PHP/ Markdown: Need to match code blocks inside backticks - php

I am creating a developers site with code views,
but when they type code i need to it a certain way so in the php and can convert it to html a special way,
The markdown i need to be able to work with is
```codechanger
``php
<?php ?>
``
``c#
$foo = bar;
``
```
So once the first regex select code changer I then need to be able to select each code but i just need to know the regex to match everything inside there even if it is on multiple lines.
This is what i was trying to use
preg_match_all("/\`\`codechanger.*?^\`\`[^\r\n]*/s", $text, $out);
Any questions feel free to ask.

If you want to get the text between a start and end point, you can do something like this: START .*? END
```codechanger(.*?)```
When combined with the s flag like you have, that will give you everything in $1 between the starting and ending positions.
Once you have the results you can do another preg_match_all to get the inner tags.
Here is a demo

Related

PHP: Setting missing " in HTML-code with preg_replace?

I've got a database with a lot of user made entries grown about 10 years. The users had the option to put HTML-code in their content. And some didn't that well. So I've a lot of content in where the quotes are missing. Need a valid HTML-code for an ex/import via XML.
Had tested to replace width but my regex doesn't work. Do you've an idea where's my fault?
$out=preg_replace("/<a href=h(.)*>/","<a href=\"h$1\">",$out);
PS: If you have an idea how to automatically make a correction on wrong html source this would alternatively be great.
I think you wanted to use "/<a href=h(.*)>/" (mind the star inside the parenthesis) since you want to capture all characters after the h and before the > inside the capture group.
You can also use <a href=([^"].*)> since the href may not start with h. This regex captures all href values that do not start with ".
Yet, all of these assume that the href is the last attribute in your a, i.e.., ending with >.
As a more general rule, I came up with (?<key>\w*)\s*=\s*(?<value>[^"][^\s>]*) that finds attribute-value pairs, separated by =. The values may not start with ", and they go until the next whitespace or >. Use this with caution, since it may fail in serveral circumstances: Multi-line html, inline JavaScript, etc.
Whether it is a good idea to use RegEx for such a task is a different discussion.

Recursive Regex in PHP with variable names

I try to make bbcode-ish engine for me website. But the thing is, it is not clear which codes are available, because the codes are made by the users. And on top of that, the whole thing has to be recursive.
For example:
Hello my name is [name user-id="1"]
I [bold]really[/bold] like cheeseburgers
These are the easy ones and i achieved making it work.
Now the problem is, what happens, when two of those codes are behind each other:
I [bold]really[/bold] like [bold]cheeseburgers[/bold]
Or inside each other
I [bold]really like [italic]cheeseburgers[/italic][/bold]
These codes can also have attributes
I [bold strengh="600"]really like [text font-size="24px"]cheeseburgers[/text][bold]
The following one worked quite well, but lacks in the recursive part (?R)
(?P<code>\[(?P<code_open>\w+)\s?(?P<attributes>[a-zA-Z-0-1-_=" .]*?)](?:(?P<content>.*?)\[\/(?P<code_close>\w+)\])?)
I just dont know where to put the (?R) recursive tag.
Also the system has to know that in this string here
I [bold]really like [italic]cheeseburgers[/italic][/bold] and [bold]football[/bold]
are 2 "code-objects":
1. [bold]really like [italic]cheeseburgers[/italic][/bold]
and
2. [bold]football[/bold]
... and the content of the first one is
really like [italic]cheeseburgers[/italic]
which again has a code in it
[italic]cheeseburgers[/italic]
which content is
cheeseburgers
I searched the web for two days now and i cant figure it out.
I thought of something like this:
Look for something like [**** attr="foo"] where the attributes are optional and store it in a capturing group
Look up wether there is a closing tag somewhere (can be optional too)
If a closing tag exists, everything between the two tags should be stored as a "content"-capturing group - which then has to go through the same procedure again.
I hope there are some regex specialist which are willing to help me. :(
Thank you!
EDIT
As this might be difficult to understand, here is an input and an expected output:
Input:
[heading icon="rocket"]I'm a cool heading[/heading][textrow][text]<p>Hi!</p>[/text][/textrow]
I'd like to have an array like
array[0][name] = heading
array[0][attributes][icon] = rocket
array[0][content] = I'm a cool heading
array[1][name] = textrow
array[1][content] = [text]<p>Hi!</p>[/text]
array[1][0][name] = text
array[1][0][content] = <p>Hi!</p>
Having written multiple BBCode parsing systems, I can suggest NOT using regexes only. Instead, you should actually parse the text.
How you do this is up to you, but as a general idea you would want to use something like strpos to locate the first [ in your string, then check what comes after it to see if it looks like a BBCode tag and process it if so. Then, search for [ again starting from where you ended up.
This has certain advantages, such as being able to examine each code and skip it if it's invalid, as well as enforcing proper tag closing order ([bold][italic]Nesting![/bold][/italic] should be considered invalid) and being able to provide meaningful error messages to the user if something is wrong (invalid parameter, perhaps) because the parser knows exactly what is going on, whereas a regex would output something unexpected and potentially harmful.
It might be more work (or less, depending on your skill with regex), but it's worth it.

PHP How to find string after Match/Wildcard/Match

Say I have the following string, $mytext:
[QUOTE=FirstUserRANDOMNUMBER]First user's post[/QUOTE]
Great post, FirstUser
[QUOTE=SecondUserRANDOMNUMBER]Second user's post[/QUOTE]
Awful post. I didn't like it.
Given a Username, how can I find the text below the quoted User? (ignoring RANDOMNUMBER)
I want to be able to input "SecondUser" into a function and have it return: "Awful post. I didn't like it."
Basically, I just want the response to the quoted user.
I thought I'd do a substr on $mytext based on the following:
strpos($username, $mytext) + strlen("[QUOTE=$username") + strlen("[/QUOTE]")
But I don't know how to get the length of the wildcard text in between [QUOTE=$username and the next instance of [/quote]
This must support the occurrence of multiple quotes in $mytext, like the example above.
Thanks!
You can use a regex like this:
\[QUOTE=SecondUser.*\[\/QUOTE\]([^[]*)
Working demo
Search for, but don't capture (within (...) groups) everything you want to exclude. In this case, \[Quote.*. Then search for (and capture) everything you DO want to keep. It will be saved in the \1 reference:
^\[QUOTE.*\n+|(^.*$)
It will match the [QUOTE...] line, but it doesn't capture that line: The only lines that are kept are
Great post, FirstUser
Awful post. I didn't like it.
Example

Can't use OR( | ) in php Regular expression

I'm a newbie here. I'm facing a weird problem in using regex in PHP.
$result = "some very long long string with different kind of links";
$regex='/<.*?href.*?="(.*?net.*?)"/'; //this is the regex rule
preg_match_all($regex,$result,$parts);
Here in this code I'm trying to get the links from the result string. But it will provide me only those links which contains .net. But I also want to get those links which have .com. For this I tried this code
$regex='/<.*?href.*?="(.*?net|com.*?)"/';
But it shows nothing.
SOrry for my bad English.
Thanks in advance.
Update 1 :
now i'm using this
$regex='/<.*?href.*?="(.*?)"/';
this rule grab all the links from the string. But this is not perfect. Because it also grabs other substrings like "javascript".
The | character applies to everything within the capturing group, so (.*?net|com.*?) will match either .*?net or com.*?, I think what you want is (.*?(net|com).*?).
If you do not want the extra capturing group, you can use (.*?(?:net|com).*?).
You could also use (.*?net.*?|.*?com.*?), but this is not recommended because of the unnecessary repetition.
Your regex gets interpreted as .*?net or com.*?. You'll want (.*?(net|com).*?).
Try this:
$regex='/<.*?href.*?="(.*?\.(?:net|com)\b.*?)"/i';
or better:
$regex='/<a .*?href\s*+=\s*+"\K.*?\.(?:net|com)\b[^"]*+/i';
<.*?href
is a problem. This will match from the first < on the current line to the first href, regardless of whether they belong to the same tag.
Generally, it's unwise to try and parse HTML with regexes; if you absolutely insist on doing that, at least be a bit more specific (but still not perfect):
$regex='/<[^<>]*href[^<>=]*="(?:[^"]*(net|com)[^"]*)"/';

Matching all three kinds of PHP comments with a regular expression

I need to match all three types of comments that PHP might have:
# Single line comment
// Single line comment
/* Multi-line comments */
 
/**
* And all of its possible variations
*/
Something I should mention: I am doing this in order to be able to recognize if a PHP closing tag (?>) is inside a comment or not. If it is then ignore it, and if not then make it count as one. This is going to be used inside an XML document in order to improve Sublime Text's recognition of the closing tag (because it's driving me nuts!). I tried to achieve this a couple of hours, but I wasn't able. How can I translate for it to work with XML?
So if you could also include the if-then-else login I would really appreciate it. BTW, I really need it to be in pure regular expression expression, no language features or anything. :)
Like Eicon reminded me, I need all of them to be able to match at the start of the line, or at the end of a piece of code, so I also need the following with all of them:
<?php
echo 'something'; # this is a comment
?>
Parsing a programming language seems too much for regexes to do. You should probably look for a PHP parser.
But these would be the regexes you are looking for. I assume for all of them that you use the DOTALL or SINGLELINE option (although the first two would work without it as well):
~#[^\r\n]*~
~//[^\r\n]*~
~/\*.*?\*/~s
Note that any of these will cause problems, if the comment-delimiting characters appear in a string or somewhere else, where they do not actually open a comment.
You can also combine all of these into one regex:
~(?:#|//)[^\r\n]*|/\*.*?\*/~s
If you use some tool or language that does not require delimiters (like Java or C#), remove those ~. In this case you will also have to apply the DOTALL option differently. But without knowing where you are going to use this, I cannot tell you how.
If you cannot/do not want to set the DOTALL option, this would be equivalent (I also left out the delimiters to give an example):
(?:#|//)[^\r\n]*|/\*[\s\S]*?\*/
See here for a working demo.
Now if you also want to capture the contents of the comments in a group, then you could do this
(?|(?:#|//)([^\r\n]*)|/\*([\s\S]*?)\*/)
Regardless of the type of comment, the comments content (without the syntax delimiters) will be found in capture 1.
Another working demo.
Single-line comments
singleLineComment = /'[^']*'|"[^"]*"|((?:#|\/\/).*$)/gm
With this regex you have to replace (or remove) everything that was captured by ((?:#|\/\/).*$). This regex will ignore contents of strings that would look like comments (e.g. $x = "You are the #1"; or $y = "You can start comments with // or # in PHP, but I'm a code string";)
Multiline comments
multilineComment = /^\s*\/\*\*?[^!][.\s\t\S\n\r]*?\*\//gm

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