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

If you have not installed class-transformer, you need to install it:

$ npm install class-transformer

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:

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

Example

There are some examples in the example directory. Please refer to the README.md.

License

This library is licensed under the MIT license.

Testing

To run tests, execute:

$ pnpm test