Why do you need to encode URLs?

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?

Solution 1:

Because some characters have special meanings.

For instance, in a query string, the ampersand (&) is used as a separator between key-value pairs. If you were to put an ampersand into one of those values, it would look like the separator between the end of a value and the beginning of the next key. So for special characters like this, we use percent encoding so that we can be sure that the data is unambiguously encoded.

Solution 2:

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.