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code /
prosody-modules
Changeset
349:ee99eafdd168
mod_json_streams: An implementation of XEP-0295: JSON Encodings for XMPP.
author | Waqas Hussain <waqas20@gmail.com> |
---|---|
date | Sat, 02 Apr 2011 00:04:26 +0500 (2011-04-01) |
parents | 348:03e1dc036a28 |
children | 350:98569ec25ac2 |
files | mod_json_streams/mod_json_streams.lua |
diffstat | 1 files changed, 123 insertions(+), 0 deletions(-) [+] |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mod_json_streams/mod_json_streams.lua Sat Apr 02 00:04:26 2011 +0500 @@ -0,0 +1,123 @@ +-- +-- XEP-0295: JSON Encodings for XMPP +-- + +module.host = "*" + +local filters = require "util.filters" +local json = require "util.json" + +local json_escapes = { + ["\""] = "\\\"", ["\\"] = "\\\\", ["\b"] = "\\b", ["\f"] = "\\f", + ["\n"] = "\\n", ["\r"] = "\\r", ["\t"] = "\\t"}; + +local s_char = string.char; +for i=0,31 do + local ch = s_char(i); + if not json_escapes[ch] then json_escapes[ch] = ("\\u%.4X"):format(i); end +end + +local state_out = 0; +local state_key_before = 1; +local state_key_in = 2; +local state_key_escape = 3; +local state_key_after = 4; +local state_val_before = 5; +local state_val_in = 6; +local state_val_escape = 7; +local state_val_after = 8; + +local whitespace = { [" "] = true, ["\n"] = true, ["\r"] = true, ["\t"] = true }; +function json_decoder() + local state = state_out; + local quote; + local output = ""; + local buffer = ""; + return function(input) + for ch in input:gmatch(".") do + module:log("debug", "%s | %d", ch, state) + local final = false; + if state == state_out then + if whitespace[ch] then + elseif ch ~= "{" then return nil, "{ expected"; + else state = state_key_before end + elseif state == state_key_before then + if whitespace[ch] then + elseif ch ~= "'" and ch ~= "\"" then return nil, "\" expected"; + else quote = ch; state = state_key_in; end + elseif state == state_key_in then + if ch == quote then state = state_key_after; + elseif ch ~= "s" then return nil, "invalid key, 's' expected"; -- only s as key allowed + else end -- ignore key + elseif state == state_key_after then + if whitespace[ch] then + elseif ch ~= ":" then return nil, ": expected"; + else state = state_val_before; end + elseif state == state_val_before then + if whitespace[ch] then + elseif ch ~= "'" and ch ~= "\"" then return nil, "\" expected"; + else quote = ch; state = state_val_in; end + elseif state == state_val_in then + if ch == quote then state = state_val_after; + elseif ch == "\\" then state = state_val_escape; + else end + elseif state == state_val_after then + if whitespace[ch] then + elseif ch ~= "}" then return nil, "} expected"; + else state = state_out; + final = true; + end + elseif state == state_val_escape then + state = state_val_in; + else + module:log("error", "Unhandled state: "..state); + return nil, "Unhandled state in parser" + end + buffer = buffer..ch; + if final then + module:log("debug", "%s", buffer) + local tmp; + pcall(function() tmp = json.decode(buffer); end); + if not tmp then return nil, "Invalid JSON"; end + output, buffer = output..tmp.s, ""; + end + end + local _ = output; output = ""; + return _; + end; +end + +function filter_hook(session) + local determined = false; + local is_json = false; + local function in_filter(t) + if not determined then + is_json = (t:sub(1,1) == "{") and json_decoder(); + determined = true; + end + if is_json then + local s, err = is_json(t); + if not err then return s; end + session:close("not-well-formed"); + return; + end + return t; + end + local function out_filter(t) + if is_json then + return '{"s":"' .. t:gsub(".", json_escapes) .. '"}'; -- encode + end + return t; + end + filters.add_filter(session, "bytes/in", in_filter, 100); + filters.add_filter(session, "bytes/out", out_filter, 100); +end + +function module.load() + filters.add_filter_hook(filter_hook); +end +function module.unload() + filters.remove_filter_hook(filter_hook); +end + +