I'm using simpleXML to parse this xml file. It's a feed I'm using to access the YouTube API. I want to embed the most recent video in an object and display the next four thumbnails.

So I'm using simplexml_load_file on this, going using a foreach loop to access the values in each feed.

I can access the values no problem, but I run into the problem that it stores each video in a separate SimpleXMLElement Object. I don't have any control over which object I'm accessing as they are not stored in an array. So I can't get, say, $thumb[4] or $entry[4]->thumb.

I tried to use SimpleXMLIterator, but for whatever reason, any values that have the same beginning render as blank. For example, the video could have eleven variations of:

And these would each render as [1]="", [2]="", [3]="", etc.

I'll happily provide some more information to anyone who can help!

Edit

Here is the print_r of my results. This is done on a single variable to give you an idea of the structure issue I'm facing. The entire print_r($entry) would give variables for each node in the XML file.

SimpleXMLElement Object
(
    [0] => 159
)
SimpleXMLElement Object
(
    [0] => 44
)

Also, the print_r is simply inside the PHP block for testing. I'm actually looking to access the variables within echoes in the HTML.

Comments

Could you maybe give us a print_r or var_dump of part of the structure? Not the whole thing, but just enough that we can see what it looks like.

Written by Chacha102

Absolutely, chacha. Added. Let me know if something else would give more clarity.

Written by Joshua Cody

What are the Objects contained in?

Written by Chacha102

Nothing, that's a print_r of the variable. Perhaps I'm misunderstanding your question. Context (likely overkill): This (droplr.com/lMQ70) is a print_r of $entry, which is being fed from this (droplr.com/lMR2X) PHP.

Written by Joshua Cody

Accepted Answer

You ran into the problem of namespaces and SimpleXML. The feed starts with

<feed xmlns='http://www.w3.org/2005/Atom' xmlns:media='http://search.yahoo.com/mrss/' xmlns:openSearch='http://a9.com/-/spec/opensearchrss/1.0/' xmlns:gd='http://schemas.google.com/g/2005' xmlns:yt='http://gdata.youtube.com/schemas/2007'>

The xmlns='http://www.w3.org/2005/Atom' sets the default namespace to http://www.w3.org/2005/Atom. I.e. its child elements are not really id, updated, category but http://www.w3.org/2005/Atom:id, http://www.w3.org/2005/Atom:updated and so on...
So you can't access the the id element via $feed->id, you need the method SimpleXMLELement::children(). It lets you specify the namespace of the child elements you want to retrieve.

For example,

$feed = simplexml_load_file('http://gdata.youtube.com/feeds/api/videos?author=ofcoursegolf&max-results=5&prettyprint=true');
$children = $feed->children('http://www.w3.org/2005/Atom');
echo $children->updated;

Currently prints 2010-02-06T05:23:33.858Z.

To get the id of the first entry element you can use echo $children->entry[0]->id;.
But then you'll hit the <media:group> element and its children <media:category, <media:player> and so on..., which are in the xmlns:media='http://search.yahoo.com/mrss/' namespace.

$feed = simplexml_load_file('http://gdata.youtube.com/feeds/api/videos?author=ofcoursegolf&max-results=5&prettyprint=true');
$group = $feed->children('http://www.w3.org/2005/Atom')
  ->entry[0]
  ->children('http://search.yahoo.com/mrss/')
  ->group
  ->children('http://search.yahoo.com/mrss/')
;
echo $group->player->attributes()->url, "\n";
foreach( $group->thumbnail as $thumb) {
  echo 'thumb: ', $thumb->attributes()->url, "\n";
}

(Currently) prints

http://www.youtube.com/watch?v=ikACkCpJ-js&feature=youtube_gdata
thumb: http://i.ytimg.com/vi/ikACkCpJ-js/2.jpg
thumb: http://i.ytimg.com/vi/ikACkCpJ-js/1.jpg
thumb: http://i.ytimg.com/vi/ikACkCpJ-js/3.jpg
thumb: http://i.ytimg.com/vi/ikACkCpJ-js/0.jpg

Edit: I'd probably do that within the browser with a lot more JavaScript, but here's a (simple, ugly) example app.

<?php
//define('TESTENV' , true);
function getFeed($author) {
  // <-- add caching here if needed -->
  if ( !defined('TESTENV') ) {
    $url = sprintf('http://gdata.youtube.com/feeds/api/videos?author=%s&max-results=5',
      urlencode($author)
    );
  }
  else {
    $url = 'feed.xml';
  }
  return simplexml_load_file($url);
}
$feed = getFeed('jonlajoie');

if ( !isset($_GET['id']) ) {
  $selected = '';
}
else {
  $selected =  $_GET['id'];
  printf ('
    <object width="425" height="344">
      <param name="movie" value="http://www.youtube.com/v/%s"></param>
      <param name="allowFullScreen" value="true"></param>
      <param name="allowscriptaccess" value="always">
      </param>
      <embed src="http://www.youtube.com/v/%s" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed>
    </object>',
    htmlspcialchars($selected), htmlspcialchars($selected)
  );
}

$item = 0;
foreach( $feed->children('http://www.w3.org/2005/Atom')->entry as $entry ) {
  $entryElements = $entry->children('http://www.w3.org/2005/Atom');
  $groupElements = $entry
    ->children('http://search.yahoo.com/mrss/')
    ->group
    ->children('http://search.yahoo.com/mrss/')
  ;

  if ( !preg_match('!^http://gdata.youtube.com/feeds/api/videos/([^/]+)!', $entryElements->id, $m) ) {
    // google can choose whatever id they want. But this is only a simple example....
    die('unexpected id: '.htmlspecialchars($entryElements->id));
  }
  $id = $m[1];
  if ( $selected!==$id ) {
    printf('<a href="?id=%s"><img src="%s" /></a>',
      urlencode($id),
      $groupElements->thumbnail[0]->attributes()->url
    );
  }
}

Edit 2: "And when I click the thumbnails, I'll use jQuery to load the video in the main space. Seems like I'll need precise access to node[#], right?"
If you're already using JavaScript/jQuery your PHP script (if needed at all) could simply return a (JSON encoded) array of all the data for all the video and your jQuery script could figure out what to do with the data.

Written by VolkerK
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