npm package: @sourceloop/in-mail-service
Description: In mail microservice.
Author: Sourcefuse
Latest version: 16.0.6

# @sourceloop/in-mail-service

[![LoopBack](<https://github.com/strongloop/loopback-next/raw/master/docs/site/imgs/branding/Powered-by-LoopBack-Badge-(blue)-@2x.png>)](http://loopback.io/)

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## Overview

A Microservice primarily used for in-mail implementation to compose and view in-mails for any client application.

## Installation

```bash
npm i @sourceloop/in-mail-service
```

## Usage

- Create a new Loopback4 Application (If you don't have one already)
  `lb4 testapp`
- Install the in mail service
  `npm i @sourceloop/in-mail-service`
- Set the [environment variables](#environment-variables).
- Run the [migrations](#migrations).
- Add the `InMailServiceComponent` to your Loopback4 Application (in `application.ts`).
  ```typescript
  // import the InMailServiceComponent
  // No need to destructure
  import InMailServiceComponent from '@sourceloop/in-mail-service';
  // add Component for InMailServiceComponent
  this.component(InMailServiceComponent);
  ```
- Set up a [Loopback4 Datasource](https://loopback.io/doc/en/lb4/DataSource.html) with `dataSourceName` property set to `InMailDatasourceName`. You can see an example datasource [here](#setting-up-a-datasource).
- Start the application
  `npm start`

### Setting up a `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';
import {InMailDatasourceName} from '@sourceloop/in-mail-service';

const config = {
  name: InMailDatasourceName,
  connector: 'postgresql',
  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 InmailDataSource
  extends juggler.DataSource
  implements LifeCycleObserver
{
  static dataSourceName = InMailDatasourceName;
  static readonly defaultConfig = config;

  constructor(
    @inject(`datasources.config.${SchedulerDatasourceName}`, {optional: true})
    dsConfig: object = config,
  ) {
    super(dsConfig);
  }
}
```

### Migration

The migrations required for this service are processed during the installation automatically if you set the `INMAIL_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 databases, they may be affected. In such a scenario, it is advised that you copy the migration files in your project root, using the `INMAIL_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 users, this choice can be specified during the scaffolding process by selecting the "type of datasource" option.

#### Database Model

![db-schema](./migrations/in_mail_db.png)

### 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);
  }
}
```

### Setting Environment Variables

Do not forget to set Environment variables. The examples below show a common configuration for a PostgreSQL Database running locally.

```environment
NODE_ENV=dev
LOG_LEVEL=DEBUG
HOST=0.0.0.0
PORT=3000
DB_HOST=localhost
DB_PORT=5432
DB_USER=pg_service_user
DB_PASSWORD=pg_service_user_password
DB_DATABASE=in_mail_db
DB_SCHEMA=public
JWT_SECRET=super_secret_string
JWT_ISSUER=https://authentication.service
```

| 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`                                                                  |
| `HOST`        | Y        |               | Host for the service to run under, i.e. `0.0.0.0`                                                                                  |
| `PORT`        | Y        | `3000`        | Port for the service to listen on.                                                                                                 |
| `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        | `public`      | 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.                                                                                                           |

### 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

##### POST /mails

**Description:** Compose or draft a Mail to various Recipients

**Request Body:**

```javascript
{
  "threadId": "string", // Optional, add if you want the messages in a same thread
  "groups": [ // You can define one or more recipients in a group array.
    {
      "party": "string", // email of the recipient
      "type": "to", // type can be to | cc | bcc
    }
  ],
  "attachments": [ // Optional
    {
      "name": "string", // name of the attachment file
      "path": "string", // It can be url like s3 url
      "thumbnail": "string", // Smaller/Compressed version of attachment path. can be s3 url
      "mime": "string", // Content Type of a file (example: image/jpg)
    }
  ],
  "meta": [ // Optional
    {
      "key": "string", // Key Name like Content-Type
      "value": "string", // Value like application/json, text/html etc.
    }
  ],
  "body": "string", // The Message Body
  "subject": "string", // The title  of the Message
  "status": "string", // Draft if you don't want to send message Now
  "extId": "string", // External Id from the Client (Optional)
  "extMetadata": {} // External Metadata from the Client (Optional)
}
```

**Successful Response:**

```javascript
{
  "id": "string", // id of the message
  "version": "string" // API version
}
```

##### PUT /mails/{messageId}

**Description:** Update Drafted Messages such as modifying attachment, recipients, message body, subject etc.

**Request path Parameters:**

{messageId}: Unique Id of the message which needs to be updated

**Request Body:**

```javascript
{
  "groups": [ // You can define one or more recipients in a group array.
    {
      "party": "string", // email of the recipient
      "type": "to", // type can be to | cc | bcc
    }
  ],
  "attachments": [ // Optional
    {
      "name": "string", // name of the attachment file
      "path": "string", // It can be url like s3 url
      "thumbnail": "string", // Smaller/Compressed version of attachment path. can be s3 url
      "mime": "string", // Content Type of a file (example: image/jpg)
    }
  ],
  "meta": [ // Optional
    {
      "key": "string", // Key Name like Content-Type
      "value": "string", // Value like application/json, text/html etc.
    }
  ],
  "body": "string", // The Message Body (Optional)
  "subject": "string", // The title  of the Message (Optional)
  "status": "string", // Draft if you don't want to send message Now, otherwise, send
  "extId": "string", // External Id from the Client (Optional)
  "extMetadata": "object" // External Metadata from the Client (Optional)
}
```

Success Response:

```javascript
{
  "id": "string", // id of the message
  "version": "string" // API version
}
```

##### POST /mails/{messageId}/attachments

**Description:** add an attachment to an existing drafted mail

**Request path Parameters:**

{messageId}: The unique id of a mail

**Request Body:**

```javascript
{
  "attachments": [
    {
      "name": "string", // name of the attachment file
      "path": "string", // It can be url like s3 url
      "thumbnail": "string", // Smaller/Compressed version of attachment path. can be s3 url
      "mime": "string" // Content Type of a file (example: image/jpg)
    }
  ]
}
```

**Successful Response:**

```javascript
{
  "items": "array", // array containing attachments,
  "version": "string", // an API version
}
```

##### DELETE /mails/bulk/{storage}/{action}

**Description:** Move inbox/sent items to trash or delete the trashed item

**Request path parameters:**

{storage}: inbox/send/trash (to trash the inbox/sent message or to delete the trashed message)

{action}: trash/delete

**Request body parameters**

```javascript
{
  "messageIds": "Array<string>"
}
```

**Successful Response:**

```javascript
{
  "version" : "string", // the API version
  "item": "Array<object>" // recipient/sender details which was marked for deletion/trash
}
```

##### PATCH /mails/bulk/restore

**Description:** Restore the trashed Mail

**Request body parameters**

```javascript
{
  "messageIds": "Array<string>"
}
```

**Successful Response:**

```javascript
{
  "version": "string", // the API version
  "items": "Array<object>" // recipient/sender details which was restored from trash
}
```

##### PATCH /mails/{messageId}/forward

**Description:** Forward the mail to another recipient

**Request path Parameter:**

{messageId}: Unique message Id

**Request Body:**

```javascript
{
  "groups": [ // you can specify more recipients in groups array for forwarding the mail to multiple recipients
    {
      "party": "string", // email of the recipient
      "type": "to" | "bcc" | "cc", // recipient type
    }
  ]
}
```

**Successful Response:**

```javascript
{
  "version": "string", // the API version
  "id": "string" // the message Id
}
```

##### PATCH /mails/{messageId}/send

**Description:** Send the drafted mail to the recipient

**Request path Parameter:**

{messageId}: Unique Message Id

Successful response

```javascript
{
  "id": "string",
  "version": "string"
}
```

##### PATCH /mails/marking/{markType}

**Description:** mark the mails as read/unread/important/not-important

**Request path Parameter:**

{markType}: read/unread/important/not-important

Successful response

```javascript
{
  success : true,
}
```

##### GET /threads/{threadId}

**Request path Parameters:**

{threadId}: Unique id of thread

**Request query Parameter(Optional):**

filter: Object which contains attribute(s) key value pairs of thread model which is used to filter data.

**Successful Response:**

```javascript
{
  "version": "string", // the API version
  "item": "object" // item containing the thread and the related message, attachment and/or meta-data details
}
```

##### GET /threads

**Request query parameter(s):**

groupFilter: Object which contains attribute(s) key value pairs of group model which is used to filter items.
threadFilter: Object which contains attribute(s) key value pairs of thread model which is used to filter items.

**Successful Response:**

```javascript
{
   "version": "string", // the API version
   "items": "array"  // array containing thread details and the corresponding messages, attachments etc.
}
```

##### GET /mails

**Request query parameter(s):**

groupFilter: Object which contains attribute(s) key value pairs of group model which is used to filter items.
threadFilter: Object which contains attribute(s) key value pairs of thread model which is used to filter items.

## API's Details

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