A request library, Undici, is introduced

preface

In the browser, we used to use XHR if we wanted to make a request, but the underlying API was often called in a crude way. JQuery’s $. Ajax was probably the best choice for efficiency, but a more modern FETCH API has since come along.

However, considering the compatibility of FETCH and the fact that it does not support some global configurations and request interrupts, we may use the AXIOS request library to make some requests in actual use. In Node.js, almost all requests are made through the request library. Unfortunately, Request went out of maintenance two years ago, and it’s not easy to find a replacement library in Node.js.

In the request issues section, there is a table that recommends some common request libraries in Node.js:

Axios, which is used a lot in browsers, doesn’t work well in Node.js, especially when it comes to uploading files, which can cause unexpected problems.

Recently, when I was online at 🏄🏿, I found that Node.js officially has a request library called Undici, which is quite complicated to obtain. So, today’s article will introduce undici. By the way, undici is the meaning of Italian 11, as if double eleven is coming soon, good Maotai 🤔.

Undici means eleven in Italian. 1.1 -> 11 -> Eleven -> Undici. It is also a Stranger Things reference.

Get started

We can install undici directly via NPM:

npm install undici -S
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Undici exposes an object that provides several apis:

• undici.fetch: initiates a request, and the browserfetchMethod consistency;
• undici.request: Initiate a request, andrequestThe library is similar in that this method supports Promise;
• undici.stream: Handle file stream, can be used for file download;

undici.fetch

Note: This method requires Node version >= V16.5.0

Before requesting the service through Undici.fetch, you need to start a simple login service through KOA.

const Koa = require('koa')
const bodyParser = require('koa-bodyparser')

const app = new Koa()

app.use(bodyParser())
app.use(ctx= > {
  const { url, method, body } = ctx.request
  if (url === '/login') {
    if (method === 'POST') {
      if (body.account === 'shenfq' && body.password === '123456') {
        ctx.body = JSON.stringify({
          name: 'shenfq'.mobile: '130xxxxxx'
        })
        return
      }
    }
  }
  ctx.status = 404
  ctx.body = JSON.stringify({})
})

app.listen(3100)
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The above code is very simple and only supports accepting a POST method to /login route. Let’s use Undici.fetch to make a POST request.

const { fetch } = require('undici')

const bootstrap = async() = > {const api = 'http://localhost:3100/login'
  const rsp = await fetch(api, {
    method: 'POST'.headers: {
      'content-type': 'application/json'
    },
    body: JSON.stringify({
      account: 'shenfq'.password: '123456'})})if(rsp.status ! = =200) {
    console.log(rsp.status, 'Request failed')
    return
  }
  const json = await rsp.json()
  console.log(rsp.status, json)
}

bootstrap()
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If you change the request to GET, a 404 is returned.

const rsp = await fetch(api, {
  method: 'GET'
})
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undici.request

Undici. Request is called in a similar way to Undici. Fetch, and its parameter form is similar.

const { request } = require('undici')

const bootstrap = async() = > {const api = 'http://localhost:3100/login'
  const { body, statusCode } = await request(api, {
    method: 'POST'.headers: {
      'content-type': 'application/json'
    },
    body: JSON.stringify({
      account: 'shenfq'.password: '123456'})})const json = await body.json()
  console.log(statusCode, json)
}

bootstrap()
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The request method returns the HTTP response in the body property, which also supports methods like.json()/.text().

Interrupt request

Install the abort controller library, and then instantiate abort Controller to pass the interrupt signal into the Request configuration.

npm i abort-controller
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const undici = require('undici')
const AbortController = require('abort-controller')

// Instantiate abort-controller
const abortController = new AbortController()
undici.request('http://127.0.0.1:3100', {
  method: 'GET'.// Incoming interrupt semaphore
  signal: abortController.signal,
}).then(({ statusCode, body }) = > {
  body.on('data'.(data) = > {
    console.log(statusCode, data.toString())
  })
})
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We run the code and find that we can request success because we didn’t actively call the interrupt method.

undici.request('http://127.0.0.1:3100', {
  method: 'GET'.signal: abortController.signal,
}).then(({ statusCode, body }) = > {
  console.log('Request successful')
  body.on('data'.(data) = > {
    console.log(statusCode, data.toString())
  })
}).catch(error= > {
  // Catch an error triggered by an interrupt
  console.log('error', error.name)
})

// Call interrupt
abortController.abort()
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Now when you run the code, instead of logging the success of the request, you enter the catch logic and interrupt the request successfully.

undici.steam

The undici. Steam method can be used for file downloads, or interface proxies.

File download

const fs = require('fs')const { stream } = require('undici')const out = fs.createWriteStream('./ Song Dynasty - Ge Yao - Gold Wire and Iron Wire. JPG ')const url = 'https://img.dpm.org.cn/Uploads/Picture/dc/cegift/cegift6389.jpg'stream(url, { opaque: out }, ({ opaque }) = > opaque)
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The interface agent

const http = require('http')const undici = require('undici')// The request for port 3100, Const client = new undici.client ('http://localhost')http.createServer((req, res) => {const {url, method } = req client.stream( { method, path: url,opaque: res }, ({ opaque }) => opaque )}).listen(3100)
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conclusion

This article only introduces the use of several APIS of Undici, it seems that undici is relatively low. However, compatibility is not very good, for example, fetch only supports versions above [email protected].

Although Request has been deprecated, we still use some long-tested libraries, such as urllib used in egg framework, and node-fetch. The fetch API is used in the same way as in the browser.