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local M = { _NAME = "uri.data" }
local Util = require "uri._util"
local URI = require "uri"
Util.subclass_of(M, URI)
-- This implements the 'data' scheme defined in RFC 2397.
local Filter = Util.attempt_require("datafilter")
local function _valid_base64 (data) return data:find("^[0-9a-zA-Z/+]*$") end
local function _split_path (path)
local _, _, mediatype, data = path:find("^([^,]*),(.*)")
if not mediatype then return "must have comma in path" end
local base64 = false
if mediatype:find(";base64$") then
base64 = true
mediatype = mediatype:sub(1, -8)
end
if base64 and not _valid_base64(data) then
return "illegal character in base64 encoding"
end
return nil, mediatype, base64, data
end
function M.init (self)
if M._SUPER.host(self) then
return nil, "data URIs may not have authority parts"
end
local err, mediatype, base64, data = _split_path(M._SUPER.path(self))
if err then return nil, "invalid data URI (" .. err .. ")" end
return self
end
function M.data_media_type (self, ...)
local _, old, base64, data = _split_path(M._SUPER.path(self))
if select('#', ...) > 0 then
local new = ... or ""
new = Util.uri_encode(new, "^A-Za-z0-9%-._~!$&'()*+;=:@/")
if base64 then new = new .. ";base64" end
M._SUPER.path(self, new .. "," .. data)
end
if old ~= "" then
if old:find("^;") then old = "text/plain" .. old end
return Util.uri_decode(old)
else
return "text/plain;charset=US-ASCII" -- default type
end
end
local function _urienc_len (s)
local num_unsafe_chars = s:gsub("[A-Za-z0-9%-._~!$&'()*+,;=:@/]", ""):len()
local num_safe_chars = s:len() - num_unsafe_chars
return num_safe_chars + num_unsafe_chars * 3
end
local function _base64_len (s)
local num_blocks = (s:len() + 2) / 3
num_blocks = num_blocks - num_blocks % 1
return num_blocks * 4
+ 7 -- because of ";base64" marker
end
local function _do_filter (algorithm, input)
return Filter[algorithm](input)
end
function M.data_bytes (self, ...)
local _, mediatype, base64, old = _split_path(M._SUPER.path(self))
if base64 then
if not Filter then
error("'datafilter' Lua module required to decode base64 data")
end
old = _do_filter("base64_decode", old)
else
old = Util.uri_decode(old)
end
if select('#', ...) > 0 then
local new = ... or ""
local urienc_len = _urienc_len(new)
local base64_len = _base64_len(new)
if base64_len < urienc_len and Filter then
mediatype = mediatype .. ";base64"
new = _do_filter("base64_encode", new)
else
new = new:gsub("%%", "%%25")
end
M._SUPER.path(self, mediatype .. "," .. new)
end
return old
end
function M.path (self, ...)
local old = M._SUPER.path(self)
if select('#', ...) > 0 then
local new = ...
if not new then error("there must be a path in a data URI") end
local err = _split_path(new)
if err then error("invalid data URI (" .. err .. ")") end
M._SUPER.path(self, new)
end
return old
end
Util.uri_part_not_allowed(M, "userinfo")
Util.uri_part_not_allowed(M, "host")
Util.uri_part_not_allowed(M, "port")
return M
-- vi:ts=4 sw=4 expandtab
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