Cognition

This is a gem that parses a message, and compares it to various matchers. When it finds the first match, it executes an associated block of code or method, returning the output of whatever was run.

Installation

Add this line to your application's Gemfile:

gem 'cognition'

And then execute:

$ bundle

Or install it yourself as:

$ gem install cognition

Usage

Instantiate:

bot = Cognition::Bot.new

Process your message:

result = bot.process('command I need to process')

You can also include metadata with your message, like user info, or whatever:

result = bot.process('another command', {user_id: 15, name: 'Bob'})

Internally, Cognition will turn your values into a Cognition::Message so the metadata will be passed along with the message, and arbitrary metadata is available in the #metadata Hash:

msg = Cognition::Message('another command', {user_id: 15, name: 'Bob'})
msg.metadata   # Returns { user_id: 15, name: 'Bob' }

Special metadata

If you include a callback_url key in your metadata, we'll give you a convenience method to reply to it using the reply method. This will invoke a HTTParty POST back to the URL with your text sent as the content variable.

msg = Cognition::Message('another command', {
  callback_url: "http://foo.bar/baz",
  user_id: 15,
  name: 'Bob'
})

msg.reply("foo")   # Posts 'content=foo' to http://foo.bar/baz

Creating a Plugin

Creating plugins is easy. Subclass Cognition::Plugins::Base and setup your matches and logic that should be run. Your methods will be passed the msg object and any metadata you've passed to the bot's process method. Here's an example plugin:

class Hello < Cognition::Plugins::Base
  # Simple string based matcher. Must match *EXACTLY*
  match 'hello', :hello, help: { 'hello' => 'Returns Hello World' }

  # Advanced Regexp based matcher. Capture groups are made available
  # via MatchData in the matches method
  match /hello\s*(?<name>.*)/, :hello_person, help: {
    'hello <name>' => 'Greets you by name!'
  }

  def hello(*)
    'Hello World'
  end

  def hello_person(msg, match_data = nil)
    name = match_data[:name]
    "Hello #{name}"
  end
end

After you've done that, you will be able to do:

bot.register(Hello)
bot.process("help hello")  # "hello <name> - Greets you by name!"
bot.process("hello")       # "Hello World"
bot.process("hello foo")   # "Hello foo"

Rendering templates

Templates are opt-in right now, you need to call render yourself, and it will return a string with the rendered contents of a template. What template, you ask? The default for /path/to/hello.rb will look for a templates in /path/to/hello/views/.

Given the following plugin:

class Hello < Cognition::Plugins::Base
  # ...snipped

  def hello(*)
    render
  end

  def hi(*)
    render(template: "/path/to/template.html.erb")
  end

  def hey(*)
    render(type: "text", extension: "haml")
  end
end

1. The hello method will look for /path/to/hello/views/hello.html.erb
2. The hi method will look for /path/to/template.html.erb
3. The hey method will look for /path/to/hello/views/hey.text.haml

Setting instance variables or passing locals is up to the plugin creator. The render method takes a hash with the following keys:

{
  template: "full/path/to/template/file", # FULL path to template file
  type: "type of response"                # text, html, json, etc...
  extension: "engine file extension"      # erb, haml, etc...
  locals: {x: "foo", y: "bar"}            # local variables, access as x & y
}

Contributing

1. Fork it ( https://github.com/anoldguy/cognition/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request