A Good URL Regular Expression?

For checking the format of the url it seems to me to be the most logical approach to use regular expressions. Up until now I always discarded them as being to “geeky”, meaning i don’t consider it my life’s biggest goal to be typing (/?[]\w) all day long (so why did i become a programmer, aaaah yes to make life easier for other people)

Anyway.. to find a good regular expression to that validates urls not url domains. One that doesn’t allow spaces in the domainname and where the domain can be suffixed with the port number.  Also I need support for the ~/ paths

This is what I came up with.. if somebody as a better idea… or finds a mistake please let me know.. Always happy to learn something new.

^(((ht|f)tps?:\/\/)|~/|/)?([a-zA-Z]{1}([\w-]+.)+([\w]{2,5})(:[\d]{1,5})?)/?(\w+.[\w]{3,4})?((\?\w+=\w+)?(&\w+=\w+)*)?

I was a bit quickly in using this regex. Simeon pilgrim indicated that the ftp urls won’t validate when you add a username and a password.

I don’t really need to validate ftp so I should have removed the ftp protocol from the list of choices.  I need this just to validate urls for weblinks and the link element in an rss feed.  When I need them for ftp I will post the ftp version.. but for now I don’t have time to spend on elaborating the regex.

Anyway here is the right one : ^(http(s?):\/\/|~/|/)?([a-zA-Z]{1}([\w-]+.)+([\w]{2,5}))(:[\d]{1,5})?/?(\w+.[\w]{3,4})?((\?\w+=\w+)?(&\w+=\w+)*)?

A full url validation would include resolving names through dns or making a webrequest to the provided url to see if we get a 200 response. The only way to be sure is to test if it is there in my opinion.

Thanks Simeon.

And for those who really want the ftp validation : ^((ht|f)tp(s?):\/\/|~/|/)?([\w]+:\w+@)?([a-zA-Z]{1}([\w-]+.)+([\w]{2,5}))(:[\d]{1,5})?/?(\w+.[\w]{3,4})?((\?\w+=\w+)?(&\w+=\w+)*)?

I am not sure about numbers in the username but I believe you can have a username of numbers alone.

Comments don’t seem to work on this blog engine.. so just send me a mail through the contact form. thanks

Two days later …

I discovered there is still a problem with my regular expressions… folders don’t get parsed.

I’ve solved the path issue, so now it should be finding all url’s

Expression:

^((ht|f)tp(s?):\/\/|~/|/)?([\w]+:\w+@)?([a-zA-Z]{1}([\w-]+.)+([\w]{2,5}))(:[\d]{1,5})?((/?\w+/)+|/?)(\w+.[\w]{3,4})?((\?\w+=\w+)?(&\w+=\w+)*)?

Should parse the url below

http://hh-1hallo.msn.blabla.com:80800/test/test/test.aspx?dd=dd&id=dki

But not :

http://hh-1hallo. msn.blablabla.com:80800/test/test.aspx?dd=dd&id=dki

Update 29/11/2008:

Joe posted what seems to be a great regular expression in the comments

he tested it with the following urls:

http://www.google.com/search?q=good+url+regex&rls=com.microsoft:*&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1

ftp://joe:password@ftp.filetransferprotocal.com

google.ru

https://some-url.com?query=&name=joe?filter=.#some_anchor

Expression:

^(?#Protocol)(?:(?:ht|f)tp(?:s?)\:\/\/|~/|/)?(?#Username:Password)(?:\w+:\w+@)?(?#Subdomains)(?:(?:[-\w]+\.)+(?#TopLevel Domains)(?:com|org|net|gov|mil|biz|info|mobi|name|aero|jobs|museum|travel|[a-z]{2}))(?#Port)(?::[\d]{1,5})?(?#Directories)(?:(?:(?:/(?:[-\w~!$+|.,=]|%[a-f\d]{2})+)+|/)+|\?|#)?(?#Query)(?:(?:\?(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)(?:&(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)*)*(?#Anchor)(?:#(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)?$

Update 8/11/2009:

Expression:

^(?#Protocol)(?:(?:ht|f)tp(?:s?)\:\/\/|~\/|\/)?(?#Username:Password)(?:\w+:\w+@)?(?#Subdomains)(?:(?:[-\w]+\.)+(?#TopLevel Domains)(?:com|org|net|gov|mil|biz|info|mobi|name|aero|jobs|museum|travel|[a-z]{2}))(?#Port)(?::[\d]{1,5})?(?#Directories)(?:(?:(?:\/(?:[-\w~!$+|.,=]|%[a-f\d]{2})+)+|\/)+|\?|#)?(?#Query)(?:(?:\?(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=?(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)(?:&(?:[-\w~!$+|.,*:]|%[a-f\d{2}])+=?(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)*)*(?#Anchor)(?:#(?:[-\w~!$+|.,*:=]|%[a-f\d]{2})*)?$

There is a wave for this regex:

https://wave.google.com/wave/?pli=1#restored:wave:googlewave.com!w%252BsFbGJUukA