Using Xpath in php, return an empty array

Question

Hi guys i'm trying to get all artist from this XML:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<metadata created="2015-02-03T04:03:18.468Z"
    xmlns="http://musicbrainz.org/ns/mmd-2.0#"
    xmlns:ext="http://musicbrainz.org/ns/ext#-2.0">
    <artist-list count="6310" offset="0">
        <artist id="d51955f3-df06-432c-a90d-0308f3c48273" type="Person" ext:score="100">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <gender>male</gender>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <begin-area id="82f3a697-ba65-404d-a1ed-360147af7d10">
                <name>San Diego</name>
                <sort-name>San Diego</sort-name>
            </begin-area>
            <end-area id="ae0110b6-13d4-4998-9116-5b926287aa23">
                <name>California</name>
                <sort-name>California</sort-name>
            </end-area>
            <disambiguation>jazz pianist, composer, arranger and bandleader</disambiguation>
            <life-span>
                <begin>1922-04-17</begin>
                <end>2013-06-29</end>
                <ended>true</ended>
            </life-span>
            <alias-list>
                <alias sort-name="Smith, Paul T.">Paul T. Smith</alias>
            </alias-list>
        </artist>
        <artist id="443ead81-02ce-4136-a759-71453184c002" type="Person" ext:score="100">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <gender>male</gender>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <begin-area id="f83bde89-c84a-4846-a89a-d5d0874e9ddc">
                <name>Calumet</name>
                <sort-name>Calumet</sort-name>
            </begin-area>
            <end-area id="6db2e45d-d7f3-43da-ac0b-7ba5ca627373">
                <name>Glendale</name>
                <sort-name>Glendale</sort-name>
            </end-area>
            <disambiguation>film and television composer, Disney Legends honoree</disambiguation>
            <life-span>
                <begin>1906-10-30</begin>
                <end>1985-01-25</end>
                <ended>true</ended>
            </life-span>
            <alias-list>
                <alias sort-name="Smith, Paul J.">Paul J. Smith</alias>
            </alias-list>
        </artist>
        <artist id="fac3e6c4-6d3c-4086-a590-95e4a057ac42" ext:score="95">
            <name>Paul Smith</name>
            <sort-name>Paul Smith</sort-name>
            <disambiguation>Banjo</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="8ffc42c7-4083-4435-b91c-6ddf4095eeb3" ext:score="95">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <disambiguation>American soul artist</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="2f727018-1e83-4797-8433-32c8b99dd057" type="Person" ext:score="94">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <gender>male</gender>
            <country>GB</country>
            <area id="8a754a16-0027-3a29-b6d7-2b40ea0481ed">
                <name>United Kingdom</name>
                <sort-name>United Kingdom</sort-name>
            </area>
            <disambiguation>of Maxïmo Park</disambiguation>
            <life-span>
                <begin>1979-03-13</begin>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="e44ae2fa-9367-4691-bdb7-d097446ee3ce" type="Person" ext:score="94">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <disambiguation>Gabba/Acid techno artist</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="32c7cf45-867e-4076-a24c-ba38dccaa7bd" type="Person" ext:score="94">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <disambiguation>American folk artist</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="bb57b210-bf27-4af1-8561-600f131bfc81" type="Person" ext:score="94">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <disambiguation>drum n bass producer aka Spinback</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="35287ce6-2fd4-41af-9248-d07e84eeb0df" type="Person" ext:score="94">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <disambiguation>Contemporary Christian artist peformed with The Imperials</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="6ece7fa3-c397-48a6-99f7-05e900b73d81" type="Person" ext:score="82">
            <name>Nicholas Paul Smith</name>
            <sort-name>Smith, Nicholas Paul</sort-name>
            <gender>male</gender>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="3c1fbcf7-4bb8-49ac-8d35-3f4ee8b71e0a" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <gender>male</gender>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <disambiguation>recording engineer, David "Honeyboy" Edwards recordings</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="24e472f9-6003-4873-aac5-c79763105a51" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <gender>male</gender>
            <country>GB</country>
            <area id="8a754a16-0027-3a29-b6d7-2b40ea0481ed">
                <name>United Kingdom</name>
                <sort-name>United Kingdom</sort-name>
            </area>
            <disambiguation>UK drummer</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="662c9cd6-73e2-426f-8e76-a8f2a8233215" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <country>AU</country>
            <area id="106e0bec-b638-3b37-b731-f53d507dc00e">
                <name>Australia</name>
                <sort-name>Australia</sort-name>
            </area>
            <disambiguation>Australian bassist for Laughing Clowns/Ed Kuepper</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="0e911646-290a-4345-b3dc-e5ca91faaf88" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <gender>male</gender>
            <country>GB</country>
            <area id="8a754a16-0027-3a29-b6d7-2b40ea0481ed">
                <name>United Kingdom</name>
                <sort-name>United Kingdom</sort-name>
            </area>
            <disambiguation>British a cappella singer</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="75ffe808-187a-4488-8c84-7467efa2b277" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <disambiguation>of Dengue Fever</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="79d145cb-d862-487d-a340-b723a7c8eb26" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <country>GB</country>
            <area id="8a754a16-0027-3a29-b6d7-2b40ea0481ed">
                <name>United Kingdom</name>
                <sort-name>United Kingdom</sort-name>
            </area>
            <disambiguation>Scottish electronic artist performing as Reverbaphon</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="1f483d17-7510-44d1-95a7-8c16c53c57a1" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <disambiguation>US underground hip hop MC Breeze Brewin, of Weatherman, Def Jux</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="76e04e2a-e440-4729-8036-59928521c677" type="Person" ext:score="79">
            <name>Paul Smith</name>
            <sort-name>Smith, Paul</sort-name>
            <gender>male</gender>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <disambiguation>sound engineer, Randy Crawford &amp; Joe Sample recordings</disambiguation>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="7a81a64e-4fdc-44a8-b33b-a447c611cf33" type="Group" ext:score="76">
            <name>The Paul Smith Trio</name>
            <sort-name>Paul Smith Trio, The</sort-name>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="7b458c24-ce5b-4b77-a1dc-616ff53d1e70" type="Group" ext:score="76">
            <name>The Paul Smith Quartet</name>
            <sort-name>Paul Smith Quartet, The</sort-name>
            <country>US</country>
            <area id="489ce91b-6658-3307-9877-795b68554c98">
                <name>United States</name>
                <sort-name>United States</sort-name>
            </area>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="1c86fcf3-b56c-4427-856b-344d898abc33" ext:score="76">
            <name>Paul Gerard Smith</name>
            <sort-name>Smith, Paul Gerard</sort-name>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="e5fcb860-3210-4721-a44f-7bd3dcb4b5d5" ext:score="76">
            <name>Paul Joseph Smith</name>
            <sort-name>Paul Joseph Smith</sort-name>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="3eedd38b-f7ca-43d2-b635-adc4ad95371b" type="Person" ext:score="74">
            <name>Margaret Thatcher</name>
            <sort-name>Thatcher, Margaret</sort-name>
            <gender>female</gender>
            <country>GB</country>
            <area id="8a754a16-0027-3a29-b6d7-2b40ea0481ed">
                <name>United Kingdom</name>
                <sort-name>United Kingdom</sort-name>
            </area>
            <life-span>
                <begin>1925-10-13</begin>
                <end>2013-04-08</end>
                <ended>true</ended>
            </life-span>
            <tag-list>
                <tag count="1">
                    <name>politician</name>
                </tag>
                <tag count="1">
                    <name>non-musician</name>
                </tag>
            </tag-list>
        </artist>
        <artist id="646c86db-d0af-403e-bef9-3deafd9c3d43" type="Person" ext:score="74">
            <name>Brad Thatcher</name>
            <sort-name>Thatcher, Brad</sort-name>
            <life-span>
                <ended>false</ended>
            </life-span>
        </artist>
        <artist id="b5425c52-3e9c-4144-9467-eaa4d69389b8" type="Person" ext:score="74">
            <name>Jim Thatcher</name>
            <sort-name>Thatcher, Jim</sort-name>
            <life-span>
                <ended>false</ended>
            </life-span>
            <alias-list>
                <alias sort-name="Thatcher, James" type="Legal name">James Thatcher</alias>
            </alias-list>
        </artist>
    </artist-list>
</metadata>

but all that i get is an empty array.

this is my code:

<!doctype html>
<html>
<head>
<body>
<meta charset="utf-8">
<title>XML: Descrizione, Immagine, Link a Discogs</title>
</head>
<body>
<?php 
$bb = "Paul Thatcher Smith"; //Example.
$name = strtolower(str_replace(" ","%20",$bb)); //all whitespaces must be coded with %20
$html = "http://musicbrainz.org/ws/2/artist/?query=".$name;

if (($response_xml_data = file_get_contents($html))===false){
    echo "Error fetching XML\n";
} 
else {
   libxml_use_internal_errors(true);
   $data = new SimpleXmlElement($response_xml_data); //all ok, you can do an echo, xml is well formed
   $data->registerXPathNamespace('c',$html); //according to w3s
   if (!$data) { //always have this error -.-
       echo "Error loading XML\n";
       foreach(libxml_get_errors() as $error) {
           echo "\t", $error->message;
       }
   } 
   else {
        $xpath='//c:artist'; //simple xpath query, if i put //* it gives me all xml
        print_r($result = $data->xpath($xpath)); 
        foreach ($result as $artist){
            echo $artist . "<br>";
        }
    }
}
?>

instead of comment, edit your question to clarify it and delete the comment — jean
– jean, Commented Feb 2, 2015 at 16:07
done any basic debugging, like checking if file_get_contents() actually succeeds? If it fails, it'll return boolean false, which would be loaded by simplexml as an empty string. — Marc B
– Marc B, Commented Feb 2, 2015 at 16:26
@MarcB if i put $xpath='//*' it gives me all xml, so no problem there :/ Is an xpath problem. — Blink
– Blink, Commented Feb 2, 2015 at 16:35

JLRishe · Accepted Answer · 2015-02-02 16:56:49Z

2

This line is incorrect:

$data->registerXPathNamespace('c',$html);

$html is the URL that you are querying, but in this line you need to specify the namespace of the XML you are using. That namespace is:

http://musicbrainz.org/ns/mmd-2.0#

So use this:

$data->registerXPathNamespace('c','http://musicbrainz.org/ns/mmd-2.0#');

answered Feb 2, 2015 at 16:56

JLRishe

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3 Comments

Blink Over a year ago

ok, it works! now i have ` $xpath='//c:artist[1]'; print_r( $result = $data->xpath($xpath)); $result = reset($result); echo $result->name; ` because i can't get it with $xpath='//c:artist/name any advice? p.s. TY man, you saved me :P

JLRishe Over a year ago

@Blink It would be //c:artist/c:name, or I would recommend using /*/c:artist-list/c:artist/c:name. It's a good idea to avoid using // when possible.

Blink Over a year ago

if i could i would give you a +10! Thank you!

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