--[[ LuCI - Lua Configuration Interface Copyright 2008 Steven Barth <steven@midlink.org> Copyright 2008 Jo-Philipp Wich <xm@leipzig.freifunk.net> Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 $Id$ Decoder: Info: null will be decoded to luci.json.null if first parameter of Decoder() is true Example: decoder = luci.json.Decoder() luci.ltn12.pump.all(luci.ltn12.source.string("decodableJSON"), decoder:sink()) luci.util.dumptable(decoder:get()) Known issues: does not support unicode conversion \uXXYY with XX != 00 will be ignored Encoder: Info: Accepts numbers, strings, nil, booleans as they are Accepts luci.json.null as replacement for nil Accepts full associative and full numerically indexed tables Mixed tables will loose their associative values during conversion Iterator functions will be encoded as an array of their return values Non-iterator functions will probably corrupt the encoder Example: encoder = luci.json.Encoder(encodableData) luci.ltn12.pump.all(encoder:source(), luci.ltn12.sink.file(io.open("someFile", w))) ]]-- local util = require "luci.util" local table = require "table" local string = require "string" local coroutine = require "coroutine" local assert = assert local tonumber = tonumber local tostring = tostring local error = error local type = type local pairs = pairs local ipairs = ipairs local next = next local getmetatable = getmetatable --- LuCI JSON-Library -- @cstyle instance module "luci.json" --- Null replacement function -- @return null function null() return null end --- Create a new JSON-Encoder. -- @class function -- @name Encoder -- @param data Lua-Object to be encoded. -- @param buffersize Blocksize of returned data source. -- @param fastescape Use non-standard escaping (don't escape control chars) -- @return JSON-Encoder Encoder = util.class() function Encoder.__init__(self, data, buffersize, fastescape) self.data = data self.buffersize = buffersize or 512 self.buffer = "" self.fastescape = fastescape getmetatable(self).__call = Encoder.source end --- Create an LTN12 source providing the encoded JSON-Data. -- @return LTN12 source function Encoder.source(self) local source = coroutine.create(self.dispatch) return function() local res, data = coroutine.resume(source, self, self.data, true) if res then return data else return nil, data end end end function Encoder.dispatch(self, data, start) local parser = self.parsers[type(data)] parser(self, data) if start then if #self.buffer > 0 then coroutine.yield(self.buffer) end coroutine.yield() end end function Encoder.put(self, chunk) if self.buffersize < 2 then corountine.yield(chunk) else if #self.buffer + #chunk > self.buffersize then local written = 0 local fbuffer = self.buffersize - #self.buffer coroutine.yield(self.buffer .. chunk:sub(written + 1, fbuffer)) written = fbuffer while #chunk - written > self.buffersize do fbuffer = written + self.buffersize coroutine.yield(chunk:sub(written + 1, fbuffer)) written = fbuffer end self.buffer = chunk:sub(written + 1) else self.buffer = self.buffer .. chunk end end end function Encoder.parse_nil(self) self:put("null") end function Encoder.parse_bool(self, obj) self:put(obj and "true" or "false") end function Encoder.parse_number(self, obj) self:put(tostring(obj)) end function Encoder.parse_string(self, obj) if self.fastescape then self:put('"' .. obj:gsub('\\', '\\\\'):gsub('"', '\\"') .. '"') else self:put('"' .. obj:gsub('[%c\\"]', function(char) return '\\u00%02x' % char:byte() end ) .. '"') end end function Encoder.parse_iter(self, obj) if obj == null then return self:put("null") end if type(obj) == "table" and (#obj == 0 and next(obj)) then self:put("{") local first = true for key, entry in pairs(obj) do first = first or self:put(",") first = first and false self:parse_string(tostring(key)) self:put(":") self:dispatch(entry) end self:put("}") else self:put("[") local first = true if type(obj) == "table" then for i=1, #obj do first = first or self:put(",") first = first and nil self:dispatch(obj[i]) end else for entry in obj do first = first or self:put(",") first = first and nil self:dispatch(entry) end end self:put("]") end end Encoder.parsers = { ['nil'] = Encoder.parse_nil, ['table'] = Encoder.parse_iter, ['number'] = Encoder.parse_number, ['string'] = Encoder.parse_string, ['boolean'] = Encoder.parse_bool, ['function'] = Encoder.parse_iter } --- Create a new JSON-Decoder. -- @class function -- @name Decoder -- @param customnull Use luci.json.null instead of nil for decoding null -- @return JSON-Decoder Decoder = util.class() function Decoder.__init__(self, customnull) self.cnull = customnull getmetatable(self).__call = Decoder.sink end --- Create an LTN12 sink from the decoder object which accepts the JSON-Data. -- @return LTN12 sink function Decoder.sink(self) local sink = coroutine.create(self.dispatch) return function(...) return coroutine.resume(sink, self, ...) end end --- Get the decoded data packets after the rawdata has been sent to the sink. -- @return Decoded data function Decoder.get(self) return self.data end function Decoder.dispatch(self, chunk, src_err, strict) local robject, object local oset = false while chunk do while chunk and #chunk < 1 do chunk = self:fetch() end assert(not strict or chunk, "Unexpected EOS") if not chunk then break end local char = chunk:sub(1, 1) local parser = self.parsers[char] or (char:match("%s") and self.parse_space) or (char:match("[0-9-]") and self.parse_number) or error("Unexpected char '%s'" % char) chunk, robject = parser(self, chunk) if parser ~= self.parse_space then assert(not oset, "Scope violation: Too many objects") object = robject oset = true if strict then return chunk, object end end end assert(not src_err, src_err) assert(oset, "Unexpected EOS") self.data = object end function Decoder.fetch(self) local tself, chunk, src_err = coroutine.yield() assert(chunk or not src_err, src_err) return chunk end function Decoder.fetch_atleast(self, chunk, bytes) while #chunk < bytes do local nchunk = self:fetch() assert(nchunk, "Unexpected EOS") chunk = chunk .. nchunk end return chunk end function Decoder.fetch_until(self, chunk, pattern) local start = chunk:find(pattern) while not start do local nchunk = self:fetch() assert(nchunk, "Unexpected EOS") chunk = chunk .. nchunk start = chunk:find(pattern) end return chunk, start end function Decoder.parse_space(self, chunk) local start = chunk:find("[^%s]") while not start do chunk = self:fetch() if not chunk then return nil end start = chunk:find("[^%s]") end return chunk:sub(start) end function Decoder.parse_literal(self, chunk, literal, value) chunk = self:fetch_atleast(chunk, #literal) assert(chunk:sub(1, #literal) == literal, "Invalid character sequence") return chunk:sub(#literal + 1), value end function Decoder.parse_null(self, chunk) return self:parse_literal(chunk, "null", self.cnull and null) end function Decoder.parse_true(self, chunk) return self:parse_literal(chunk, "true", true) end function Decoder.parse_false(self, chunk) return self:parse_literal(chunk, "false", false) end function Decoder.parse_number(self, chunk) local chunk, start = self:fetch_until(chunk, "[^0-9eE.+-]") local number = tonumber(chunk:sub(1, start - 1)) assert(number, "Invalid number specification") return chunk:sub(start), number end function Decoder.parse_string(self, chunk) local str = "" local object = nil assert(chunk:sub(1, 1) == '"', 'Expected "') chunk = chunk:sub(2) while true do local spos = chunk:find('[\\"]') if spos then str = str .. chunk:sub(1, spos - 1) local char = chunk:sub(spos, spos) if char == '"' then -- String end chunk = chunk:sub(spos + 1) break elseif char == "\\" then -- Escape sequence chunk, object = self:parse_escape(chunk:sub(spos)) str = str .. object end else str = str .. chunk chunk = self:fetch() assert(chunk, "Unexpected EOS while parsing a string") end end return chunk, str end function Decoder.parse_escape(self, chunk) local str = "" chunk = self:fetch_atleast(chunk:sub(2), 1) local char = chunk:sub(1, 1) chunk = chunk:sub(2) if char == '"' then return chunk, '"' elseif char == "\\" then return chunk, "\\" elseif char == "u" then chunk = self:fetch_atleast(chunk, 4) local s1, s2 = chunk:sub(1, 2), chunk:sub(3, 4) s1, s2 = tonumber(s1, 16), tonumber(s2, 16) assert(s1 and s2, "Invalid Unicode character") -- ToDo: Unicode support return chunk:sub(5), s1 == 0 and string.char(s2) or "" elseif char == "/" then return chunk, "/" elseif char == "b" then return chunk, "\b" elseif char == "f" then return chunk, "\f" elseif char == "n" then return chunk, "\n" elseif char == "r" then return chunk, "\r" elseif char == "t" then return chunk, "\t" else error("Unexpected escaping sequence '\\%s'" % char) end end function Decoder.parse_array(self, chunk) chunk = chunk:sub(2) local array = {} local nextp = 1 local chunk, object = self:parse_delimiter(chunk, "%]") if object then return chunk, array end repeat chunk, object = self:dispatch(chunk, nil, true) table.insert(array, nextp, object) nextp = nextp + 1 chunk, object = self:parse_delimiter(chunk, ",%]") assert(object, "Delimiter expected") until object == "]" return chunk, array end function Decoder.parse_object(self, chunk) chunk = chunk:sub(2) local array = {} local name local chunk, object = self:parse_delimiter(chunk, "}") if object then return chunk, array end repeat chunk = self:parse_space(chunk) assert(chunk, "Unexpected EOS") chunk, name = self:parse_string(chunk) chunk, object = self:parse_delimiter(chunk, ":") assert(object, "Separator expected") chunk, object = self:dispatch(chunk, nil, true) array[name] = object chunk, object = self:parse_delimiter(chunk, ",}") assert(object, "Delimiter expected") until object == "}" return chunk, array end function Decoder.parse_delimiter(self, chunk, delimiter) while true do chunk = self:fetch_atleast(chunk, 1) local char = chunk:sub(1, 1) if char:match("%s") then chunk = self:parse_space(chunk) assert(chunk, "Unexpected EOS") elseif char:match("[%s]" % delimiter) then return chunk:sub(2), char else return chunk, nil end end end Decoder.parsers = { ['"'] = Decoder.parse_string, ['t'] = Decoder.parse_true, ['f'] = Decoder.parse_false, ['n'] = Decoder.parse_null, ['['] = Decoder.parse_array, ['{'] = Decoder.parse_object } --- Create a new Active JSON-Decoder. -- @class function -- @name ActiveDecoder -- @param customnull Use luci.json.null instead of nil for decoding null -- @return Active JSON-Decoder ActiveDecoder = util.class(Decoder) function ActiveDecoder.__init__(self, source, customnull) Decoder.__init__(self, customnull) self.source = source self.chunk = nil getmetatable(self).__call = self.get end --- Fetches one JSON-object from given source -- @return Decoded object function ActiveDecoder.get(self) local chunk, src_err, object if not self.chunk then chunk, src_err = self.source() else chunk = self.chunk end self.chunk, object = self:dispatch(chunk, src_err, true) return object end function ActiveDecoder.fetch(self) local chunk, src_err = self.source() assert(chunk or not src_err, src_err) return chunk end