URL Decode

The URL-DECODE directive decodes a string from the application/x-www-form-urlencoded MIME format to a string.

Syntax

url-decode <column>

The <column> contains an encoded URL to be decoded.

Usage Notes

The conversion process is the reverse of that used by the URL-ENCODE directive. It is assumed that all characters in the encoded string are one of the following: a through z, A through Z, 0 through 9, and -, _, ., and *. The character % is allowed but is interpreted as the start of a special escaped sequence.

See https://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1 for details.

These rules are applied in the conversion:

  • The alphanumeric characters a through z, A through Z, and 0 through 9 remain unchanged
  • The special characters ., -, *, and _ remain unchanged
  • The plus sign (+) is converted into a space character ` `
  • A sequence of the form %xy will be treated as representing a byte where xy is the two-digit hexadecimal representation of the 8-bit byte. Then, all substrings that contain one or more of these byte sequences consecutively will be replaced by the character(s) whose encoding would result in those consecutive bytes. The encoding scheme used to decode these characters may be specified, or if unspecified, the default encoding of the platform will be used.

Note: Uses UTF-8 as the decoding scheme for the string.