NOTE: XMPP compression has unresolved security concerns, and this module has been removed from Prosody and renamed.
While the bandwidth usage of XMPP isn’t that much, 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.
mod_compression implements XEP-0138, and supports the zlib compression algorithm.
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.
apt-get install lua-zlib
luarocks install lua-zlib
= {
modules_enabled -- Other modules
"compression_unsafe"; -- Enable mod_compression_unsafe
}
The compression level can be set using the
compression_level
option which can be a number from 1 to 9.
Higher compression levels will use more resources but less
bandwidth.
= {
modules_enabled -- Other modules
"compression_unsafe"; -- Enable mod_compression_unsafe
}
= 5 compression_level
With the plugin installer in Prosody 0.12 you can use:
sudo prosodyctl install --server=https://modules.prosody.im/rocks/ mod_compression_unsafe
For earlier versions see the documentation for installing 3rd party modules