I have a string of a comment that looks like this:
**#First Last** rest of comment info.
What I need to do is replace the ** with <b> and </b> so that the name is bold.
I currently have this:
$result = preg_replace('/\*\*/i', '<b>$0</b>', $comment);
But that results in:
"<b>**</b>#First Last<b>**</b> rest of comment info"
Which is obviously not what I need. Does anyone have any suggestions on how to achieve this?
A better idea would be to use a markdown parser library which does this for you.
Improper use of the regular expressions can lead to security vulnerabilities with unclosed tags etc..
However, a simple approach could be this:
$result = preg_replace('/\*\*(.+)\*\*/sU', '<b>$1</b>', $comment);
The U means ungreedy and takes the first possible match.
The s modifies . to be any character, including newline.
(see modifiers page)
This also works with an example text like this:
**#First Last** rest of comment info **also bold**.
The next line also **has a bold example**. This spans **two
lines**.
I am sure there are counter examples which are broken with this. Again, please use a proper markdown library to do this for you (or copy their implementation if the LICENSE allows it).
Related
I need to remove the comment lines from my code.
preg_replace('!//(.*)!', '', $test);
It works fine. But it removes the website url also and left the url like http:
So to avoid this I put the same like preg_replace('![^:]//(.*)!', '', $test);
It's work fine. But the problem is if my code has the line like below
$code = 'something';// comment here
It will replace the comment line with the semicolon. that is after replace my above code would be
$code = 'something'
So it generates error.
I just need to delete the single line comments and the url should remain same.
Please help. Thanks in advance
try this
preg_replace('#(?<!http:)//.*#','',$test);
also read more about PCRE assertions http://cz.php.net/manual/en/regexp.reference.assertions.php
If you want to parse a PHP file, and manipulate the PHP code it contains, the best solution (even if a bit difficult) is to use the Tokenizer : it exists to allow manipulation of PHP code.
Working with regular expressions for such a thing is a bad idea...
For instance, you thought about http:// ; but what about strings that contain // ?
Like this one, for example :
$str = "this is // a test";
This can get complicated fast. There are more uses for // in strings. If you are parsing PHP code, I highly suggest you take a look at the PHP tokenizer. It's specifically designed to parse PHP code.
Question: Why are you trying to strip comments in the first place?
Edit: I see now you are trying to parse JavaScript, not PHP. So, why not use a javascript minifier instead? It will strip comments, whitespace and do a lot more to make your file as small as possible.
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.
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
I'm trying to put together a plug-in for vBulletin to filter out links to filesharing sites. But, as I'm sure you often hear, I'm a newb to php let alone regexes.
Basically, I'm trying to put together a regex and use a preg_replace to find any urls that are from these domains and replace the entire link with a message that they aren't allowed. I'd want it to find the link whether it's hyperlinked, posted as plain text, or enclosed in [CODE] bb tags.
As for regex, I would need it to find URLS with the following, I think:
Starts with http or an anchor tag. I believe that the URLS in [CODE] tags could be processed the same as the plain text URLS and it's fine if the replacement ends up inside the [CODE] tag afterward.
Could contain any number of any characters before the domain/word
Has the domain somewhere in the middle
Could contain any number of any characters after the domain
Ends with a number of extentions such as (html|htm|rar|zip|001) or in a closing anchor tag.
I have a feeling that it's numbers 2 and 4 that are tripping me up (if not much more). I found a similar question on here and tried to pick apart the code a bit (even though I didn't really understand it). I now have this which I thought might work, but it doesn't:
<?php
$filterthese = array('domain1', 'domain2', 'domain3');
$replacement = 'LINKS HAVE BEEN FILTERED MESSAGE';
$regex = array('!^http+([a-z0-9-]+\.)*$filterthese+([a-z0-9-]+\.)*(html|htm|rar|zip|001)$!',
'!^<a+([a-z0-9-]+\.)*$filterthese+([a-z0-9-]+\.)*</a>$!');
$this->post['message'] = preg_replace($regex, $replacement, $this->post['message']);
?>
I have a feeling that I'm way off base here, and I admit that I don't fully understand php let alone regexes. I'm open to any suggestions on how to do this better, how to just make it work, or links to RTM (though I've read up a bit and I'm going to continue).
Thanks.
You can use parse_url on the URLs and look into the hashmap it returns. That allows you to filter for domains or even finer-grained control.
I think you can avoid the overhead of this in using the filter_var built-in function.
You may use this feature since PHP 5.2.0.
$good_url = filter_var( filter_var( $raw_url, FILTER_SANITIZE_URL), FILTER_VALIDATE_URL);
Hmm, my first guess: You put $filterthese directly inside a single-quoted string. That single quotes don't allow for variable substitution. Also, the $filterthese is an array, that should first be joined:
var $filterthese = implode("|", $filterthese);
Maybe I'm way off, because I don't know anything about vBulletin plugins and their embedded magic, but that points seem worth a check to me.
Edit: OK, on re-checking your provided source, I think the regexp line should read like this:
$regex = '!(?#
possible "a" tag [start]: )(<a[^>]+href=["\']?)?(?#
offending link: )https?://(?#
possible subdomains: )(([a-z0-9-]+\.)*\.)?(?#
domains to block: )('.implode("|", $filterthese).')(?#
possible path: )(/[^ "\'>]*)?(?#
possible "a" tag [end]: )(["\']?[^>]*>)?!';
First things first: Neither this, this, this nor this answered my question. So I'll open a new one.
Please read
Okay okay. I know that regexes are not the way to parse general HTML. Please take note that the created documents are written using a limited, controlled HTML subset. And people writing the docs know what they're doing. They are all IT professionals!
Given the controlled syntax it is possible to parse the documents I have here using regexes.
I am not trying to download arbitrary documents from the web and parse them!
And if the parsing does fail, the document is edited, so it'll parse. The problem I am addressing here is more general than that (i.e. not replace patterns inside two other patterns).
A little bit of background (you can skip this...)
In our office we are supposed to "pretty print" our documentation. Hence why some came up with putting it all into Word documents. So far we're thankfully not quite there yet. And, if I get this done, we might not need to.
The current state (... and this)
The main part of the docs are stored in a TikiWiki database. I've created a daft PHP script which converts the documents from HTML (via LaTeX) to PDF. One of the must have features of the selected Wiki-System was a WYSIWYG editor. Which, as expected leaves us with documents with a less then formal DOM.
Consequently, I am transliterating the document using "simple" regexes. It all works (mostly) fine so far, but I encountered one problem I haven't figured out on my own yet.
The problem
Some special characters need to replaced by LaTeX markup. For exaple, the \ character should be replaced by $\backslash$ (unless someone knows another solution?).
Except while in a verbatim block!
I do replace <code> tags with verbatim sections. But if this code block contains backslashes (as is the case for Windows folder names), the script still replaces these backslashes.
I reckon I could solve this using negative LookBehinds and/or LookAheads. But my attempts did not work.
Granted, I would be better off with a real parser. In fact, it is something on my "in-brain-roadmap", but it is currently out of the scope. The script works well enough for our limited knowledge domain. Creating a parser would require me to start pretty much from scratch.
My attempt
Example Input
The Hello \ World document is located in:
<code>C:\documents\hello_world.txt</code>
Expected output
The Hello $\backslash$ World document is located in:
\begin{verbatim}C:\documents\hello_world.txt\end{verbatim}
This is the best I could come up with so far:
<?php
$patterns = array(
"special_chars2" => array( '/(?<!<code[^>]*>.*)\\\\[^$](?!.*<\/code>)/U', '$\\backslash$'),
);
foreach( $patterns as $name => $p ){
$tex_input = preg_replace( $p[0], $p[1], $tex_input );
}
?>
Note that this is only an excerpt, and the [^$] is another LaTeX requirement.
Another attempt which seemed to work:
<?php
$patterns = array(
"special_chars2" => array( '/\\\\[^$](?!.*<\/code>)/U', '$\\backslash$'),
);
foreach( $patterns as $name => $p ){
$tex_input = preg_replace( $p[0], $p[1], $tex_input );
}
?>
... in other words: leaving out the negative lookbehind.
But this looks more error-prone than with both lookbehind and lookahead.
A related question
As you may have noticed, the pattern is ungreedy (/.../U). So will this match only as little possible inside a <code> block? Considering the look-arounds?
If me, I will try to find HTML parser and will do with that.
Another option is will try to chunk the string into <code>.*?</code> and other parts.
and will update other parts, and will recombine it.
$x="The Hello \ World document is located in:\n<br>
<code>C:\documents\hello_world.txt</code>";
$r=preg_split("/(<code>.*?<\/code>)/", $x,-1,PREG_SPLIT_DELIM_CAPTURE);
for($i=0;$i<count($r);$i+=2)
$r[$i]=str_replace("\\","$\\backslash$",$r[$i]);
$x=implode($r);
echo $x;
Here is the results.
The Hello $\backslash$ World document is located in:
C:\documents\hello_world.txt
Sorry, If my approach is not suitable for you.
I reckon I could solve this using negative LookBehinds and/or LookAheads.
You reckon wrong. Regular expressions are not a replacement for a parser.
I would suggest that you pipe the html through htmltidy, then read it with a dom-parser and then transform the dom to your target output format. Is there anything preventing your from taking this route?
Parser FTW, ok. But if you can't use a parser, and you can be certain that <code> tags are never nested, you could try the following:
Find <code>.*?</code> sections of your file (probably need to turn on dot-matches-newlines mode).
Replace all backslashes inside that section with something unique like #?#?#?#
Replace the section found in 1 with that new section
Replace all backslashes with $\backslash$
Replace als <code> with \begin{verbatim} and all </code> with \end{verbatim}
Replace #?#?#?# with \
FYI, regexes in PHP don't support variable-length lookbehind. So that makes this conditional matching between two boundaries difficult.
Pandoc? Pandoc converts between a bunch of formats. you can also concatenate a bunch of flies together then covert them. Maybe a few shell scripts combined with your php scraping scripts?
With your "expected input" and the command pandoc -o text.tex test.html the output is:
The Hello \textbackslash{} World document is located in:
\verb!C:\documents\hello_world.txt!
pandoc can read from stdin, write to stdout or pipe right into a file.
Provided that your <code> blocks are not nested, this regex would find a backslash after ^ start-of-string or </code> with no <code> in between.
((?:^|</code>)(?:(?!<code>).)+?)\\
| | |
| | \-- backslash
| \-- least amount of anything not followed by <code>
\-- start-of-string or </code>
And replace it with:
$1$\backslash$
You'd have to run this regex in "singleline" mode, so . matches newlines. You'd also have to run it multiple times, specifying global replacement is not enough. Each replacement will only replace the first eligible backslash after start-of-string or </code>.
Write a parser based on an HTML or XML parser like DOMDocument. Traverse the parsed DOM and replace the \ on every text node that is not a descendent of a code node with $\backslash$ and every node that is a code node with \begin{verbatim} … \end{verbatim}.