MPLew-is / slack-message-client

Slack message generator and API client, written in Swift with Result Builders and Concurrency

Slack Message Client

This package provides a Swift object model for a Slack Block Kit message, as well as a Result Builder convenience interface for easy message creation. Also provides an asynchronous API client for sending messages based on the async-http-client from the Swift Server Workgroup.

This is still in extremely early development, and only currently supports sending messages and a narrow subset of the full Block Kit API.

Quick Start

See the command-line interface example for an example implementation runnable from the command line, with configurable message text.

Add to your Package.Swift:

...
	dependencies: [
		...
		.package(url: "https://github.com/MPLew-is/slack-message-client", branch: "main"),
	],
	targets: [
		...
		.target(
			...
			dependencies: [
				...
				.product(name: "BlockKitMessage", package: "slack-message-client"),
				.product(name: "SlackMessageClient", package: "slack-message-client"),
			]
		),
		...
	]
]

Create and send a message:

import BlockKitMessage
import SlackMessageClient

@main
struct SlackMessageExample {
	static func main() async throws {
		let message = Message.build {
			Header("Header")

			Section(mrkdwn: "Section")

			Context.build {
				Image(url: "https://example.com", alternateText: "Alt text")
				Mrkdwn("User")
			}
		}

		let client = SlackMessageClient(authToken: "YOUR_SLACK_BOT_TOKEN")
		try await client.post(message, to: "YOUR_SLACK_CHANNEL_ID")
	}
}

(See the command-line interface example for more detailed instructions on how to set up a Slack app and get the required authentication/configuration values)

Targets provided

• BlockKitMessage: object model for a Slack Block Kit message, if you just want to create messages but not send them

  • A Message object conforms to Codable, so you can use this to just generate the JSON expected by Slack, for instance

• SlackApiClient: a thin wrapper around an AsyncHTTPClient which auto-injects the correct headers needed for the Slack API

  • You can use this by itself if you want to perform actions against the Slack API other than chat.postMessage

• SlackMessageClient: full client integrating the previous two targets into a simple interface for sending messages to a channel

Features supported and planned

If you don't see something on this list, it's not currently planned. Feel free to file an issue/PR to change that though.

Block Kit

• Top-level message objects

  • Basic integration (blocks argument)
  • Alternate text (text argument)

• Mrkdwn result builder

  • Basic support for mrkdwn embedded in a string is already present, this will just provide a better way to build complicated messages

• Header blocks

• Section blocks

  • Basic support (text)
  • Fields and accessories not currently planned

• Context blocks

• Divider blocks

• Image blocks

• Actions, file, and input blocks not currently planned

Slack message client

• chat.postMessage method integration

  • channel argument
  • Attachments and optional arguments not currently planned

• Sending Message object

• Sending raw JSON blocks generated externally

• Optional credentials verification on initialization to fail quickly (api.test method)

• Better parsing and handling of HTTP and Slack API errors