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@gruber
Last active March 20, 2024 20:28
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Liberal, Accurate Regex Pattern for Matching All URLs
The regex patterns in this gist are intended to match any URLs,
including "mailto:foo@example.com", "x-whatever://foo", etc. For a
pattern that attempts only to match web URLs (http, https), see:
https://gist.github.com/gruber/8891611
# Single-line version of pattern:
(?i)\b((?:[a-z][\w-]+:(?:/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’]))
# Multi-line commented version of same pattern:
(?xi)
\b
( # Capture 1: entire matched URL
(?:
[a-z][\w-]+: # URL protocol and colon
(?:
/{1,3} # 1-3 slashes
| # or
[a-z0-9%] # Single letter or digit or '%'
# (Trying not to match e.g. "URI::Escape")
)
| # or
www\d{0,3}[.] # "www.", "www1.", "www2." … "www999."
| # or
[a-z0-9.\-]+[.][a-z]{2,4}/ # looks like domain name followed by a slash
)
(?: # One or more:
[^\s()<>]+ # Run of non-space, non-()<>
| # or
\(([^\s()<>]+|(\([^\s()<>]+\)))*\) # balanced parens, up to 2 levels
)+
(?: # End with:
\(([^\s()<>]+|(\([^\s()<>]+\)))*\) # balanced parens, up to 2 levels
| # or
[^\s`!()\[\]{};:'".,<>?«»“”‘’] # not a space or one of these punct char
)
)
@DanieleQ97
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Hi

Sorry for asking but regex like this are a bit over my head :-)

I was trying to parse some wsdl files (basicaly xml) and I was wondering: Is there any way to avoid matching things like ab:1234, xs:complexType or this:isnotanurl?

@jonpincus
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Using node 14.2, it hangs when I try to match the string

https://en.wikipedia.org/wiki/Learning_to_Fly_(Tom_Petty_and_the_Heartbreakers)

Looks like some kind of catastrophic backtracking in the balanced parens clauses, but i'm not sure how to fix it.

@makew0rld
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My version of this:

(?i)\b(?:[a-z][\w.+-]+:(?:/{1,3}|[?+]?[a-z0-9%]))(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s\x60!()\[\]{};:'".,<>?«»“”‘’])

Changes:

  • Supports Go (Changed backtick to \x60)
  • Non-URLs like bit.com/test aren't recognized
  • Protocol section is required
  • Applied change mentioned above

@glensc
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glensc commented Dec 27, 2021

putting wide characters (Unicode of more than 1 byte) is incorrect into a bracket expression ([ ]):

    [^\s`!()\[\]{};:'".,<>?«»“”‘’]		# not a space or one of these punct char

« is two bytes: "\xc2\xab", which means the pattern will accept \xc2 and \xab anywhere in the sequence not in a specific order or not even close to each other!

php -r '$s="\xab \xc2 \xc2 \xab"; $v=preg_match_all("/[«]/", $s, $m); var_dump([$v, $m, $s]);' > foo.txt

you need to open foo.txt with a program which can print you bytes.

@solaluset
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putting wide characters (Unicode of more than 1 byte) is incorrect into a bracket expression ([ ])

It depends on the language/library. Works fine in Python and node.js

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