XMPP/Jabber Library and DSL for Ruby written on EventMachine and Nokogiri.
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Blather Build status

XMPP DSL (and more) for Ruby written on EventMachine and Nokogiri.


  • evented architecture
  • uses Nokogiri
  • simplified starting point

Project Pages



gem install blather


See the examples directory for more advanced examples.

This will auto-accept any subscription requests and echo back any chat messages.

require 'rubygems'
require 'blather/client'

setup 'echo@jabber.local', 'echo'

# Auto approve subscription requests
subscription :request? do |s|
  write_to_stream s.approve!

# Echo back what was said
message :chat?, :body do |m|
  write_to_stream m.reply


Setup handlers by calling their names as methods.

# Will only be called for messages where #chat? responds positively
# and #body == 'exit'
message :chat?, :body => 'exit'

Non-Stanza Handlers

So far there are two non-stanza related handlers.

# Called after the connection has been connected. It's good for initializing
# your system.
# DSL:
when_ready {}
# Client:
client.register_handler(:ready) {}

# Called after the connection has been terminated. Good for teardown or
# automatic reconnection.
# DSL:
disconnected {}
# Client
client.register_handler(:disconnected) {}
# The following will reconnect every time the connection is lost:
disconnected { client.connect }

Handler Guards

Guards act like AND statements. Each condition must be met if the handler is to be used.

# Equivalent to saying (stanza.chat? && stanza.body)
message :chat?, :body

The different types of guards are:

# Symbol
#   Checks for a non-false reply to calling the symbol on the stanza
#   Equivalent to stanza.chat?
message :chat?

# Hash with any value (:body => 'exit')
#   Calls the key on the stanza and checks for equality
#   Equivalent to stanza.body == 'exit'
message :body => 'exit'

# Hash with regular expression (:body => /exit/)
#   Calls the key on the stanza and checks for a match
#   Equivalent to stanza.body.match /exit/
message :body => /exit/

# Hash with array (:name => [:gone, :forbidden])
#   Calls the key on the stanza and check for inclusion in the array
#   Equivalent to [:gone, :forbidden].include?(stanza.name)
stanza_error :name => [:gone, :fobidden]

# Proc
#   Calls the proc passing in the stanza
#   Checks that the ID is modulo 3
message proc { |m| m.id % 3 == 0 }

# Array
#   Use arrays with the previous types effectively turns the guard into
#   an OR statement.
#   Equivalent to stanza.body == 'foo' || stanza.body == 'baz'
message [{:body => 'foo'}, {:body => 'baz'}]

# XPath
#   Runs the xpath query on the stanza and checks for results
#   This guard type cannot be combined with other guards
#   Equivalent to !stanza.find('/iq/ns:pubsub', :ns => 'pubsub:namespace').empty?
iq '/iq/ns:pubsub', :ns => 'pubsub:namespace'


Blather provides before and after filters that work much the way regular handlers work. Filters come in a before and after flavor. They're called in order of definition and can be guarded like handlers.

before { |s| "I'm run before any handler" }
before { |s| "I'm run next" }

before(:message) { |s| "I'm only run in front of message stanzas" }
before(nil, :id => 1) { |s| "I'll only be run when the stanza's ID == 1" }

# ... handlers

after { |s| "I'm run after everything" }

On the Command Line:

Default usage is:

[blather_script] [options] node@domain.com/resource password [host] [port]

Command line options:

-D, --debug       Run in debug mode (you will see all XMPP communication)
-d, --daemonize   Daemonize the process
    --pid=[PID]   Write the PID to this file
    --log=[LOG]   Write to the [LOG] file instead of stdout/stderr
-h, --help        Show this message
-v, --version     Show version

Health warning:

Some parts of Blather will allow you to do stupid things that don't conform to XMPP spec. You should exercise caution and read the relevant specifications (indicated in the preamble to most relevant classes).


All contributions are welcome, even encouraged. However, contributions must be well tested. If you send me a branch name to merge that'll get my attention faster than a change set made directly on master.


Jeff Smick



Copyright (c) 2011 Jeff Smick. See LICENSE for details.