feat: write a module for postal

.eslintrc.js

@@ -0,0 +1,25 @@
+module.exports = {
+  parser: '@typescript-eslint/parser',
+  parserOptions: {
+    project: 'tsconfig.json',
+    tsconfigRootDir: __dirname,
+    sourceType: 'module',
+  },
+  plugins: ['@typescript-eslint/eslint-plugin'],
+  extends: [
+    'plugin:@typescript-eslint/recommended',
+    'plugin:prettier/recommended',
+  ],
+  root: true,
+  env: {
+    node: true,
+    jest: true,
+  },
+  ignorePatterns: ['.eslintrc.js'],
+  rules: {
+    '@typescript-eslint/interface-name-prefix': 'off',
+    '@typescript-eslint/explicit-function-return-type': 'off',
+    '@typescript-eslint/explicit-module-boundary-types': 'off',
+    '@typescript-eslint/no-explicit-any': 'off',
+  },
+};

.prettierrc

@@ -0,0 +1,4 @@
+{
+  "singleQuote": true,
+  "trailingComma": "all"
+}

README.md

@@ -1,3 +1,73 @@
-# nestjs-postal-client
+<p align="center">
+  <a href="http://nestjs.com/" target="blank"><img src="https://nestjs.com/img/logo-small.svg" width="200" alt="Nest Logo" /></a>
+</p>
 
-This is an API client for Postal.
+[circleci-image]: https://img.shields.io/circleci/build/github/nestjs/nest/master?token=abc123def456
+[circleci-url]: https://circleci.com/gh/nestjs/nest
+
+  <p align="center">A progressive <a href="http://nodejs.org" target="_blank">Node.js</a> framework for building efficient and scalable server-side applications.</p>
+    <p align="center">
+<a href="https://www.npmjs.com/~nestjscore" target="_blank"><img src="https://img.shields.io/npm/v/@nestjs/core.svg" alt="NPM Version" /></a>
+<a href="https://www.npmjs.com/~nestjscore" target="_blank"><img src="https://img.shields.io/npm/l/@nestjs/core.svg" alt="Package License" /></a>
+<a href="https://www.npmjs.com/~nestjscore" target="_blank"><img src="https://img.shields.io/npm/dm/@nestjs/common.svg" alt="NPM Downloads" /></a>
+<a href="https://circleci.com/gh/nestjs/nest" target="_blank"><img src="https://img.shields.io/circleci/build/github/nestjs/nest/master" alt="CircleCI" /></a>
+<a href="https://coveralls.io/github/nestjs/nest?branch=master" target="_blank"><img src="https://coveralls.io/repos/github/nestjs/nest/badge.svg?branch=master#9" alt="Coverage" /></a>
+<a href="https://discord.gg/G7Qnnhy" target="_blank"><img src="https://img.shields.io/badge/discord-online-brightgreen.svg" alt="Discord"/></a>
+<a href="https://opencollective.com/nest#backer" target="_blank"><img src="https://opencollective.com/nest/backers/badge.svg" alt="Backers on Open Collective" /></a>
+<a href="https://opencollective.com/nest#sponsor" target="_blank"><img src="https://opencollective.com/nest/sponsors/badge.svg" alt="Sponsors on Open Collective" /></a>
+  <a href="https://paypal.me/kamilmysliwiec" target="_blank"><img src="https://img.shields.io/badge/Donate-PayPal-ff3f59.svg"/></a>
+    <a href="https://opencollective.com/nest#sponsor"  target="_blank"><img src="https://img.shields.io/badge/Support%20us-Open%20Collective-41B883.svg" alt="Support us"></a>
+  <a href="https://twitter.com/nestframework" target="_blank"><img src="https://img.shields.io/twitter/follow/nestframework.svg?style=social&label=Follow"></a>
+</p>
+  <!--[![Backers on Open Collective](https://opencollective.com/nest/backers/badge.svg)](https://opencollective.com/nest#backer)
+  [![Sponsors on Open Collective](https://opencollective.com/nest/sponsors/badge.svg)](https://opencollective.com/nest#sponsor)-->
+
+## Description
+
+[Nest](https://github.com/nestjs/nest) framework TypeScript starter repository.
+
+## Installation
+
+```bash
+$ npm install
+```
+
+## Running the app
+
+```bash
+# development
+$ npm run start
+
+# watch mode
+$ npm run start:dev
+
+# production mode
+$ npm run start:prod
+```
+
+## Test
+
+```bash
+# unit tests
+$ npm run test
+
+# e2e tests
+$ npm run test:e2e
+
+# test coverage
+$ npm run test:cov
+```
+
+## Support
+
+Nest is an MIT-licensed open source project. It can grow thanks to the sponsors and support by the amazing backers. If you'd like to join them, please [read more here](https://docs.nestjs.com/support).
+
+## Stay in touch
+
+- Author - [Kamil Myśliwiec](https://kamilmysliwiec.com)
+- Website - [https://nestjs.com](https://nestjs.com/)
+- Twitter - [@nestframework](https://twitter.com/nestframework)
+
+## License
+
+Nest is [MIT licensed](LICENSE).

nest-cli.json

@@ -0,0 +1,8 @@
+{
+  "$schema": "https://json.schemastore.org/nest-cli",
+  "collection": "@nestjs/schematics",
+  "sourceRoot": "src",
+  "compilerOptions": {
+    "deleteOutDir": true
+  }
+}

package.json

@@ -0,0 +1,77 @@
+{
+  "name": "nestjs-postal-client",
+  "version": "0.0.1",
+  "description": "",
+  "author": "",
+  "private": true,
+  "license": "UNLICENSED",
+  "scripts": {
+    "build": "nest build",
+    "format": "prettier --write \"src/**/*.ts\" \"test/**/*.ts\"",
+    "start": "nest start",
+    "start:dev": "nest start --watch",
+    "start:debug": "nest start --debug --watch",
+    "start:prod": "node dist/main",
+    "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
+    "test": "jest",
+    "test:watch": "jest --watch",
+    "test:cov": "jest --coverage",
+    "test:debug": "node --inspect-brk -r tsconfig-paths/register -r ts-node/register node_modules/.bin/jest --runInBand",
+    "test:e2e": "jest --config ./test/jest-e2e.json",
+    "prepare": "ts-patch install && typia patch"
+  },
+  "dependencies": {
+    "@furality/nestjs-http-promise": "^2.0.97",
+    "@nestjs/common": "^10.0.0",
+    "@nestjs/core": "^10.0.0",
+    "@nestjs/platform-express": "^10.0.0",
+    "@opentelemetry/api": "^1.9.0",
+    "axios": "^1.7.2",
+    "axios-retry": "^4.4.1",
+    "nestjs-otel": "^6.1.1",
+    "reflect-metadata": "^0.2.0",
+    "rxjs": "^7.8.1",
+    "typia": "^6.5.1"
+  },
+  "devDependencies": {
+    "@nestjs/cli": "^10.0.0",
+    "@nestjs/schematics": "^10.0.0",
+    "@nestjs/testing": "^10.0.0",
+    "@types/express": "^4.17.17",
+    "@types/jest": "^29.5.2",
+    "@types/node": "^20.3.1",
+    "@types/supertest": "^6.0.0",
+    "@typescript-eslint/eslint-plugin": "^7.0.0",
+    "@typescript-eslint/parser": "^7.0.0",
+    "eslint": "^8.42.0",
+    "eslint-config-prettier": "^9.0.0",
+    "eslint-plugin-prettier": "^5.0.0",
+    "jest": "^29.5.0",
+    "prettier": "^3.0.0",
+    "source-map-support": "^0.5.21",
+    "supertest": "^7.0.0",
+    "ts-jest": "^29.1.0",
+    "ts-loader": "^9.4.3",
+    "ts-node": "^10.9.1",
+    "ts-patch": "^3.2.1",
+    "tsconfig-paths": "^4.2.0",
+    "typescript": "^5.5.2"
+  },
+  "jest": {
+    "moduleFileExtensions": [
+      "js",
+      "json",
+      "ts"
+    ],
+    "rootDir": "src",
+    "testRegex": ".*\\.spec\\.ts$",
+    "transform": {
+      "^.+\\.(t|j)s$": "ts-jest"
+    },
+    "collectCoverageFrom": [
+      "**/*.(t|j)s"
+    ],
+    "coverageDirectory": "../coverage",
+    "testEnvironment": "node"
+  }
+}

src/index.ts

@@ -0,0 +1,5 @@
+export * from './postal.constant';
+export * from './postal.interface';
+export { PostalClientModule } from './postal.module';
+export { PostalClientService } from './postal.service';
+export * from './interface';

src/interface/error.interface.ts

@@ -0,0 +1,12 @@
+export enum ErrorType {
+  ValidationError = 'ValidationError',
+  NoRecipients = 'NoRecipients',
+  NoContent = 'NoContent',
+  TooManyToAddresses = 'TooManyToAddresses',
+  TooManyCCAddresses = 'TooManyCCAddresses',
+  TooManyBCCAddresses = 'TooManyBCCAddresses',
+  FromAddressMissing = 'FromAddressMissing',
+  UnauthenticatedFromAddress = 'UnauthenticatedFromAddress',
+  AttatchmentMissingName = 'AttatchmentMissingName',
+  AttachmentMissingData = 'AttachmentMissingData',
+}

src/interface/index.ts

@@ -0,0 +1,2 @@
+export * from './send.interface';
+export * from './error.interface';

src/interface/send.interface.ts

@@ -0,0 +1,38 @@
+import type { tags } from 'typia';
+import typia from 'typia';
+
+export const validateSendMessage = typia.createAssertGuard<SendMessage>();
+
+export type SendMessage = {
+  // The e-mail addresses of the recipients (max 50)
+  to: Array<string> & tags.MaxItems<50> & tags.MinItems<1>;
+  // The e-mail addresses of any CC contacts (max 50)
+  cc?: Array<string> & tags.MaxItems<50> & tags.MinItems<1>;
+  // The e-mail addresses of any BCC contacts (max 50)
+  bcc?: Array<string> & tags.MaxItems<50> & tags.MinItems<1>;
+  // The e-mail address for the From header
+  from: string;
+  // The e-mail address for the Sender header
+  sender?: string;
+  // The subject of the e-mail
+  subject?: string;
+  //The tag of the email
+  tag?: string;
+  // Reply to email address
+  reply_to?: string;
+
+  // The Plain Text content of the e-mail
+  plain_body: string;
+
+  // The HTML content of the e-mail
+  html_body?: string;
+
+  //An array of attachments
+  attachments?: Array<any>;
+
+  //Additional headers to add to the e-mail
+  headers?: any;
+
+  //Is this message a bounce?
+  bounce?: boolean;
+};

src/postal.constant.ts

@@ -0,0 +1,12 @@
+export const POSTAL_HTTP_SERVICE = Symbol('POSTAL_HTTP_SERVICE');
+export const POSTAL_CONFIG_OPTIONS = Symbol('POSTAL_CONFIG_OPTIONS');
+
+// API Endpoints
+
+// Sending Messages API
+export const SEND_MESSAGE_API_URL = '/api/v1/send/message';
+export const SEND_MESSAGE_RAW_API_URL = '/api/v1/send/raw';
+
+// Message Status API
+export const RETURN_MESSAGE_API_URL = '/api/v1/messages/message';
+export const RETURN_DELIVERY_API_URL = '/api/v1/messages/deliveries';

src/postal.interface.ts

@@ -0,0 +1,37 @@
+import type {
+  InjectionToken,
+  ModuleMetadata,
+  OptionalFactoryDependency,
+  Provider,
+  Type,
+} from '@nestjs/common';
+import type { AxiosRequestConfig } from 'axios';
+import { IAxiosRetryReturn } from 'axios-retry';
+import { createAssert } from 'typia';
+
+export interface PostalServiceOptions {
+  baseURL: string;
+  apiKey: string;
+}
+
+export const assertPostalServiceOptions = createAssert<PostalServiceOptions>();
+
+export interface PostalModuleOptions {
+  http: Omit<AxiosRequestConfig, 'baseUrl'> & IAxiosRetryReturn;
+  postal: PostalServiceOptions;
+}
+
+export interface PostalModuleOptionsFactory {
+  createPostalOptions(): Promise<PostalModuleOptions> | PostalModuleOptions;
+}
+
+export interface PostalModuleAsyncOptions
+  extends Pick<ModuleMetadata, 'imports'> {
+  useExisting?: Type<PostalModuleOptionsFactory>;
+  useClass?: Type<PostalModuleOptionsFactory>;
+  useFactory?: (
+    ...args: any[]
+  ) => Promise<PostalModuleOptions> | PostalModuleOptions;
+  inject?: (InjectionToken | OptionalFactoryDependency)[];
+  extraProviders?: Provider[];
+}

src/postal.module.ts

@@ -0,0 +1,124 @@
+import { HttpModule, HttpService } from '@furality/nestjs-http-promise';
+import type { DynamicModule, Provider } from '@nestjs/common';
+import { Module } from '@nestjs/common';
+import http from 'http';
+import https from 'https';
+
+import { POSTAL_HTTP_SERVICE, POSTAL_CONFIG_OPTIONS } from './postal.constant';
+
+import type {
+  PostalModuleAsyncOptions,
+  PostalModuleOptionsFactory,
+  PostalModuleOptions,
+} from './postal.interface';
+
+import { PostalClientService } from './postal.service';
+
+@Module({})
+export class PostalClientModule {
+  static register(config: PostalModuleOptions): DynamicModule {
+    return {
+      module: PostalClientModule,
+      imports: [
+        HttpModule.register({
+          baseURL: config.postal.baseURL,
+          ...config.http,
+        }),
+      ],
+      providers: [
+        PostalClientService,
+        {
+          provide: POSTAL_CONFIG_OPTIONS,
+          useValue: config.postal,
+        },
+      ],
+      exports: [PostalClientService],
+    };
+  }
+
+  static registerAsync(asyncOptions: PostalModuleAsyncOptions): DynamicModule {
+    const providers = this.createAsyncProviders(asyncOptions);
+
+    return {
+      module: PostalClientModule,
+      imports: [
+        HttpModule.registerAsync({
+          ...(asyncOptions.imports && { imports: asyncOptions.imports }),
+          useFactory: (options: PostalModuleOptions) => ({
+            httpAgent: new http.Agent({
+              keepAlive: true,
+              keepAliveMsecs: 10 * 60 * 1000,
+            }),
+            httpsAgent: new https.Agent({
+              keepAlive: true,
+              keepAliveMsecs: 10 * 60 * 1000,
+            }),
+            baseURL: options.postal.baseURL,
+            ...options.http,
+          }),
+          inject: [POSTAL_CONFIG_OPTIONS],
+          extraProviders: providers,
+        }),
+        ...(asyncOptions.imports ?? []),
+      ],
+      providers: [
+        PostalClientService,
+        {
+          provide: POSTAL_CONFIG_OPTIONS,
+          useFactory: (options: PostalModuleOptions) => options.postal,
+          inject: [POSTAL_CONFIG_OPTIONS],
+        },
+        {
+          provide: POSTAL_HTTP_SERVICE,
+          useExisting: HttpService,
+        },
+        ...providers,
+      ],
+      exports: [PostalClientService, POSTAL_HTTP_SERVICE],
+    };
+  }
+
+  private static createAsyncProviders(
+    options: PostalModuleAsyncOptions,
+  ): Provider[] {
+    if (!!options.useExisting || !!options.useFactory) {
+      return [this.createAsyncOptionsProvider(options)];
+    }
+
+    const providers = [this.createAsyncOptionsProvider(options)];
+
+    if (options.useClass) {
+      providers.push({
+        provide: options.useClass,
+        useClass: options.useClass,
+      });
+    }
+
+    return providers;
+  }
+
+  private static createAsyncOptionsProvider(
+    options: PostalModuleAsyncOptions,
+  ): Provider {
+    if (options.useFactory) {
+      return {
+        provide: POSTAL_CONFIG_OPTIONS,
+        useFactory: options.useFactory,
+        inject: options.inject ?? [],
+      };
+    }
+
+    const inject = options.useExisting
+      ? [options.useExisting]
+      : options.useClass
+        ? [options.useClass]
+        : null;
+
+    return {
+      provide: POSTAL_CONFIG_OPTIONS,
+      useFactory: async (optionsFactory: PostalModuleOptionsFactory) =>
+        await optionsFactory.createPostalOptions(),
+      ...(inject && { inject }),
+    };
+  }
+}

src/postal.service.ts

@@ -0,0 +1,39 @@
+import { Inject, Injectable } from '@nestjs/common';
+import {
+  POSTAL_CONFIG_OPTIONS,
+  POSTAL_HTTP_SERVICE,
+  SEND_MESSAGE_API_URL,
+} from './postal.constant';
+import { HttpService } from '@furality/nestjs-http-promise';
+import { PostalServiceOptions } from './postal.interface';
+import { Span } from 'nestjs-otel';
+import { SpanKind } from '@opentelemetry/api';
+import { SendMessage } from './interface/send.interface';
+
+@Injectable()
+export class PostalClientService {
+  constructor(
+    @Inject(POSTAL_HTTP_SERVICE) private readonly httpService: HttpService,
+    @Inject(POSTAL_CONFIG_OPTIONS)
+    private readonly config: PostalServiceOptions,
+  ) {}
+
+  @Span(undefined, { kind: SpanKind.CLIENT })
+  async sendMessage(message: SendMessage): Promise<any> {
+    const response = await this.httpService.post(
+      SEND_MESSAGE_API_URL,
+      message,
+      {
+        headers: {
+          'X-Postal-Api-Key': this.config.apiKey,
+        },
+      },
+    );
+
+    const { data } = response;
+
+    if (data.status === 'error') {
+      throw new Error(data.data.message);
+    }
+  }
+}

src/utils/axios.util.ts

@@ -0,0 +1,13 @@
+import type { AxiosError } from 'axios';
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export function isAxiosError<T = any, D = any>(
+  payload: unknown,
+): payload is AxiosError<T, D> {
+  return (
+    typeof payload === 'object' &&
+    !!payload &&
+    'name' in payload &&
+    payload.name === 'AxiosError'
+  );
+}

src/utils/type.util.ts

@@ -0,0 +1,24 @@
+export type RequiredBy<T, K extends keyof T> = Omit<T, K> &
+  Pick<Required<T>, K>;
+
+export type RequireAtLeastOne<T, Keys extends keyof T = keyof T> = Pick<
+  T,
+  Exclude<keyof T, Keys>
+> &
+  {
+    [K in Keys]-?: Required<Pick<T, K>> & Partial<Pick<T, Exclude<Keys, K>>>;
+  }[Keys];
+
+export function hasProperties<T extends object, K extends keyof T>(
+  obj: T | RequiredBy<T, K>,
+  ...keys: readonly K[]
+): obj is RequiredBy<T, K> {
+  return keys.every((x) => obj[x] !== undefined);
+}
+
+export function hasAtLeastOneProperty<T extends object, K extends keyof T>(
+  obj: T | RequireAtLeastOne<T, K>,
+  ...keys: readonly K[]
+): obj is RequireAtLeastOne<T, K> {
+  return keys.some((x) => obj[x] !== undefined);
+}

tsconfig.json

@@ -0,0 +1,26 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "declaration": true,
+    "removeComments": true,
+    "emitDecoratorMetadata": true,
+    "experimentalDecorators": true,
+    "allowSyntheticDefaultImports": true,
+    "target": "ES2021",
+    "sourceMap": true,
+    "outDir": "./dist",
+    "baseUrl": "./",
+    "incremental": true,
+    "skipLibCheck": true,
+    "strictNullChecks": true,
+    "noImplicitAny": false,
+    "strictBindCallApply": false,
+    "forceConsistentCasingInFileNames": false,
+    "noFallthroughCasesInSwitch": false,
+    "plugins": [
+      {
+        "transform": "typia/lib/transform"
+      }
+    ]
+  }
+}