Replacing a string in an xml/plist file using PHP

Question

I have two .plist files in a directory both of them look something like this:

<dict>
    <key>bundle-identifier</key>
    <string>TEXT</string>
    <key>bundle-version</key>
    <string>VESRION</string>
    <key>kind</key>
    <string>software</string>
    <key>subtitle</key>
    <string>TEXT</string>
    <key>title</key>
    <string>TEXT</string>
  </dict>

I was able to get the value/string of title with this:

$files = array();
foreach (glob("../../plists/*.plist") as $file) {
    $files[] = $file;
    //echo "$file";

    $fileContent = file_get_contents($file);
    $xml = simplexml_load_string($fileContent) or die("Error: Cannot create object");
    $resultNames = $xml->dict->array->dict->dict->string[4] . '<br /> <br />';
    //echo $resultNames;

}

Now I want to change the value/string of title for each of them with php, like if I changed the title value/string of one of them I don't want the other one to get effected by it, is it possible?

Answer 1

Not sure how your echo of the title worked, but in this code I've used XPath to find the <key> element which has the content title . It then fetches the value of the following <string> element.

To update it, you use a slight fudge in SimpleXML to make it set the value of the <string> element and then save the result XML back to the same file name....

$xml = simplexml_load_string($fileContent) or die("Error: Cannot create object");
// Find the correct string element from the preceding key for title
$titleString = $xml->xpath('//key[.="title"]/following-sibling::string')[0];

// Set new value
$titleString[0] = "new Title1";
// Save the file
$xml->asXML($file);

If you identify the content by the file name, then check $file , but if you can only identify it by the title, then you would need to check if this finds the title you are after.

$titleToUpdate = "Correct Title2";
$fileContent = file_get_contents($file);
$xml = simplexml_load_string($fileContent) or die("Error: Cannot create object");
$titleString = $xml->xpath('//key[.="title"]/following-sibling::string[.="'.$titleToUpdate.'"]');


// Check there is 1 matching item
if ( count($titleString) == 1 )  {
    $titleString[0][0] = "new Title12";
    $xml->asXML($file);
}

Answer 2

I'm not sure to understand everything but you can use DomDocument to change the values.

$doc = new DOMDocument;
$doc->load('your_xml_file.xml');

$elements = $doc->getElementsByTagName("string");

foreach ($elements as $element) {
   //$element->nodeName will be "string"
   $nodes = $element->childNodes;

   foreach ($nodes as $node) {
      $node->nodeValue = 'New value';
    }
}

$doc->save("newfile.xml")

Answer 3

Its not pretty but works.

$doc = new DOMDocument;
$doc->load('file_address');

$elements = $doc->documentElement;

$found = false;
foreach ($elements->childNodes AS $item) {
    if($found){
        $item->nodeValue = 'changed';
        $found = false;
    }else{
        if($item->nodeName == 'key' && $item->nodeValue == 'title'){
            $found = true;
        }
    }
}
$doc->saveXML();

Answer 4

Using Xpath with DOM is possible as well.

$titleToUpdate = 'Original Title';

$document = new DOMDocument();
// load from string, for file: $document->load($fileName);
$document->loadXML($xml);
$xpath = new DOMXpath($document);

$expression = '//dict/key[.="title"]/following-sibling::string[.="'.$titleToUpdate.'"]';

$modified = FALSE; 
foreach ($xpath->evaluate($expression) as $titleValueNode) {
    $titleValueNode->textContent = 'Changed Title';
    $modified = TRUE;
}

if ($modified) {
  // output string, to save file: $document->save($fileName);
  echo $document->saveXML();
}

Output:

<?xml version="1.0"?>
<dict>
    <key>bundle-identifier</key>
    <string>TEXT</string>
    <key>bundle-version</key>
    <string>VESRION</string>
    <key>kind</key>
    <string>software</string>
    <key>subtitle</key>
    <string>TEXT</string>
    <key>title</key>
    <string>Changed Title</string>
</dict>

This approach would change any matching item and just store that it modified one or more.

Now if you do need to lookup different files for that, I would suggest moving the action into a function.

function replaceTitle(string $fileName, string $title): bool {
    // the actual action from the example
    return $modified;
}

$files = new GlobIterator(__DIR__.'/path/*.plist');
foreach ($files as $file) {
    if (replaceTitle((string)$file, 'Original Title')) {
        echo "Modified: $file\n";
    }
}