[Sommaire] [Imprimer]

   1  MAGPIERSS RECIPES:  Cooking with Corbies
   2  
   3           "Four and twenty blackbirds baked in a pie."
   4  
   5  1. LIMIT THE NUMBER OF HEADLINES(AKA ITEMS) RETURNED.
   6  
   7  PROBLEM:
   8  
   9  You want to display the 10 (or 3) most recent headlines, but the RSS feed
  10  contains 15.
  11  
  12  SOLUTION:
  13  
  14  $num_items = 10;
  15  $rss = fetch_rss($url);
  16  
  17  $items = array_slice($rss->items, 0, $num_items);
  18  
  19  DISCUSSION:
  20  
  21  Rather then trying to limit the number of items Magpie parses, a much simpler,
  22  and more flexible approach is to take a "slice" of the array of items.  And
  23  array_slice() is smart enough to do the right thing if the feed has less items
  24  then $num_items.
  25  
  26  See: http://www.php.net/array_slice
  27  
  28  
  29  2. DISPLAY A CUSTOM ERROR MESSAGE IF SOMETHING GOES WRONG
  30  
  31  PROBLEM:
  32  
  33  You don't want Magpie's error messages showing up if something goes wrong.
  34  
  35  SOLUTION:
  36  
  37  # Magpie throws USER_WARNINGS only
  38  # so you can cloak these, by only showing ERRORs
  39  error_reporting(E_ERROR);
  40  
  41  # check the return value of fetch_rss()
  42  
  43  $rss = fetch_rss($url);
  44  
  45  if ( $rss ) {
  46  ...display rss feed...
  47  }
  48  else {
  49      echo "An error occured!  " .
  50           "Consider donating more $$$ for restoration of services." .
  51           "<br>Error Message: "    . magpie_error();
  52  }
  53  
  54  DISCUSSION:
  55  
  56  MagpieRSS triggers a warning in a number of circumstances.  The 2 most common
  57  circumstances are:  if the specified RSS file isn't properly formed (usually
  58  because it includes illegal HTML), or if Magpie can't download the remote RSS
  59  file, and there is no cached version.  
  60  
  61  If you don't want your users to see these warnings change your error_reporting
  62  settings to only display ERRORs.  Another option is to turn off display_error,
  63  so that WARNINGs, and NOTICEs still go to the error_log but not to the webpages.
  64  
  65  You can do this with:
  66  
  67  ini_set('display_errors', 0);
  68  
  69  See: http://www.php.net/error_reporting,
  70       http://www.php.net/ini_set, 
  71       http://www.php.net/manual/en/ref.errorfunc.php
  72  
  73  3. GENERATE A NEW RSS FEED
  74  
  75  PROBLEM:
  76  
  77  Create an RSS feed for other people to use.
  78  
  79  SOLUTION:
  80  
  81  Use Useful Inc's RSSWriter (http://usefulinc.com/rss/rsswriter/)
  82  
  83  DISCUSSION:
  84  
  85  An example of turning a Magpie parsed RSS object back into an RSS file is forth
  86  coming.  In the meantime RSSWriter has great documentation.
  87  
  88  4. DISPLAY HEADLINES MORE RECENT THEN X DATE
  89  
  90  PROBLEM:
  91  
  92  You only want to display headlines that were published on, or after a certain
  93  date.
  94  
  95  
  96  SOLUTION:
  97  
  98  require  'rss_utils.inc';
  99  
 100  # get all headlines published today
 101  $today = getdate();
 102  
 103  # today, 12AM
 104  $date = mktime(0,0,0,$today['mon'], $today['mday'], $today['year']);
 105  
 106  $rss = fetch_rss($url);
 107  
 108  foreach ( $rss->items as $item ) {
 109      $published = parse_w3cdtf($item['dc']['date']);
 110      if ( $published >= $date ) {
 111          echo "Title: " . $item['title'];
 112          echo "Published: " . date("h:i:s A", $published);
 113          echo "<p>";
 114      }
 115  }
 116  
 117  DISCUSSION:
 118  
 119  This recipe only works for RSS 1.0 feeds that include the <dc:date> field.
 120  (which is very good RSS style)
 121  
 122  parse_w3cdtf is defined in rss_utils.inc, and parses RSS style dates into Unix
 123  epoch seconds.  
 124  
 125  See: http://www.php.net/manual/en/ref.datetime.php