standards - Using duplicate parameters in a URL

Question

We are building an API in-house and often are passing a parameter with multiple values.

They use: mysite.com?id=1&id=2&id=3

Instead of: mysite.com?id=1,2,3

I favor the second approach but I was curious if it was actually incorrect to do the first?

Answer 1

I'm not an HTTP guru, but from what I understand there's not a definitive standard on the query part of the URL regarding multiple values, it's typically up to the CGI that handles the request to parse the query string.

RFC 1738 section 3.3 mentions a searchpart and that it should go after the ? but doesn't seem to elaborate on its format.

http://<host>:<port>/<path>?<searchpart>