php search and replace <h2> to <h1> in my view source [duplicate] - php

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How do you parse and process HTML/XML in PHP?
(31 answers)
Closed 3 years ago.
I have the following html
<!-- START: .paragraph-content -->
<div class="paragraph-content">
<div class="container"><div class="row"><div class="col-sm-10">
<!-- START: .paragraph-columns -->
<div class="paragraph-columns">
<div class="field-wysiwyg">
<div data-quickedit-field-id="paragraph/167/field_mt_body/en/default" class="field field--name-field-mt-body field--type-text-long field--label-hidden field__items">
<div class="field__item">
<h2> </h2>
<h2> </h2>
<h2>INNOVATION.</h2>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
</div>
</div>
</div>
</div>
<!-- END: .paragraph-columns -->
</div></div></div>
</div>
<!-- END: .paragraph-content -->
I want to capture where the html begins with <div class="paragraph-content">
in that block, I want to change the <h2> to <h1>
so the end result will look like this:
<!-- START: .paragraph-content -->
<div class="paragraph-content">
<div class="container"><div class="row"><div class="col-sm-10">
<!-- START: .paragraph-columns -->
<div class="paragraph-columns">
<div class="field-wysiwyg">
<div data-quickedit-field-id="paragraph/167/field_mt_body/en/default" class="field field--name-field-mt-body field--type-text-long field--label-hidden field__items">
<div class="field__item">
<h2> </h2>
<h2> </h2>
<h1>INNOVATION.</h1>
<p> </p>
<p> </p>
<p> </p>
<p> </p>
</div>
</div>
</div>
</div>
<!-- END: .paragraph-columns -->
</div></div></div>
</div>
<!-- END: .paragraph-content -->
I have tried it with this regex pattern but nothing works:
'/(?:<h2((?!\s").*?)?>)(.*?)(?:<\/h2>)/si'

Answer 1

If you have the HTML page as a string variable, accomplished by:
$fileStr = file_get_contents('HTML_FILE.htm');
You can then find the start of the section you are after by using the text "<!-- START: .paragraph-content -->" and the end of the section of the string by using the text "<!-- END: .paragraph-content -->".
Having the start and end of the string, we can extract the portion of the $fileStr in which we want to run our regular expression against.
The regular expression required to find the string you want to change is:
<h2>.{2,}<\/h2>
The issue you have to to extract and replace the <h2> and </h2> with <h1> and </h1> whilst retaining everything in between these.
Doing that isn't going to be a simple neat solution. I would do a loop which would look for <h2>, then find if there is any alphanumerics between that and the closing </h2>, then extract the contents between the two if there is, replacing the tags appropriately.
Whilst not providing you with code to cut and paste, I hope I've given you something to ponder.

Answer 2

Regex works as a finite state machine, it has no way to parse recursive things, like XML tags that might contain other XML tags.
Basically, you cant match exactly the closing tag that matches the opening tag, because that requires recursion, which is not possible in finite state machines (there is Python module regex that has recursion and some other implementations, but this is not true regex).
For your problem exaclty you need a whole top-down recursive parser or some tool that works with XML/HTML specifically.
Just replacing the h2 tags with h1 in the whole regex'ed string is as simple as <(/?)h2> -> <$1h1> though.