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JavaScript Node.js Basics (2014) Building a Command Line Application Perfecting: Getting Multiple Profiles

Andrey Konovalenko
Andrey Konovalenko
9,409 Points
Posted by Andrey Konovalenko
Andrey Konovalenko
9,409 Points

My solution for command line weather app using maps.googleapis.com and api.forecost.io

Hi everybody, I used maps.googleapis.com for getting latitude and longitude from google.map response object.

So your request should be: "https://maps.googleapis.com/maps/api/geocode/json?address=" + post code;

var https = require("https");
var post_code = process.argv[2];
console.log(post_code);

function printError(error){
    console.error(error.message);
}

function get(post_code){
    var request = https.get("https://maps.googleapis.com/maps/api/geocode/json?address=" + post_code, function(response){
        console.log(response.statusCode);
        var body = "";
        response.on('data', function(chunk){
            body += chunk;
        });
        response.on('end', function(){
            if (response.statusCode === 200) {
                try {
                    var coordinates = JSON.parse(body);
                    var lat = coordinates.results[0].geometry.location.lat;
                    var lng = coordinates.results[0].geometry.location.lng;
                    var post_code_coord = lat + "," +lng;
                    get_weather(post_code_coord);
                } catch(error) {
                    printError(error);
                }
            } else {
                printError({message: "There was an error getting coordinates " + " (" + response.statusCode+")"});
            }
        });
    request.on("error", printError); 
    });
}

function get_weather(coordinates){
    var APIkey = 'YOUR API key';
    var options = "https://api.forecast.io/forecast/" + APIkey + coordinates+ "?units=si";
    var request = https.get(options, function(response){
        console.log(response.statusCode);
        var body = "";
        response.on('data', function(chunk){
            body += chunk;
        });
        response.on('end', function(){
            if (response.statusCode === 200) {
                try {
                        var weather = JSON.parse(body);
                    console.log(weather.timezone + " " + weather.currently.temperature);
                } catch(error) {
                    printError(error);
                }
            } else {
            printError({message: "There was an error getting forecast data " + " (" + response.statusCode+")"});
            }
        });
    request.on("error", printError); 
    });
}
get(post_code);

I will be grateful for any thoughts about improving my solution. I know I should create a object constructor for request to avoid code repetition, but I don't know good way.

3 Answers

Thomas Nilsen
Thomas Nilsen
14,957 Points
Thomas Nilsen
Thomas Nilsen
14,957 Points

Good work! :)

I have a couple of suggestions -

  • Instead of using the http/https modules, use request. It's built on top of these modules and it's easier to use.
  • Instead of using callbacks, try to use Promises. It's very similar, but makes it easier to chain function calls (I'll post my version below).
  • Your printError() function just console.log stuff. Drop the function and just use console.log.
  • If other people were supposed to use your code (e.g. include it as a module). You should consider making the first function accept an object with params. One of the params being the API_KEY.

Here is my version of your code:

var request = require('request');

var param = process.argv[2];
var API_KEY = 'MY_API_KEY';


function getLocation() {
    return new Promise(function(resolve, reject) {
        var locationUrl = 'https://maps.googleapis.com/maps/api/geocode/json?address=' + param;
        var data = null
        return request(locationUrl, function(err, response, body) {
            if(!err) {
                try {
                    data = JSON.parse(body);

                    var lat = data.results[0].geometry.location.lat;
                    var lng = data.results[0].geometry.location.lng;
                    var coords = lat + ',' + lng;

                    resolve(coords);

                } catch(err) {
                    reject('Error during parsing of location-data: ' + err.message);
                }
            } else {
                reject('Unable to get location-data. Statuscode: ' + response.statusCode);
            }
        });
    });
}


function getWeather(coords) {
    return new Promise(function(resolve, reject) {
        var weatherUrl = 'https://api.forecast.io/forecast/' + API_KEY + '/' + coords + '?units=si';
        var data = null;
        return request(weatherUrl, function(err, response, body) {
            if(!err) {
                try {
                    data = JSON.parse(body);
                    resolve('The temperature in ' + data.timezone + ' is ' + data.currently.temperature);

                } catch(err) {
                    reject('Error during parsing of weather-data: ' + err.message);
                }
            } else {
                reject('Unable to get weather-data. Statuscode: ' + response.statusCode);
            }
        });

    });
}



getLocation().then(function(coords) {
    return getWeather(coords);
}).then(function(weatherInfo) {
    console.log(weatherInfo);
}).catch(function(err) {
    console.log(err);
});
Andrey Konovalenko
Andrey Konovalenko
9,409 Points
Andrey Konovalenko
Andrey Konovalenko
9,409 Points

Thanks for response. I had no idea about existing Promise before))) I still have much to learn)

Tan Guven
Tan Guven
3,379 Points
Tan Guven
Tan Guven
3,379 Points

This is my way and i like promise :) also

// app.js
const weather = require("./forecast.js");

weather.tellMeTheWeather();

// forecast.js
const request  = require("request"),
      postCode = "N101LR",
      API_KEY  = "My_API_KEY";

function weather(getLocation, coordinates) {
   function getLocation() {
      return new Promise((resolve, reject)=> {
         let locationUrl = `https://maps.googleapis.com/maps/api/geocode/json?address=${postCode}`,
             data        = null;

         return request(locationUrl, (err, response, body)=> {
            if (!err) {
               try {
                  data = JSON.parse(body);

                  let lat         = data.results[0].geometry.location.lat,
                      lng         = data.results[0].geometry.location.lng,
                      coordinates = `${lat},${lng}`;
                  resolve(coordinates);
               } catch (err) {
                  reject(`Error during the parsing of location-data: ${err.message}`);
               }
            } else {
               reject(`unable to get location-data. Status code: ${response.statusCode}`);
            }
         });
      });
   }

   function getWeather(coordinates) {
      return new Promise((resolve, reject)=> {
         let weatherUrl = `https://api.forecast.io/forecast/${API_KEY}/${coordinates}?units=ca`,
             data       = null;

         return request(weatherUrl, (err, response, body)=> {
            if (response.statusCode === 200) {

               try {
                  data = JSON.parse(body);
                  resolve(`THe temperature in ${data.timezone} is ${data.currently.temperature}`);
               } catch (err) {
                  reject(`Error happen during the parsing of weather-data: ${err.message}`);
               }

            } else {
               reject(`Unable to get weather-data. Status code: ${response.statusCode}`);
            }
         });
      });
   }

   getLocation().then((coordinates)=> {
      return getWeather(coordinates);
   }).then((weatherInfo)=> {
      console.log(weatherInfo);
   }).catch((err)=> {
      console.log(err);
   });
}

module.exports.weather = weather;
Christopher Johnson
Christopher Johnson
12,829 Points
Christopher Johnson
Christopher Johnson
12,829 Points

What is the 7units=si in the var options?