npm package: @sourceloop/chat-service
Description: chat-service microservice.
Author: Sourcefuse
Latest version: 17.0.6

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# [@sourceloop/chat-service](https://github.com/sourcefuse/loopback4-microservice-catalog/tree/master/services/chat-service)

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## Overview

A microservice designed to facilitate real-time communication between users and user groups. It provides a scalable and modular solution for handling both individual and group chat functionalities.This service supports Sequelize as the underlying ORM via the @loopback/sequelize extension, allowing for easy integration with relational databases.

Additionally, it includes functionality for handling file attachments, allowing users to upload and download files as part of their chat interactions. The service ensures that only authenticated and authorized users can download attachments, providing secure access to files. It also tracks who downloads each attachment for auditing purposes.

### Installation

```bash
npm i @sourceloop/chat-service
```

### Usage

### Using with Sequelize

This service supports Sequelize as the underlying ORM using [@loopback/sequelize](https://www.npmjs.com/package/@loopback/sequelize) extension. And in order to use it, you'll need to do following changes.

1.To use Sequelize in your application, add following to application.ts:

```ts
this.bind(ChatServiceBindings.Config).to({
  useCustomSequence: false,
  useSequelize: true,
});
```

2. Use the `SequelizeDataSource` in your audit datasource as the parent class. Refer [this](https://www.npmjs.com/package/@loopback/sequelize#step-1-configure-datasource) for more.

## Implementation

Create a new Application using Loopback CLI and add the Component for `ChatService` in `application.ts`

```typescript
import {BootMixin} from '@loopback/boot';
import {ApplicationConfig} from '@loopback/core';
import {RepositoryMixin} from '@loopback/repository';
import {RestApplication} from '@loopback/rest';
import {
  RestExplorerBindings,
  RestExplorerComponent,
} from '@loopback/rest-explorer';
import {ServiceMixin} from '@loopback/service-proxy';
import {ChatServiceComponent} from '@sourceloop/chat-service';
import path from 'path';
import {MySequence} from './sequence';

export {ApplicationConfig};

export class ChatApplication extends BootMixin(
  ServiceMixin(RepositoryMixin(RestApplication)),
) {
  constructor(options: ApplicationConfig = {}) {
    super(options);

    // Set up the custom sequence
    this.sequence(MySequence);

    // Set up default home page
    this.static('/', path.join(__dirname, '../public'));

    // Customize @loopback/rest-explorer configuration here
    this.configure(RestExplorerBindings.COMPONENT).to({
      path: '/explorer',
    });
    this.component(RestExplorerComponent);

    // add Component for ChatService
    this.component(ChatServiceComponent);

    this.projectRoot = __dirname;
    // Customize @loopback/boot Booter Conventions here
    this.bootOptions = {
      controllers: {
        // Customize ControllerBooter Conventions here
        dirs: ['controllers'],
        extensions: ['.controller.js'],
        nested: true,
      },
    };
  }
}
```

### Asymmetric Token Signing and Verification

If you are using asymmetric token signing and verification, you should have auth datasource present in the service and auth redis datasource on the facade level. Example datasource file for auth database is:-

Auth DB datasource :-

```ts
import {inject, lifeCycleObserver, LifeCycleObserver} from '@loopback/core';
import {juggler} from '@loopback/repository';
import {AuthDbSourceName} from '@sourceloop/core';
const DEFAULT_MAX_CONNECTIONS = 25;
const DEFAULT_DB_IDLE_TIMEOUT_MILLIS = 60000;
const DEFAULT_DB_CONNECTION_TIMEOUT_MILLIS = 2000;

const config = {
  name: 'auth',
  connector: 'postgresql',
  host: process.env.DB_HOST,
  port: process.env.DB_PORT,
  user: process.env.DB_USER,
  schema: process.env.DB_SCHEMA,
  password: process.env.DB_PASSWORD,
  database: process.env.AUTH_DB,
};

// Observe application's life cycle to disconnect the datasource when
// application is stopped. This allows the application to be shut down
// gracefully. The `stop()` method is inherited from `juggler.DataSource`.
// Learn more at https://loopback.io/doc/en/lb4/Life-cycle.html
@lifeCycleObserver('datasource')
export class AuthDataSource
  extends juggler.DataSource
  implements LifeCycleObserver
{
  static dataSourceName = AuthDbSourceName;

  static readonly defaultConfig = config;

  constructor(
    @inject('datasources.config.auth', {optional: true})
    dsConfig: object = config,
  ) {
    if (!!+(process.env.ENABLE_DB_CONNECTION_POOLING ?? 0)) {
      const dbPool = {
        max: +(process.env.DB_MAX_CONNECTIONS ?? DEFAULT_MAX_CONNECTIONS),
        idleTimeoutMillis: +(
          process.env.DB_IDLE_TIMEOUT_MILLIS ?? DEFAULT_DB_IDLE_TIMEOUT_MILLIS
        ),
        connectionTimeoutMillis: +(
          process.env.DB_CONNECTION_TIMEOUT_MILLIS ??
          DEFAULT_DB_CONNECTION_TIMEOUT_MILLIS
        ),
      };

      dsConfig = {...dsConfig, ...dbPool};
    }

    super(dsConfig);
  }
}
```

Auth Cache Redis Datasource:-

```ts
import {inject, lifeCycleObserver, LifeCycleObserver} from '@loopback/core';
import {AnyObject, juggler} from '@loopback/repository';
import {readFileSync} from 'fs';
import {AuthCacheSourceName} from '@sourceloop/core';

const config = {
  name: process.env.REDIS_NAME,
  connector: 'kv-redis',
  host: process.env.REDIS_HOST,
  port: process.env.REDIS_PORT,
  password: process.env.REDIS_PASSWORD,
  db: process.env.REDIS_DATABASE,
  url: process.env.REDIS_URL,
  tls:
    +process.env.REDIS_TLS_ENABLED! && process.env.REDIS_TLS_CERT
      ? {
          ca: readFileSync(process.env.REDIS_TLS_CERT),
        }
      : undefined,
  sentinels:
    +process.env.REDIS_HAS_SENTINELS! && process.env.REDIS_SENTINELS
      ? JSON.parse(process.env.REDIS_SENTINELS)
      : undefined,
  sentinelPassword:
    +process.env.REDIS_HAS_SENTINELS! && process.env.REDIS_SENTINEL_PASSWORD
      ? process.env.REDIS_SENTINEL_PASSWORD
      : undefined,
  role:
    +process.env.REDIS_HAS_SENTINELS! && process.env.REDIS_SENTINEL_ROLE
      ? process.env.REDIS_SENTINEL_ROLE
      : undefined,
};

@lifeCycleObserver('datasource')
export class RedisDataSource
  extends juggler.DataSource
  implements LifeCycleObserver
{
  static readonly dataSourceName = AuthCacheSourceName;
  static readonly defaultConfig = config;

  constructor(
    @inject(`datasources.config.${process.env.REDIS_NAME}`, {optional: true})
    dsConfig: AnyObject = config,
  ) {
    if (
      +process.env.REDIS_HAS_SENTINELS! &&
      !!process.env.REDIS_SENTINEL_HOST &&
      !!process.env.REDIS_SENTINEL_PORT
    ) {
      dsConfig.sentinels = [
        {
          host: process.env.REDIS_SENTINEL_HOST,
          port: +process.env.REDIS_SENTINEL_PORT,
        },
      ];
    }
    super(dsConfig);
  }
}
```

### Environment Variables

| Name          | Required | Default Value | Description                                                                                                                        |
| ------------- | -------- | ------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| `NODE_ENV`    | Y        |               | Node environment value, i.e. `dev`, `test`, `prod`                                                                                 |
| `LOG_LEVEL`   | Y        |               | Log level value, i.e. `error`, `warn`, `info`, `verbose`, `debug`                                                                  |
| `DB_HOST`     | Y        |               | Hostname for the database server.                                                                                                  |
| `DB_PORT`     | Y        |               | Port for the database server.                                                                                                      |
| `DB_USER`     | Y        |               | User for the database.                                                                                                             |
| `DB_PASSWORD` | Y        |               | Password for the database user.                                                                                                    |
| `DB_DATABASE` | Y        |               | Database to connect to on the database server.                                                                                     |
| `DB_SCHEMA`   | Y        |               | Database schema used for the data source. In PostgreSQL, this will be `public` unless a schema is made explicitly for the service. |
| `JWT_SECRET`  | Y        |               | Symmetric signing key of the JWT token.                                                                                            |
| `JWT_ISSUER`  | Y        |               | Issuer of the JWT token.                                                                                                           |

### Setting up `DataSource`

Here is a sample Implementation `DataSource` implementation using environment variables and PostgreSQL as the data source.

```typescript
import {inject, lifeCycleObserver, LifeCycleObserver} from '@loopback/core';
import {juggler} from '@loopback/repository';

const config = {
  name: 'chatDb',
  connector: 'postgresql',
  url: '',
  host: process.env.DB_HOST,
  port: process.env.DB_PORT,
  user: process.env.DB_USER,
  password: process.env.DB_PASSWORD,
  database: process.env.DB_DATABASE,
  schema: process.env.DB_SCHEMA,
};

@lifeCycleObserver('datasource')
export class ChatDataSource
  extends juggler.DataSource
  implements LifeCycleObserver
{
  static dataSourceName = 'chatDb';
  static readonly defaultConfig = config;

  constructor(
    // You need to set datasource configuration name as 'datasources.config.Chat' otherwise you might get Errors
    @inject('datasources.config.Chat', {optional: true})
    dsConfig: object = config,
  ) {
    super(dsConfig);
  }
}
```

### Migrations

The migrations required for this service are processed during the installation automatically if you set the `CHAT_MIGRATION` or `SOURCELOOP_MIGRATION` env variable. The migrations use [`db-migrate`](https://www.npmjs.com/package/db-migrate) with [`db-migrate-pg`](https://www.npmjs.com/package/db-migrate-pg) driver for migrations, so you will have to install these packages to use auto-migration. Please note that if you are using some pre-existing migrations or databasea, they may be affected. In such a scenario, it is advised that you copy the migration files in your project root, using the `CHAT_MIGRATION_COPY` or `SOURCELOOP_MIGRATION_COPY` env variables. You can customize or cherry-pick the migrations in the copied files according to your specific requirements and then apply them to the DB.

This migration script supports both MySQL and PostgreSQL databases, controlled by environment variables. By setting MYSQL_MIGRATION to 'true', the script runs migrations using MySQL configuration files; otherwise, it defaults to PostgreSQL. .

Additionally, there is now an option to choose between SQL migration or PostgreSQL migration.
NOTE: For [`@sourceloop/cli`](https://www.npmjs.com/package/@sourceloop/cli?activeTab=readme) users, this choice can be specified during the scaffolding process by selecting the "type of datasource" option.

### API Documentation

#### Common Headers

Authorization: Bearer <token> where <token> is a JWT token signed using JWT issuer and secret.
`Content-Type: application/json` in the response and in request if the API method is NOT GET

#### Common Request path Parameters

{version}: Defines the API Version

### Common Responses

200: Successful Response. Response body varies w.r.t API
401: Unauthorized: The JWT token is missing or invalid
403: Forbidden : Not allowed to execute the concerned API
404: Entity Not Found
400: Bad Request (Error message varies w.r.t API)
201: No content: Empty Response

## API Details

Visit the [OpenAPI spec docs](./openapi.md)

## License

Sourceloop is [MIT licensed](./LICENSE).