I'm using preg_match to match the first contact page link within some HTML markup.
I have spent many hours investigating, reading PHP regex documents, debugging, and trying to find a similar solution on StackOverflow. There is a lot of advice for regex, just could not find it specific to my subpattern issue.
Example HTML:-
<ul class='root dropdown'><li class="item1 current-item-root first-item current-item">Home</li><li class="item2">Contact Us</li><li class="item3 parent category-page"><a
Instead of returning
/contact-us
it returns
"/">Home</a></li><li class="item2"><a href="/contact-us
Here is the code:-
preg_match( '/href.{1,5}"(?P<link>.{0,50}contact.{0,20})"/isxU', $input_line, $output_array);
I expected the regex U setting to make {0,50} non-greedy, but it's grabbing too much text.
The code is designed to pick up href links in various formats like below:-
/contact
/contact-us
websitename.com/contact-me
Here is a working example:-
https://www.phpliveregex.com/p/Dh2
Many thanks for your help. The answer was to exclude any other quotes captured in the sub-pattern, which was part of your example. The best and most fantastic part of your answer was to direct me to use https://regex101.com/ . That's an amazing tool for regex, great highlighting and explanations of the expression.
My answer:-
href="(?<link>[^"]{0,50}contact.*[^"]{0,50})"
Related
I know there are other posts with a similar name but I've looked through them and they haven't helped me resolve this.
I'm trying to get my head around regex and preg_match. I am going through a body of text and each time a link exists I want it to be extracted. I'm currently using the following:
$reg_exUrl = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/";
which works fine until it finds one that has <br after it. Then I get the url plus the <br which means it doesn't work correctly. How can I have it so that it stops at the < without including it?
Also, I have been looking everywhere for a clear explanation of using regex and I'm still confused by it. Has anyone any good guides on it for future reference?
\S* is too broad. In particular, I could inject into your code with a URL like:
http://hax.hax/"><script>alert('HAAAAAAAX!');</script>
You should only allow characters that are allowed in URLs:
[-A-Za-z0-9._~:/?#[]#!$&'()*+,;=]*
Some of these characters are only allowed in specific places (such as ?) so if you want better validation you will need more cleverness
Instead of \S exclude the open tag char from the class:
$reg_exUrl = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/[^<]*)?/";
You might even want to be more restrictive by only allowing characters valid in URLs:
$reg_exUrl = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/[a-zA-Z_\-\.%\?&]*)?/";
(or some more characters)
You could use this one as presented on the:
http://regex101.com/r/zV1uI7
On the bottom of the site you got it explained step by step.
I have this regular expression:
preg_match_all("/<a\s.*?href\s*=\s*['|\"](.*?)(?=#|\"|')/si", $data, $matches);
to find all urls, it works fine, BUT how can I modificate it to find urls with question marks ONLY?
Example:
0123
And preg_match_all will return:
http://site.com/index.php?id=1
http://site.com/calc/index.php?id=1&scheme=Venus
preg_match_all("#<a\s*href\s*=[\'\"]([^\'\"]+\?[^\'\"]+)[\'\"]#si", $data, $matches);
Try this.
Don't try to make everything happen in one regex. Use your existing method, and then separately check the URL that you get back to see if it has a question mark in it.
That said, don't use regular expressions to parse HTML. You cannot reliably parse HTML with regular expressions, and you will face sorrow and frustration down the road. As soon as the HTML changes from your expectations, your code will be broken. See http://htmlparsing.com/php for examples of how to properly parse HTML with PHP modules that have already been written, tested and debugged.
Andy Lester gave you the answer with right thing to do.
Here's your regex though:
<a\s.*?href\s*=\s*['|\"](.*?\?.*?)(?=#|\"|')
as seen here:
http://rubular.com/r/LHi11VMMR9
I have been struggling for a while now to make the following work. Basically, I'd like to be able to extract a URL from an expression contained in an HTML template, as follows:
{rssfeed:url(http://www.example.com/feeds/posts/default)}
The idea is that, when this is found, the URL is extracted, and an RSS feed parser is used to get the RSS and insert it here. It all works, for example, if I hardcode the URL in my PHP code, but I just need to get this regex figured out so the template is actually flexible enough to be useful in many situations.
I've tried at least ten different regex expressions, mostly found here on SO, but none are working. The regex doesn't even need to validate the URL; I just want to find it and extract it, and the delimiters for the URL don't need to be parens, either.
Thank you!
Could this work for you?
'#((https?://)?([-\w]+\.[-\w\.]+)+\w(:\d+)?(/([-\w/_\.]*(\?\S+)?)?)*)#'
I use it to match URLs in text.
Example:
$subject = "{rssfeed:url(http://www.example.com/feeds/posts/default)}";
$pattern ='#((https?://)?([-\w]+\.[-\w\.]+)+\w(:\d+)?(/([-\w/_\.]*(\?\S+)?)?)*)#';
preg_match_all($pattern, $subject, $matches);
print($matches[1][0]);
Output:
http://www.example.com/feeds/posts/default
Note:
There is also a nice article on Daring Fireball called An Improved Liberal, Accurate Regex Pattern for Matching URLs that could be interesting for you.
/\{rssfeed\:url\(([^)]*)\)\}/
preg_match_all('/\{rssfeed\:url\(([^)]*)\)\}/', '{rssfeed:url(http://www.example.com/feeds/posts/default)}', $matches, PREG_PATTERN_ORDER);
print_r($matches[1]);
you should be able to get ALL the urls on the content available in $matches[1]..
Note: this will only get urls with the {rssfeed:url()} format, not all the urls in the content.
you can try this here: http://www.spaweditor.com/scripts/regex/index.php
I'm stuck with php preg_match_all function. Maybe someone wil help me with regexp. Let's assume we have some code:
[a]a[/a]
[s]a[/s]
[b]1[/b]
[b]2[/b]
...
...
[b]n[/b]
[e]a[/e]
[b]8[/b]
[b]9[/b]
...
...
[b]n[/b]
I need to match all that inside [b] tags located between [s] and [e] tags. Any ideas?
if your structure is exactly the same as above I would personally avoid regex (not a good idea with these fort of languages) and just check the second char of each line. Once you see an s go into consume mode and for each line until you see an e find the first ] and read in everything between that and the next [
For simplicity use two preg_match calls.
First to retrieve the list you want to inspect /\[s](.+?)\[e]/s.
And then use that result string and match for the contained /\[b](.+?)\[\/b]/s things.
It looks like you are trying to pattern match something that has a treelike structure, essentially like HTML or XML. Any time you find yourself saying "find X located inside matching Y tags" you are going to have this problem.
Trying to do this sort of work with with regular expressions is a Bad Idea.
Here's some info copy/pasted from a different answer of mine for a similar question:
Some references to similar SO posts which will give you an idea of the difficulty you're getting into:
Regex to match all HTML tags except <p> and </p>
Regex to replace all \n in a String, but no those inside [code] [/code] tag
RegEx match open tags except XHTML self-contained tags - bobince says it much more thoroughly than I do (:
The "Right Thing" to do is to parse your input, maintaining state as you go. This can be as simple as scanning your text and keeping a stack of current tags.
Regular expressions alone aren't sufficient to parse XML, and this appears to be a simplified XML language here.
I've checked google for help on this subject but all the answers keep overlooking a fatal flaw in the replacement method.
Essentially I have a set of emoticons such as :) LocK :eek and so on and need to replace them with image tags. The problem I'm having is identifying that a particular emoticon is not part of a word and is alone on a line. For example on our site we allow 'quick links' which are not included in the smiley replacement which take the format go:forum, user:Username and so on. Pretty much all answers I've read don't allow for this possiblity and as such break these links (i.e. go<img src="image.gif" />orum). I've tried experimenting around with different ways to get around this to check for the start of the line, spaces/newline characters and so on but I've not had much luck.
Any help with this problem would be greatly appreciated. Oh also I'm using PHP 5 and the preg_% functions.
Thanks,
Rupert S.
Edit 18/04/2011:
Thanks for your help peeps :) Have created the final regex that I though I'd share with everyone, had a couple problems to do with special space chars including newline but it's now working like a dream the final regex is:
(?<=\s|\A|\n|\r|\t|\v|\<br \/\>|\<br\>)(:S)(?=\s|\Z|$|\n|\r|\t|\v|\<br \/\>|\<br\>)
To complete the comment into an answer: The simplest workaround would be to assert that the emoticons are always surrounded by whitespace.
(?<=\s|^)[<:-}]+(?=\s|$)
The \s covers normal spaces and line breaks. Just to be safe ^ and $ cover occurrences at the start or very end of the text subject. The assertions themselves do not match, so can be ignored in the replacement string/callback.
If you want to do all the replace in one single preg_replace, try this:
preg_replace('/(?<=^|\s)(:\)|:eek)(?=$|\s)/e'
,"'$1'==':)'?'<img src=\"smile.gif\"/>':('$1'==':eek'?'<img src=\"eek.gif\"/>':'$1')"
,$input);