Merge pull request #98 from Derpthemeus/google-maps-geocoding

Use Google Maps for geocoding

.gitignore

@@ -11,3 +11,4 @@ baselineEToData/*.png
 baselineEToData/*.tif
 baselineEToData/dataPreparer[.exe]
 observations.json
+geocoderCache.json

routes/geocoders/Geocoder.ts

@@ -0,0 +1,49 @@
+import fs = require("fs");
+
+import { GeoCoordinates } from "../../types";
+
+export abstract class Geocoder {
+
+	private static cacheFile: string = __dirname + "/../../../geocoderCache.json";
+
+	private cache: Map<string, GeoCoordinates>;
+
+	public constructor() {
+		// Load the cache from disk.
+		if ( fs.existsSync( Geocoder.cacheFile ) ) {
+			this.cache = new Map( JSON.parse( fs.readFileSync( Geocoder.cacheFile, "utf-8" ) ) );
+		} else {
+			this.cache = new Map();
+		}
+
+		// Write the cache to disk every 5 minutes.
+		setInterval( () => {
+			this.saveCache();
+		}, 5 * 60 * 1000 );
+	}
+
+	private saveCache(): void {
+		fs.writeFileSync( Geocoder.cacheFile, JSON.stringify( Array.from( this.cache.entries() ) ) );
+	}
+
+	/**
+	 * Converts a location name to geographic coordinates.
+	 * @param location A location name.
+	 * @return A Promise that will be resolved with the GeoCoordinates of the specified location, or rejected with a
+	 * CodedError.
+	 */
+	protected abstract geocodeLocation( location: string ): Promise<GeoCoordinates>;
+
+	/**
+	 * Converts a location name to geographic coordinates, first checking the cache and updating it if necessary.
+	 */
+	public async getLocation( location: string ): Promise<GeoCoordinates> {
+		if ( this.cache.has( location ) ) {
+			return this.cache.get( location );
+		}
+
+		const coords: GeoCoordinates = await this.geocodeLocation( location );
+		this.cache.set( location, coords );
+		return coords;
+	}
+}

routes/geocoders/GoogleMaps.ts

@@ -0,0 +1,35 @@
+import { GeoCoordinates } from "../../types";
+import { CodedError, ErrorCode } from "../../errors";
+import { httpJSONRequest } from "../weather";
+import { Geocoder } from "./Geocoder";
+
+export default class GoogleMaps extends Geocoder {
+	private readonly API_KEY: string;
+
+	public constructor() {
+		super();
+		this.API_KEY = process.env.GOOGLE_MAPS_API_KEY;
+		if ( !this.API_KEY ) {
+			throw "GOOGLE_MAPS_API_KEY environment variable is not defined.";
+		}
+	}
+
+	public async geocodeLocation( location: string ): Promise<GeoCoordinates> {
+		// Generate URL for Google Maps geocoding request
+		const url = `https://maps.googleapis.com/maps/api/geocode/json?key=${ this.API_KEY }&address=${ encodeURIComponent( location ) }`;
+
+		let data;
+		try {
+			data = await httpJSONRequest( url );
+		} catch ( err ) {
+			// If the request fails, indicate no data was found.
+			throw new CodedError( ErrorCode.LocationServiceApiError );
+		}
+
+		if ( !data.results.length ) {
+			throw new CodedError( ErrorCode.NoLocationFound );
+		}
+
+		return [ data.results[ 0 ].geometry.location.lat, data.results[ 0 ].geometry.location.lng ];
+	}
+}

routes/geocoders/WUnderground.ts

@@ -0,0 +1,31 @@
+import { GeoCoordinates } from "../../types";
+import { CodedError, ErrorCode } from "../../errors";
+import { httpJSONRequest } from "../weather";
+import { Geocoder } from "./Geocoder";
+
+export default class WUnderground extends Geocoder {
+	public async geocodeLocation( location: string ): Promise<GeoCoordinates> {
+		// Generate URL for autocomplete request
+		const url = "http://autocomplete.wunderground.com/aq?h=0&query=" +
+			encodeURIComponent( location );
+
+		let data;
+		try {
+			data = await httpJSONRequest( url );
+		} catch ( err ) {
+			// If the request fails, indicate no data was found.
+			throw new CodedError( ErrorCode.LocationServiceApiError );
+		}
+
+		// Check if the data is valid
+		if ( typeof data.RESULTS === "object" && data.RESULTS.length && data.RESULTS[ 0 ].tz !== "MISSING" ) {
+
+			// If it is, reply with an array containing the GPS coordinates
+			return [ parseFloat( data.RESULTS[ 0 ].lat ), parseFloat( data.RESULTS[ 0 ].lon ) ];
+		} else {
+
+			// Otherwise, indicate no data was found
+			throw new CodedError( ErrorCode.NoLocationFound );
+		}
+	}
+}

routes/weather.ts

@@ -14,9 +14,11 @@ import ZimmermanAdjustmentMethod from "./adjustmentMethods/ZimmermanAdjustmentMe
 import RainDelayAdjustmentMethod from "./adjustmentMethods/RainDelayAdjustmentMethod";
 import EToAdjustmentMethod from "./adjustmentMethods/EToAdjustmentMethod";
 import { CodedError, ErrorCode, makeCodedError } from "../errors";
+import { Geocoder } from "./geocoders/Geocoder";
 
 const WEATHER_PROVIDER: WeatherProvider = new ( require("./weatherProviders/" + ( process.env.WEATHER_PROVIDER || "OWM" ) ).default )();
 const PWS_WEATHER_PROVIDER: WeatherProvider = new ( require("./weatherProviders/" + ( process.env.PWS_WEATHER_PROVIDER || "WUnderground" ) ).default )();
+const GEOCODER: Geocoder = new ( require("./geocoders/" + ( process.env.GEOCODER || "WUnderground" ) ).default )();
 
 // Define regex filters to match against location
 const filters = {
@@ -55,28 +57,7 @@ export async function resolveCoordinates( location: string ): Promise< GeoCoordi
 		const split: string[] = location.split( "," );
 		return [ parseFloat( split[ 0 ] ), parseFloat( split[ 1 ] ) ];
 	} else {
-		// Generate URL for autocomplete request
-		const url = "http://autocomplete.wunderground.com/aq?h=0&query=" +
-			encodeURIComponent( location );
-
-		let data;
-		try {
-			data = await httpJSONRequest( url );
-		} catch (err) {
-			// If the request fails, indicate no data was found.
-			throw new CodedError( ErrorCode.LocationServiceApiError );
-		}
-
-		// Check if the data is valid
-		if ( typeof data.RESULTS === "object" && data.RESULTS.length && data.RESULTS[ 0 ].tz !== "MISSING" ) {
-
-			// If it is, reply with an array containing the GPS coordinates
-			return [ parseFloat( data.RESULTS[ 0 ].lat ), parseFloat( data.RESULTS[ 0 ].lon ) ];
-		} else {
-
-			// Otherwise, indicate no data was found
-			throw new CodedError( ErrorCode.NoLocationFound );
-		}
+		return GEOCODER.getLocation( location );
 	}
 }