why do you need to encode urls?

Question

Why do you need to encode urls? Is there a good reason why you have to change every space in the GET data to %20?

Answer 1

From RFC 2936, section 2.4.3:

The space character is excluded because significant spaces may disappear and insignificant spaces may be introduced when URI are transcribed or typeset or subjected to the treatment of word- processing programs. Whitespace is also used to delimit URI in many contexts.

Answer 2

Since URLs often contains characters outside the ASCII set, the URL has to be converted. URL encoding converts the URL into a valid ASCII format.

Therefore URL encoding converts characters into a format that can be safely transmitted over the Internet.

URLs can only be sent over the Internet using the ASCII character-set.

URL encoding replaces unsafe ASCII characters with "%" followed by two hexadecimal digits corresponding to the character values in the ISO-8859-1 character-set. URLs cannot contain spaces. URL encoding normally replaces a space with a + sign

Answer 3

Well, you do so because every different browsers knows how the string that makes up the URL is encoded. converting the space to %20, etc makes that URL/URI portable. It could be latin-1 it could be unicode. It needs normalized to something that is understood universally. Take a look at rfc3986 http://tools.ietf.org/html/rfc3986#section-2.1