PHP & XML Read element by attribute value

Question

$xml = '<?xml version="1.0"?>
<entries>
    <response>
        <category>client</category>
        <action>Greeting</action>
        <code>1000</code> 
        <msg>Your Connection with API Server is Successful</msg> 
        <resData> 
            <data name="svDate">2010-10-10 02:27:14</data> 
        </resData>
    </response>

    <response>
        <category>client</category>
        <action>Login</action>
        <code>1000</code>
        <msg>Command completed successfully</msg>
        <value>L116:no value</value>
    </response>

    <response>
        <category>domain</category>
        <action>InfoDomain</action>
        <code>1000</code>
        <msg>Command completed successfully</msg>
        <value>L125:no value</value>
        <resData>
            <data name="domain">google.com</data>
            <data name="crDate">2004-12-16</data>
            <data name="exDate">2013-12-16</data>
        </resData>
    </response>
</entries>';

$xml = simplexml_load_string($xml);

$domain = $xml->response[2]->resData[0]->data[0];
$crdate = $xml->response[2]->resData[0]->data[1];
$exdate = $xml->response[2]->resData[0]->data[2];

With the above code i can get the values. But how can i get the values by attribute value?

For example i want to get the values with something like this:

$domain = $xml->response[2]->resData[0]->data["domain"];
$crdate = $xml->response[2]->resData[0]->data["crdate"];
$exdate = $xml->response[2]->resData[0]->data["exdate"];

One more question.

If i have two elements with the same name? For example i would like to parse the dns. How could i do it?

The xml code is like this:

    <?xml version="1.0"?>
<entries>
    <response>
        <category>client</category>
        <action>Greeting</action>
        <code>1000</code> 
        <msg>Your Connection with API Server is Successful</msg> 
        <resData> 
            <data name="svDate">2010-10-10 02:27:14</data> 
        </resData>
    </response>

    <response>
        <category>client</category>
        <action>Login</action>
        <code>1000</code>
        <msg>Command completed successfully</msg>
        <value>L116:no value</value>
    </response>

    <response>
        <category>domain</category>
        <action>InfoDomain</action>
        <code>1000</code>
        <msg>Command completed successfully</msg>
        <value>L125:no value</value>
        <resData>
            <data name="domain">google.com</data>
            <data name="crDate">2004-12-16</data>
            <data name="exDate">2013-12-16</data>
            <data name="dns">ns1.google.com</data>
          <data name="dns">ns2.google.com</data>
        </resData>
    </response>
</entries>

As you can see the ns1 and ns2 have the same name. name="dns". How can i parse each one in a different variable?

Thank you!

salathe · Accepted Answer · 2011-09-29 11:50:42Z

1

With the element["attribute"] syntax, attribute is the name of an attribute on the element. It is not the value of some randomly chosen attribute belonging to an element.

The example below creates an array containing a mapping for the data elements of name attribute value to text value.

$data = array();
foreach ($xml->response[2]->resData->data as $d) {
    $data[strtolower($d['name'])] = (string) $d;
}

// Now you can access the values via $data['domain'], $data['crdate'], etc.

Nick, your code expects XML structured like:

<resData>
    <data domain="google.com" crdate="2004-12-16" exdate="2013-12-16" />
</resData>

Edit due to question change

In a marvelous dose of eating my own words, due to the change in the question an XPath approach would be more appropriate (don't you love OPs who do that?).

You can easily get an array of the name="dns" elements with a basic XPath expression.

$xml = simplexml_load_string($xml);
$dns = $xml->xpath('response[category="domain"]/resData/data[@name="dns"]');

edited Sep 29, 2011 at 11:50

answered Sep 29, 2011 at 9:58

salathe

52.1k12 gold badges108 silver badges134 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Gordon Over a year ago

I wont downvote but I think an XPath solution would be less cumbersome and in general more appropriate because it operates on the tree itself and not some copy. Copying the values into the array is just a waste of memory. Any changes the OP will do to the tree after the copy wont be reflected in it either and vice versa. Writing the values back to XML requires extra effort then.

salathe Over a year ago

As we discussed on chat, I don't think an XPath solution would be less cumbersome, nor more appropriate. Changes to the tree are a non-issue as the OP is only reading, until the question changes I don't care about the tree... nor should you. Feel free to provide your less cumbersome, more appropriate XPath solution for the OP to choose which he prefers.

Gordon · Accepted Answer · 2011-09-29 11:34:35Z

You can use XPath to to do queries against your XML, e.g.

$entries = simplexml_load_string($xml);
$dataElements = $entries->xpath('/entries/response/resData/data[@name="dns"]');
foreach ($dataElements as $dataElement) {
    echo $dataElement;
}

The above XPath finds all <data> elements with a name attribute of "dns" that are direct children of the given element hierarchy, e.g.

 <entries>
     …
     <response>                            
         …
         <resData>                         
             …
             <data name="dns">

IMO this is easier and more appropriate than having the extra step of copying over the values into an array which would disconnect it from the actual DOM tree and which you would have to repeat for all the elements you want to map this way. XPath is built-in. You just query and get the result.

Because $dataElements is an array, you can also access the elements in it individually with

echo $dataElements[0]; // prints "ns1.google.com"
echo $dataElements[1]; // prints "ns2.google.com"

Note that the $dataElements array actually contains SimpleXmlElements connected to the main document. Any changes you do to them will also be reflected in the main document.

Collectives™ on Stack Overflow

PHP & XML Read element by attribute value

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related