Regex for URL with port validation - regex

Question

I need to validate a url like those of web servers.
Something like http://localhost:8080/xyz
How do we do that using regex. Sorry, new to regex.

Answer 1

the relevant specs can be found in rfc 3986 and include regular syntax definitions for all possible url components. however, for your purposes these will probably be too general. a somewhat condensed expression matching only urls under the http(s) protocol would be
http[s]?://(([[:alpha:][:digit:]-._~!$&'\(\)*+,;=]|%([0-9A-F]{2}))+|([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5]))(:[0-9]+)?(/([[:alpha:][:digit:]-._~!$&'\(\)*+,;=]|%([0-9A-F]{2}))*)+(\?([[:alpha:][:digit:]-._~!$&'\(\)*+,;=/?]|%([0-9A-F]{2}))+)?(#([[:alpha:][:digit:]-._~!$&'\(\)*+,;=/?]|%([0-9A-F]{2}))+)?
which can be simplified to
http[s]?://(([^/:\.[:space:]]+(\.[^/:\.[:space:]]+)*)|([0-9](\.[0-9]{3})))(:[0-9]+)?((/[^?#[:space:]]+)(\?[^#[:space:]]+)?(\#.+)?)?
in case you can be confident about the proper syntax of the url components.
note that you might wish more restrictive patterns e.g. for full text search and to only allow for iana-registered top-level-domains.
hope it helps,
best regards, carsten