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Retrieving Data - Solution

2:15 with Andrew Chalkley

In this video I'll show you how I retrieved information from a weather API.

Documentation

OpenWeatherMap API Solution Code

The OpenWeatherMap API works a little differently than the API shown in the video:

  • You can't pass it a city/state combination, but you can either pass it a city name or a zip code
  • You need to specify the units format as an additional query string parameter in order to get the temperature in fahrenheit
    • Temperature is available in Fahrenheit, Celsius and Kelvin units
    • For temperature in Fahrenheit use units=imperial
    • For temperature in Celsius use units=metric
    • Temperature in Kelvin is used by default, no need to use units parameter in API call

Here's an overview of the differences from the code shown in the video:

  • app.js
    • Removed the code that replaces spaces with underscores
  • weather.js
    • Switched to using the querystring.stringify() method to URL encode a parameters object
    • Added a check to see if the provided query is a number or not in order to determine which API endpoint to use

Here's the code:

app.js
const weather = require('./weather');

const query = process.argv.slice(2).join(' ');

//query: 90201
//query: Los Angeles

weather.get(query);
weather.js
const https = require('https');
const querystring = require('querystring');
const api = require('./api.json');

// Print out temp details
// Print out error message

function get(query) {
    const parameters = {
      APPID: api.key,
      units: 'imperial'
    };

    const zipCode = parseInt(query);
    if (!isNaN(zipCode)) {
      parameters.zip = zipCode + ',us';
    } else {
      parameters.q = query + ',us';
    }

    const url = `https://api.openweathermap.org/data/2.5/weather?${querystring.stringify(parameters)}`;
    console.log(url);

    const request = https.get(url, response => {
        let body = "";
        // Read the data
        response.on('data', chunk => {
            body += chunk;
        });
        response.on('end', () => {
            console.log(body);
            //Parse data
            //Print the data
        });
    });
}

module.exports.get = get;

//TODO: Handle any errors
  • 0:00

    In my app.js file, I included the weather module

  • 0:04

    that includes all the functionality to get the weather based on a query.

  • 0:10

    The next line of code cleans up the user input to create queries for

  • 0:13

    the WeatherUnderground API.

  • 0:18

    Maybe other API queries would have plus symbols instead of underscores.

  • 0:23

    On the next line, I pass the query into the weather module's get function.

  • 0:29

    Let's take a look at the weather code.

  • 0:32

    The first line is straightforward.

  • 0:34

    I'm including the HTTPS module.

  • 0:37

    The second line is something new.

  • 0:39

    I'm requiring a json file.

  • 0:42

    In Node.js you can require JSON files as well as JavaScript modules.

  • 0:46

    Requiring a JSON file can be handy to store configuration you don't want to

  • 0:51

    include in your git repository such as an API key or database credentials.

  • 0:59

    You don't want other people using your API key and

  • 1:02

    attributing their usage of the API to you or your application.

  • 1:07

    Then I have some comments to remind me of the things that I need to do like print

  • 1:12

    out the temperature details or to print out error messages.

  • 1:17

    Then, we have the get function that takes in the query generated from the command

  • 1:21

    line arguments.

  • 1:23

    The WeatherUnderground API requires you to build your query up like this.

  • 1:27

    With the API key, And

  • 1:32

    the query in the URL like this.

  • 1:40

    Then, I read in the body, and then I log out the body.

  • 1:48

    I've also included reminders that I need to parse and

  • 1:51

    print out the data once it's parsed.

  • 1:55

    Then, I export the get function here.

  • 1:58

    Finally, I've added a reminder to add errors later.

  • 2:02

    How did my solution differ from yours?

  • 2:05

    Your next challenge is to pas the JSON, look for the appropriate keys, and

  • 2:10

    print out the temperature message for the city you're querying about.

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