Regex for URL with query string

Question

I'm trying to create a regular expression to use as a rule in fiddler. I'm not very good at regular expressions.

This regular expression:

http://myServer:28020/MyService/ItemWebService.json?([a-zA-Z]+)

Matches the URL below:

http://myServer:28020/MyService/ItemWebService.json?action=keywordSearch&username=StockOnHandPortlet&sessionId=2H7Rr9kCWPgIZfrxQiDHKp0&keywords=blue&itemStatus=A

So far so good. But why when I try this regular expression:

http://myServer:28020/MyService/ItemWebService.json?action=keywordSearch([a-zA-Z]+)

It does not match the above URL. Why would that be?

Answer 1

In a regular expression, you need to escape . and ? outside of character class.

So, this is enough to match the URL itself:

http://myServer:28020/MyService/ItemWebService\.json

URL with query string can be matched with

http://myServer:28020/MyService/ItemWebService\.json\??(?:&?[^=&]*=[^=&]*)*

See demo

Explanation:

• http://myServer:28020/MyService/ItemWebService\.json - matches the base URL where we need to escape . to match it literally
• \?? - matches 0 or 1 (due to ? quantifier) literal ?
• (?:&?[^=&]*=[^=&]*)* - matches 0 or more (due to *) sequences of &?[^=&]*=[^=&]*:
  • &? - 0 or 1 & (no need escaping)
  • [^=&]* - 0 or more characters other than = and &
  • = - n equals sign
  • [^=&]* - 0 or more characters other than = and &

If you want to match a URL that has the first query parameter=value set to action=keywordSearch, you can use the following regex:

http://myServer:28020/MyService/ItemWebService\.json\?action=keywordSearch(?:&?[^=&]*=[^=&]*)*