Solved

Need a PHP regular expression that matches variables outside tags

Posted on 2011-03-21
11
317 Views
Last Modified: 2012-05-11
I have the following text

<p>Sample text that contains a {myvariable} string and {variable} string</p>
<textarea cols='40' rows='4'>This text comes from an outside file but uses the same {myvariable} string.</textarea>
<p>Additional text that contains different {variable} strings</p>

I'm using the following code to replace the strings with variables defined elsewhere:

foreach($arrTags as $tag){
$myvar = preg_replace('/(?!\{'.$tag.'\}[^<textarea]*<\/textarea>)\{'.$tag.'\}/',$$tag,$myvar);
}

I can't seem to get it to NOT replace the {myvariable} tags that fall between the <textarea> tags. What am I missing?
0
Comment
Question by:tmcclint
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 3
  • 3
11 Comments
 
LVL 35

Expert Comment

by:Terry Woods
ID: 35185158
Try this:
foreach($arrTags as $tag){
    $myvar = preg_replace('/(?!\{'.$tag.'\}[^<]*<\/textarea>)\{'.$tag.'\}/',$$tag,$myvar);
}

Open in new window

0
 
LVL 35

Expert Comment

by:Terry Woods
ID: 35185172
[^<textarea] means one character that is not any of these: <texra

In:
<textarea cols='40' rows='4'>This text comes from an outside file but uses the same {myvariable} string.</textarea>
There is a t in " string." (after {myvariable}, but before the </textarea> tag) so the negative lookahead fails to match.
0
 

Author Comment

by:tmcclint
ID: 35185457
My text includes the textarea tags but what falls in between can span an indeterminate number of lines. While the solution you sent works on a single line, is it possible to have it look ahead or behind over several lines? So see this text:

<html>
<body>
<p>my sample {myvariable} text</p>
<textarea cols='40' rows='4'>
<html>
<body>
<p>This is 1 line</p>
<p>This is another with the {myvariable} string in it.
<p>More Text</p>
</body>
</html>
</textarea>
<p>More text with the {variable} string in it.</p>

What I'm looking for would be this:

<html>
<body>
<p>my sample REPLACED text</p>
<textarea cols='40' rows='4'>
<html>
<body>
<p>This is 1 line</p>
<p>This is another with the {myvariable} string in it.
<p>More Text</p>
</body>
</html>
</textarea>
<p>More text with the REPLACED string in it.</p>

Right now it still seems to be catching the {myvariable} string at line 8.
0
PeopleSoft Has Never Been Easier

PeopleSoft Adoption Made Smooth & Simple!

On-The-Job Training Is made Intuitive & Easy With WalkMe's On-Screen Guidance Tool.  Claim Your Free WalkMe Account Now

 
LVL 35

Expert Comment

by:Terry Woods
ID: 35185489
Adding the s pattern modifier *might* work - I will test it in 30mins or so if I don't hear back from you:
    $myvar = preg_replace('/(?!\{'.$tag.'\}[^<]*<\/textarea>)\{'.$tag.'\}/s',$$tag,$myvar);
0
 

Author Comment

by:tmcclint
ID: 35186224
Nope, the /s didn't do it. It's still catching the internal {myvariable}.
0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 35186597
Is there a reason why you can't just do a simple string replace using str_replace?
0
 

Author Comment

by:tmcclint
ID: 35189749
How would str_replace look to see if what it was replacing was within the <textarea> tags?
0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 35190195

>>  How would str_replace look to see if what it was replacing was within the <textarea> tags?

Ah. I didn't realize you wanted to conditionally replace based on where a particular variable occurs. Try this out:
$src = preg_replace('/\{'.$tag.'\}(?!(?:.(?!<textarea))+?<\/textarea>)/s', $$tag, $myvar);

Open in new window

0
 

Author Comment

by:tmcclint
ID: 35190371
It still doesn't seem to catch what I'm look for. I tried this:

preg_replace('/(?!<textarea)\{'.$tag.'\}*(?!<\/textarea>)/s',$$tag,$myvar);

But it only seems to catch {myvariable} strings that are NOT preceded by <textarea> and not ones that occur after the </textarea>.

In this string:
<p>This is a real {string}</p>
<textarea id='taEditor' name='fileEditor' cols='80' rows='30'><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>{sitename} : {title}</title>
</textarea>
<p>{test}</p>

Open in new window


It only catches {string} and NOT {test}. At least it appears to be skipping the ones that fall within the TEXTAREA tags.
0
 
LVL 75

Accepted Solution

by:
käµfm³d   👽 earned 500 total points
ID: 35190757
>>  preg_replace('/(?!<textarea)\{'.$tag.'\}*(?!<\/textarea>)/s',$$tag,$myvar);

That's not going to work the way you think it will anyway.


I scaled down the test since I don't have your exact setup, but I don't perceive a reason why it shouldn't work. This is the test I performed (TextArea expanded to see all text):
<html>
	<body>
	<?php

		$myvar = "<html>
		<body>
		<p>my sample {myvariable} text</p>
		<textarea cols='40' rows='15'>
		<html>
		<body>
		<p>This is 1 line</p>
		<p>This is another with the {myvariable} string in it.
		<p>More Text</p>
		</body>
		</html>
		</textarea>
		<p>More text with the {myvariable} string in it.</p>";

		$myvar = preg_replace('/\{myvariable\}(?!(?:.(?!<textarea))+?<\/textarea>)/s', 'AWESOME', $myvar);

		echo $myvar;
	?>
	</body>
</html>

Open in new window

untitled.PNG
0
 

Author Closing Comment

by:tmcclint
ID: 35191936
That was what I needed. I was able to utilize the code he presented and come to the solution. Thanks a million.
0

Featured Post

Online Training Solution

Drastically shorten your training time with WalkMe's advanced online training solution that Guides your trainees to action. Forget about retraining and skyrocket knowledge retention rates.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article discusses four methods for overlaying images in a container on a web page
Many old projects have bad code, but the budget doesn't exist to rewrite the codebase. You can update this code to be safer by introducing contemporary input validation, sanitation, and safer database queries.
The viewer will learn how to look for a specific file type in a local or remote server directory using PHP.
The viewer will learn how to create and use a small PHP class to apply a watermark to an image. This video shows the viewer the setup for the PHP watermark as well as important coding language. Continue to Part 2 to learn the core code used in creat…

617 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question