Created
September 27, 2012 21:06
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erlang percent encoding that works with utf-8
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-module(encode_uri_rfc3986). | |
-author('Renato Albano <renatoalbano@gmail.com>'). | |
-export([encode/1]). | |
%% Taken from <http://erlangexamples.com/>, | |
%% from <http://github.com/CapnKernul/httparadise> | |
%% and <http://www.erlang.org/doc/man/edoc_lib.html> | |
encode([C | Cs]) when C >= $a, C =< $z -> | |
[C | encode(Cs)]; | |
encode([C | Cs]) when C >= $A, C =< $Z -> | |
[C | encode(Cs)]; | |
encode([C | Cs]) when C >= $0, C =< $9 -> | |
[C | encode(Cs)]; | |
encode([C | Cs]) when C == 16#20 -> % space to + | |
[$+ | encode(Cs)]; | |
% unreserved | |
encode([C = $- | Cs]) -> | |
[C | encode(Cs)]; | |
encode([C = $_ | Cs]) -> | |
[C | encode(Cs)]; | |
encode([C = 46 | Cs]) -> % . | |
[C | encode(Cs)]; | |
encode([C = $! | Cs]) -> | |
[C | encode(Cs)]; | |
encode([C = $~ | Cs]) -> | |
[C | encode(Cs)]; | |
encode([C = $* | Cs]) -> | |
[C | encode(Cs)]; | |
encode([C = 39 | Cs]) -> % ' | |
[C | encode(Cs)]; | |
encode([C = $( | Cs]) -> | |
[C | encode(Cs)]; | |
encode([C = $) | Cs]) -> | |
[C | encode(Cs)]; | |
encode([C | Cs]) when C =< 16#7f -> | |
escape_byte(C) | |
++ encode(Cs); | |
encode([C | Cs]) when (C >= 16#7f) and (C =< 16#07FF) -> | |
escape_byte((C bsr 6) + 16#c0) | |
++ escape_byte(C band 16#3f + 16#80) | |
++ encode(Cs); | |
encode([C | Cs]) when (C > 16#07FF) -> | |
escape_byte((C bsr 12) + 16#e0) % (0xe0 | C >> 12) | |
++ escape_byte((16#3f band (C bsr 6)) + 16#80) % 0x80 | ((C >> 6) & 0x3f) | |
++ escape_byte(C band 16#3f + 16#80) % 0x80 | (C >> 0x3f) | |
++ encode(Cs); | |
encode([C | Cs]) -> | |
escape_byte(C) ++ encode(Cs); | |
encode([]) -> []. | |
% from edoc_lib source | |
hex_octet(N) when N =< 9 -> | |
[$0 + N]; | |
hex_octet(N) when N > 15 -> | |
hex_octet(N bsr 4) ++ hex_octet(N band 15); | |
hex_octet(N) -> | |
[N - 10 + $a]. | |
escape_byte(C) -> | |
H = hex_octet(C), | |
normalize(H). | |
%% Append 0 if length == 1 | |
normalize(H) when length(H) == 1 -> | |
"%0" ++ H; | |
normalize(H) -> | |
"%" ++ H. |
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This is very helpful, thanks!