Slackify is a gem that allows to build slackbots on Rails using the Event API from Slack.
Table of Contents
- How does it work
- Handlers
- Plain messages
- Interactive messages
- Slash Command
- Custom handler for message subtypes
- Custom handler for event types
- Custom unhandled handler
- Slack client
- Sending a simple message
- Sending an interactive message
- Slack 3 second reply window
- Handlers
- How to run your own slackify
- Initial Setup
- Slack Setup
How does it work
The core logic of the bot resides in its handlers. When the app starts, a list of handler gets initialized from a config file (config/handlers.yml
). This initializes all the plain message handlers. Out of the box, the application supports three types of events
- Plain messages
- Interactive messages
- Slash Command
Handlers
Handling plain messages
These are the basic handlers. They use a regex to identify if they should be called. When a message event gets sent to the bots, the slack controller sends the message to the list of handlers. The message will be checked against the regex of every handler until there is a match. When there is a match, the handler will get called with all the parameters provided by slack. If no handler matches the command, the unhandled handler will be called instead.
Those handlers are configured via the config/handlers.yml
configuration file. Let's dissect the configuration of a handler.
- repeat_handler:
commands:
- name: Repeat
description: "`repeat [sentence]`: Repeats the sentence you wrote"
regex: !ruby/regexp "/^repeat (?<sentence>.+)/i"
action: repeat
The ruby class repeat_handler.rb
would look something like this:
class RepeatHandler < Slackify::Handlers::Base
class << self
def repeat(params)
slack_client.chat_postMessage(
as_user: true,
channel: params[:event][:user],
text: "you just said: #{params[:command_arguments][:sentence]}",
)
end
end
end
config/handlers.yml
is configured to be an array of handlers. This examples only shows one handler. The top level key refers to the name of the handler in snake_case. In this case repeat_handler
refers to RepeatHandler. This handler can handle multiple commands. In our example, it only handles one command: repeat. A command is defined by a name
, description
, regex
and action
. The name and description are more there to allow you to implement a custom help handler that would display all the commands. The core part is the regex and the action. If the regex match, the action is the method that will be called in the handler. In this example, if the regex matches, we'll call RepeatHandler#repeat
.
To add a new handler, you can add a new file under app/handlers/
and start adding new commands. You will also need to update the config/handlers.yml
configuration to register the command.
Note: The regex supports named capture. In this example, we have a name example of sentence
. When the handler command will be called, a key in the parameter hash will be added: command_arguments
. This key will point to a hash of the capture name and value. In this case, command_arguments => {sentence: "the sentence you wrote"}
Handling messages with defined parameters
The regular expression matching in the previous example provides a mechanism to supply named parameters to a method. However, many handlers may want to use named & typed parameters. This can be done using the base_command
and parameters
options.
We can rewrite the command above to
- repeat_handler:
commands:
- name: Repeat
description: "`repeat [sentence]`: Repeats the sentence you wrote"
base_command: "repeat"
parameters:
- sentence: string
- times: 10
action: repeat
And call the command with
slackify repeat sentence="Why hullo there" times=10
This will supply a command arguments that are typed and coerced to the defined types:
command_arguments => {sentence: "Why hullo there", time: 10}
Handling interactive messages
When sending an interactive message to a user, slack let's you define the callback_id
. The app uses the callback id to select the proper handler for the message that was sent. The callback id must follow the given format: class_name#method_name
. For instance if you set the callback id to repeat_handler#repeat
, then RepeatHandler#repeat
will be called. Adding new handlers does not require to update the config/handlers.yml
configuration. You only need to update the callback id to define the proper handler to be used when you send an interactive message.
Handling slash commands
The code also has an example of a slash command and its handler (slash_handler.rb
). To add a command on the bot, head to you app configuration on https://api.slack.com/apps and navigate to Slack Commands using the sidebar. Create a new one. The important part is to set the path properly. To bind with the demo handler, you would need to setup the path like this: /slackify/slash/slash_handler/example_slash
. The format is /slackify/slash/[handler_name]/[action_name]
. An app shouldn't have many slash commands. Keep in mind that adding a slash command means that the whole organization will see it.
You will need to allow the method in the handler to indicate it can be used as a slash command using allow_slash_method
class DummyHandler < Slackify::Handlers::Base
allow_slash_method :slash_command
class << self
def slash_command(_params)
"dummy_handler slash_command() was called"
end
end
end
Custom handler for message subtypes
If you wish to add more functionalities to your bot, you can specify define new behaviours for different message subtypes. You can specify a hash with the event subtype as a key and the handler class as the value. Slackify will call .handle_event
on your class and pass the controller params as parameters.
Slackify.configuration.custom_message_subtype_handlers = {
file_share: MessageImageHandler
}
In this example, all message of subtype file_share
will be sent to the MessageImageHandler
class.
Custom handler for event types
If you wish to add more functionalities to your bot, you can specify define new behaviours for different event types. You can specify a hash with the event type as a key and the handler class as the value. Slackify will call .handle_event
on your class and pass the controller params as parameters.
Slackify.configuration.custom_event_type_handlers = {
file_share: ImageHandler
}
In this example, all events of type file_share
will be sent to the ImageHandler
class.
Custom unhandled handler
By default, the Slackify has a handler that will be called if there is no regex match for a plain text message. Slackify::Handlers::UnhandledHandler#unhandled
is called and it replies to the user by saying "This command is not handled at the moment". You can update this in the configuration by specifying a handler class for unhandled_handler
that responds to a class method named unhandled
. If you do not wish to use any handler for unhandled message, you can call remove_unhandled_handler
# config/application.rb
Slackify.configure do |config|
# ...
config.unhandled_handler = MyCustomHandlerClass # enables a custom unhandled handler
config.remove_unhandled_handler # removes the unhandled_handler
end
# app/handlers/my_custom_handler_class.rb
class MyCustomHandlerClass
def self.unhandled(params)
# ...
end
end
Slack client
In order to send messages, the slack ruby client gem was used. You can send plain text messages, images and interactive messages. Since the bot was envisioned being more repsonsive than proactive, the client was made available for handlers to call using the slack_client
method. If you wish to send messages outside of handlers, you can get the slack client by calling Slackify.configuration.slack_client
Sending a simple message
slack_client.chat_postMessage(channel: 'MEMBER ID OR CHANNEL ID', text: 'Hello World', as_user: true)
Sending an interactive message
slack_client.chat_postMessage(
channel: 'MEMBER ID OR CHANNEL ID',
as_user: true,
attachments: [{
"fallback": "Would you recommend it to customers?",
"title": "Would you recommend it to customers?",
"callback_id": "repeat_handler#repeat",
"color": "#3AA3E3",
"attachment_type": "default",
"actions": [
{
"name": "recommend",
"text": "Recommend",
"type": "button",
"value": "recommend"
},
{
"name": "no",
"text": "No",
"type": "button",
"value": "No"
}
]
}]
)
Slack 3 seconds reply window
Slack introduced a 3 seconds reply window for interactive messages. That means that if you reply to an interactive message or slash command event with a json, slack will show either update the attachment or send a new one without having to use chat_postMessage
. If you wish to use this feature with Slackify, you only need to return either a json of an attachment or a plain text string when you handler method is called. Your method should always return nil
otherwise.
How to run your own slackify
Initial Setup
- Install slackify in your app by adding the following line in your
Gemfile
:
gem "slackify"
- run the following command in your terminal:
bundle install
-
Add handlers to your application. Remember to make them extend
Slackify::Handlers::Base
-
Create a
config/handlers.yml
file and define your triggers for specific commands. -
Proceed to connect your bot to slack
Slack Setup
First, you'll need to create a new app on slack. Head over to slack api and create a new app.
-
Set Slack Secret Token
In order to verify that the requets are coming from slack, we'll need to set the slack secret token in slackify. This value can be found as the signing secret in the app credentials section of the basic information page.
-
Add a bot user
Under the feature section, click on "bot users". Pick a name for you slack bot and toggle on "Always Show My Bot as Online". Save the setting.
-
Enable events subscription
Under the feature section, click "Events subscription". Turn the feature on and use your app url followed by
/slackify/event
. Ngrok can easily get you a public url if you are developing locally. The app needs to be running when you configure this url. After the url is configured, under the section "Subscribe to Bot Events", add the bot user eventmessage.im
. -
Activate the interactive components
Under the feature section, click "interactive components". Turn the feature on and use your ngrok url followed by
/slackify/interactive
. Save the setting. -
Install the App
Under the setting section, click "install app" and proceed to install the app to the workspace. Once the app is installed, go back to the "install app" page and copy the Bot User OAuth Access Token.
-
Configure Slackify Add a new initializer with the following code
# config/initializers/slackify.rb
Slackify.configure do |config|
config.slack_bot_token = "xoxb-sdkjlkjsdflsd..."
config.slack_secret_token = "1234dummysecret"
end
- Define handlers specific subtypes (Optional) You can set custom message subtype handlers or custom event type handlers inside your configuration
# config/initializers/slackify.rb
Slackify.configure do |config|
config.slack_bot_token = "xoxb-sdkjlkjsdflsd..."
config.slack_secret_token = "1234dummysecret"
config.custom_message_subtype_handlers = {
file_share: ImageHandler,
channel_join: JoinHandler,
...
}
config.custom_event_type_handlers = {
app_mention: ...
}
end
- Handle bot messages (Highly optional) If you want your bot to accept other bot messages (which you probably should not do), you can. In the configuration step, you can set an array of approved bot ids.
# config/initializers/slackify.rb
Slackify.configure do |config|
...
config.approved_bot_ids = ['abc123', 'def456']
...
end
At this point, you are ready to go 😄
LICENSE
Copyright (c) 2019 Justin Léger, Michel Chatmajian. See LICENSE for further details.