Open Weather Map Example

Introduction

This example shows how to download data from open weather map. http://openweathermap.com/

To access open weather map you have to register their. Open Weather Map allows you to download different data about

• current Weather conditions,
• past Weather conditions,
• Weather Forecast.

Also it is possible to setup an own Weather Station and send data to open Weather Map.

You find more details about the API and the data you can download here: http://openweathermap.com/api

Example: Download Current Weather Data

This example just downloads the current weather condition of a given location ID. You only have to fill in your network ID, Network Password and your open Weather Map API Key. This example was tested with ESP32 and should also work with any other Espruino with network connection (wifi).

Time in this example is GMT! This is important if you like to use sunrise and sunset time. If you like to use the second example, please put a comment around the first example.

Example: Download Weather Forecast

This example downloads the weather for the next 5 days with a 3 hour resolution. You only have to fill in your network ID, Network Password and your open Weather Map API Key. This example was tested with ESP32 and should also work with any other Espruino with network connection (wifi).

You should put the weather example into comments and remove the comments from this example to use it.

Time in this example is GMT! This is important if you like to use sunrise and sunset time.

Source Code

var wifi = require("Wifi");
var http = require("http");

// Request your own Key at: http://openweathermap.com/
var API_Key = "<your API Key>";
var Location = "2912573";
var SSID = "<your network ID>";
var PSWD = "<your network PSWD>";


function OnConnect ( ) {
  print ("Wifi Connected");
}

/*
 if you like to see more details just dump the entire data!
*/
function DumpWeather( OWMData ) {

  /* remove comment below to see full data */
  // console.log(OWMData);
  console.log("Temperature: " +  (OWMData.main.temp-273.15));
  console.log("Pressure:    " +  (OWMData.main.pressure) + "hPa");
  console.log("Humidity:    " +  (OWMData.main.humidity) +"%");
  console.log("Wind speed:  " +  OWMData.wind.speed + "m/s");
  console.log("Weather:     " +  OWMData.weather[0].description);
  var SRD = new Date(OWMData.sys.sunrise*1000);
  console.log("Sunrise:     " +  SRD.getHours() + ":" +SRD.getMinutes());
  var SSD = new Date(OWMData.sys.sunset*1000);
  console.log("Sunset:      " +  SSD.getHours() + ":" +SSD.getMinutes());
  var SAM = new Date(OWMData.dt*1000);
  console.log("Sample:      " +  SAM.getHours() + ":" +SAM.getMinutes());

}

/*
 This function dump the data which is received when forecast was requested.
*/
function DumpForecast( OWMData ) {
  //console.log(OWMData);    
  for (i=0; i < OWMData.cnt; i++ )
  {
    console.log(OWMData.list[i].dt_txt + " - " + (OWMData.list[i].main.temp-273.15) );
  }
}

/* Generate the OWM Request 
This function generates a string which can be used to request the weather data.
*/
function GetOWM_Request ( RequestType, LocationID, APIKey )
{
  var OWM = "https://api.openweathermap.org/data/2.5/";
  var Result = "error";
  if ( ( RequestType == "weather") || (( RequestType == "forecast")) )
  {
    Result = OWM + RequestType+ "?id=" + Location + "&appid=" + APIKey;
  } else {
    console.log ( "unsupported OWM Request" );
  }
  return Result;
}

function DoInit() {
  print(wifi.getStatus()  );
  print(wifi.stopAP()  );
  wifi.connect(SSID, { password:PSWD}, function(err) { OnConnect(err); } );
  print(wifi.getStatus()  );

  var Req = "";
  // Request weather data
  Req = GetOWM_Request("weather", Location, API_Key);
  print ("Request: "+ Req);
  http.get(Req, function(res) {
    var contents = "";
    res.on('data', function(data) { contents += data; });
    res.on('close', function() { DumpWeather(JSON.parse(contents)); });
  }); 

  /* 
  // Reqeust forecast data
  Req = GetOWM_Request("forecast", Location, API_Key);
  print ("Request: "+ Req);
  http.get( Req, function(res) {
    var contents = "";
    res.on('data', function(data) { contents += data; });
    res.on('close', function() { DumpForecast(JSON.parse(contents)); });
  });
  */

  wifi.on('disconnected', function(details) {
    print("Lost Connection" + details );
  });
}

DoInit();