PHP preg_match and replace multiple instances between tags

Question

Sorry if the title is a little confusing its hard to explain so will try my best :)

Ok I have a blog and in the back end I want to be able to add multiple galleries for each product in a post

Example blog:

Some Product Title 1
blah blah blah blah
[Gallery::product_id_01]

Some Product Title 2
blah blah blah blah
[Gallery::product_id_02]

So in this example, there are 2 products each with a Gallery tag. I want to be able to find and replace these example tags [Gallery::product_id_01] and [Gallery::product_id_02] with the actual image gallery, which is done via a php function called ProdImgGallery() this passes the same ID example: product_id_01

The tags will always have [Gallery::*] but the text after the :: indicated by * will be different and needs to be captured from the tag for the next stage.

Using preg_match_all("/\\[Gallery::([^\\]]*)\\]/", $blog_content, $product_id); finds all the tags as you would expect but I then need to replace the tags with the correct gallery indicated by its unique ID

This is as far as I can get but this just fetches each gallery based on all the ids found by preg_match_all I cant figure out how to replace each one with the corresponding gallery

//Find all Matches and put in array    
preg_match_all("/\[Gallery::([^\]]*)\]/", $blog_content, $product_id);

//Count all matches
$all_matches = count($product_id[1]);

//Loop through them
for($x=0;$x<$all_matches;$x++)
{
echo $product_id[1][$x]."<br>";
$prod_img_gallery = ProdImgGallery($product_id[1][$x]);
}
$blog_content = preg_replace("/\[Gallery::([^\]]*)\]/",$prod_img_gallery,$blog_content);

Hope this makes some kind of sense, I have trouble explaining things so please forgive me :) I did try searching too but could not find an answer that matched my exact problem

Many thanks!

Answer 1

You may try using preg_replace_callback :

$input = "Some Product Title 1
blah blah blah blah
[Gallery::product_id_01]

Some Product Title 2
blah blah blah blah
[Gallery::product_id_02]";

$out = preg_replace_callback(
    "/\[Gallery::(.*?)\]/", function($m) {
                                $val = "[Gallery::" . ProdImgGallery($m[1]) . "]";
                                return $val;
                            },
    $input);
echo $out;

The idea here is to capture every occurrence of [Gallery::...] , and than pass the captured group into a callback function. The above script uses an inline anonymous function for the callback, which then returns the replacement you want, using the ProdImgGallery() function.