Question

I’m trying to iterate through a Twitter XML File, where the container tag is <users>, and each user is <user>. I need to create a variable $id based on the XML attribute <id> for each user.

Username is already instantiated.

$url = "http://api.twitter.com/1/statuses/friends/$username.xml";
$xmlpure = file_get_contents($url);
$listxml = simplexml_load_string($xmlpure);

foreach($listxml->users->children() as $child)
  {
 $id  = $child->{"id"};
//Do another action
}

But I’m getting this error:

Warning: main() [function.main]: Node no longer exists in /home/…/bonus.php on line 32

Line 32 is the foreach statement, and I don’t actually USE the main() method.

Answer 1

It might be that the node represented by $child does not have an <id/> child. You can check that out using isset() or even by outputing the node’s XML with echo $child->asXML();

Also, if you intent to use $id as a string, you should cast it as such.

$id = (string) $child->id;

Another thing, you could load the document like this:

$listxml = simplexml_load_file($url);

Finally, when asking a question here, please always link to a relevant sample of the original XML document.

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Update

As suspected, you just don’t access the right nodes. If you specify the name of an inexistent node (“users” in your example) SimpleXML creates some kind of a temporary phantom node instead of generating an error. This is to allow creating new nodes more easily I believe.

Anyway, here’s what your script should look like:

$users = simplexml_load_file($url);

foreach ($users->user as $user)
{
    $id = (string) $user->id;
}

Always name your PHP vars according to the node they represent so that you always know where you are in the tree; it will save you a lot of future similar troubles. The root node is <users/> therefore the variable is $users and same for <user/>/$user.