Which characters are allowed in GET parameters without encoding or escaping them? I mean something like this:
http://www.example.org/page.php?name=XYZ
What can you have there instead of XYZ? I think only the following characters:
Is this the full list or are there additional characters allowed?
I hope you can help me. Thanks in advance!
All of the rules concerning the encoding of URIs (which contains URNs and URLs) are specified in the RFC1738 and the RFC3986, here's a TL;DR of these long and boring documents:
Percent-encoding, also known as URL encoding, is a mechanism for encoding information in a URI under certain circumstances. The characters allowed in a URI are either reserved or unreserved. Reserved characters are those characters that sometimes have special meaning, but they are not the only characters that needs encoding.
There are 66 unreserved characters that doesn't need any encoding:
abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~
There are 18 reserved characters which needs to be encoded: !*'();:@&=+$,/?#[], and all the other characters must be encoded.
To percent-encode a character, simply concatenate "%" and its ASCII value in hexadecimal. The php functions "urlencode" and "rawurlencode" do this job for you.
