Find an element by id and replace its contents with php

Question

I want to use PHP to search through the contents of a file for an element with a specific id, replace its contents, then save my changes to the file. I'm able to load in the HTML, and save it back out again, but am having trouble with the 'find and replace' (currently trying to use preg_replace).

Here's what I have so far:

<?php
// read in the content
$file = file_get_contents('file.php');

// parse $file, looking for the id.
$replace_with = "id='" . 'myID' . "'>" . $replacement_content . "<";
if ($updated = preg_replace('/id\=\"myID\"\>.*?\</', $replace_with, $file)) {   
    // write the contents of $file back to index.php, and then refresh the page.
    file_put_contents('file.php', $updated);
}

However, while it successfully loads in the content and writes it out (I've tested it by writing to a separate file), it appears that $updated doesn't actually change.

Any ideas?

*(related)* [Best Methods to parse HTML](http://stackoverflow.com/questions/3577641/best-methods-to-parse-html/3577662#3577662) — Gordon, Dec 03 '10 at 22:07

score 11 · Accepted Answer · answered Dec 03 '10 at 21:56

11

You can use PHP's DOMDocument for this:

$html = new DOMDocument(); 
$html->loadHTMLFile('file.php'); 
$html->getElementById('myId')->nodeValue = 'New value';
$html->saveHTMLFile("foo.html");

answered Dec 03 '10 at 21:56

karim79

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Thanks. Would I not be able to save it as a php file this way? There's a possibility it may also be xml files in the future. – Chris Armstrong Dec 03 '10 at 21:58
You can, but I don't see the point as the the output will still be HTML. – karim79 Dec 03 '10 at 22:02
It needs to be php for now to be used elsewhere. – Chris Armstrong Dec 03 '10 at 22:06
Thanks, tried this and it works perfectly, also a lot simpler for me to keep track of! – Chris Armstrong Dec 03 '10 at 22:27

score 1 · Answer 2 · answered Dec 03 '10 at 21:55

1

just thinking why are you escaping "=", it should be /id=\"myID\"\>.*?\</

answered Dec 03 '10 at 21:55

TomaszSobczak

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score 1 · Answer 3 · answered Dec 03 '10 at 22:06

1

I think you have some escaping issues going on ;-)

try this:

$replace_with = 'id="myID">' . $replacement_content . '</';
if ($updated = preg_replace('#id="myID">.*?</#Umsi', $replace_with, $file)) {   
    // write the contents of $file back to index.php, and then refresh the page.
    file_put_contents('file.php', $updated);
}

answered Dec 03 '10 at 22:06

Alex

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That's the modifiers. U is for ungreedy, m is for multiline, s for including newlines and i for case insensitive. Have a look at the manual: http://php.net/manual/en/reference.pcre.pattern.modifiers.php – Alex Dec 04 '10 at 09:29
Is it true that with this solution the id must be at the end of the tag? And if so, is there a solution for elements with id's not matching this requirement? – Pepijn Gieles Aug 14 '14 at 08:18

Find an element by id and replace its contents with php

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