regex function[filename] pattern and function[string_with_escaped_characters] pattern - php

Question

I'm trying to script and parse a file,
Please help with regex in php to find and replace the following patterns:
From: "This is a foo[/www/bar.txt] within a foo[/etc/bar.txt]"
To: "This is a bar_txt_content within a bar2_txt_content"
Something along those lines:
$subject = "This is a foo[/www/bar.txt] within a foo[/etc/bar.txt]";
$pattern = '/regex-needed/';
preg_match($pattern, $subject, $matches);
foreach($matches as $match) {
$subject = str_replace('foo['.$match[0].']', file_get_contents($match[0]), $subject);
}
And my second request is to have:
From: 'This is a foo2[bar bar ] bar bar].'
To: "this is a returned"
Something along those lines:
$subject = 'This is a foo2[bar bar \] bar bar].';
$pattern = '/regex-needed/';
preg_match($pattern, $subject, $matches);
foreach($matches as $match) {
$subject = str_replace('foo2['.$match[0].']', my_function($match[0]), $subject);
}
Please help in constructing these patterns...

Answer 1

If you always have a structure like foo[ ... ]
Then is very easy:
foo\[([^]]+)\]
That is .NET syntax but i'm sure the expressions is simple enough for you to convert.
Description of the regex:
Match the characters “foo” literally «foo»
Match the character “[” literally «[»
Match the regular expression below and capture its match into backreference number 1 «([^]]+)»
Match any character that is NOT a “]” «[^]]+»
Between one and unlimited times, as many times as possible, giving back as needed (greedy) «+»
Match the character “]” literally «]»

Answer 2

Luc,
this should help you get started.
http://php.net/manual/en/function.preg-replace.php
You may have to setup a loop and increase the counter, using preg_replace with a limit of 1 to replace only the first instance.
In order to match foo[/www/bar.txt]:
the regex should be something like:
foo\[\/www\/([A-Za-z0-9]*)\.txt\]
The backslashes are there to cancel the special meaning of some characters in your regexp.
It will match foo[/www/.[some file name].txt, and ${1} will contain the filename without the .txt as brackets form groups which can be used in the replaced expression. ${1} will contain what was matched in the first round brackets, ${2} will contain what was matched in the second one, etc ...
Therefore your replaced expression should be something like "${1}_txt_content". Or in the second iteration "${1}2_txt_content".
[A-Za-z0-9]* means any alphanumeric character 0 or more times, you may want to replace the * with a + if you want at least 1 character.
So try:
$pattern = foo\[\/www\/([A-Za-z0-9]*)\.txt\];
$replace = "${1}_txt_content";
$total_count = 1;
do {
echo preg_replace($pattern, $replace, $subject, 1, $count);
$replace = "${1}" + ++$total_count + "_txt_content";
} while ($count != 0);
(warning, this is my first ever PHP program, so it may have mistakes as I cannot test it ! but I hope you get the idea)
Hope that helps !
Tony
PS: I am not a PHP programmer but I know this works in C#, for example, and looking at the PHP documentation it seems that it should work.
PS2: I always keep this website bookmarked for reference when I need it: http://www.regular-expressions.info/

Answer 3

$pattern = '/\[([^\]]+)\]/';
preg_match_all($pattern, $subject, $matches);
print_r($matches['1']);

Answer 4

found the correct regex I needed for escaping:
'/foo\[[^\[]*[^\\\]\]/'