ejabberd for Elixir Developers

Building ejabberd with Mix

You can build ejabberd with Elixir mix tool directly. This can be done as follow:

Clone ejabberd project from Github:

git clone https://github.com/processone/ejabberd.git

Make sure you have all dependencies installed. For example, on MacOS, you need to use Homebrew and set up your environment.
Build ejabberd with mix like any standard Elixir project:
```
cd ejabberd/
mix deps.get
mix compile
```

Configure ejabberd. You can create config/ejabberd.yml file from scratch or, as shown, start from a template one:

(cd config; wget https://gist.githubusercontent.com/mremond/e3a05f7a18f87c4c5145547a3fd3e9e1/raw/a412004b37c7fa7f1d1f7179b4cc73045b9b8da9/ejabberd.yml)

Adapt configuration file to your needs. You can modify the standard config/ejabberd.yml file or use the experimental Elixir config file config/ejabberd.exs. To use it, change the file to use in config/config.exs.
Start ejabberd with standard Elixir tools:
```
iex -S mix
```

You should see that ejabberd is properly started:

  Erlang/OTP 18 [erts-7.2.1] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
  Compiled lib/ejabberd.ex
  Compiled lib/ejabberd/hooks.ex
  Compiled lib/ejabberd/logger.ex
  Compiled lib/mod_presence_demo.ex
  Generated ejabberd app
  Consolidated List.Chars
  Consolidated String.Chars
  Consolidated Enumerable
  Consolidated Collectable
  Consolidated IEx.Info
  Consolidated Inspect
  19:24:52.462 [info] Application lager started on node nonode@nohost
  19:24:52.477 [info] Application sasl started on node nonode@nohost
  19:24:52.484 [info] Application fast_yaml started on node nonode@nohost
  19:24:52.501 [info] Application fast_tls started on node nonode@nohost
  19:24:52.516 [info] Application fast_xml started on node nonode@nohost
  19:24:52.519 [info] Application stringprep started on node nonode@nohost
  19:24:52.529 [info] Application ezlib started on node nonode@nohost
  19:24:52.533 [info] Application cache_tab started on node nonode@nohost
  19:24:52.689 [info] Application mnesia started on node nonode@nohost
  19:24:55.243 [info] FQDN used to check DIGEST-MD5 SASL authentication: MacBook-Pro-de-Mickael
  19:24:55.343 [info] Application iconv started on node nonode@nohost
  19:24:55.699 [info] Reusing listening port for {5222,{0,0,0,0},tcp}
  19:24:55.699 [info] Reusing listening port for {5269,{0,0,0,0},tcp}
  19:24:55.700 [info] Reusing listening port for {5280,{0,0,0,0},tcp}
  19:24:55.700 [info] ejabberd 16.06.1 is started in the node nonode@nohost
  19:24:55.700 [info] Application ejabberd started on node nonode@nohost
  Interactive Elixir (1.2.0) - press Ctrl+C to exit (type h() ENTER for help)
  iex(1)>

Embedding ejabberd in an Elixir application

Starting from version 16.02, ejabberd is packaged as an Hex.pm application: ejabberd on hex.pm.

It means that you can now build a customized XMPP messaging platform with Elixir on top of ejabberd by leveraging ejabberd code base in your app and providing only your custom modules.

This makes the management of your ejabberd plugins easier and cleaner.

To create your own application depending on ejabberd, you can go through the following steps, starting with creating a new Elixir app with mix:

      mix new ejapp
      * creating README.md
      * creating .gitignore
      * creating mix.exs
      * creating config
      * creating config/config.exs
      * creating lib
      * creating lib/ejapp.ex
      * creating test
      * creating test/test_helper.exs
      * creating test/ejapp_test.exs

      Your Mix project was created successfully.
      You can use "mix" to compile it, test it, and more:

      cd ejapp
      mix test

      Run "mix help" for more commands.

Get to your new app directory:
```
 cd ejapp
```

Add ejabberd package as a dependency in your mix.exs file:

 defmodule Ejapp.Mixfile do
 ...
   defp deps do
     [{:ejabberd, "~> 19.2"}]
   end
 end

As you added ejabberd as a dependency, there is no need to explicitely start it in extra_applications list with latest Elixir and mix versions. ejabberd start will be properly inferred by mix and started accordingly.

Create or get ejabberd config file:

 (cd config; wget https://gist.githubusercontent.com/mremond/e3a05f7a18f87c4c5145547a3fd3e9e1/raw/a412004b37c7fa7f1d1f7179b4cc73045b9b8da9/ejabberd.yml)

Define ejabberd configuration reference in config/config.exs:

 config :ejabberd,
   file: "config/ejabberd.yml",
   log_path: 'logs/ejabberd.log'

 # Customize Mnesia directory:
 config :mnesia,
   dir: 'mnesiadb/'

Create log dir:
```
 mkdir logs
```
Compile everything:
```
 mix do deps.get, compile
```
Start your app, ejabberd will be started as a dependency:
```
 iex -S mix
```

 :ejabberd_auth.try_register("test", "localhost", "passw0rd")

You are all set, you can now connect with an XMPP client !