Display children that exist in both XML responses

Question

Still very new to php and XML and have been trying to find a solution to this for a while.

I am trying to compare two XML returns and only display the children that exist in both of them. To be specific i am using the steam api go get game libraries from two entered steam id's and i want to display the games that are owned by both users.

Instead of doing that it will now show all the games owned by user 1.

Here is the part that i am having problems with, $apinyckel is the API key and i am not including it in this post as it should not be shared.

$steamid2 = $_SESSION['steamid2'];
$steamid3 = $_SESSION['steamid3'];

    //user1
    $url4 = "http://api.steampowered.com/IPlayerService/GetOwnedGames/v0001/?key=$apinyckel&steamid=$steamid2&format=xml&&include_appinfo=1";
    $data4 = file_get_contents($url4);
    $xml4 = simplexml_load_string($data4);

    //user2
    $url5 = "http://api.steampowered.com/IPlayerService/GetOwnedGames/v0001/?key=$apinyckel&steamid=$steamid3&format=xml&&include_appinfo=1";
    $data5 = file_get_contents($url5);
    $xml5 = simplexml_load_string($data5);


    foreach ($xml4->games->children() as $item2):
    if ($xml4->games->child->appid === $xml5->games->child->appid) {
    ?><img src="http://media.steampowered.com/steamcommunity/public/images/apps/<?echo htmlentities($item2->appid);?>/<?echo htmlentities($item2->img_logo_url);?>.jpg"><?
    } 
    endforeach;

Here is an example of what the XML structure looks like for one of the users.

<response>
<game_count>6</game_count>
<games>
<message>
<appid>520</appid>
<name>Team Fortress 2 Beta</name>
<img_icon_url>e3f595a92552da3d664ad00277fad2107345f743</img_icon_url>
<img_logo_url>6f6d22ab0c357d9f02a11f76ff35797e4ccdf19f</img_logo_url>
<has_community_visible_stats>true</has_community_visible_stats>
</message>
<message>
<appid>440</appid>
<name>Team Fortress 2</name>
<playtime_forever>30659</playtime_forever>
<img_icon_url>e3f595a92552da3d664ad00277fad2107345f743</img_icon_url>
<img_logo_url>07385eb55b5ba974aebbe74d3c99626bda7920b8</img_logo_url>
<has_community_visible_stats>true</has_community_visible_stats>
</message>
<message>
<appid>550</appid>
<name>Left 4 Dead 2</name>
<playtime_forever>1822</playtime_forever>
<img_icon_url>7d5a243f9500d2f8467312822f8af2a2928777ed</img_icon_url>
<img_logo_url>205863cc21e751a576d6fff851984b3170684142</img_logo_url>
<has_community_visible_stats>true</has_community_visible_stats>
</message>
<message>
<appid>223530</appid>
<name>Left 4 Dead 2 Beta</name>
<img_icon_url/>
<img_logo_url/>
</message>
<message>
<appid>320</appid>
<name>Half-Life 2: Deathmatch</name>
<playtime_forever>70</playtime_forever>
<img_icon_url>795e85364189511f4990861b578084deef086cb1</img_icon_url>
<img_logo_url>6dd9f66771300f2252d411e50739a1ceae9e5b30</img_logo_url>
<has_community_visible_stats>true</has_community_visible_stats>
</message>
<message>
<appid>340</appid>
<name>Half-Life 2: Lost Coast</name>
<img_icon_url>795e85364189511f4990861b578084deef086cb1</img_icon_url>
<img_logo_url>867cce5c4f37d5ed4aeffb57c60e220ddffe4134</img_logo_url>
</message>
</games>
</response>

Any help is appreciated, thanks!

Answer 1

To get array of messages you can use xpath:

$xml1 = $xml1->xpath('//message');
$xml2 = $xml2->xpath('//message');

, and then loop through array to compare them.

EDIT:

Code for loop, extract names from array and intersect them:

$messages1 = array();
array_map(
    function($message) use (&$messages1) { 
        $messages1[(string) $message->appid] = (array) $message; 
    },
    $xml1
); 

$messages2 = array();
array_map(
    function($message) use (&$messages2) { 
        $messages2[(string) $message->appid] = (array) $message; 
    },
    $xml2
); 


$result = array_intersect_key( $messages1, $messages2 );

foreach ( $result as $value ) {
    echo '<img src="http://media.steampowered.com/steamcommunity/public/images/apps/'. htmlentities($value['appid']) .'/'. htmlentities($value['img_logo_url']) .'.jpg">';
}

Hope it helps.