# HG changeset patch # User Kim Alvefur # Date 1486302051 -3600 # Node ID c96a53b0b8203d776370ac71ba92e9d037b64c77 # Parent 854aaa1f01b2fb9e29c03859b432c97bb98ebcf4 mod_compression: Import from Prosody, revision 0c69305ab525 diff -r 854aaa1f01b2 -r c96a53b0b820 mod_compression/README.markdown --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mod_compression/README.markdown Sun Feb 05 14:40:51 2017 +0100 @@ -0,0 +1,51 @@ +While the bandwidth usage of XMPP isn't great, compressing the data sent +to/from your server can give significant benefits to those on slow +connections, such as dial-up or mobile networks. Prosody supports +compression for client-to-server (if your client supports it) and +server-to-server streams using the mod\_compression plugin. + +# Details + +mod\_compression implements +[XEP-0138](http://xmpp.org/extensions/xep-0138.html "http://xmpp.org/extensions/xep-0138.html"){.urlextern}, +and supports the zlib compression algorithm. + +## Dependencies + +The XMPP protocol specifies that all clients and servers supporting +compression must support the "zlib" compression method, and this is what +Prosody uses. However you will need to install zlib support for Lua on +your system. There are different ways of doing this depending on your +system. If in doubt whether it is installed correctly, the command \`lua +-lzlib\` in a console should open a Lua prompt with no errors. + +For more information on obtaining lua-zlib for your platform, see our +[dependencies page](/doc/depends#lua-zlib "doc:depends"){.wikilink1}. + +# Usage + +``` lua +modules_enabled = { + -- Other modules + "compression"; -- Enable mod_compression +} +``` + +Configuration +------------- + + Option Default Notes + -------------------- --------- -------------------------------------------------------------------------------------------------------------------- + compression\_level 7 Can be a number from 1 to 9, where 9 is best. Higher compression levels will use more resources but less bandwidth + +Example +------- + +``` lua +modules_enabled = { + -- Other modules + "compression"; -- Enable mod_compression +} +  +compression_level = 5 +``` diff -r 854aaa1f01b2 -r c96a53b0b820 mod_compression/mod_compression.lua --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mod_compression/mod_compression.lua Sun Feb 05 14:40:51 2017 +0100 @@ -0,0 +1,198 @@ +-- Prosody IM +-- Copyright (C) 2009-2012 Tobias Markmann +-- +-- This project is MIT/X11 licensed. Please see the +-- COPYING file in the source package for more information. +-- + +local st = require "util.stanza"; +local zlib = require "zlib"; +local pcall = pcall; +local tostring = tostring; + +local xmlns_compression_feature = "http://jabber.org/features/compress" +local xmlns_compression_protocol = "http://jabber.org/protocol/compress" +local xmlns_stream = "http://etherx.jabber.org/streams"; +local compression_stream_feature = st.stanza("compression", {xmlns=xmlns_compression_feature}):tag("method"):text("zlib"):up(); +local add_filter = require "util.filters".add_filter; + +local compression_level = module:get_option_number("compression_level", 7); + +if not compression_level or compression_level < 1 or compression_level > 9 then + module:log("warn", "Invalid compression level in config: %s", tostring(compression_level)); + module:log("warn", "Module loading aborted. Compression won't be available."); + return; +end + +module:hook("stream-features", function(event) + local origin, features = event.origin, event.features; + if not origin.compressed and origin.type == "c2s" then + features:add_child(compression_stream_feature); + end +end); + +module:hook("s2s-stream-features", function(event) + local origin, features = event.origin, event.features; + if not origin.compressed and origin.type == "s2sin" then + features:add_child(compression_stream_feature); + end +end); + +-- Hook to activate compression if remote server supports it. +module:hook_stanza(xmlns_stream, "features", + function (session, stanza) + if not session.compressed and session.type == "s2sout" then + -- does remote server support compression? + local comp_st = stanza:get_child("compression", xmlns_compression_feature); + if comp_st then + -- do we support the mechanism + for a in comp_st:childtags("method") do + local algorithm = a:get_text(); + if algorithm == "zlib" then + session.sends2s(st.stanza("compress", {xmlns=xmlns_compression_protocol}):tag("method"):text("zlib")) + session.log("debug", "Enabled compression using zlib.") + return true; + end + end + session.log("debug", "Remote server supports no compression algorithm we support.") + end + end + end +, 250); + + +-- returns either nil or a fully functional ready to use inflate stream +local function get_deflate_stream(session) + local status, deflate_stream = pcall(zlib.deflate, compression_level); + if status == false then + local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"); + (session.sends2s or session.send)(error_st); + session.log("error", "Failed to create zlib.deflate filter."); + module:log("error", "%s", tostring(deflate_stream)); + return + end + return deflate_stream +end + +-- returns either nil or a fully functional ready to use inflate stream +local function get_inflate_stream(session) + local status, inflate_stream = pcall(zlib.inflate); + if status == false then + local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"); + (session.sends2s or session.send)(error_st); + session.log("error", "Failed to create zlib.inflate filter."); + module:log("error", "%s", tostring(inflate_stream)); + return + end + return inflate_stream +end + +-- setup compression for a stream +local function setup_compression(session, deflate_stream) + add_filter(session, "bytes/out", function(t) + local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync'); + if status == false then + module:log("warn", "%s", tostring(compressed)); + session:close({ + condition = "undefined-condition"; + text = compressed; + extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed"); + }); + return; + end + return compressed; + end); +end + +-- setup decompression for a stream +local function setup_decompression(session, inflate_stream) + add_filter(session, "bytes/in", function(data) + local status, decompressed, eof = pcall(inflate_stream, data); + if status == false then + module:log("warn", "%s", tostring(decompressed)); + session:close({ + condition = "undefined-condition"; + text = decompressed; + extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed"); + }); + return; + end + return decompressed; + end); +end + +module:hook("stanza/http://jabber.org/protocol/compress:compressed", function(event) + local session = event.origin; + + if session.type == "s2sout" then + session.log("debug", "Activating compression...") + -- create deflate and inflate streams + local deflate_stream = get_deflate_stream(session); + if not deflate_stream then return true; end + + local inflate_stream = get_inflate_stream(session); + if not inflate_stream then return true; end + + -- setup compression for session.w + setup_compression(session, deflate_stream); + + -- setup decompression for session.data + setup_decompression(session, inflate_stream); + session:reset_stream(); + session:open_stream(session.from_host, session.to_host); + session.compressed = true; + return true; + end +end); + +module:hook("stanza/http://jabber.org/protocol/compress:failure", function(event) + local err = event.stanza:get_child(); + (event.origin.log or module._log)("warn", "Compression setup failed (%s)", err and err.name or "unknown reason"); + return true; +end); + +module:hook("stanza/http://jabber.org/protocol/compress:compress", function(event) + local session, stanza = event.origin, event.stanza; + + if session.type == "c2s" or session.type == "s2sin" then + -- fail if we are already compressed + if session.compressed then + local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"); + (session.sends2s or session.send)(error_st); + session.log("debug", "Client tried to establish another compression layer."); + return true; + end + + -- checking if the compression method is supported + local method = stanza:get_child_text("method"); + if method == "zlib" then + session.log("debug", "zlib compression enabled."); + + -- create deflate and inflate streams + local deflate_stream = get_deflate_stream(session); + if not deflate_stream then return true; end + + local inflate_stream = get_inflate_stream(session); + if not inflate_stream then return true; end + + (session.sends2s or session.send)(st.stanza("compressed", {xmlns=xmlns_compression_protocol})); + session:reset_stream(); + + -- setup compression for session.w + setup_compression(session, deflate_stream); + + -- setup decompression for session.data + setup_decompression(session, inflate_stream); + + session.compressed = true; + elseif method then + session.log("debug", "%s compression selected, but we don't support it.", tostring(method)); + local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method"); + (session.sends2s or session.send)(error_st); + else + (session.sends2s or session.send)(st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed")); + end + return true; + end +end); +