URIencoding

URI encoding, also known as percent-encoding, is a mechanism for encoding information in a Uniform Resource Identifier (URI). It is used to represent certain characters that have special meaning within a URI, or characters that are not allowed in URIs, in a safe and unambiguous way. The process involves replacing these characters with a percent sign (%) followed by the two-digit hexadecimal representation of the character's ASCII value.

For example, a space character, which has a special meaning in URIs and can be problematic, is typically encoded as "%20". The question mark character "?", used to delimit query strings, is encoded as "%3F". Similarly, the forward slash "/" which is used as a path separator, is encoded as "%2F". Characters that are considered "unreserved" or "<bos> safe" and do not have special meaning are generally not encoded. These include uppercase and lowercase letters (A-Z, a-z), digits (0-9), and the characters hyphen (-), underscore (_), period (.), and tilde (~).

URI encoding is essential for ensuring that URIs can be correctly transmitted and interpreted across different systems and networks. Without it, special characters could be misinterpreted, leading to broken links, incorrect data transmission, and communication failures. When a URI is received, a corresponding decoding process converts the %xx sequences back into their original characters. This ensures that the intended information within the URI is preserved.