Files
opensprinkler-weather/routes/weather.js
2015-07-01 19:57:01 -05:00

306 lines
10 KiB
JavaScript

( function() {
// Define regex filters to match against location
var http = require( "http" ),
parseXML = require( "xml2js" ).parseString,
filters = {
gps: /^[-+]?([1-8]?\d(\.\d+)?|90(\.0+)?),\s*[-+]?(180(\.0+)?|((1[0-7]\d)|([1-9]?\d))(\.\d+)?)$/,
pws: /^(?:pws|icao):/,
url: /^https?:\/\/([\w\.-]+)(:\d+)?(\/.*)?$/,
time: /(\d{4})-(\d{2})-(\d{2})T(\d{2}):(\d{2}):(\d{2})([+-])(\d{2})(\d{2})/
};
// Generic HTTP request handler that parses the URL and uses the
// native Node.js http module to perform the request
function httpRequest( url, callback ) {
url = url.match( filters.url );
var options = {
host: url[1],
port: url[2] || 80,
path: url[3]
};
http.get( options, function( response ) {
var data = "";
// Reassemble the data as it comes in
response.on( "data", function( chunk ) {
data += chunk;
} );
// Once the data is completely received, return it to the callback
response.on( "end", function() {
callback( data );
} );
} ).on( "error", function() {
// If the HTTP request fails, return false
callback( false );
} );
}
// Converts IP string to integer
function ipToInt( ip ) {
ip = ip.split( "." );
return ( ( ( ( ( ( +ip[0] ) * 256 ) + ( +ip[1] ) ) * 256 ) + ( +ip[2] ) ) * 256 ) + ( +ip[3] );
}
// Resolves the Month / Day / Year of a Date object
Date.prototype.toUSDate = function(){
return ( this.getMonth() + 1 ) + "/" + this.getDate() + "/" + this.getFullYear();
};
// Takes a PWS or ICAO location and resolves the GPS coordinates
function getPWSCoordinates( location, weatherUndergroundKey, callback ) {
var url = "http://api.wunderground.com/api/" + weatherUndergroundKey +
"/conditions/forecast/q/" + encodeURIComponent( location ) + ".json";
httpRequest( url, function( data ) {
data = JSON.parse( data );
if ( typeof data === "object" && data.current_observation && data.current_observation.observation_location ) {
callback( [ data.current_observation.observation_location.latitude,
data.current_observation.observation_location.longitude ] );
} else {
callback( false );
}
} );
}
// If location does not match GPS or PWS/ICAO, then attempt to resolve
// location using Weather Underground autocomplete API
function resolveCoordinates( location, callback ) {
var url = "http://autocomplete.wunderground.com/aq?h=0&query=" +
encodeURIComponent( location );
httpRequest( url, function( data ) {
data = JSON.parse( data );
if ( typeof data.RESULTS === "object" && data.RESULTS.length ) {
callback( [ data.RESULTS[0].lat, data.RESULTS[0].lon ] );
}
} );
}
// Accepts a time string formatted in ISO-8601 and returns the timezone.
// The timezone output is formatted for OpenSprinkler Unified firmware.
function getTimezone( time ) {
time = time.match( filters.time );
var hour = parseInt( time[7] + time[8] ),
minute = parseInt( time[9] );
minute = ( minute / 15 >> 0 ) / 4.0;
hour = hour + ( hour >=0 ? minute : -minute );
return ( ( hour + 12 ) * 4 ) >> 0;
}
// Retrieve weather data to complete the weather request
function getWeatherData( location, callback ) {
// Get the API key from the environment variables
var WSI_API_KEY = process.env.WSI_API_KEY,
// Generate URL using The Weather Company API v1 in Imperial units
url = "http://api.weather.com/v1/geocode/" + location[0] + "/" + location[1] +
"/observations/current.json?apiKey=" + WSI_API_KEY + "&language=en-US&units=e";
// Perform the HTTP request to retrieve the weather data
httpRequest( url, function( data ) {
callback( JSON.parse( data ) );
} );
}
// Retrieve the historical weather data for the provided location
function getYesterdayWeatherData( location, callback ) {
// Get the API key from the environment variables
var WSI_HISTORY_KEY = process.env.WSI_HISTORY_KEY,
today = new Date(),
yesterday = new Date( today.getTime() - 1000 * 60 * 60 * 24 ),
// Generate URL using WSI Cleaned History API in Imperial units showing daily average values
url = "http://cleanedobservations.wsi.com/CleanedObs.svc/GetObs?ID=" + WSI_HISTORY_KEY +
"&Lat=" + location[0] + "&Long=" + location[1] +
"&Req=davg&startdate=" + yesterday.toUSDate() + "&enddate=" + today.toUSDate() + "&TS=LST";
// Perform the HTTP request to retrieve the weather data
httpRequest( url, function( xml ) {
parseXML( xml, function ( err, result ) {
callback( result.WeatherResponse.WeatherRecords[0].WeatherData[0].$ );
});
} );
}
// Calculates the resulting water scale using the provided weather data, adjustment method and options
function calculateWeatherScale( adjustmentMethod, adjustmentOptions, weather ) {
// Calculate the average temperature
var temp = ( weather.observation.imperial.temp_max_24hour + weather.observation.imperial.temp_min_24hour ) / 2,
// Relative humidity and if unavailable default to 0
rh = weather.observation.imperial.rh || 0,
// The absolute precipitation in the past 48 hours
precip = weather.observation.imperial.precip_2day || weather.observation.imperial.precip_24hour;
if ( typeof temp !== "number" ) {
// If the maximum and minimum temperatures are not available then use the current temperature
temp = weather.observation.imperial.temp;
}
// Zimmerman method
if ( adjustmentMethod == 1 ) {
var humidityFactor = ( 30 - rh ),
tempFactor = ( ( temp - 70 ) * 4 ),
precipFactor = ( precip * -2 );
// Apply adjustment options if available
if ( adjustmentOptions ) {
if ( adjustmentOptions.hasOwnProperty( "h" ) ) {
humidityFactor = humidityFactor * ( adjustmentOptions.h / 100 );
}
if ( adjustmentOptions.hasOwnProperty( "t" ) ) {
tempFactor = tempFactor * ( adjustmentOptions.t / 100 );
}
if ( adjustmentOptions.hasOwnProperty( "r" ) ) {
precipFactor = precipFactor * ( adjustmentOptions.r / 100 );
}
}
return parseInt( Math.min( Math.max( 0, 100 + humidityFactor + tempFactor + precipFactor ), 200 ) );
}
return -1;
}
// Function to return the sunrise and sunset times from the weather reply
function getSunData( weather ) {
// Sun times must be converted from strings into date objects and processed into minutes from midnight
var sunrise = weather.observation.sunrise.match( filters.time ),
sunset = weather.observation.sunset.match( filters.time );
return [
parseInt( sunrise[4] ) * 60 + parseInt( sunrise[5] ),
parseInt( sunset[4] ) * 60 + parseInt( sunset[5] )
];
}
// Checks if the weather data meets any of the restrictions set by OpenSprinkler.
// Restrictions prevent any watering from occurring and are similar to 0% watering level.
// California watering restriction prevents watering if precipitation over two days is greater
// than 0.01" over the past 48 hours.
function checkWeatherRestriction( adjustmentValue, weather ) {
var californiaRestriction = ( adjustmentValue >> 7 ) & 1;
if ( californiaRestriction ) {
// If the California watering restriction is in use then prevent watering
// if more then 0.01" of rain has accumulated in the past 48 hours
if ( weather.observation.imperial.precip_2day > 0.01 || weather.observation.imperial.precip_24hour > 0.01 ) {
return true;
}
}
return false;
}
// API Handler when using the weatherX.py where X represents the
// adjustment method which is encoded to also carry the watering
// restriction and therefore must be decoded
exports.getWeather = function( req, res ) {
// The adjustment method is encoded by the OpenSprinkler firmware and must be
// parsed. This allows the adjustment method and the restriction type to both
// be saved in the same byte.
var adjustmentMethod = req.params[0] & ~( 1 << 7 ),
adjustmentOptions = req.query.wto,
location = req.query.loc,
weatherUndergroundKey = req.query.key,
outputFormat = req.query.format,
firmwareVersion = req.query.fwv,
remoteAddress = req.headers[ "x-forwarded-for" ] || req.connection.remoteAddress,
finishRequest = function( weather ) {
if ( !weather || typeof weather.observation !== "object" || typeof weather.observation.imperial !== "object" ) {
res.send( "Error: No weather data found." );
return;
}
var data = {
scale: calculateWeatherScale( adjustmentMethod, adjustmentOptions, weather ),
restrict: checkWeatherRestriction( req.params[0], weather ) ? 1 : 0,
tz: getTimezone( weather.observation.obs_time_local ),
sunrise: getSunData( weather )[0],
sunset: getSunData( weather )[1],
eip: ipToInt( remoteAddress )
};
// Return the response to the client
if ( outputFormat === "json" ) {
res.json( data );
} else {
res.send( "&scale=" + data.scale +
"&restrict=" + data.restrict +
"&tz=" + data.tz +
"&sunrise=" + data.sunrise +
"&sunset=" + data.sunset +
"&eip=" + data.eip
);
}
};
// Exit if no location is provided
if ( !location ) {
res.send( "Error: No location provided." );
return;
}
remoteAddress = remoteAddress.split(",")[0];
// Parse weather adjustment options
try {
// Reconstruct JSON string from deformed controller output
adjustmentOptions = JSON.parse( "{" + adjustmentOptions + "}" );
} catch (err) {
adjustmentOptions = false;
}
// Parse location string
if ( filters.gps.test( location ) ) {
// Handle GPS coordinates
location = location.split( "," );
location = [ parseFloat( location[0] ), parseFloat( location[1] ) ];
getWeatherData( location, finishRequest );
} else if ( filters.pws.test( location ) ) {
if ( !weatherUndergroundKey ) {
res.send( "Error: Weather Underground key required when using PWS or ICAO location." );
return;
}
// Handle Weather Underground specific location
getPWSCoordinates( location, weatherUndergroundKey, function( result ) {
location = result;
getWeatherData( location, finishRequest );
} );
} else {
// Attempt to resolve provided location to GPS coordinates
resolveCoordinates( location, function( result ) {
location = result;
getWeatherData( location, finishRequest );
} );
}
};
} )();