 137       *
 138       * @since 2.2.0
 139       * @since 4.4.0 The `$sep` parameter was deprecated and renamed to `$deprecated`.
 140       *
 141       * @see get_wp_title_rss()
 142       *
 143       * @param string $wp_title_rss The current blog title.
 144       * @param string $deprecated   Unused.
 145       */
 146      echo apply_filters( 'wp_title_rss', get_wp_title_rss(), $deprecated );
 147  }
 148  
 149  /**
 150   * Retrieve the current post title for the feed.
 151   *
 152   * @since 2.0.0
 153   *
 154   * @return string Current post title.
 155   */
 156  function get_the_title_rss() {
 157      $title = get_the_title();
 158  
 159      /**
 160       * Filters the post title for use in a feed.
 161       *
 162       * @since 1.2.0
 163       *
 164       * @param string $title The current post title.
 165       */
 166      return apply_filters( 'the_title_rss', $title );
 167  }
 168  
 169  /**
 170   * Display the post title in the feed.
 171   *
 172   * @since 0.71
 173   */
 174  function the_title_rss() {
 175      echo get_the_title_rss();
 176  }
 177  
 178  /**
 179   * Retrieve the post content for feeds.
 180   *
 181   * @since 2.9.0
 182   *
 183   * @see get_the_content()
 184   *
 185   * @param string $feed_type The type of feed. rss2 | atom | rss | rdf
 186   * @return string The filtered content.
 187   */
 188  function get_the_content_feed( $feed_type = null ) {
 189      if ( ! $feed_type ) {
 190          $feed_type = get_default_feed();
 191      }
 192  
 193      /** This filter is documented in wp-includes/post-template.php */
 194      $content = apply_filters( 'the_content', get_the_content() );
 195      $content = str_replace( ']]>', ']]&gt;', $content );
 196  
 197      /**
 198       * Filters the post content for use in feeds.
 199       *
 200       * @since 2.9.0
 201       *
 202       * @param string $content   The current post content.
 203       * @param string $feed_type Type of feed. Possible values include 'rss2', 'atom'.
 204       *                          Default 'rss2'.
 205       */
 206      return apply_filters( 'the_content_feed', $content, $feed_type );
 207  }
 208  
 209  /**
 210   * Display the post content for feeds.
 211   *
 212   * @since 2.9.0
 213   *
 214   * @param string $feed_type The type of feed. rss2 | atom | rss | rdf
 215   */
 216  function the_content_feed( $feed_type = null ) {
 217      echo get_the_content_feed( $feed_type );
 218  }
 219  
 220  /**
 221   * Display the post excerpt for the feed.
 222   *
 223   * @since 0.71
 224   */
 225  function the_excerpt_rss() {
 226      $output = get_the_excerpt();
 227      /**
 228       * Filters the post excerpt for a feed.
 229       *
 230       * @since 1.2.0
 231       *
 232       * @param string $output The current post excerpt.
 233       */
 234      echo apply_filters( 'the_excerpt_rss', $output );
 235  }
 236  
 237  /**
 238   * Display the permalink to the post for use in feeds.
 239   *
 240   * @since 2.3.0
 241   */
 242  function the_permalink_rss() {
 243      /**
 244       * Filters the permalink to the post for use in feeds.
 245       *
 246       * @since 2.3.0
 247       *
 248       * @param string $post_permalink The current post permalink.
 249       */
 250      echo esc_url( apply_filters( 'the_permalink_rss', get_permalink() ) );
 251  }
 252  
 253  /**
 254   * Outputs the link to the comments for the current post in an xml safe way
 255   *
 256   * @since 3.0.0
 257   */
 258  function comments_link_feed() {
 259      /**
 260       * Filters the comments permalink for the current post.
 261       *
 262       * @since 3.6.0
 263       *
 264       * @param string $comment_permalink The current comment permalink with
 265       *                                  '#comments' appended.
 266       */
 267      echo esc_url( apply_filters( 'comments_link_feed', get_comments_link() ) );
 268  }
 269  
 270  /**
 271   * Display the feed GUID for the current comment.
 272   *
 273   * @since 2.5.0
 274   *
 275   * @param int|WP_Comment $comment_id Optional comment object or ID. Defaults to global comment object.
 276   */
 277  function comment_guid( $comment_id = null ) {
 278      echo esc_url( get_comment_guid( $comment_id ) );
 279  }
 280  
 281  /**
 282   * Retrieve the feed GUID for the current comment.
 283   *
 284   * @since 2.5.0
 285   *
 286   * @param int|WP_Comment $comment_id Optional comment object or ID. Defaults to global comment object.
 287   * @return string|false GUID for comment on success, false on failure.
 288   */
 289  function get_comment_guid( $comment_id = null ) {
 290      $comment = get_comment( $comment_id );
 291  
 292      if ( ! is_object( $comment ) ) {
 293          return false;
 294      }
 295  
 296      return get_the_guid( $comment->comment_post_ID ) . '#comment-' . $comment->comment_ID;
 297  }
 298  
 299  /**
 300   * Display the link to the comments.
 301   *
 302   * @since 1.5.0
 303   * @since 4.4.0 Introduced the `$comment` argument.
 304   *
 305   * @param int|WP_Comment $comment Optional. Comment object or ID. Defaults to global comment object.
 306   */
 307  function comment_link( $comment = null ) {
 308      /**
 309       * Filters the current comment's permalink.
 310       *
 311       * @since 3.6.0
 312       *
 313       * @see get_comment_link()
 314       *
 315       * @param string $comment_permalink The current comment permalink.
 316       */
 317      echo esc_url( apply_filters( 'comment_link', get_comment_link( $comment ) ) );
 318  }
 319  
 320  /**
 321   * Retrieve the current comment author for use in the feeds.
 322   *
 323   * @since 2.0.0
 324   *
 325   * @return string Comment Author
 326   */
 327  function get_comment_author_rss() {
 328      /**
 329       * Filters the current comment author for use in a feed.
 330       *
 331       * @since 1.5.0
 332       *
 333       * @see get_comment_author()
 334       *
 335       * @param string $comment_author The current comment author.
 336       */
 337      return apply_filters( 'comment_author_rss', get_comment_author() );
 338  }
 339  
 340  /**
 341   * Display the current comment author in the feed.
 342   *
 343   * @since 1.0.0
 344   */
 345  function comment_author_rss() {
 346      echo get_comment_author_rss();
 347  }
 348  
 349  /**
 350   * Display the current comment content for use in the feeds.
 351   *
 352   * @since 1.0.0
 353   */
 354  function comment_text_rss() {
 355      $comment_text = get_comment_text();
 356      /**
 357       * Filters the current comment content for use in a feed.
 358       *
 359       * @since 1.5.0
 360       *
 361       * @param string $comment_text The content of the current comment.
 362       */
 363      $comment_text = apply_filters( 'comment_text_rss', $comment_text );
 364      echo $comment_text;
 365  }
 366  
 367  /**
 368   * Retrieve all of the post categories, formatted for use in feeds.
 369   *
 370   * All of the categories for the current post in the feed loop, will be
 371   * retrieved and have feed markup added, so that they can easily be added to the
 372   * RSS2, Atom, or RSS1 and RSS0.91 RDF feeds.
 373   *
 374   * @since 2.1.0
 375   *
 376   * @param string $type Optional, default is the type returned by get_default_feed().
 377   * @return string All of the post categories for displaying in the feed.
 378   */
 379  function get_the_category_rss( $type = null ) {
 380      if ( empty( $type ) ) {
 381          $type = get_default_feed();
 382      }
 383      $categories = get_the_category();
 384      $tags       = get_the_tags();
 385      $the_list   = '';
 386      $cat_names  = array();
 387  
 388      $filter = 'rss';
 389      if ( 'atom' === $type ) {
 390          $filter = 'raw';
 391      }
 392  
 393      if ( ! empty( $categories ) ) {
 394          foreach ( (array) $categories as $category ) {
 395              $cat_names[] = sanitize_term_field( 'name', $category->name, $category->term_id, 'category', $filter );
 396          }
 397      }
 398  
 399      if ( ! empty( $tags ) ) {
 400          foreach ( (array) $tags as $tag ) {
 401              $cat_names[] = sanitize_term_field( 'name', $tag->name, $tag->term_id, 'post_tag', $filter );
 402          }
 403      }
 404  
 405      $cat_names = array_unique( $cat_names );
 406  
 407      foreach ( $cat_names as $cat_name ) {
 408          if ( 'rdf' === $type ) {
 409              $the_list .= "\t\t<dc:subject><![CDATA[$cat_name]]></dc:subject>\n";
 410          } elseif ( 'atom' === $type ) {
 411              $the_list .= sprintf( '<category scheme="%1$s" term="%2$s" />', esc_attr( get_bloginfo_rss( 'url' ) ), esc_attr( $cat_name ) );
 412          } else {
 413              $the_list .= "\t\t<category><![CDATA[" . html_entity_decode( $cat_name, ENT_COMPAT, get_option( 'blog_charset' ) ) . "]]></category>\n";
 414          }
 415      }
 416  
 417      /**
 418       * Filters all of the post categories for display in a feed.
 419       *
 420       * @since 1.2.0
 421       *
 422       * @param string $the_list All of the RSS post categories.
 423       * @param string $type     Type of feed. Possible values include 'rss2', 'atom'.
 424       *                         Default 'rss2'.
 425       */
 426      return apply_filters( 'the_category_rss', $the_list, $type );
 427  }
 428  
 429  /**
 430   * Display the post categories in the feed.
 431   *
 432   * @since 0.71
 433   *
 434   * @see get_the_category_rss() For better explanation.
 435   *
 436   * @param string $type Optional, default is the type returned by get_default_feed().
 437   */
 438  function the_category_rss( $type = null ) {
 439      echo get_the_category_rss( $type );
 440  }
 441  
 442  /**
 443   * Display the HTML type based on the blog setting.
 444   *
 445   * The two possible values are either 'xhtml' or 'html'.
 446   *
 447   * @since 2.2.0
 448   */
 449  function html_type_rss() {
 450      $type = get_bloginfo( 'html_type' );
 451      if ( strpos( $type, 'xhtml' ) !== false ) {
 452          $type = 'xhtml';
 453      } else {
 454          $type = 'html';
 455      }
 456      echo $type;
 457  }
 458  
 459  /**
 460   * Display the rss enclosure for the current post.
 461   *
 462   * Uses the global $post to check whether the post requires a password and if
 463   * the user has the password for the post. If not then it will return before
 464   * displaying.
 465   *
 466   * Also uses the function get_post_custom() to get the post's 'enclosure'
 467   * metadata field and parses the value to display the enclosure(s). The
 468   * enclosure(s) consist of enclosure HTML tag(s) with a URI and other
 469   * attributes.
 470   *
 471   * @since 1.5.0
 472   */
 473  function rss_enclosure() {
 474      if ( post_password_required() ) {
 475          return;
 476      }
 477  
 478      foreach ( (array) get_post_custom() as $key => $val ) {
 479          if ( 'enclosure' === $key ) {
 480              foreach ( (array) $val as $enc ) {
 481                  $enclosure = explode( "\n", $enc );
 482  
 483                  // Only get the first element, e.g. 'audio/mpeg' from 'audio/mpeg mpga mp2 mp3'.
 484                  $t    = preg_split( '/[ \t]/', trim( $enclosure[2] ) );
 485                  $type = $t[0];
 486  
 487                  /**
 488                   * Filters the RSS enclosure HTML link tag for the current post.
 489                   *
 490                   * @since 2.2.0
 491                   *
 492                   * @param string $html_link_tag The HTML link tag with a URI and other attributes.
 493                   */
 494                  echo apply_filters( 'rss_enclosure', '<enclosure url="' . esc_url( trim( $enclosure[0] ) ) . '" length="' . absint( trim( $enclosure[1] ) ) . '" type="' . esc_attr( $type ) . '" />' . "\n" );
 495              }
 496          }
 497      }
 498  }
 499  
 500  /**
 501   * Display the atom enclosure for the current post.
 502   *
 503   * Uses the global $post to check whether the post requires a password and if
 504   * the user has the password for the post. If not then it will return before
 505   * displaying.
 506   *
 507   * Also uses the function get_post_custom() to get the post's 'enclosure'
 508   * metadata field and parses the value to display the enclosure(s). The
 509   * enclosure(s) consist of link HTML tag(s) with a URI and other attributes.
 510   *
 511   * @since 2.2.0
 512   */
 513  function atom_enclosure() {
 514      if ( post_password_required() ) {
 515          return;
 516      }
 517  
 518      foreach ( (array) get_post_custom() as $key => $val ) {
 519          if ( 'enclosure' === $key ) {
 520              foreach ( (array) $val as $enc ) {
 521                  $enclosure = explode( "\n", $enc );
 522  
 523                  $url    = '';
 524                  $type   = '';
 525                  $length = 0;
 526  
 527                  $mimes = get_allowed_mime_types();
 528  
 529                  // Parse URL.
 530                  if ( isset( $enclosure[0] ) && is_string( $enclosure[0] ) ) {
 531                      $url = trim( $enclosure[0] );
 532                  }
 533  
 534                  // Parse length and type.
 535                  for ( $i = 1; $i <= 2; $i++ ) {
 536                      if ( isset( $enclosure[ $i ] ) ) {
 537                          if ( is_numeric( $enclosure[ $i ] ) ) {
 538                              $length = trim( $enclosure[ $i ] );
 539                          } elseif ( in_array( $enclosure[ $i ], $mimes, true ) ) {
 540                              $type = trim( $enclosure[ $i ] );
 541                          }
 542                      }
 543                  }
 544  
 545                  $html_link_tag = sprintf(
 546                      "<link href=\"%s\" rel=\"enclosure\" length=\"%d\" type=\"%s\" />\n",
 547                      esc_url( $url ),
 548                      esc_attr( $length ),
 549                      esc_attr( $type )
 550                  );
 551  
 552                  /**
 553                   * Filters the atom enclosure HTML link tag for the current post.
 554                   *
 555                   * @since 2.2.0
 556                   *
 557                   * @param string $html_link_tag The HTML link tag with a URI and other attributes.
 558                   */
 559                  echo apply_filters( 'atom_enclosure', $html_link_tag );
 560              }
 561          }
 562      }
 563  }
 564  
 565  /**
 566   * Determine the type of a string of data with the data formatted.
 567   *
 568   * Tell whether the type is text, HTML, or XHTML, per RFC 4287 section 3.1.
 569   *
 570   * In the case of WordPress, text is defined as containing no markup,
 571   * XHTML is defined as "well formed", and HTML as tag soup (i.e., the rest).
 572   *
 573   * Container div tags are added to XHTML values, per section 3.1.1.3.
 574   *
 575   * @link http://www.atomenabled.org/developers/syndication/atom-format-spec.php#rfc.section.3.1
 576   *
 577   * @since 2.5.0
 578   *
 579   * @param string $data Input string
 580   * @return array array(type, value)
 581   */
 582  function prep_atom_text_construct( $data ) {
 583      if ( strpos( $data, '<' ) === false && strpos( $data, '&' ) === false ) {
 584          return array( 'text', $data );
 585      }
 586  
 587      if ( ! function_exists( 'xml_parser_create' ) ) {
 588          trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML extension." ) );
 589  
 590          return array( 'html', "<![CDATA[$data]]>" );
 591      }
 592  
 593      $parser = xml_parser_create();
 594      xml_parse( $parser, '<div>' . $data . '</div>', true );
 595      $code = xml_get_error_code( $parser );
 596      xml_parser_free( $parser );
 597      unset( $parser );
 598  
 599      if ( ! $code ) {
 600          if ( strpos( $data, '<' ) === false ) {
 601              return array( 'text', $data );
 602          } else {
 603              $data = "<div xmlns='http://www.w3.org/1999/xhtml'>$data</div>";
 604              return array( 'xhtml', $data );
 605          }
 606      }
 607  
 608      if ( strpos( $data, ']]>' ) === false ) {
 609          return array( 'html', "<![CDATA[$data]]>" );
 610      } else {
 611          return array( 'html', htmlspecialchars( $data ) );
 612      }
 613  }
 614  
 615  /**
 616   * Displays Site Icon in atom feeds.
 617   *
 618   * @since 4.3.0
 619   *
 620   * @see get_site_icon_url()
 621   */
 622  function atom_site_icon() {
 623      $url = get_site_icon_url( 32 );
 624      if ( $url ) {
 625          echo '<icon>' . convert_chars( $url ) . "</icon>\n";
 626      }
 627  }
 628  
 629  /**
 630   * Displays Site Icon in RSS2.
 631   *
 632   * @since 4.3.0
 633   */
 634  function rss2_site_icon() {
 635      $rss_title = get_wp_title_rss();
 636      if ( empty( $rss_title ) ) {
 637          $rss_title = get_bloginfo_rss( 'name' );
 638      }
 639  
 640      $url = get_site_icon_url( 32 );
 641      if ( $url ) {
 642          echo '
 643  <image>
 644      <url>' . convert_chars( $url ) . '</url>
 645      <title>' . $rss_title . '</title>
 646      <link>' . get_bloginfo_rss( 'url' ) . '</link>
 647      <width>32</width>
 648      <height>32</height>
 649  </image> ' . "\n";
 650      }
 651  }
 652  
 653  /**
 654   * Returns the link for the currently displayed feed.
 655   *
 656   * @since 5.3.0
 657   *
 658   * @return string Correct link for the atom:self element.
 659   */
 660  function get_self_link() {
 661      $host = parse_url( home_url() );
 662      return set_url_scheme( 'http://' . $host['host'] . wp_unslash( $_SERVER['REQUEST_URI'] ) );
 663  }
 664  
 665  /**
 666   * Display the link for the currently displayed feed in a XSS safe way.
 667   *
 668   * Generate a correct link for the atom:self element.
 669   *
 670   * @since 2.5.0
 671   */
 672  function self_link() {
 673      /**
 674       * Filters the current feed URL.
 675       *
 676       * @since 3.6.0
 677       *
 678       * @see set_url_scheme()
 679       * @see wp_unslash()
 680       *
 681       * @param string $feed_link The link for the feed with set URL scheme.
 682       */
 683      echo esc_url( apply_filters( 'self_link', get_self_link() ) );
 684  }
 685  
 686  /**
 687   * Get the UTC time of the most recently modified post from WP_Query.
 688   *
 689   * If viewing a comment feed, the time of the most recently modified
 690   * comment will be returned.
 691   *
 692   * @global WP_Query $wp_query WordPress Query object.
 693   *
 694   * @since 5.2.0
 695   *
 696   * @param string $format Date format string to return the time in.
 697   * @return string|false The time in requested format, or false on failure.
 698   */
 699  function get_feed_build_date( $format ) {
 700      global $wp_query;
 701  
 702      $datetime          = false;
 703      $max_modified_time = false;
 704      $utc               = new DateTimeZone( 'UTC' );
 705  
 706      if ( ! empty( $wp_query ) && $wp_query->have_posts() ) {
 707          // Extract the post modified times from the posts.
 708          $modified_times = wp_list_pluck( $wp_query->posts, 'post_modified_gmt' );
 709  
 710          // If this is a comment feed, check those objects too.
 711          if ( $wp_query->is_comment_feed() && $wp_query->comment_count ) {
 712              // Extract the comment modified times from the comments.
 713              $comment_times = wp_list_pluck( $wp_query->comments, 'comment_date_gmt' );
 714  
 715              // Add the comment times to the post times for comparison.
 716              $modified_times = array_merge( $modified_times, $comment_times );
 717          }
 718  
 719          // Determine the maximum modified time.
 720          $datetime = date_create_immutable_from_format( 'Y-m-d H:i:s', max( $modified_times ), $utc );
 721      }
 722  
 723      if ( false === $datetime ) {
 724          // Fall back to last time any post was modified or published.
 725          $datetime = date_create_immutable_from_format( 'Y-m-d H:i:s', get_lastpostmodified( 'GMT' ), $utc );
 726      }
 727  
 728      if ( false !== $datetime ) {
 729          $max_modified_time = $datetime->format( $format );
 730      }
 731  
 732      /**
 733       * Filters the date the last post or comment in the query was modified.
 734       *
 735       * @since 5.2.0
 736       *
 737       * @param string|false $max_modified_time Date the last post or comment was modified in the query, in UTC.
 738       *                                        False on failure.
 739       * @param string       $format            The date format requested in get_feed_build_date().
 740       */
 741      return apply_filters( 'get_feed_build_date', $max_modified_time, $format );
 742  }
 743  
 744  /**
 745   * Return the content type for specified feed type.
 746   *
 747   * @since 2.8.0
 748   *
 749   * @param string $type Type of feed. Possible values include 'rss', rss2', 'atom', and 'rdf'.
 750   */
 751  function feed_content_type( $type = '' ) {
 752      if ( empty( $type ) ) {
 753          $type = get_default_feed();
 754      }
 755  
 756      $types = array(
 757          'rss'      => 'application/rss+xml',
 758          'rss2'     => 'application/rss+xml',
 759          'rss-http' => 'text/xml',
 760          'atom'     => 'application/atom+xml',
 761          'rdf'      => 'application/rdf+xml',
 762      );
 763  
 764      $content_type = ( ! empty( $types[ $type ] ) ) ? $types[ $type ] : 'application/octet-stream';
 765  
 766      /**
 767       * Filters the content type for a specific feed type.
 768       *
 769       * @since 2.8.0
 770       *
 771       * @param string $content_type Content type indicating the type of data that a feed contains.
 772       * @param string $type         Type of feed. Possible values include 'rss', rss2', 'atom', and 'rdf'.
 773       */
 774      return apply_filters( 'feed_content_type', $content_type, $type );
 775  }
 776  
 777  /**
 778   * Build SimplePie object based on RSS or Atom feed from URL.
 779   *
 780   * @since 2.8.0
 781   *
 782   * @param string|string[] $url URL of feed to retrieve. If an array of URLs, the feeds are merged
 783   *                             using SimplePie's multifeed feature.
 784   *                             See also {@link http://simplepie.org/wiki/faq/typical_multifeed_gotchas}
 785   * @return SimplePie|WP_Error SimplePie object on success or WP_Error object on failure.
 786   */
 787  function fetch_feed( $url ) {
 788      if ( ! class_exists( 'SimplePie', false ) ) {
 789          require_once  ABSPATH . WPINC . '/class-simplepie.php';
 790      }
 791  
 792      require_once  ABSPATH . WPINC . '/class-wp-feed-cache-transient.php';
 793      require_once  ABSPATH . WPINC . '/class-wp-simplepie-file.php';
 794      require_once  ABSPATH . WPINC . '/class-wp-simplepie-sanitize-kses.php';
 795  
 796      $feed = new SimplePie();
 797  
 798      $feed->set_sanitize_class( 'WP_SimplePie_Sanitize_KSES' );
 799      // We must manually overwrite $feed->sanitize because SimplePie's
 800      // constructor sets it before we have a chance to set the sanitization class.
 801      $feed->sanitize = new WP_SimplePie_Sanitize_KSES();
 802  
 803      // Register the cache handler using the recommended method for SimplePie 1.3 or later.
 804      if ( method_exists( 'SimplePie_Cache', 'register' ) ) {
 805          SimplePie_Cache::register( 'wp_transient', 'WP_Feed_Cache_Transient' );
 806          $feed->set_cache_location( 'wp_transient' );
 807      } else {
 808          // Back-compat for SimplePie 1.2.x.
 809          require_once  ABSPATH . WPINC . '/class-wp-feed-cache.php';
 810          $feed->set_cache_class( 'WP_Feed_Cache' );
 811      }
 812  
 813      $feed->set_file_class( 'WP_SimplePie_File' );
 814  
 815      $feed->set_feed_url( $url );
 816      /** This filter is documented in wp-includes/class-wp-feed-cache-transient.php */
 817      $feed->set_cache_duration( apply_filters( 'wp_feed_cache_transient_lifetime', 12 * HOUR_IN_SECONDS, $url ) );
 818  
 819      /**
 820       * Fires just before processing the SimplePie feed object.
 821       *
 822       * @since 3.0.0
 823       *
 824       * @param SimplePie       $feed SimplePie feed object (passed by reference).
 825       * @param string|string[] $url  URL of feed or array of URLs of feeds to retrieve.
 826       */
 827      do_action_ref_array( 'wp_feed_options', array( &$feed, $url ) );
 828  
 829      $feed->init();
 830      $feed->set_output_encoding( get_option( 'blog_charset' ) );
 831  
 832      if ( $feed->error() ) {
 833          return new WP_Error( 'simplepie-error', $feed->error() );
 834      }
 835  
 836      return $feed;
 837  }


Generated: Sat Nov 28 01:00:03 2020 Cross-referenced by PHPXref 0.7.1