Module:Jf-JSON
MyWikiBiz, Author Your Legacy — Friday November 15, 2024
Jump to navigationJump to searchThis is Jeffrey Friedl's JSON.lua library, copied from http://regex.info/blog/lua/json (source code). It is licensed under CC-BY 3.0.
The suggested loading code of JSON = assert(loadfile "JSON.lua")() will not work in Scribunto. Instead, load the module as follows:
<syntaxhighlight lang="lua"> local JSON = require('Module:jf-JSON') </syntaxhighlight>
You can then use the module as documented in the module comments.
-- -*- coding: utf-8 -*-
--
-- Simple JSON encoding and decoding in pure Lua.
--
-- Copyright 2010-2016 Jeffrey Friedl
-- http://regex.info/blog/
-- Latest version: http://regex.info/blog/lua/json
--
-- This code is released under a Creative Commons CC-BY "Attribution" License:
-- http://creativecommons.org/licenses/by/3.0/deed.en_US
--
-- It can be used for any purpose so long as:
-- 1) the copyright notice above is maintained
-- 2) the web-page links above are maintained
-- 3) the 'AUTHOR_NOTE' string below is maintained
--
local VERSION = '20161109.21' -- version history at end of file
local AUTHOR_NOTE = "-[ JSON.lua package by Jeffrey Friedl (http://regex.info/blog/lua/json) version 20161109.21 ]-"
--
-- The 'AUTHOR_NOTE' variable exists so that information about the source
-- of the package is maintained even in compiled versions. It's also
-- included in OBJDEF below mostly to quiet warnings about unused variables.
--
local OBJDEF = {
VERSION = VERSION,
AUTHOR_NOTE = AUTHOR_NOTE,
}
--
-- Simple JSON encoding and decoding in pure Lua.
-- JSON definition: http://www.json.org/
--
--
-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
--
-- local lua_value = JSON:decode(raw_json_text)
--
-- local raw_json_text = JSON:encode(lua_table_or_value)
-- local pretty_json_text = JSON:encode_pretty(lua_table_or_value) -- "pretty printed" version for human readability
--
--
--
-- DECODING (from a JSON string to a Lua table)
--
--
-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
--
-- local lua_value = JSON:decode(raw_json_text)
--
-- If the JSON text is for an object or an array, e.g.
-- { "what": "books", "count": 3 }
-- or
-- [ "Larry", "Curly", "Moe" ]
--
-- the result is a Lua table, e.g.
-- { what = "books", count = 3 }
-- or
-- { "Larry", "Curly", "Moe" }
--
--
-- The encode and decode routines accept an optional second argument,
-- "etc", which is not used during encoding or decoding, but upon error
-- is passed along to error handlers. It can be of any type (including nil).
--
--
--
-- ERROR HANDLING
--
-- With most errors during decoding, this code calls
--
-- JSON:onDecodeError(message, text, location, etc)
--
-- with a message about the error, and if known, the JSON text being
-- parsed and the byte count where the problem was discovered. You can
-- replace the default JSON:onDecodeError() with your own function.
--
-- The default onDecodeError() merely augments the message with data
-- about the text and the location if known (and if a second 'etc'
-- argument had been provided to decode(), its value is tacked onto the
-- message as well), and then calls JSON.assert(), which itself defaults
-- to Lua's built-in assert(), and can also be overridden.
--
-- For example, in an Adobe Lightroom plugin, you might use something like
--
-- function JSON:onDecodeError(message, text, location, etc)
-- LrErrors.throwUserError("Internal Error: invalid JSON data")
-- end
--
-- or even just
--
-- function JSON.assert(message)
-- LrErrors.throwUserError("Internal Error: " .. message)
-- end
--
-- If JSON:decode() is passed a nil, this is called instead:
--
-- JSON:onDecodeOfNilError(message, nil, nil, etc)
--
-- and if JSON:decode() is passed HTML instead of JSON, this is called:
--
-- JSON:onDecodeOfHTMLError(message, text, nil, etc)
--
-- The use of the fourth 'etc' argument allows stronger coordination
-- between decoding and error reporting, especially when you provide your
-- own error-handling routines. Continuing with the the Adobe Lightroom
-- plugin example:
--
-- function JSON:onDecodeError(message, text, location, etc)
-- local note = "Internal Error: invalid JSON data"
-- if type(etc) = 'table' and etc.photo then
-- note = note .. " while processing for " .. etc.photo:getFormattedMetadata('fileName')
-- end
-- LrErrors.throwUserError(note)
-- end
--
-- :
-- :
--
-- for i, photo in ipairs(photosToProcess) do
-- :
-- :
-- local data = JSON:decode(someJsonText, { photo = photo })
-- :
-- :
-- end
--
--
--
-- If the JSON text passed to decode() has trailing garbage (e.g. as with the JSON "[123]xyzzy"),
-- the method
--
-- JSON:onTrailingGarbage(json_text, location, parsed_value, etc)
--
-- is invoked, where:
--
-- json_text is the original JSON text being parsed,
-- location is the count of bytes into json_text where the garbage starts (6 in the example),
-- parsed_value is the Lua result of what was successfully parsed ({123} in the example),
-- etc is as above.
--
-- If JSON:onTrailingGarbage() does not abort, it should return the value decode() should return,
-- or nil + an error message.
--
-- local new_value, error_message = JSON:onTrailingGarbage()
--
-- The default handler just invokes JSON:onDecodeError("trailing garbage"...), but you can have
-- this package ignore trailing garbage via
--
-- function JSON:onTrailingGarbage(json_text, location, parsed_value, etc)
-- return parsed_value
-- end
--
--
-- DECODING AND STRICT TYPES
--
-- Because both JSON objects and JSON arrays are converted to Lua tables,
-- it's not normally possible to tell which original JSON type a
-- particular Lua table was derived from, or guarantee decode-encode
-- round-trip equivalency.
--
-- However, if you enable strictTypes, e.g.
--
-- JSON = assert(loadfile "JSON.lua")() --load the routines
-- JSON.strictTypes = true
--
-- then the Lua table resulting from the decoding of a JSON object or
-- JSON array is marked via Lua metatable, so that when re-encoded with
-- JSON:encode() it ends up as the appropriate JSON type.
--
-- (This is not the default because other routines may not work well with
-- tables that have a metatable set, for example, Lightroom API calls.)
--
--
-- ENCODING (from a lua table to a JSON string)
--
-- JSON = assert(loadfile "JSON.lua")() -- one-time load of the routines
--
-- local raw_json_text = JSON:encode(lua_table_or_value)
-- local pretty_json_text = JSON:encode_pretty(lua_table_or_value) -- "pretty printed" version for human readability
-- local custom_pretty = JSON:encode(lua_table_or_value, etc, { pretty = true, indent = "| ", align_keys = false })
--
-- On error during encoding, this code calls:
--
-- JSON:onEncodeError(message, etc)
--
-- which you can override in your local JSON object.
--
-- The 'etc' in the error call is the second argument to encode()
-- and encode_pretty(), or nil if it wasn't provided.
--
--
-- ENCODING OPTIONS
--
-- An optional third argument, a table of options, can be provided to encode().
--
-- encode_options = {
-- -- options for making "pretty" human-readable JSON (see "PRETTY-PRINTING" below)
-- pretty = true,
-- indent = " ",
-- align_keys = false,
--
-- -- other output-related options
-- null = "\0", -- see "ENCODING JSON NULL VALUES" below
-- stringsAreUtf8 = false, -- see "HANDLING UNICODE LINE AND PARAGRAPH SEPARATORS FOR JAVA" below
-- }
--
-- json_string = JSON:encode(mytable, etc, encode_options)
--
--
--
-- For reference, the defaults are:
--
-- pretty = false
-- null = nil,
-- stringsAreUtf8 = false,
--
--
--
-- PRETTY-PRINTING
--
-- Enabling the 'pretty' encode option helps generate human-readable JSON.
--
-- pretty = JSON:encode(val, etc, {
-- pretty = true,
-- indent = " ",
-- align_keys = false,
-- })
--
-- encode_pretty() is also provided: it's identical to encode() except
-- that encode_pretty() provides a default options table if none given in the call:
--
-- { pretty = true, align_keys = false, indent = " " }
--
-- For example, if
--
-- JSON:encode(data)
--
-- produces:
--
-- {"city":"Kyoto","climate":{"avg_temp":16,"humidity":"high","snowfall":"minimal"},"country":"Japan","wards":11}
--
-- then
--
-- JSON:encode_pretty(data)
--
-- produces:
--
-- {
-- "city": "Kyoto",
-- "climate": {
-- "avg_temp": 16,
-- "humidity": "high",
-- "snowfall": "minimal"
-- },
-- "country": "Japan",
-- "wards": 11
-- }
--
-- The following three lines return identical results:
-- JSON:encode_pretty(data)
-- JSON:encode_pretty(data, nil, { pretty = true, align_keys = false, indent = " " })
-- JSON:encode (data, nil, { pretty = true, align_keys = false, indent = " " })
--
-- An example of setting your own indent string:
--
-- JSON:encode_pretty(data, nil, { pretty = true, indent = "| " })
--
-- produces:
--
-- {
-- | "city": "Kyoto",
-- | "climate": {
-- | | "avg_temp": 16,
-- | | "humidity": "high",
-- | | "snowfall": "minimal"
-- | },
-- | "country": "Japan",
-- | "wards": 11
-- }
--
-- An example of setting align_keys to true:
--
-- JSON:encode_pretty(data, nil, { pretty = true, indent = " ", align_keys = true })
--
-- produces:
--
-- {
-- "city": "Kyoto",
-- "climate": {
-- "avg_temp": 16,
-- "humidity": "high",
-- "snowfall": "minimal"
-- },
-- "country": "Japan",
-- "wards": 11
-- }
--
-- which I must admit is kinda ugly, sorry. This was the default for
-- encode_pretty() prior to version 20141223.14.
--
--
-- HANDLING UNICODE LINE AND PARAGRAPH SEPARATORS FOR JAVA
--
-- If the 'stringsAreUtf8' encode option is set to true, consider Lua strings not as a sequence of bytes,
-- but as a sequence of UTF-8 characters.
--
-- Currently, the only practical effect of setting this option is that Unicode LINE and PARAGRAPH
-- separators, if found in a string, are encoded with a JSON escape instead of being dumped as is.
-- The JSON is valid either way, but encoding this way, apparently, allows the resulting JSON
-- to also be valid Java.
--
-- AMBIGUOUS SITUATIONS DURING THE ENCODING
--
-- During the encode, if a Lua table being encoded contains both string
-- and numeric keys, it fits neither JSON's idea of an object, nor its
-- idea of an array. To get around this, when any string key exists (or
-- when non-positive numeric keys exist), numeric keys are converted to
-- strings.
--
-- For example,
-- JSON:encode({ "one", "two", "three", SOMESTRING = "some string" }))
-- produces the JSON object
-- {"1":"one","2":"two","3":"three","SOMESTRING":"some string"}
--
-- To prohibit this conversion and instead make it an error condition, set
-- JSON.noKeyConversion = true
--
--
-- ENCODING JSON NULL VALUES
--
-- Lua tables completely omit keys whose value is nil, so without special handling there's
-- no way to get a field in a JSON object with a null value. For example
-- JSON:encode({ username = "admin", password = nil })
-- produces
-- {"username":"admin"}
--
-- In order to actually produce
-- {"username":"admin", "password":null}
-- one can include a string value for a "null" field in the options table passed to encode()....
-- any Lua table entry with that value becomes null in the JSON output:
-- JSON:encode({ username = "admin", password = "xyzzy" }, nil, { null = "xyzzy" })
-- produces
-- {"username":"admin", "password":null}
--
-- Just be sure to use a string that is otherwise unlikely to appear in your data.
-- The string "\0" (a string with one null byte) may well be appropriate for many applications.
--
-- The "null" options also applies to Lua tables that become JSON arrays.
-- JSON:encode({ "one", "two", nil, nil })
-- produces
-- ["one","two"]
-- while
-- NULL = "\0"
-- JSON:encode({ "one", "two", NULL, NULL}, nil, { null = NULL })
-- produces
-- ["one","two",null,null]
--
--
--
--
-- HANDLING LARGE AND/OR PRECISE NUMBERS
--
--
-- Without special handling, numbers in JSON can lose precision in Lua.
-- For example:
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- produces
--
-- small: number 12345
-- big: number 1.2345678901235e+28
-- precise: number 9876.6789012346
--
-- Precision is lost with both 'big' and 'precise'.
--
-- This package offers ways to try to handle this better (for some definitions of "better")...
--
-- The most precise method is by setting the global:
--
-- JSON.decodeNumbersAsObjects = true
--
-- When this is set, numeric JSON data is encoded into Lua in a form that preserves the exact
-- JSON numeric presentation when re-encoded back out to JSON, or accessed in Lua as a string.
--
-- (This is done by encoding the numeric data with a Lua table/metatable that returns
-- the possibly-imprecise numeric form when accessed numerically, but the original precise
-- representation when accessed as a string. You can also explicitly access
-- via JSON:forceString() and JSON:forceNumber())
--
-- Consider the example above, with this option turned on:
--
-- JSON.decodeNumbersAsObjects = true
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- This now produces:
--
-- small: table 12345
-- big: table 12345678901234567890123456789
-- precise: table 9876.67890123456789012345
--
-- However, within Lua you can still use the values (e.g. T.precise in the example above) in numeric
-- contexts. In such cases you'll get the possibly-imprecise numeric version, but in string contexts
-- and when the data finds its way to this package's encode() function, the original full-precision
-- representation is used.
--
-- Even without using the JSON.decodeNumbersAsObjects option, you can encode numbers
-- in your Lua table that retain high precision upon encoding to JSON, by using the JSON:asNumber()
-- function:
--
-- T = {
-- imprecise = 123456789123456789.123456789123456789,
-- precise = JSON:asNumber("123456789123456789.123456789123456789")
-- }
--
-- print(JSON:encode_pretty(T))
--
-- This produces:
--
-- {
-- "precise": 123456789123456789.123456789123456789,
-- "imprecise": 1.2345678912346e+17
-- }
--
--
--
-- A different way to handle big/precise JSON numbers is to have decode() merely return
-- the exact string representation of the number instead of the number itself.
-- This approach might be useful when the numbers are merely some kind of opaque
-- object identifier and you want to work with them in Lua as strings anyway.
--
-- This approach is enabled by setting
--
-- JSON.decodeIntegerStringificationLength = 10
--
-- The value is the number of digits (of the integer part of the number) at which to stringify numbers.
--
-- Consider our previous example with this option set to 10:
--
-- JSON.decodeIntegerStringificationLength = 10
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- This produces:
--
-- small: number 12345
-- big: string 12345678901234567890123456789
-- precise: number 9876.6789012346
--
-- The long integer of the 'big' field is at least JSON.decodeIntegerStringificationLength digits
-- in length, so it's converted not to a Lua integer but to a Lua string. Using a value of 0 or 1 ensures
-- that all JSON numeric data becomes strings in Lua.
--
-- Note that unlike
-- JSON.decodeNumbersAsObjects = true
-- this stringification is simple and unintelligent: the JSON number simply becomes a Lua string, and that's the end of it.
-- If the string is then converted back to JSON, it's still a string. After running the code above, adding
-- print(JSON:encode(T))
-- produces
-- {"big":"12345678901234567890123456789","precise":9876.6789012346,"small":12345}
-- which is unlikely to be desired.
--
-- There's a comparable option for the length of the decimal part of a number:
--
-- JSON.decodeDecimalStringificationLength
--
-- This can be used alone or in conjunction with
--
-- JSON.decodeIntegerStringificationLength
--
-- to trip stringification on precise numbers with at least JSON.decodeIntegerStringificationLength digits after
-- the decimal point.
--
-- This example:
--
-- JSON.decodeIntegerStringificationLength = 10
-- JSON.decodeDecimalStringificationLength = 5
--
-- T = JSON:decode('{ "small":12345, "big":12345678901234567890123456789, "precise":9876.67890123456789012345 }')
--
-- print("small: ", type(T.small), T.small)
-- print("big: ", type(T.big), T.big)
-- print("precise: ", type(T.precise), T.precise)
--
-- produces:
--
-- small: number 12345
-- big: string 12345678901234567890123456789
-- precise: string 9876.67890123456789012345
--
--
--
--
--
-- SUMMARY OF METHODS YOU CAN OVERRIDE IN YOUR LOCAL LUA JSON OBJECT
--
-- assert
-- onDecodeError
-- onDecodeOfNilError
-- onDecodeOfHTMLError
-- onTrailingGarbage
-- onEncodeError
--
-- If you want to create a separate Lua JSON object with its own error handlers,
-- you can reload JSON.lua or use the :new() method.
--
---------------------------------------------------------------------------
local default_pretty_indent = " "
local default_pretty_options = { pretty = true, align_keys = false, indent = default_pretty_indent }
local isArray = { __tostring = function() return "JSON array" end } isArray.__index = isArray
local isObject = { __tostring = function() return "JSON object" end } isObject.__index = isObject
function OBJDEF:newArray(tbl)
return setmetatable(tbl or {}, isArray)
end
function OBJDEF:newObject(tbl)
return setmetatable(tbl or {}, isObject)
end
local function getnum(op)
return type(op) == 'number' and op or op.N
end
local isNumber = {
__tostring = function(T) return T.S end,
__unm = function(op) return getnum(op) end,
__concat = function(op1, op2) return tostring(op1) .. tostring(op2) end,
__add = function(op1, op2) return getnum(op1) + getnum(op2) end,
__sub = function(op1, op2) return getnum(op1) - getnum(op2) end,
__mul = function(op1, op2) return getnum(op1) * getnum(op2) end,
__div = function(op1, op2) return getnum(op1) / getnum(op2) end,
__mod = function(op1, op2) return getnum(op1) % getnum(op2) end,
__pow = function(op1, op2) return getnum(op1) ^ getnum(op2) end,
__lt = function(op1, op2) return getnum(op1) < getnum(op2) end,
__eq = function(op1, op2) return getnum(op1) == getnum(op2) end,
__le = function(op1, op2) return getnum(op1) <= getnum(op2) end,
}
isNumber.__index = isNumber
function OBJDEF:asNumber(item)
if getmetatable(item) == isNumber then
-- it's already a JSON number object.
return item
elseif type(item) == 'table' and type(item.S) == 'string' and type(item.N) == 'number' then
-- it's a number-object table that lost its metatable, so give it one
return setmetatable(item, isNumber)
else
-- the normal situation... given a number or a string representation of a number....
local holder = {
S = tostring(item), -- S is the representation of the number as a string, which remains precise
N = tonumber(item), -- N is the number as a Lua number.
}
return setmetatable(holder, isNumber)
end
end
--
-- Given an item that might be a normal string or number, or might be an 'isNumber' object defined above,
-- return the string version. This shouldn't be needed often because the 'isNumber' object should autoconvert
-- to a string in most cases, but it's here to allow it to be forced when needed.
--
function OBJDEF:forceString(item)
if type(item) == 'table' and type(item.S) == 'string' then
return item.S
else
return tostring(item)
end
end
--
-- Given an item that might be a normal string or number, or might be an 'isNumber' object defined above,
-- return the numeric version.
--
function OBJDEF:forceNumber(item)
if type(item) == 'table' and type(item.N) == 'number' then
return item.N
else
return tonumber(item)
end
end
local function unicode_codepoint_as_utf8(codepoint)
--
-- codepoint is a number
--
if codepoint <= 127 then
return string.char(codepoint)
elseif codepoint <= 2047 then
--
-- 110yyyxx 10xxxxxx <-- useful notation from http://en.wikipedia.org/wiki/Utf8
--
local highpart = math.floor(codepoint / 0x40)
local lowpart = codepoint - (0x40 * highpart)
return string.char(0xC0 + highpart,
0x80 + lowpart)
elseif codepoint <= 65535 then
--
-- 1110yyyy 10yyyyxx 10xxxxxx
--
local highpart = math.floor(codepoint / 0x1000)
local remainder = codepoint - 0x1000 * highpart
local midpart = math.floor(remainder / 0x40)
local lowpart = remainder - 0x40 * midpart
highpart = 0xE0 + highpart
midpart = 0x80 + midpart
lowpart = 0x80 + lowpart
--
-- Check for an invalid character (thanks Andy R. at Adobe).
-- See table 3.7, page 93, in http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf#G28070
--
if ( highpart == 0xE0 and midpart < 0xA0 ) or
( highpart == 0xED and midpart > 0x9F ) or
( highpart == 0xF0 and midpart < 0x90 ) or
( highpart == 0xF4 and midpart > 0x8F )
then
return "?"
else
return string.char(highpart,
midpart,
lowpart)
end
else
--
-- 11110zzz 10zzyyyy 10yyyyxx 10xxxxxx
--
local highpart = math.floor(codepoint / 0x40000)
local remainder = codepoint - 0x40000 * highpart
local midA = math.floor(remainder / 0x1000)
remainder = remainder - 0x1000 * midA
local midB = math.floor(remainder / 0x40)
local lowpart = remainder - 0x40 * midB
return string.char(0xF0 + highpart,
0x80 + midA,
0x80 + midB,
0x80 + lowpart)
end
end
function OBJDEF:onDecodeError(message, text, location, etc)
if text then
if location then
message = string.format("%s at byte %d of: %s", message, location, text)
else
message = string.format("%s: %s", message, text)
end
end
if etc ~= nil then
message = message .. " (" .. OBJDEF:encode(etc) .. ")"
end
if self.assert then
self.assert(false, message)
else
assert(false, message)
end
end
function OBJDEF:onTrailingGarbage(json_text, location, parsed_value, etc)
return self:onDecodeError("trailing garbage", json_text, location, etc)
end
OBJDEF.onDecodeOfNilError = OBJDEF.onDecodeError
OBJDEF.onDecodeOfHTMLError = OBJDEF.onDecodeError
function OBJDEF:onEncodeError(message, etc)
if etc ~= nil then
message = message .. " (" .. OBJDEF:encode(etc) .. ")"
end
if self.assert then
self.assert(false, message)
else
assert(false, message)
end
end
local function grok_number(self, text, start, options)
--
-- Grab the integer part
--
local integer_part = text:match('^-?[1-9]%d*', start)
or text:match("^-?0", start)
if not integer_part then
self:onDecodeError("expected number", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local i = start + integer_part:len()
--
-- Grab an optional decimal part
--
local decimal_part = text:match('^%.%d+', i) or ""
i = i + decimal_part:len()
--
-- Grab an optional exponential part
--
local exponent_part = text:match('^[eE][-+]?%d+', i) or ""
i = i + exponent_part:len()
local full_number_text = integer_part .. decimal_part .. exponent_part
if options.decodeNumbersAsObjects then
return OBJDEF:asNumber(full_number_text), i
end
--
-- If we're told to stringify under certain conditions, so do.
-- We punt a bit when there's an exponent by just stringifying no matter what.
-- I suppose we should really look to see whether the exponent is actually big enough one
-- way or the other to trip stringification, but I'll be lazy about it until someone asks.
--
if (options.decodeIntegerStringificationLength
and
(integer_part:len() >= options.decodeIntegerStringificationLength or exponent_part:len() > 0))
or
(options.decodeDecimalStringificationLength
and
(decimal_part:len() >= options.decodeDecimalStringificationLength or exponent_part:len() > 0))
then
return full_number_text, i -- this returns the exact string representation seen in the original JSON
end
local as_number = tonumber(full_number_text)
if not as_number then
self:onDecodeError("bad number", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
return as_number, i
end
local function grok_string(self, text, start, options)
if text:sub(start,start) ~= '"' then
self:onDecodeError("expected string's opening quote", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local i = start + 1 -- +1 to bypass the initial quote
local text_len = text:len()
local VALUE = ""
while i <= text_len do
local c = text:sub(i,i)
if c == '"' then
return VALUE, i + 1
end
if c ~= '\\' then
VALUE = VALUE .. c
i = i + 1
elseif text:match('^\\b', i) then
VALUE = VALUE .. "\b"
i = i + 2
elseif text:match('^\\f', i) then
VALUE = VALUE .. "\f"
i = i + 2
elseif text:match('^\\n', i) then
VALUE = VALUE .. "\n"
i = i + 2
elseif text:match('^\\r', i) then
VALUE = VALUE .. "\r"
i = i + 2
elseif text:match('^\\t', i) then
VALUE = VALUE .. "\t"
i = i + 2
else
local hex = text:match('^\\u([0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF])', i)
if hex then
i = i + 6 -- bypass what we just read
-- We have a Unicode codepoint. It could be standalone, or if in the proper range and
-- followed by another in a specific range, it'll be a two-code surrogate pair.
local codepoint = tonumber(hex, 16)
if codepoint >= 0xD800 and codepoint <= 0xDBFF then
-- it's a hi surrogate... see whether we have a following low
local lo_surrogate = text:match('^\\u([dD][cdefCDEF][0123456789aAbBcCdDeEfF][0123456789aAbBcCdDeEfF])', i)
if lo_surrogate then
i = i + 6 -- bypass the low surrogate we just read
codepoint = 0x2400 + (codepoint - 0xD800) * 0x400 + tonumber(lo_surrogate, 16)
else
-- not a proper low, so we'll just leave the first codepoint as is and spit it out.
end
end
VALUE = VALUE .. unicode_codepoint_as_utf8(codepoint)
else
-- just pass through what's escaped
VALUE = VALUE .. text:match('^\\(.)', i)
i = i + 2
end
end
end
self:onDecodeError("unclosed string", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local function skip_whitespace(text, start)
local _, match_end = text:find("^[ \n\r\t]+", start) -- [http://www.ietf.org/rfc/rfc4627.txt] Section 2
if match_end then
return match_end + 1
else
return start
end
end
local grok_one -- assigned later
local function grok_object(self, text, start, options)
if text:sub(start,start) ~= '{' then
self:onDecodeError("expected '{'", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local i = skip_whitespace(text, start + 1) -- +1 to skip the '{'
local VALUE = self.strictTypes and self:newObject { } or { }
if text:sub(i,i) == '}' then
return VALUE, i + 1
end
local text_len = text:len()
while i <= text_len do
local key, new_i = grok_string(self, text, i, options)
i = skip_whitespace(text, new_i)
if text:sub(i, i) ~= ':' then
self:onDecodeError("expected colon", text, i, options.etc)
return nil, i -- in case the error method doesn't abort, return something sensible
end
i = skip_whitespace(text, i + 1)
local new_val, new_i = grok_one(self, text, i, options)
VALUE[key] = new_val
--
-- Expect now either '}' to end things, or a ',' to allow us to continue.
--
i = skip_whitespace(text, new_i)
local c = text:sub(i,i)
if c == '}' then
return VALUE, i + 1
end
if text:sub(i, i) ~= ',' then
self:onDecodeError("expected comma or '}'", text, i, options.etc)
return nil, i -- in case the error method doesn't abort, return something sensible
end
i = skip_whitespace(text, i + 1)
end
self:onDecodeError("unclosed '{'", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local function grok_array(self, text, start, options)
if text:sub(start,start) ~= '[' then
self:onDecodeError("expected '['", text, start, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
local i = skip_whitespace(text, start + 1) -- +1 to skip the '['
local VALUE = self.strictTypes and self:newArray { } or { }
if text:sub(i,i) == ']' then
return VALUE, i + 1
end
local VALUE_INDEX = 1
local text_len = text:len()
while i <= text_len do
local val, new_i = grok_one(self, text, i, options)
-- can't table.insert(VALUE, val) here because it's a no-op if val is nil
VALUE[VALUE_INDEX] = val
VALUE_INDEX = VALUE_INDEX + 1
i = skip_whitespace(text, new_i)
--
-- Expect now either ']' to end things, or a ',' to allow us to continue.
--
local c = text:sub(i,i)
if c == ']' then
return VALUE, i + 1
end
if text:sub(i, i) ~= ',' then
self:onDecodeError("expected comma or ']'", text, i, options.etc)
return nil, i -- in case the error method doesn't abort, return something sensible
end
i = skip_whitespace(text, i + 1)
end
self:onDecodeError("unclosed '['", text, start, options.etc)
return nil, i -- in case the error method doesn't abort, return something sensible
end
grok_one = function(self, text, start, options)
-- Skip any whitespace
start = skip_whitespace(text, start)
if start > text:len() then
self:onDecodeError("unexpected end of string", text, nil, options.etc)
return nil, start -- in case the error method doesn't abort, return something sensible
end
if text:find('^"', start) then
return grok_string(self, text, start, options.etc)
elseif text:find('^[-0123456789 ]', start) then
return grok_number(self, text, start, options)
elseif text:find('^%{', start) then
return grok_object(self, text, start, options)
elseif text:find('^%[', start) then
return grok_array(self, text, start, options)
elseif text:find('^true', start) then
return true, start + 4
elseif text:find('^false', start) then
return false, start + 5
elseif text:find('^null', start) then
return nil, start + 4
else
self:onDecodeError("can't parse JSON", text, start, options.etc)
return nil, 1 -- in case the error method doesn't abort, return something sensible
end
end
function OBJDEF:decode(text, etc, options)
--
-- If the user didn't pass in a table of decode options, make an empty one.
--
if type(options) ~= 'table' then
options = {}
end
--
-- If they passed in an 'etc' argument, stuff it into the options.
-- (If not, any 'etc' field in the options they passed in remains to be used)
--
if etc ~= nil then
options.etc = etc
end
if type(self) ~= 'table' or self.__index ~= OBJDEF then
local error_message = "JSON:decode must be called in method format"
OBJDEF:onDecodeError(error_message, nil, nil, options.etc)
return nil, error_message -- in case the error method doesn't abort, return something sensible
end
if text == nil then
local error_message = "nil passed to JSON:decode()"
self:onDecodeOfNilError(error_message, nil, nil, options.etc)
return nil, error_message -- in case the error method doesn't abort, return something sensible
elseif type(text) ~= 'string' then
local error_message = "expected string argument to JSON:decode()"
self:onDecodeError(string.format("%s, got %s", error_message, type(text)), nil, nil, options.etc)
return nil, error_message -- in case the error method doesn't abort, return something sensible
end
if text:match('^%s*$') then
-- an empty string is nothing, but not an error
return nil
end
if text:match('^%s*<') then
-- Can't be JSON... we'll assume it's HTML
local error_message = "HTML passed to JSON:decode()"
self:onDecodeOfHTMLError(error_message, text, nil, options.etc)
return nil, error_message -- in case the error method doesn't abort, return something sensible
end
--
-- Ensure that it's not UTF-32 or UTF-16.
-- Those are perfectly valid encodings for JSON (as per RFC 4627 section 3),
-- but this package can't handle them.
--
if text:sub(1,1):byte() == 0 or (text:len() >= 2 and text:sub(2,2):byte() == 0) then
local error_message = "JSON package groks only UTF-8, sorry"
self:onDecodeError(error_message, text, nil, options.etc)
return nil, error_message -- in case the error method doesn't abort, return something sensible
end
--
-- apply global options
--
if options.decodeNumbersAsObjects == nil then
options.decodeNumbersAsObjects = self.decodeNumbersAsObjects
end
if options.decodeIntegerStringificationLength == nil then
options.decodeIntegerStringificationLength = self.decodeIntegerStringificationLength
end
if options.decodeDecimalStringificationLength == nil then
options.decodeDecimalStringificationLength = self.decodeDecimalStringificationLength
end
--
-- Finally, go parse it
--
local success, value, next_i = pcall(grok_one, self, text, 1, options)
if success then
local error_message = nil
if next_i ~= #text + 1 then
-- something's left over after we parsed the first thing.... whitespace is allowed.
next_i = skip_whitespace(text, next_i)
-- if we have something left over now, it's trailing garbage
if next_i ~= #text + 1 then
value, error_message = self:onTrailingGarbage(text, next_i, value, options.etc)
end
end
return value, error_message
else
-- If JSON:onDecodeError() didn't abort out of the pcall, we'll have received
-- the error message here as "value", so pass it along as an assert.
local error_message = value
if self.assert then
self.assert(false, error_message)
else
assert(false, error_message)
end
-- ...and if we're still here (because the assert didn't throw an error),
-- return a nil and throw the error message on as a second arg
return nil, error_message
end
end
local function backslash_replacement_function(c)
if c == "\n" then
return "\\n"
elseif c == "\r" then
return "\\r"
elseif c == "\t" then
return "\\t"
elseif c == "\b" then
return "\\b"
elseif c == "\f" then
return "\\f"
elseif c == '"' then
return '\\"'
elseif c == '\\' then
return '\\\\'
else
return string.format("\\u%04x", c:byte())
end
end
local chars_to_be_escaped_in_JSON_string
= '['
.. '"' -- class sub-pattern to match a double quote
.. '%\\' -- class sub-pattern to match a backslash
.. '%z' -- class sub-pattern to match a null
.. '\001' .. '-' .. '\031' -- class sub-pattern to match control characters
.. ']'
local LINE_SEPARATOR_as_utf8 = unicode_codepoint_as_utf8(0x2028)
local PARAGRAPH_SEPARATOR_as_utf8 = unicode_codepoint_as_utf8(0x2029)
local function json_string_literal(value, options)
local newval = value:gsub(chars_to_be_escaped_in_JSON_string, backslash_replacement_function)
if options.stringsAreUtf8 then
--
-- This feels really ugly to just look into a string for the sequence of bytes that we know to be a particular utf8 character,
-- but utf8 was designed purposefully to make this kind of thing possible. Still, feels dirty.
-- I'd rather decode the byte stream into a character stream, but it's not technically needed so
-- not technically worth it.
--
newval = newval:gsub(LINE_SEPARATOR_as_utf8, '\\u2028'):gsub(PARAGRAPH_SEPARATOR_as_utf8,'\\u2029')
end
return '"' .. newval .. '"'
end
local function object_or_array(self, T, etc)
--
-- We need to inspect all the keys... if there are any strings, we'll convert to a JSON
-- object. If there are only numbers, it's a JSON array.
--
-- If we'll be converting to a JSON object, we'll want to sort the keys so that the
-- end result is deterministic.
--
local string_keys = { }
local number_keys = { }
local number_keys_must_be_strings = false
local maximum_number_key
for key in pairs(T) do
if type(key) == 'string' then
table.insert(string_keys, key)
elseif type(key) == 'number' then
table.insert(number_keys, key)
if key <= 0 or key >= math.huge then
number_keys_must_be_strings = true
elseif not maximum_number_key or key > maximum_number_key then
maximum_number_key = key
end
else
self:onEncodeError("can't encode table with a key of type " .. type(key), etc)
end
end
if #string_keys == 0 and not number_keys_must_be_strings then
--
-- An empty table, or a numeric-only array
--
if #number_keys > 0 then
return nil, maximum_number_key -- an array
elseif tostring(T) == "JSON array" then
return nil
elseif tostring(T) == "JSON object" then
return { }
else
-- have to guess, so we'll pick array, since empty arrays are likely more common than empty objects
return nil
end
end
table.sort(string_keys)
local map
if #number_keys > 0 then
--
-- If we're here then we have either mixed string/number keys, or numbers inappropriate for a JSON array
-- It's not ideal, but we'll turn the numbers into strings so that we can at least create a JSON object.
--
if self.noKeyConversion then
self:onEncodeError("a table with both numeric and string keys could be an object or array; aborting", etc)
end
--
-- Have to make a shallow copy of the source table so we can remap the numeric keys to be strings
--
map = { }
for key, val in pairs(T) do
map[key] = val
end
table.sort(number_keys)
--
-- Throw numeric keys in there as strings
--
for _, number_key in ipairs(number_keys) do
local string_key = tostring(number_key)
if map[string_key] == nil then
table.insert(string_keys , string_key)
map[string_key] = T[number_key]
else
self:onEncodeError("conflict converting table with mixed-type keys into a JSON object: key " .. number_key .. " exists both as a string and a number.", etc)
end
end
end
return string_keys, nil, map
end
--
-- Encode
--
-- 'options' is nil, or a table with possible keys:
--
-- pretty -- If true, return a pretty-printed version.
--
-- indent -- A string (usually of spaces) used to indent each nested level.
--
-- align_keys -- If true, align all the keys when formatting a table.
--
-- null -- If this exists with a string value, table elements with this value are output as JSON null.
--
-- stringsAreUtf8 -- If true, consider Lua strings not as a sequence of bytes, but as a sequence of UTF-8 characters.
-- (Currently, the only practical effect of setting this option is that Unicode LINE and PARAGRAPH
-- separators, if found in a string, are encoded with a JSON escape instead of as raw UTF-8.
-- The JSON is valid either way, but encoding this way, apparently, allows the resulting JSON
-- to also be valid Java.)
--
--
local encode_value -- must predeclare because it calls itself
function encode_value(self, value, parents, etc, options, indent, for_key)
--
-- keys in a JSON object can never be null, so we don't even consider options.null when converting a key value
--
if value == nil or (not for_key and options and options.null and value == options.null) then
return 'null'
elseif type(value) == 'string' then
return json_string_literal(value, options)
elseif type(value) == 'number' then
if value ~= value then
--
-- NaN (Not a Number).
-- JSON has no NaN, so we have to fudge the best we can. This should really be a package option.
--
return "null"
elseif value >= math.huge then
--
-- Positive infinity. JSON has no INF, so we have to fudge the best we can. This should
-- really be a package option. Note: at least with some implementations, positive infinity
-- is both ">= math.huge" and "<= -math.huge", which makes no sense but that's how it is.
-- Negative infinity is properly "<= -math.huge". So, we must be sure to check the ">="
-- case first.
--
return "1e+9999"
elseif value <= -math.huge then
--
-- Negative infinity.
-- JSON has no INF, so we have to fudge the best we can. This should really be a package option.
--
return "-1e+9999"
else
return tostring(value)
end
elseif type(value) == 'boolean' then
return tostring(value)
elseif type(value) ~= 'table' then
self:onEncodeError("can't convert " .. type(value) .. " to JSON", etc)
elseif getmetatable(value) == isNumber then
return tostring(value)
else
--
-- A table to be converted to either a JSON object or array.
--
local T = value
if type(options) ~= 'table' then
options = {}
end
if type(indent) ~= 'string' then
indent = ""
end
if parents[T] then
self:onEncodeError("table " .. tostring(T) .. " is a child of itself", etc)
else
parents[T] = true
end
local result_value
local object_keys, maximum_number_key, map = object_or_array(self, T, etc)
if maximum_number_key then
--
-- An array...
--
local ITEMS = { }
for i = 1, maximum_number_key do
table.insert(ITEMS, encode_value(self, T[i], parents, etc, options, indent))
end
if options.pretty then
result_value = "[ " .. table.concat(ITEMS, ", ") .. " ]"
else
result_value = "[" .. table.concat(ITEMS, ",") .. "]"
end
elseif object_keys then
--
-- An object
--
local TT = map or T
if options.pretty then
local KEYS = { }
local max_key_length = 0
for _, key in ipairs(object_keys) do
local encoded = encode_value(self, tostring(key), parents, etc, options, indent, true)
if options.align_keys then
max_key_length = math.max(max_key_length, #encoded)
end
table.insert(KEYS, encoded)
end
local key_indent = indent .. tostring(options.indent or "")
local subtable_indent = key_indent .. string.rep(" ", max_key_length) .. (options.align_keys and " " or "")
local FORMAT = "%s%" .. string.format("%d", max_key_length) .. "s: %s"
local COMBINED_PARTS = { }
for i, key in ipairs(object_keys) do
local encoded_val = encode_value(self, TT[key], parents, etc, options, subtable_indent)
table.insert(COMBINED_PARTS, string.format(FORMAT, key_indent, KEYS[i], encoded_val))
end
result_value = "{\n" .. table.concat(COMBINED_PARTS, ",\n") .. "\n" .. indent .. "}"
else
local PARTS = { }
for _, key in ipairs(object_keys) do
local encoded_val = encode_value(self, TT[key], parents, etc, options, indent)
local encoded_key = encode_value(self, tostring(key), parents, etc, options, indent, true)
table.insert(PARTS, string.format("%s:%s", encoded_key, encoded_val))
end
result_value = "{" .. table.concat(PARTS, ",") .. "}"
end
else
--
-- An empty array/object... we'll treat it as an array, though it should really be an option
--
result_value = "[]"
end
parents[T] = false
return result_value
end
end
local function top_level_encode(self, value, etc, options)
local val = encode_value(self, value, {}, etc, options)
if val == nil then
--PRIVATE("may need to revert to the previous public verison if I can't figure out what the guy wanted")
return val
else
return val
end
end
function OBJDEF:encode(value, etc, options)
if type(self) ~= 'table' or self.__index ~= OBJDEF then
OBJDEF:onEncodeError("JSON:encode must be called in method format", etc)
end
--
-- If the user didn't pass in a table of decode options, make an empty one.
--
if type(options) ~= 'table' then
options = {}
end
return top_level_encode(self, value, etc, options)
end
function OBJDEF:encode_pretty(value, etc, options)
if type(self) ~= 'table' or self.__index ~= OBJDEF then
OBJDEF:onEncodeError("JSON:encode_pretty must be called in method format", etc)
end
--
-- If the user didn't pass in a table of decode options, use the default pretty ones
--
if type(options) ~= 'table' then
options = default_pretty_options
end
return top_level_encode(self, value, etc, options)
end
function OBJDEF.__tostring()
return "JSON encode/decode package"
end
OBJDEF.__index = OBJDEF
function OBJDEF:new(args)
local new = { }
if args then
for key, val in pairs(args) do
new[key] = val
end
end
return setmetatable(new, OBJDEF)
end
return OBJDEF:new()
--
-- Version history:
--
-- 20161109.21 Oops, had a small boo-boo in the previous update.
--
-- 20161103.20 Used to silently ignore trailing garbage when decoding. Now fails via JSON:onTrailingGarbage()
-- http://seriot.ch/parsing_json.php
--
-- Built-in error message about "expected comma or ']'" had mistakenly referred to '['
--
-- Updated the built-in error reporting to refer to bytes rather than characters.
--
-- The decode() method no longer assumes that error handlers abort.
--
-- Made the VERSION string a string instead of a number
--
-- 20160916.19 Fixed the isNumber.__index assignment (thanks to Jack Taylor)
--
-- 20160730.18 Added JSON:forceString() and JSON:forceNumber()
--
-- 20160728.17 Added concatenation to the metatable for JSON:asNumber()
--
-- 20160709.16 Could crash if not passed an options table (thanks jarno heikkinen <jarnoh@capturemonkey.com>).
--
-- Made JSON:asNumber() a bit more resilient to being passed the results of itself.
--
-- 20160526.15 Added the ability to easily encode null values in JSON, via the new "null" encoding option.
-- (Thanks to Adam B for bringing up the issue.)
--
-- Added some support for very large numbers and precise floats via
-- JSON.decodeNumbersAsObjects
-- JSON.decodeIntegerStringificationLength
-- JSON.decodeDecimalStringificationLength
--
-- Added the "stringsAreUtf8" encoding option. (Hat tip to http://lua-users.org/wiki/JsonModules )
--
-- 20141223.14 The encode_pretty() routine produced fine results for small datasets, but isn't really
-- appropriate for anything large, so with help from Alex Aulbach I've made the encode routines
-- more flexible, and changed the default encode_pretty() to be more generally useful.
--
-- Added a third 'options' argument to the encode() and encode_pretty() routines, to control
-- how the encoding takes place.
--
-- Updated docs to add assert() call to the loadfile() line, just as good practice so that
-- if there is a problem loading JSON.lua, the appropriate error message will percolate up.
--
-- 20140920.13 Put back (in a way that doesn't cause warnings about unused variables) the author string,
-- so that the source of the package, and its version number, are visible in compiled copies.
--
-- 20140911.12 Minor lua cleanup.
-- Fixed internal reference to 'JSON.noKeyConversion' to reference 'self' instead of 'JSON'.
-- (Thanks to SmugMug's David Parry for these.)
--
-- 20140418.11 JSON nulls embedded within an array were being ignored, such that
-- ["1",null,null,null,null,null,"seven"],
-- would return
-- {1,"seven"}
-- It's now fixed to properly return
-- {1, nil, nil, nil, nil, nil, "seven"}
-- Thanks to "haddock" for catching the error.
--
-- 20140116.10 The user's JSON.assert() wasn't always being used. Thanks to "blue" for the heads up.
--
-- 20131118.9 Update for Lua 5.3... it seems that tostring(2/1) produces "2.0" instead of "2",
-- and this caused some problems.
--
-- 20131031.8 Unified the code for encode() and encode_pretty(); they had been stupidly separate,
-- and had of course diverged (encode_pretty didn't get the fixes that encode got, so
-- sometimes produced incorrect results; thanks to Mattie for the heads up).
--
-- Handle encoding tables with non-positive numeric keys (unlikely, but possible).
--
-- If a table has both numeric and string keys, or its numeric keys are inappropriate
-- (such as being non-positive or infinite), the numeric keys are turned into
-- string keys appropriate for a JSON object. So, as before,
-- JSON:encode({ "one", "two", "three" })
-- produces the array
-- ["one","two","three"]
-- but now something with mixed key types like
-- JSON:encode({ "one", "two", "three", SOMESTRING = "some string" }))
-- instead of throwing an error produces an object:
-- {"1":"one","2":"two","3":"three","SOMESTRING":"some string"}
--
-- To maintain the prior throw-an-error semantics, set
-- JSON.noKeyConversion = true
--
-- 20131004.7 Release under a Creative Commons CC-BY license, which I should have done from day one, sorry.
--
-- 20130120.6 Comment update: added a link to the specific page on my blog where this code can
-- be found, so that folks who come across the code outside of my blog can find updates
-- more easily.
--
-- 20111207.5 Added support for the 'etc' arguments, for better error reporting.
--
-- 20110731.4 More feedback from David Kolf on how to make the tests for Nan/Infinity system independent.
--
-- 20110730.3 Incorporated feedback from David Kolf at http://lua-users.org/wiki/JsonModules:
--
-- * When encoding lua for JSON, Sparse numeric arrays are now handled by
-- spitting out full arrays, such that
-- JSON:encode({"one", "two", [10] = "ten"})
-- returns
-- ["one","two",null,null,null,null,null,null,null,"ten"]
--
-- In 20100810.2 and earlier, only up to the first non-null value would have been retained.
--
-- * When encoding lua for JSON, numeric value NaN gets spit out as null, and infinity as "1+e9999".
-- Version 20100810.2 and earlier created invalid JSON in both cases.
--
-- * Unicode surrogate pairs are now detected when decoding JSON.
--
-- 20100810.2 added some checking to ensure that an invalid Unicode character couldn't leak in to the UTF-8 encoding
--
-- 20100731.1 initial public release
--
