Create Apex Handlers for Slack Apps
Use these Apex classes to create handlers for Slack actions, commands, shortcuts, and events.
The Slack.ActionDispatcher class enables you to invoke an action handler such as in response to a form submission.
Usage
Extend the ActionDispatcher class and override the invoke() method.
Examples
This example uses ActionDispatcher to handle a form submission.
This example uses ActionDispatcher to display a view.
You can close the modal and optionally clear the view stack by using clearModal(). To close the modal without clearing the view stack, use ack(handler) instead.
For an example of invoking an action handler on the App Home page, such as with SlashCommandDispatcher, see ChatPostMessageRequest.
These methods are for ActionDispatcher.
Signature
Return Value
Type: Boolean
Invokes the action handler.
Signature
Parameters
parameters
Type: Map<String, Object>
The action parameters or other parameters of EventParameters, ShortcutParameters, or SlashCommandParameters type.
context
Type: Slack.RequestContext
Describes the context in which a Slack action is invoked.
Return Value
Type: Slack.ActionHandler
Usage
To access the Slack context, use the invoke() method. This method is passed in by an instance of RequestContext. It exposes information about the source of the action in Slack, performs custom logic, and obtains the correct Slack client to respond to Slack based on the request.
Each action type receives different information in its RequestContext.
The Slack.ActionHandler class provides methods that control how Slack actions are handled. The handler processes a single request.
Usage
With the ActionHandler methods, you can work with modals. By responding to Slack actions with a modal you can display dynamic and interactive information. Before opening a modal, compose a view object to define the layout of the initial view.
A modal can hold up to three views simultaneously in a view stack. Only one view is visible each time. But the view stack can retain previous views and return to them with their prior state in place. An app can push new views onto a modal's view stack or update an existing view within that stack, including the currently visible view.
To use this Apex class, specify the Slack namespace when creating an instance of this class. Override the invoke() method returning a Slack.ActionHandler.
Examples
This example pushes a modal onto the modal view stack.
The message_modal.view file looks like this.
The following are methods for ActionHandler.
Acknowledge the payload back to Slack to avoid the 3-second timeout. After running this method, you can perform Slack Client API calls such as to post messages and publish to app home. For example, you can listen to the app_home_opened event and publish a new view to the user’s Home tab. ack() takes care of responding back to Slack immediately to avoid the 3-second timeout.
We don’t recommend using ack() for displaying modals subject to the trigger_id timeouts because doing so can cause your code to fail intermittently, depending on the environment.
To create, update, or push a modal view, use pushModal(), modal(), or updateModal() instead. These methods ack back to Slack within 3 seconds so that the trigger_id from Slack doesn't expire using a staging modal. Using these methods, your Handler must return a ModalView for Slack to display. See Create an Apex Handler.
Signature
Parameters
handler
Type: Slack.RunnableHandler
The handler that clears the modal from the view stack.
Return Value
Type: Slack.ActionHandler
Clears the full stack of modals. By default, Slack pops one modal off the top of the stack.
Signature
Parameters
handler
Type: RunnableHandler
The handler that clears the modal from the view stack.
Return Value
Type: Slack.ActionHandler
Displays a Loading modal with automatic staging to satisfy the 3-second timeout rule.
Signature
Parameters
handler
Type: Slack.ModalHandler
The handler for the modal.
Return Value
Type: Slack.ActionHandler
Displays a Loading modal with a title. The modal has automatic staging to satisfy the 3-second timeout rule.
Signature
Parameters
handler
Type: Slack.ModalHandler
The handler for the modal.
stagedModalTitle
Type: String
The title to display on the modal in Slack.
Return Value
Type: Slack.ActionHandler
Pushes another modal to the view stack with automatic staging to satisfy the 3-second timeout.
Signature
Parameters
handler
Type: Slack.ModalHandler
The handler that pushes the modal to the view stack.
Return Value
Type: Slack.ActionHandler
Push another modal to the view stack with a different title.
Signature
Parameters
handler
Type: Slack.ModalHandler
The handler that pushes the modal to the view stack.
stagedModalTitle
Type: String
The title to display on the modal in Slack.
Return Value
Type: Slack.ActionHandler
Updates a modal. This update can happen if the view is visible within the modals's view stack.
Signature
Parameters
handler
Type: Slack.ModalHandler
The handler that updates the modals.
Return Value
Type: Slack.ActionHandler
Updates a modals with a different title. This update can happen whether the view is visible within the modal's view stack.
Signature
Parameters
handler
Type: Slack.ModalHandler
The handler that updates the modal.
stagedModalTitle
Type: String
The title to display on the modal in Slack.
Return Value
Type: Slack.ActionHandler
Contains the name and values associated with the block element that triggered the action.
Usage
Use the ActionPayload class to register an event, such as an onchange or onclick event, and associate the event to an action. You can retrieve the value from the payload to display it in the view or use the value to perform a query and so on.
Specify your action payload in the run() callback method.
See ChatPostMessageRequest for an example that retrieves the value of the payload and publish it to a view.
The following are methods for ActionPayload.
Returns the name of the block element.
Signature
Return Value
Type: String
Returns the type of the block element.
Signature
Return Value
Type: String
Returns the value of the block element.
Signature
Return Value
Type: Object
Contains methods to build an instance of the Slack.ActionPayload class.
A Builder object is obtained by invoking one of the ActionPayload.Builder methods defined by the ActionPayload class.
The following are methods for ActionPayload.Builder.
Returns an instance of the Slack.ActionPayload object.
Signature
Return Value
Type: Slack.ActionPayload
Signature
Parameters
type
Type: String
Return Value
Type: Slack.ActionPayload.Builder
Signature
Parameters
type
Type: String
Return Value
Type: Slack.ActionPayload.Builder
Signature
Parameters
value
Type: Object
Return Value
Type: Slack.ActionPayload.Builder