Drizzle HTTP

Create API Clients with Decorators for Typescript and Javascript.

NPM Packages
Deno

What it is

Drizzle-HTTP is library inspired by Retrofit and Feign, that let you create API clients using decorators.

Table of Contents

• Deno
• Installation
• Packages
• Getting Started
• Features
• Examples
• Common Issues
• Benchmarks
• Contributing

Installation

Drizzle-HTTP is a monorepo with several packages. You will need to install at least the core module, @drizzle-http/core, along with one or more extensions.
For a basic usage in a Node.js Backend Environment, you can install:

npm i @drizzle-http/core
npm i @drizzle-http/undici

For browser environments:

npm i @drizzle-http/core
npm i @drizzle-http/fetch

Getting Started

By default, request and response bodies will be handled as JSON. Will can change this with the appropriate decorators.
It will not set the content type by default.

Overview

Usage typically looks like the example below:

import { newAPI, Timeout } from '@drizzle-http/core'
import { GET } from "@drizzle-http/core";
import { Path } from "@drizzle-http/core";
import { Param } from "@drizzle-http/core";
import { POST } from "@drizzle-http/core";
import { Body } from "@drizzle-http/core";
import { HttpResponse } from "@drizzle-http/core";
import { PUT } from "@drizzle-http/core";
import { DELETE } from "@drizzle-http/core";
import { ParseErrorBody } from "@drizzle-http/core";
import { Query } from "@drizzle-http/core";
import { HeaderMap } from "@drizzle-http/core";
import { UndiciCallFactory } from "@drizzle-http/undici";
import { ContentType } from "@drizzle-http/core";
import { MediaTypes } from "@drizzle-http/core";

@Timeout(15e30)
@Path('/customers')
@HeaderMap({ 'x-app-id': 'example-app' })
@ContentType(MediaTypes.APPLICATION_JSON)
class CustomerAPI {
  @GET()
  search (@Query('filter') filter: string, @Query('sort') sort: string): Promise<Customer[]> {
  }

  @GET('/{id}')
  @ParseErrorBody()
  byId (@Param('id') id: string): Promise<Customer> {
  }

  @POST()
  add (@Body() customer: Customer): Promise<HttpResponse> {
  }

  @PUT('/{id}')
  update (@Param('id') id: string, @Body() customer: Customer): Promise<HttpResponse> {
  }

  @DELETE('/{id}')
  remove (@Param('id') id: string): Promise<HttpResponse> {
  }
}

const api = newAPI()
  .baseUrl('https://example.com')
  .callFactory(new UndiciCallFactory())
  .build()
  .create(CustomerAPI)

const customer = await api.byId('100')

Basic Decorators

Defaults

Default values that Drizzle starts with. All values can be overridden using decorators.

• Timeout: 30 seconds
• Request Body Converter: JSON
• Response Body Converter: JSON

Error Handling

When methods are not decorated with @RawResponse(), Drizzle throws an HttpError with the following structure:

{
  message: 'Request failed with status code: 400',
  code: 'DZ_ERR_HTTP',
  request: {
    url: 'https://example.com/test,
    method: 'GET',
    headers: Headers,
    body: ''
  },
  response: {
    headers: Headers,
    status: 400,
    statusText: ''
    body: 'error from server'
  }
}

When you want to parse the error response body to, for example a JSON object, use @ParseErrorBody(). By default, @ParseErrorBody() use the same response converter used by the success scenario. If you need a different converter for the error body, pass the name of the converter to the decorator. E.g.: @ParseErrorBody(BuiltInConv.TEXT).

Features

• Define HTTP requests with decorators, including path parameters, querystring, headers, body and so on.
• Extensible
• Custom response adapters
• Request interceptors
• Abort requests
• Timeouts
• Parse responses to objects or get the raw response in a fetch like format
• Parse error response bodies
• RxJs support with RxJs Adapter
• Map responses with Response Mapper Adapter
• Circuit Breaker with Opossum with this adapter
• Deno support

Browser

For Browser usage, take a look on this implementation. It uses fetch to make HTTP requests.

Deno

A version for Deno is available on https://deno.land/x/drizzle_http.
The Deno version is simpler than the one available for Node.js. It contains the core module and a fetch client implementation specific for Deno.
More details and usage example here.

Interceptors

You can intercept requests and responses using Interceptors.
You can a simple function, chain => {}, an Intepcetor interface implementation or an InterceptorFactory implementation, if you need more configurations.
Take a look on the examples below:

class CustomerAPI {
  @GET('/{id}')
  getById (@Param('id') id: string): Promise<Customer> {
    return noop(id)
  }
}

const api = newAPI()
  .addInterceptor(async chain => {
    console.log('before request')

    const response = await chain.proceed(chain.request())

    console.log('after request')

    return response
  })
  .baseUrl('https://example.com')
  .callFactory(new UndiciCallFactory())
  .createAPI(CustomerAPI)

Circuit Breaker

With the package @drizzle-http/opossum-circuit-breaker, you can protect your endpoints with circuit breakers.
It uses Opossum circuit breaker implementation.
See a basic demonstration below. More details here.

import { CircuitBreaker } from "@drizzle-http/opossum-circuit-breaker";
import { Fallback } from "@drizzle-http/opossum-circuit-breaker";

@Timeout(15e30)
@Path('/customers')
@HeaderMap({ 'x-app-id': 'example-app' })
class CustomerAPI {
  @GET()
  @CircuitBreaker()
  search (@Query('filter') filter: string, @Query('sort') sort: string): Promise<Customer[]> {
  }

  @GET('/{id}')
  @CircuitBreaker()
  @Fallback((id: string, error: Error) => { /** fallback logic **/
  })
  byId (@Param('id') id: string): Promise<Customer> {
  }
}

Raw HTTP Response

By the default, HTTP success responses you be parsed and resolved and http errors will be rejected. If you want the raw HTTP response, including headers, status codes, body stream, decorate your method with @RawResponse() and the return will be a Promise<HttpResponse>, similar to Fetch. In this case, HTTP errors will not be rejected.

Form URL Encoded

To make application/x-www-form-urlencoded request, decorate your class or method with @FormUrlEncoded().
Use @Field() to define a parameter as a form field entry.
If using @Body(), object keys will be converted to url form encoded format.

Common Issues

ESLint and TS Check Problems

The API class methods doesn't need to have a body, but TS and some ESLint configurations will complain with the empty body and maybe the unused parameters. To solve this, you can:

• Use the helper function noop() in all method bodies. This function does nothing, but it will have the same return type as your method, and you can pass all method arguments removing any lint issues.
• Disable TS check for the API class file with the comment: // @ts-nocheck
• Disable or relax ESLint checks for the file or class

Example:

import { noop } from "@drizzle-http/core";

class CustomerAPI {
  @GET('/{id}')
  byId (@Param('id') id: string): Promise<Customer> {
    return noop(id)
  }

  @POST()
  @ParseErrorBody()
  add (@Body() customer: Customer): Promise<HttpResponse> {
    return noop(customer)
  }
}

Request/Response Mismatch

You need to be very explicitly regarding the API class and method configurations as Drizzle is unable to detect stuff like the generic return type of methods. For example, if you want the raw response, to gain access to all the details of a http response, you need to explicitly decorate your method with @RawResponse().

Benchmarks

Run

npm run benchmark

Results

Machine: MacBook Pro (13-inch, 2019)
Processor: 2,8 GHz Quad-Core Intel Core i7
Memory: 16 GB 2133 MHz LPDDR3
Node: 15

This benchmark consists in a client with multiple connections performing calls to a server that responds a 80kb JSON.

Contributing

See CONTRIBUTING for more details.

License

Drizzle HTTP is MIT Licensed.