Image Serving HTTP encoding image-serving-http-encoding

Command values must be http-encoded using %xx escape sequences, such that the value strings do not include the reserved characters ‘=’, ‘&’, and ‘%’.

Otherwise, standard HTTP encoding rules apply. The HTTP specification requires encoding of the unsafe characters, as well as any control characters, such as <return> and <tab>. URL encoding of a character consists of a “%” symbol, followed by the two-digit hexadecimal representation (case-insensitive) of the ISO-Latin code point for the character. The unsafe characters and code points are:

Reserved characters must also be encoded.

Example section-b85895e5b6a84b96b7fca987656dd34d

…&$text=rate&weight=85% 27#&…

If obfuscation is not applied, the above request fragment must be encoded as follows:

…&$text=rate%26weight%3D85%25%2027%23&…

If obfuscation is applied, encoding can be limited to remove ‘=’, ‘&’, and ‘%’ characters:

…&$text=rate%26weight%3D85%25 27#&…

See also section-295476ec34c74973962d07dfa9eb2180

Request Obfuscation, HTTP/1.1 Specification (RFC 2616)