JSON.parse() 返回意外的输入结束

Question

[`const express = require('express'); const app = express(); const https = require('https');

const url = "https://api.thevirustracker.com/free-api?countryTimeline=US";

app.get("/", (req,res) => { res.send("Server is Running")

https.get(url, (response) => {
    
    response.on("data", (data) => {

        const TimelineData = JSON.parse(data);
        console.log(TimelineData);
        
    })
})

})

app.listen(3000, ()=>console.log("Server is Running 0n 5000"));`] 1

 const express = require('express'); const app = express(); const https = require('https'); const url = "https://api.thevirustracker.com/free-api?countryTimeline=US"; app.get("/", (req,res) => { res.send("Server is Running") https.get(url, (response) => { response.on("data", (data) => { const TimelineData = JSON.parse(data); console.log(TimelineData); }) }) }) app.listen(3000, ()=>console.log("Server is Running 0n 5000"));

Answer 1

To deliver large data in an effective manner API send data in chunk/stream format. and to receive each chunk it triggers the ' data ' event and in your case, it might be possible that API sends data in chunk format. and it will not send you complete data in a single event.

Let's assume the complete response of your API is: { name: 'bella', age: 34, count: 40138 }

And API send it in 2 chunks:

• Chunk1: { name: 'bella', age: 34, count: 4013
• Chunk2: 8 }

In that case Json.Parse() on Chunk1 or Chunk2 will not work and threw an exception.

To deal with this problem you need to listen to the ' end ' event and capture data from the' data ' and parse it in the ' end ' event.

Use the below code:

 const express = require('express'); const app = express(); const https = require('https'); const url = "https://archive.org/advancedsearch.php?q=subject:google+sheets&output=json"; app.get("/", (req, res) => { res.send("Server is Running") https.get(url, (response) => { var responseData = ''; response.on("data", (dataChunk) => { responseData += dataChunk; }) response.on('end', () => { const TimelineData = JSON.parse(responseData); console.log(TimelineData); }); }).on('error', (e) => { console.error(e); }); }) app.listen(5000, () => console.log("Server is Running 0n 5000"));

Answer 2

The "data" event can be fired multiple times: https://nodejs.org/api/http.html#http_class_http_clientrequest

You have to listen for the "end" event and concat all chunks from the "data" event togehter for the full body response.

const express = require('express');
const app = express();
const https = require('https');

const url = "https://api.thevirustracker.com/free-api?countryTimeline=US";

app.get("/", (req, res) => {

    res.send("Server is Running")

    https.get(url, (response) => {

        const chunks = [];

        response.on("data", (data) => {
            chunks.push(data);
        })

        response.on("end", () => {

            let size = chunks.reduce((prev, cur) => {
                return prev + cur.length;
            }, 0);

            let data = Buffer.concat(chunks, size).toString();

            console.log(JSON.parse(data))

        });

    })

})



app.listen(3000, () => console.log("Server is Running 0n 5000"));

Answer 3

why are you using https? replace https with http and run it again.

const express = require('express');
const app = express();
const http = require('http');

const url = "https://api.thevirustracker.com/free-api?countryTimeline=US";

app.get("/", (req ,res) => {
    res.send("Server is Running")

    http.get(url, (response) => {
        
        response.on("data", (data) => {

            const TimelineData = JSON.parse(data);
            console.log(TimelineData);
            
        })
    })
})

Answer 4

const express = require('express')
const app = express()

const port = 3000

app.post('/', (req, res) => { 
  res.send('Hello World!")

})

app.listen(port, () => {
  console.log('server running')

})

When you run the program in nodejs, open the brower and type http://localhost:3000 . The output will be....

Answer 5

Listen for 'end ' the problem will be resolved

Answer 6

Try importing all the dependencies. Importing is better than requiring because you can selectively load only the pieces you need. Also in package.json file add "type":"module" before scripts. The days of const something= require('something') are a thing of the past now because of new ESM modules.

import express from 'express';
import https from 'https';
const app=express();
const port=3000;

In package.json file

"name": "restApiWithNode",
"version": "1.0.0",
"description": "",
"main": "index.js",
"type": "module",

Read this article for clarity https://formidable.com/blog/2021/node-esm-and-exports/