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socket-mode: Rewrite to Python(ish) Implementation (#1781)
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Closes #1771
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@filmaj
filmaj authored Apr 30, 2024
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234 changes: 4 additions & 230 deletions docs/_packages/socket_mode.md
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Expand Up @@ -7,133 +7,11 @@ anchor_links_header: Usage

# Slack Socket Mode

For baseline package documentation, please see the project's [`README`](https://github.com/slackapi/node-slack-sdk/tree/main/packages/socket-mode#readme) or the [documentation on npm](https://www.npmjs.com/package/@slack/socket-mode).

## Installation
The following contain additional examples that may be useful for consumers.

```shell
$ npm install @slack/socket-mode
```

---

### Prerequisites

This package requires a Slack app with an **App-level token**.

To create a new Slack app, head over to [api.slack.com/apps/new](https://api.slack.com/apps?new_app=1).

To generate an **App Token** for your app, on your app's page on [api.slack.com/apps](https://api.slack.com/apps), under the main **Basic Information** page, scroll down to **App-Level Tokens**. Click **Generate Token and Scopes**, add a name for your app token, and click **Add Scope**. Choose `connections:write` and then click **Generate**. Copy and safely store the generated token!

### Initialize the client

This package is designed to support [**Socket Mode**](https://api.slack.com/socket-mode), which allows your app to receive events from Slack over a WebSocket connection.

The package exports a `SocketModeClient` class. Your app will create an instance of the class for each workspace it communicates with.

```javascript
const { SocketModeClient } = require('@slack/socket-mode');

// Read a token from the environment variables
const appToken = process.env.SLACK_APP_TOKEN;

// Initialize
const socketModeClient = new SocketModeClient({ appToken });
```

### Connect to Slack

After your client establishes a connection, your app can send data to and receive data from Slack. Connecting is as easy as calling the `.start()` method.

```javascript
const { SocketModeClient } = require('@slack/socket-mode');
const appToken = process.env.SLACK_APP_TOKEN;

const socketModeClient = new SocketModeClient({ appToken });

(async () => {
// Connect to Slack
await socketModeClient.start();
})();
```
---

### Listen for an event

Bolt apps register [listener functions](https://slack.dev/bolt-js/reference#listener-functions), which are triggered when a specific event type is received by the client.

If you've used Node's [`EventEmitter`](https://nodejs.org/api/events.html#events_class_eventemitter) pattern
before, then you're already familiar with how this works, since the client is an `EventEmitter`.

The `event` argument passed to the listener is an object. Its content corresponds to the [type of
event](https://api.slack.com/events) it's registered for.

```javascript
const { SocketModeClient } = require('@slack/socket-mode');
const appToken = process.env.SLACK_APP_TOKEN;

const socketModeClient = new SocketModeClient({ appToken });

// Attach listeners to events by type. See: https://api.slack.com/events/message
socketModeClient.on('message', async ({ event }) => {
console.log(event);
});

(async () => {
await socketModeClient.start();
})();
```

---

### Send a message

To respond to events and send messages back into Slack, we recommend using the `@slack/web-api` package with a `bot token`.

```javascript
const { SocketModeClient } = require('@slack/socket-mode');
const { WebClient } = require('@slack/web-api');

const appToken = process.env.SLACK_APP_TOKEN;
const socketModeClient = new SocketModeClient({ appToken });

const { WebClient } = require('@slack/web-api');
const webClient = new WebClient(process.env.SLACK_BOT_TOKEN);

// Attach listeners to events by type. See: https://api.slack.com/events/message
socketModeClient.on('member_joined_channel', async ({event, body, ack}) => {
try {
// send acknowledgement back to slack over the socketMode websocket connection
// this is so slack knows you have received the event and are processing it
await ack();
await webClient.chat.postMessage({
blocks: [
{
type: 'section',
text: {
type: 'mrkdwn',
text: `Welcome to the channel, <@${event.user}>. We're here to help. Let us know if you have an issue.`,
},
accessory: {
type: 'button',
text: {
type: 'plain_text',
text: 'Get Help',
},
value: 'get_help',
},
},
],
channel: event.channel,
});
} catch (error) {
console.log('An error occurred', error);
}
});
```
---


### Listen for Interactivity Events
## Listen for Interactivity Events

To receive interactivity events such as shorcut invocations, button clicks, and modal data submission, your listener can subscribe to "interactive" events.

Expand Down Expand Up @@ -182,108 +60,4 @@ socketModeClient.on('slash_commands', async ({ body, ack }) => {
});
```

When your app has multiple interactive events or slash commands, you will need to include your own routing logic. This is a good time to consider using Slack's Bolt framework, which provides an easier ways to register listeners for events and user actions. You can learn more in [Bolt's Socket Mode documentation](https://slack.dev/bolt-js/concepts#socket-mode).

---

### Lifecycle events

The client's connection to Slack has a lifecycle. This means the client can be seen as a state machine which transitions through a few states as it connects, disconnects, reconnects, and synchronizes with Slack. The client emits an event for each state it transitions to throughout its lifecycle. If your app simply needs to know whether the client is connected or not, the `.connected` boolean property can be checked.

In the table below, the client's states are listed, which are also the names of the events you can use to observe the transition to that state. The table also includes descriptions for the states and arguments that a listener would receive.

| Event Name | Arguments | Description |
|-----------------|-----------------|-------------|
| `connecting` | | The client is in the process of connecting to the platform. |
| `authenticated` | `(connectData)` - the response from `apps.connections.open` | The client has authenticated with the platform. This is a sub-state of `connecting`. |
| `connected` | | The client is connected to the platform and incoming events will start being emitted. |
| `ready` | | The client is ready to send outgoing messages. This is a sub-state of `connected` |
| `disconnecting` | | The client is no longer connected to the platform and cleaning up its resources. It will soon transition to `disconnected`. |
| `reconnecting` | | The client is no longer connected to the platform and cleaning up its resources. It will soon transition to `connecting`. |
| `disconnected` | `(error)` | The client is not connected to the platform. This is a steady state - no attempt to connect is occurring. The `error` argument will be `undefined` when the client initiated the disconnect (normal). |

The client also emits events that are part of its lifecycle, but aren't states. Instead, they represent specific moments that might be helpful to your app. The following table lists these events, their description, and includes the arguments that a listener would receive.

| Event Name | Arguments | Description |
|-----------------|-----------|-------------|
| `error` | `(error)` | An error has occurred. See [error handling](#handle-errors) for details. |
| `slack_event` | `(eventType, event)` | An incoming Slack event has been received. |
| `unable_to_socket_mode_start` | `(error)` | A problem occurred while connecting, a reconnect may or may not occur. |

---

### Logging

The `SocketModeClient` will log interesting information to the console by default. You can use the `logLevel` to decide how much or what kind of information should be output. There are a few possible log levels, which you can find in the `LogLevel` export. By default, the value is set to `LogLevel.INFO`. While you're in development, it's sometimes helpful to set this to the most verbose: `LogLevel.DEBUG`.

```javascript
// Import LogLevel from the package
const { SocketModeClient, LogLevel } = require('@slack/socket-mode');
const appToken = process.env.SLACK_APP_TOKEN;

// Log level is one of the options you can set in the constructor
const socketModeClient = new SocketModeClient({
appToken,
logLevel: LogLevel.DEBUG,
});

(async () => {
await socketModeClient.start();
})();
```

All the log levels, in order of most to least information are: `DEBUG`, `INFO`, `WARN`, and `ERROR`.

<details>
<summary markdown="span">
<strong><i>Sending log output somewhere besides the console</i></strong>
</summary>

You can also choose to have logs sent to a custom logger using the `logger` option. A custom logger needs to implement specific methods (known as the `Logger` interface):

| Method | Parameters | Return type |
|--------------|-------------------|-------------|
| `setLevel()` | `level: LogLevel` | `void` |
| `setName()` | `name: string` | `void` |
| `debug()` | `...msgs: any[]` | `void` |
| `info()` | `...msgs: any[]` | `void` |
| `warn()` | `...msgs: any[]` | `void` |
| `error()` | `...msgs: any[]` | `void` |

A very simple custom logger might ignore the name and level, and write all messages to a file.

```javascript
const { createWriteStream } = require('fs');
const logWritable = createWriteStream('/var/my_log_file'); // Not shown: close this stream

const socketModeClient = new SocketModeClient({
appToken,
// Creating a logger as a literal object. It's more likely that you'd create a class.
logger: {
debug(...msgs): { logWritable.write('debug: ' + JSON.stringify(msgs)); },
info(...msgs): { logWritable.write('info: ' + JSON.stringify(msgs)); },
warn(...msgs): { logWritable.write('warn: ' + JSON.stringify(msgs)); },
error(...msgs): { logWritable.write('error: ' + JSON.stringify(msgs)); },
setLevel(): { },
setName(): { },
},
});

(async () => {
await socketModeClient.start();
})();
```
</details>

---

## Requirements

This package supports Node v14 and higher. It's highly recommended to use [the latest LTS version of
node](https://github.com/nodejs/Release#release-schedule), and the documentation is written using syntax and features from that version.

## Getting Help

If you get stuck, we're here to help. The following are the best ways to get assistance working through your issue:

* [Issue Tracker](http://github.com/slackapi/node-slack-sdk/issues) for questions, feature requests, bug reports and general discussion related to these packages. Try searching before you create a new issue.
When your app has multiple interactive events or slash commands, you will need to include your own routing logic. This is a good time to consider using Slack's Bolt framework, which provides an easier way to register listeners for events and user actions. You can learn more in [Bolt's Socket Mode documentation](https://slack.dev/bolt-js/concepts#socket-mode).
6 changes: 4 additions & 2 deletions lint-configs/.eslintrc.js
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Expand Up @@ -225,7 +225,7 @@ module.exports = {
},
{
selector: 'parameter',
format: ['camelCase'],
format: ['camelCase', 'snake_case'],
leadingUnderscore: 'allow',
},
{
Expand Down Expand Up @@ -271,7 +271,7 @@ module.exports = {
},
},
{
files: ['src/**/*.spec.ts'],
files: ['src/**/*.spec.ts', 'src/**/*.spec.js'],
rules: {
// Test-specific rules
// ---
Expand Down Expand Up @@ -302,6 +302,8 @@ module.exports = {
'@typescript-eslint/no-non-null-assertion': 'off',
// Using ununamed functions (e.g., null logger) in tests is fine
'func-names': 'off',
// Some packages, like socket-mode, use classes, and to test constructors, it may be useful to just create a new Whatever()
'no-new': 'off',
// In tests, don't force constructing a Symbol with a descriptor, as
// it's probably just for tests
'symbol-description': 'off',
Expand Down
3 changes: 2 additions & 1 deletion packages/socket-mode/.mocharc.json
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@@ -1,4 +1,5 @@
{
"extension": ["ts"],
"require": ["ts-node/register", "source-map-support/register"],
"timeout": 3000
}
}
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