php replace all src atributes of img in file

Question

I have in page links like this:

import.html

<h1>Title</h1>
<img src="img/pic1.jpg" alt="" title="Picture 1" class="pic">
<img src="img/pic2.jpg" alt="" title="Picture 2" class="pic">
<img src="img/pic3.jpg" alt="" title="Picture 3" class="pic">
<p>random text</p>
<img src="img/pic4.jpg" alt="" title="Picture 4" class="pic">

index.php

<?php
//get file content
$html = file_get_contents('import.html');

function replace_img_src($img_tag) {
    $doc = new DOMDocument();
    $doc->loadHTML($img_tag);
    $tags = $doc->getElementsByTagName('img');
    if (count($tags) > 0) {
        $tag = $tags->item(0);
        $old_src = $tag->getAttribute('src');
        $new_src_url = 'website.com/assets/'.$old_src;
        $tag->setAttribute('src', $new_src_url);
        return $doc->saveHTML($tag);
    }
    return false;
}

// usage
$new = replace_img_src($html);
print_r(htmlspecialchars($new));

Goal:

I want to replace all src attributes of img element in import.html file and return file with new image links. I managed to create replace one element.

How to edit this to go through whole file and replace all attributes and return new import.html with replaced src's?

Answer 1

getElementsByTagName() method will return a DOMNodeList object containing all the matched elements. Currently, you're just modifying only one img tag. To replace all the img tags, simply loop through them using a foreach:

function replace_img_src($img_tag) {
    $doc = new DOMDocument();
    $doc->loadHTML($img_tag);
    $tags = $doc->getElementsByTagName('img');
    foreach ($tags as $tag) {
        $old_src = $tag->getAttribute('src');
        $new_src_url = 'website.com/assets/'.$old_src;
        $tag->setAttribute('src', $new_src_url);
    }
    return $doc->saveHTML();
}