Develop Reference

Check if valid steam profile url

I am trying to make a regex that checks if the url a user is posting, are valid.
I have created the following regex:
/https?\:\/steamcommunity\/.com\/profiles|id\/[a-zA-Z0-9]/
But that isn't working. Is there a regex master, here that can tell me what i am doing wrong?
The links i am trying to validate are looking like:
https://steamcommunity.com/profiles/76561198009610232/
https://steamcommunity.com/id/rasmusvejby/
ANSWERE
/(?:https?:\/\/)?steamcommunity\.com\/(?:profiles|id)\/[a-zA-Z0-9]+/

Try this regex:
(?:https?:\/\/)?steamcommunity\.com\/(?:profiles|id)\/[a-zA-Z0-9]+
See this demo:
Regex Demo
The "g" modifier is just so you can see it test it in different strings, but you probably dont need it.

The accepted answer to this question will also match this url for example:
https://steamcommunity.com/profile/thisisimpossible
I am using the following regex to prevent non numeric characters when the id is prepended by profile/ rather than id/. Not necessarily prettier but it does the job.
^(?:https?:\/\/)?steamcommunity\.com\/(?:profiles\/[0-9]{17}|id\/[a-zA-Z0-9].*)$

javascript Reg Exp to match specific domain name

I have been trying to make a Reg Exp to match the URL with specific domain name.
So if i want to check if this url is from example.com
what reg exp should be the best?
This reg exp should match following type of URLs:
http://api.example.com/...
http://preview.example.com/...
http://www.example.com/...
http://purhcase.example.com/...
Just simple rule, like http://{something}.example.com/{something} then should pass.
Thank you.

I think this is what you're looking for: (https?:\/\/(.+?\.)?example\.com(\/[A-Za-z0-9\-\._~:\/\?#\[\]#!$&'\(\)\*\+,;\=]*)?).
It breaks down as follows:
https?:\/\/ to match http:// or https:// (you didn't mention https, but it seemed like a good idea).
(.+?\.)? to match anything before the first dot (I made it optional so that, for example, http://example.com/ would be found
example\.com (example.com, of course);
(\/[A-Za-z0-9\-\._~:\/\?#\[\]#!$&'\(\)\*\+,;\=]*)?): a slash followed by every acceptable character in a URL; I made this optional so that http://example.com (without the final slash) would be found.
Example: https://regex101.com/r/kT8lP2/1

Use indexOf javascript API. :)
var url = 'http://api.example.com/api/url';
var testUrl = 'example.com';
if(url.indexOf(testUrl) !== -1) {
console.log('URL passed the test');
} else{
console.log('URL failed the test');
}
EDIT:
Why use indexOf instead of Regular Expression.
You see, what you have here for matching is a simple string (example.com) not a pattern. If you have a fixed string, then no need to introduce semantic complexity by checking for patterns.
Regular expressions are best suited for deciding if patterns are matched.
For example, if your requirement was something like the domain name should start with ex end with le and between start and end, it should contain alphanumeric characters out of which 4 characters must be upper case. This is the usecase where regular expression would prove beneficial.
You have simple problem so it's unnecessary to employ army of 1000 angels to convince someone who loves you. ;)

Use this:
/^[a-zA-Z0-9_.+-]+#(?:(?:[a-zA-Z0-9-]+\.)?[a-zA-Z]+\.)?
(domain|domain2)\.com$/g
To match the specific domain of your choice.
If you want to match only one domain then remove |domain2 from (domain|domain2) portion.
It will help you. https://www.regextester.com/94044

Not sure if this would work for your case, but it would probably be better to rely on the built in URL parser vs. using a regex.
var url = document.createElement('a');
url.href = "http://www.example.com/thing";
You can then call those values using the given to you by the API
url.protocol // (http:)
url.host // (www.example.com)
url.pathname // (/thing)
If that doesn't help you, something like this could work, but is likely too brittle:
var url = "http://www.example.com/thing";
var matches = url.match(/:\/\/(.[^\/]+)(.*)/);
// matches would return something like
// ["://example.com/thing", "example.com", "/thing"]
These posts could also help:
https://stackoverflow.com/a/3213643/4954530
https://stackoverflow.com/a/6168370
Good luck out there!

There are cases where the domain you're looking for could actually be found in the query section but not in the domain section: https://www.google.com/q=www.example.com
This answer would treat that case better.
See this example on regex101.

As you you pointed you only need example.com (write domain then escaped period then com), so use it in regex.
Example
UPDATED
See the answer below

javascript url regex

How can I allow users to enter both subdomain and domain names without the http:// prefix using a regex in javascript. I need to allow: domainname.com or www.domainname.com or www.domainname.co.uk. I have this at the moment which expects www. :
/^(?=www\.)[A-Za-z0-9_-]+\.+[A-Za-z0-9.\/%&=\?_:;-]+$/ix.test(value);

Try this:
/^(?=www\.)?[A-Za-z0-9_-]+\.+[A-Za-z0-9.\/%&=\?_:;-]+$/
Marking the www group with a ? makes it a zero-or-one match, which is what you want as I understand it.
Tested with http://www.regular-expressions.info/javascriptexample.html

This seems to work when tested on http://www.regextester.com/
/^(\w+:{0,1}\w*#)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%#!\-\/]))?/

URL validation using Javascript

I'm trying to use regex to validate user entered URLs. I came up with this regex:
function is_valid_url(url)
{
return url.match(/^(ht|f)tps?:\/\/[a-z0-9-\.]+\.[a-z]{2,4}\/?([^\s<>\#%"\,\{\}\\|\\\^\[\]`]+)?$/);
}
It works fine for most of the simple URLs. However, when I tried to enter this URL from Google Maps:
http://maps.google.com/maps?f=d&source=s_d&saddr=Brooklyn%2C+NY&daddr=Stewart+Ave&hl=en&geocode=FRBFbAId0JyX-ykJIXyUFkTCiTGGeAAEdFx2gg%3BFcAqbQIdgPuX-w&mra=mift&mrsp=1&sz=12&sll=40.65%2C-73.95&sspn=0.182857%2C0.308647&g=Brooklyn%2C+New+York%2C+NY%2C+United+States&ie=UTF8&z=12
Then the function returns false, even though this URL is correct.
I know using regex for URL validation is controversial as there's no perfect solution for it, but I want to know if you have any regex that works better than mine, and can return true for that kind of URL.

Easiest option: use a regex that works.
(((http|ftp|https):\/\/)|www\.)[\w\-_]+(\.[\w\-_]+)+([\w\-\.,#?^=%&:/~\+#!]*[\w\-\#?^=%&/~\+#])?
Regexr: http://regexr.com?2tpo8

^((http|https|ftp):\/\/)?([a-z]+\.)?[a-z0-9-]+(\.[a-z]{1,4}){1,2}(/.*\?.*)?$
Matches
http://www.example.com
www.example.com
example.com
example.info
abc.com.uk
www.example.co.in
www.example.com.sg
example.com.sg
t.com
co.co
https://www.t.co
asd.com.io/abc?foo=blah
False positives
abc.com.sg.in
example.com.aero.uk

Javascript form validation/sanitizing do i need regex here?

I have a single form input that is for checking domains. Sometimes people type in www. before the domain or .com after the domain name. The service that i use to check availability automatically checks for all top level domains so when people add the .com at the end it becomes redundant. For example the string submitted is domainname.com.com which is clearly invalid.
I understand you can do this on the server side but due to some rather weird circumstance i must use javascript for this. So is regex the solution here ? If so is there some kind of regex generator i can use for this or can someone point me in the right direction with a code snippet perhaps ?
Appreciate any help thanks!

This page has an example Regex.
function isUrl(s) {
var regexp = /^(ht|f)tp(s?)\:\/\/[0-9a-zA-Z]([-.\w]*[0-9a-zA-Z])*(:(0-9)*)*(\/?)([a-zA-Z0-9\-\.\?\,\'\/\\\+&%\$#_]*)?$/
return regexp.test(s);
}
Here is another example.
function isUrl(s) {
var regexp = /(ftp|http|https):\/\/(\w+:{0,1}\w*#)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%#!\-\/]))?/
return regexp.test(s);
}

Well, regex is one possible solution. You can peel off common TLD's like this:
input = input.replace(
/\.(?:com|net|org|biz|edu|in(?:t|fo)|gov|mil|mobi|museum|[a-z][a-z])$/i, "");
Is that the kind of thing you're looking for?