I've made some regex to test for a YouTube embedded video:
/^(http:\/\/www\.youtube\.com\/embed\/)[^\/\s\\]+$/
It works for what I expect when I test it, but the problem though is that I need to pass that regex as a string to some function. Particularly I'm using htmlawed, where I pass a following string to a function:
func('iframe=-*,src(match="/^(http:\/\/www\.youtube\.com\/embed\/)[^\/\s\\]+$/")');
The problem is that the above regex sort of works, but it just ignores the slashes, and accepts anything in place of them.
That is why I suspect that there is a problem with escaping.
I would appreciate if you could advice some alternative ways of escaping these slashes and backslashes... there must be some way?
If you have a string, you will need to escape the backslashes (and quotes) for the string literal. Or, depending on how the function builds the regex from the string, you might not need to escape slashes at all (I don't think so here).
"iframe=-*,src(match=\"/^(http:\\/\\/www\\.youtube\\.com\\/embed\\/)[^\\/\\s\\\\]+$/\")"
In PHP, you can also use a different regex delimiter:
~^(http://www\.youtube\.com/embed/)[^/\s\\\\]+$~
Related
EDIT: I found a solution I didn't expect. See below.
Using regex via PHP's preg_match_all , I want to match a certain url (EDIT: that is already escaped) in a string formatted as json. The search works wonderfully in Notepad++ (using regex-matching, of course) but preg_match_all() just returns an empty array.
Testing on tryphpregex.com I found out that somehow my usual approach to escaping a backslash gives a pattern error, i.e. even the simple pattern https:\\ returns an empty result.
I'm utterly confused and have been trying to debug for too long so I may miss the obvious. Maybe one of you can see the simple error?
The string.
The pattern (that works fine in Notepad++, but not in PHP):
%(https:\\/\\/play.spotify.com\\/track\\/)(.*?)(\")%
You don't need to escape the slash in PHP %(https://play.spotify.com/track/)(.*?)(\")%
The Backslash before doule quote is only needed if you enclosures are double quotes too.
Found a solution to my problem.
According to this site, I need to match every backslash with \\\\. Horrible, but true.
So my pattern becomes:
$pattern = "%(https:\\\\/\\\\/play\.spotify\.com\\\\/track\\\\/)(.*?)(\")%";
Please observe that I tried to find a pattern inside a string that didn't contain clear urls, but urls containing escape characters (it was a json-output from spotify)
I have several strings that look like this:
Lasklé
Jones & Jon
I am trying to send them via the foursquare API to be matched, however it is failing with these characters. Is there a way to sanitise these so they only include English letters i.e. the results would be:
Lasklé
Jones Jon
As it appears using file_get_contents requests both with the 'é' and the '&' in the URL is causing issues.
I checked how the request was sent and realised that the '&' is uneeded and is causing the issues, is it possible to remove all non Letters/Numbers from the name?
What do the strings look like before you pass them? If your string looks like 'Lasklé' then I think you are using the wrong character set when reading the string, try using UTF-8.
If the string looks correct before you pass it on you should try urlencode the string first.
you can use preg_replace() function to replace the part of string using regex
to keep only letters you can use as follow it will also remove space( add \s from expression to keep space)
preg_replace('/[^a-zA-Z]/','',$string);
to keep space in the string or any character to keep you can add it in []
preg_replace('/[^a-zA-Z\s]/','',$string);
Use this to escape (space and '-'). Good for making a custom URL
$string=preg_replace("/[^A-Za-z0-9\s\/\-]/", '', $string);
I've made some regex to test for a YouTube embedded video:
/^(http:\/\/www\.youtube\.com\/embed\/)[^\/\s\\]+$/
It works for what I expect when I test it, but the problem though is that I need to pass that regex as a string to some function. Particularly I'm using htmlawed, where I pass a following string to a function:
func('iframe=-*,src(match="/^(http:\/\/www\.youtube\.com\/embed\/)[^\/\s\\]+$/")');
The problem is that the above regex sort of works, but it just ignores the slashes, and accepts anything in place of them.
That is why I suspect that there is a problem with escaping.
I would appreciate if you could advice some alternative ways of escaping these slashes and backslashes... there must be some way?
If you have a string, you will need to escape the backslashes (and quotes) for the string literal. Or, depending on how the function builds the regex from the string, you might not need to escape slashes at all (I don't think so here).
"iframe=-*,src(match=\"/^(http:\\/\\/www\\.youtube\\.com\\/embed\\/)[^\\/\\s\\\\]+$/\")"
In PHP, you can also use a different regex delimiter:
~^(http://www\.youtube\.com/embed/)[^/\s\\\\]+$~
I'm looking for a regex that will scan a document to match a function call, and return the value of the first parameter (a string literal) only.
The function call could look like any of the following:
MyFunction("MyStringArg");
MyFunction("MyStringArg", true);
MyFunction("MyStringArg", true, true);
I'm currently using:
$pattern = '/Use\s*\(\s*"(.*?)\"\s*\)\s*;/';
This pattern will only match the first form, however.
Thanks in advance for your help!
Update
I was able to solve my problem with:
$pattern = '/Use\s*\(\s*"(.*?)\"/';
Thanks Justin!
~Scott
If you only care about the value of the first parameter, you can just chop off the end of the regex:
$pattern = '/Use\s*\(\s*"(.*?)\"/';
However, you should understand that this (or any pure-regex solution for this problem) will not be perfect, and there will be some possible cases it handles incorrectly. In this case, you'll get false positives, and escaped quotes (\") will break it.
You can ignore escaped quotes by complicating it a bit:
$pattern = '/Use\s*\(\s*"(.*?)(?!<(?:\\\\)*\\)\"/';
This ignores " characters inside the quoted string if they have an odd number of backslashes in front of them.
However, the false-postives issue can't be helped without introducing false-negatives, and vice versa. This is because PHP is an irregular language, so it can't be parsed with "pure" regex, and even modern regex engines that allow recursion are going to need some pretty complex code to do a really thorough job at this.
All I'm saying is, if you're planning a one-off job to quickly scrape through some PHP you wrote yourself, regex is probably fine. If you're looking for something robust and open-ended that will do this on arbitrary PHP code, you need some kind of reflection or PHP parser.
This might be slightly simpler, though will only work if you have double quotes and not single quotes:
$pattern = /Use\s*[^\"]*\"([^\"]*)\"/
I'm having a lot of difficulty matching an image url with spaces.
I need to make this
http://site.com/site.com/files/images/img 2 (5).jpg
into a div like this:
.replace(/(http:\/\/([^\s]+\.(jpg|png|gif)))/ig, "<div style=\"background: url($1)\"></div>")
Here's the thread about that:
regex matching image url with spaces
Now I've decided to first make the spaces into entities so that the above regex will work.
But I'm really having a lot of difficulty doing so.
Something like this:
.replace(/http:\/\/(.*)\/([^\<\>?:;]*?) ([^\<\>?:;]*)(\.(jpe?g|png|gif))/ig, "http://$1/$2%20$3$4")
Replaces one space, but all the rest are still spaces.
I need to write a regex that says, make all spaces between http:// and an image extension (png|jpg|gif) into %20.
At this point, frankly not sure if it's even possible. Any help is appreciated, thanks.
Trying Paolo's escape:
.escape(/http:\/\/(.*)\/([^\<\>?:;]*?) ([^\<\>?:;]*)(\.(jpe?g|png|gif))/)
Another way I can do this is to escape serverside in PHP, and in PHP I can directly mess with the file name without having to match it in regex.
But as far as I know something like htmlentities do not apply to spaces. Any hints in this direction would be great as well.
Try the escape function:
>>> escape("test you");
test%20you
If you want to control the replacement character but don't want to use a regular expression, a simple...
$destName = str_replace(' ', '-', $sourceName);
..would probably be the more efficient solution.
Lets say you have the string variable urlWithSpaces which is set to a URL which contains spaces.
Simply go:
urlWithoutSpaces = escape(urlWithSpaces);
What about urlencode() - that may do what you want.
On the JS side you should be using encodeURI(), and escape() only as a fallback. The reason to use encodeURI() is that it uses UTF-8 for encoding, while escape() uses ISO Latin. Same problems applies for decoding.
encodeURI = encodeURI || escape;
alert(encodeURI('image name.png'));