URL encoding

URL encoding is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

The task is to provide a function or mechanism to convert a provided string into URL encoding representation.

In URL encoding, special characters, control characters and extended characters are converted into a percent symbol followed by a two digit hexadecimal code, So a space character encodes into %20 within the string.

The following characters require conversion:

• ASCII control codes (Character ranges 00-1F hex (0-31 decimal) and 7F (127 decimal).
• ASCII symbols (Character ranges 32-47 decimal (20-2F hex))
• ASCII symbols (Character ranges 58-64 decimal (3A-40 hex))
• ASCII symbols (Character ranges 91-96 decimal (5B-60 hex))
• ASCII symbols (Character ranges 123-126 decimal (7B-7E hex))
• Extended characters with character codes of 128 decimal (80 hex) and above.

Example

The string "http://foo bar/" would be encoded as "http%3A%2F%2Ffoo%20bar%2F".

See also

URL decoding

J

J has a urlencode in the gethttp package, but this task requires that all non-alphanumeric characters be encoded.

Here's an implementation that does that:

<lang j>require'strings convert' urlencode=: rplc&((#~2|_1 47 57 64 90 96 122 I.i.@#)a.;"_1'%',.hfd i.#a.)</lang>

Example use:

<lang j> urlencode 'http://foo bar/' http%3A%2F%2Ffoo%20bar%2F</lang>

Perl

Use standard CGI module: <lang perl>use 5.10.0; use CGI;

my $s = 'http://foo/bar/'; say $s = CGI::escape($s); say $s = CGI::unescape($s);</lang>