Case (in)sensitive Replace for str_ireplace for search results

Question

I have a list of items. I want to use them in search terms. Say the list is:

Hello, World!
The World is not Enough
Around the world in 80 days.
WAR of the WORLDS

Now, if I am searching for the keyword world (notice all are in small letters), I am giving this function.

preg_replace(/world/, '<span class="label label-search-results">$0</span>', $item);

Where the $item is each line, the output is:

Warning: preg_replace() [function.preg-replace]: Delimiter must not be alphanumeric or backslash in /myfile.php on line XX.

If I use str_ireplace(), I don't know the original case of the found text. It would be something like:

str_ireplace("world", '<span class="label label-search-results">world</span>', $item);

And that results in all the world, World and WORLD being in lower case. Any ideas on how to preserve the case after replace?

Rizier123 · Accepted Answer · 2015-04-26T19:51:46.290

1

That's the perfect use case for preg_replace_callback(), just use it like this:

echo preg_replace_callback("/" . preg_quote($_GET["q"], "/")  . "/i", function($m){
    return "<span class='label label-search-results'>" . $m[0] . "</span>";
}, $item);

edited Apr 26 '15 at 19:51

answered Apr 26 '15 at 19:44

Rizier123

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I don't want to make everything in lower case. I wanna preserve the case. If not, I can use `str_ireplace()`. – Praveen Kumar Purushothaman Apr 26 '15 at 19:45
@PraveenKumar Ah then just remove the `strtolower()` call in the callback function – Rizier123 Apr 26 '15 at 19:45
I am using it from `$_GET["q"]`. So, how do I do that? – Praveen Kumar Purushothaman Apr 26 '15 at 19:45
@PraveenKumar Just change `$item` with `$_GET["q"]` and save the return value of `preg_replace_callback()` into a variable as you want it – Rizier123 Apr 26 '15 at 19:47
I don't wanna use the `/world/i`. Coz that's in `$_GET["q"]`. Can you edit the answer please? `:)` – Praveen Kumar Purushothaman Apr 26 '15 at 19:50
@PraveenKumar Ah, so you mean the search sting is in `$_GET["q"]` ? – Rizier123 Apr 26 '15 at 19:51
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/76299/discussion-between-praveen-kumar-and-rizier123). – Praveen Kumar Purushothaman Apr 26 '15 at 19:51

score 0 · Answer 2 · edited Apr 26 '15 at 19:49

0

preg_replace('/(world)/i', '<span class="label label-search-results">$1</span>', $item);

Try with the flag i for case-insensitivity.

edited Apr 26 '15 at 19:49

Rizier123

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16
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answered Apr 26 '15 at 19:43

jskidie

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I am using it from `$_GET["q"]`. So, how do I do that? – Praveen Kumar Purushothaman Apr 26 '15 at 19:44
@PraveenKumar don't. never allow the user to control your regular expression, as it can lead to remote code execution. – rev Apr 26 '15 at 19:45
Exactly... So this is a search term, which is `mysqli_real_escape_string()`'ed... So lemme know. `:)` – Praveen Kumar Purushothaman Apr 26 '15 at 19:46
Notice: preg_replace (with /e modifier) http://stackoverflow.com/questions/3115559/exploitable-php-functions is exploitable only. Not with i modifier – jskidie Apr 26 '15 at 20:01

Case (in)sensitive Replace for str_ireplace for search results

2 Answers2