nest-http-interface

This library is inspired by the HTTP interface in Spring 6 and provides a similar API for Nest.js.

Features

• Provides a simplified and declarative way of creating HTTP services.
• Supports both REST and GraphQL requests.
• Provides a concise syntax for handling query parameters, path variables, request headers, request bodies, and forms.
• Offers integration with class-transformer to facilitate data transformation.
• Support both promise and observable.
• Circuit breaker support

Requirements

• Node.js
  • 18 or later if HttpClient is not specified (default: fetch)
  • if custom HttpClient is provided, you can use lower version of Node.js
• Nest.js 8 or later

Installation

$ npm install @r2don/nest-http-interface

Usage

First, the module we created must be imported into AppModule.ts:

import { Module } from '@nestjs/common';
import { HttpInterfaceModule } from '@r2don/nest-http-interface';

@Module({
  imports: [HttpInterfaceModule.forRoot()],
})
export class AppModule {}

Then, you need to create the desired HTTP service and specify several decorators:

import {
  HttpInterface,
  GetExchange,
  ResponseBody,
  imitation,
  PathVariable,
} from '@r2don/nest-http-interface';

@HttpInterface('https://example.com/api') // base url
class UserHttpService {
  @GetExchange('/users/{id}') // path
  @ResponseBody(UserResponse) // response dto
  async request(@PathVariable('id') id: number): Promise<UserResponse> {
    return imitation(id); // this is a mock function to prevent the type error
  }
}

After adding the service to the providers in the module, you can use it and make HTTP requests when calling the request method:

@Injectable()
class UserService {
  constructor(private readonly client: UserHttpService) {}

  async getUser(id: number): Promise<UserResponse> {
    return this.client.request(id);
  }
}

Decorators

• @HttpInterface(): Marks the class as an HTTP service.

• @{HTTP Method}Exchange(path: string, options?: HttpClientOptions): Marks the method as an HTTP request method, with path being the request's path or full URL.

• @GraphQLExchange(query: string, url = '/graphql', options?: HttpClientOptions): Marks the method as a GraphQL request method, with query being the GraphQL query and url being the GraphQL endpoint.

• @ResponseBody(dto: ClassConstructor, options?: ClassTransformOptions): Specifies the response DTO using a class constructor and options from the class-transformer library.

• @PathVariable(name?: string): Specifies the path variable, requiring the name of the variable.

• @RequestParam(key?: string, defaultValue?: string): Specifies the query string parameter, requiring the key of the parameter. If key is not specified, the parameter must be an object. See examples below:

  • Example with key: request(@RequestParam('foo') query: string): string
  • Example without key: request(@RequestParam() query: { foo: string }): string

• @RequestHeader(key?: string, option?: { defaultValue?: string; transform?: (value: string) => string }): Specifies the request header, requiring the key of the header optionally.

• @Bearer(): Specifies the bearer token using the Authorization header.

• @Cookie(key: string): Specifies the cookie using the Cookie header, requiring the key of the cookie.

• @RequestBody(key?: string, defalutValue?: unkown): Specifies the request body using application/json as the content type, requiring the key of the body optionally.

• @RequestForm(key?: string, defaultValue?: string): Specifies the request form using application/x-www-form-urlencoded as the content type, requiring the key of the body optionally.

• @CircuitBreaker(options?: CircuitBreaker.Options): Marks the method as a circuit breaker, with options being the options of the circuit breaker. You can use global options by setting the circuitBreakerOption property in the module. options is from opossum library.

• @ObservableResponse(): Marks the method as an observable method. If this decorator is not specified, the method will return a promise.

Auto generate @ResponseBody() from return type of exchange method

Because of limitation of reflect-metadata, @ResponseBody() is required to specify the response DTO.

But this library provides a way to auto generate @ResponseBody() and infers response DTO from return type of exchange method.

It uses CLI Plugin like @nestjs/swagger and @nestjs/graphql.

To enable the plugin, open nest-cli.json

{
  "compilerOptions": {
    "plugins": ["@r2don/nest-http-interface"]
  }
}

You can use the options property to customize the behavior of the plugin.

{
  "compilerOptions": {
    "plugins": [
      {
        "name": "@r2don/nest-http-interface",
        "options": {
          "interfaceFilenameSuffix": [".http.service.ts"]
        }
      }
    ]
  }
}

Here is the list of options:

option	default	description
interfaceFilenameSuffix	['.service.ts']	HTTP service files suffix

@ResponseBody() will be added whenever nest start or nest build is executed.

License

This library is licensed under the MIT license.

Testing

To run tests, execute:

$ pnpm test