How to read JSON files with pure javascript on a server side using node.js?

Question

I have very little experience working with Node.js and jQuery and have been searching for the last few hours for a solution. I have an API from openweathermap.com () that returns weather information in the JSON format, and I am trying to pull the temperature value.

I am using Node.js to run a program that can be accessed from any device on the network and I have previously used jQuery on the client to read the file using $.getJSON but am in the process transferring most of my code to the server side to prevent needing a browser open at all times in order for the program to run properly. Obviously you can't use jQuery with node.js but i tried server adaptations for node.js including cheerio, jsdom, and a standard jquery add-on but none of them would do the trick. I can't use XMLHttpRequest or http.get because its being run server side and I can't simply use JSON.parse because it is pulling from a website.

How can I pull the data from the website, store it as an object, and then pull data from it while using just pure javascript?

Here is what I originally had running on the client:

	var updateWeather = function(){
	
		$.getJSON('http://api.openweathermap.org/data/2.5/weather?id=5802340&units=imperial&appid=80e9f3ae5074805d4788ec25275ff8a0&units=imperial', function(data) {
			
			socket.emit("outsideTemp",data.main.temp);	

		});
	
	}
	
	updateWeather();

<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.0/jquery.min.js"></script>
</head>

A quick note... it looks like the "appid" URL parameter is your API key? You might want to edit this out of your question, or switch to a different API key, as somebody might grab this one now that it is public. — nbura
– nbura, Commented Jun 19, 2019 at 6:35

FelizNaveedad · Accepted Answer · 2019-06-18 22:51:25Z

3

NodeJS natively supports JSON -- so no "special" work needed. I would recommend using an http client that makes our life easier, like axios, but you can do this natively. I have provided two snippets below for you to get started:

Using popular HTTP Client

 const axios = require('axios');

axios.get('http://api.openweathermap.org/data/2.5/weather?id=5802340&units=imperial&appid=80e9f3ae5074805d4788ec25275ff8a0&units=imperial').then((res) => {
    console.log(res.data)
})

Plain NodeJS (taken from the NodeJS Docs)

const http = require('http');

http.get('http://api.openweathermap.org/data/2.5/weather?id=5802340&units=imperial&appid=80e9f3ae5074805d4788ec25275ff8a0&units=imperial', (res) => {
  const { statusCode } = res;
  const contentType = res.headers['content-type'];

  let error;
  if (statusCode !== 200) {
    error = new Error('Request Failed.\n' +
                      `Status Code: ${statusCode}`);
  } else if (!/^application\/json/.test(contentType)) {
    error = new Error('Invalid content-type.\n' +
                      `Expected application/json but received ${contentType}`);
  }
  if (error) {
    console.error(error.message);
    // Consume response data to free up memory
    res.resume();
    return;
  }

  res.setEncoding('utf8');
  let rawData = '';
  res.on('data', (chunk) => { rawData += chunk; });
  res.on('end', () => {
    try {
      const parsedData = JSON.parse(rawData);
      console.log(parsedData);
    } catch (e) {
      console.error(e.message);
    }
  });
}).on('error', (e) => {
  console.error(`Got error: ${e.message}`);
});

answered Jun 18, 2019 at 22:51

FelizNaveedad

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1 Comment

FelizNaveedad Over a year ago

A quick note: if you decide to use axios, you will need to install the axios dependency via npm. You can find installation instructions on their github page

baao · Accepted Answer · 2019-06-18 22:41:49Z

0

Many people use request / request promise with node

const req = require('request-promise');

req.get({
    uri: 'http://api.openweathermap.org/data/2.5/weather?id=5802340&units=imperial&appid=80e9f3ae5074805d4788ec25275ff8a0&units=imperial',
    json: true
}).then(e => {console.log(e.coord)});

answered Jun 18, 2019 at 22:41

baao

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4 Comments

jonrsharpe Over a year ago

Note that request is now deprecated.

baao Over a year ago

Is it? @jonrsharpe I can't find any notice on github. What's the replacement?

Brady Underwood Over a year ago

Thanks! So if I used this and then instead of console.log(e) i used something like var ex = JSON.parse(e); and then console.log(ex.main.temp); would that work?

baao Over a year ago

Omit the JSON.parse @BradyUnderwood, json:true already handles this.

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