Merge 'dev' into 'eto'

WateringScaleCache.ts

@@ -0,0 +1,69 @@
+import * as NodeCache from "node-cache";
+import { GeoCoordinates, PWS } from "./types";
+import { AdjustmentOptions } from "./routes/adjustmentMethods/AdjustmentMethod";
+import * as moment from "moment-timezone";
+import * as geoTZ from "geo-tz";
+import { Moment } from "moment-timezone/moment-timezone";
+
+export default class WateringScaleCache {
+	private readonly cache: NodeCache = new NodeCache();
+
+	/**
+	 * Stores the results of a watering scale calculation. The scale will be cached until the end of the day in the local
+	 * timezone of the specified coordinates. If a scale has already been cached for the specified calculation parameters,
+	 * this method will have no effect.
+	 * @param adjustmentMethodId The ID of the AdjustmentMethod used to calculate this watering scale. This value should
+	 * have the appropriate bits set for any restrictions that were used.
+	 * @param coordinates The coordinates the watering scale was calculated for.
+	 * @param pws The PWS used to calculate the watering scale, or undefined if one was not used.
+	 * @param adjustmentOptions Any user-specified adjustment options that were used when calculating the watering scale.
+	 * @param wateringScale The results of the watering scale calculation.
+	 */
+	public storeWateringScale(
+		adjustmentMethodId: number,
+		coordinates: GeoCoordinates,
+		pws: PWS,
+		adjustmentOptions: AdjustmentOptions,
+		wateringScale: CachedScale
+	): void {
+		// The end of the day in the controller's timezone.
+		const expirationDate: Moment = moment().tz( geoTZ( coordinates[ 0 ], coordinates[ 1 ] )[ 0 ] ).endOf( "day" );
+		const ttl: number = ( expirationDate.unix() - moment().unix() );
+		const key = this.makeKey( adjustmentMethodId, coordinates, pws, adjustmentOptions );
+		this.cache.set( key, wateringScale, ttl );
+	}
+
+	/**
+	 * Retrieves a cached scale that was previously calculated with the given parameters.
+	 * @param adjustmentMethodId The ID of the AdjustmentMethod used to calculate this watering scale. This value should
+	 * have the appropriate bits set for any restrictions that were used.
+	 * @param coordinates The coordinates the watering scale was calculated for.
+	 * @param pws The PWS used to calculate the watering scale, or undefined if one was not used.
+	 * @param adjustmentOptions Any user-specified adjustment options that were used when calculating the watering scale.
+	 * @return The cached result of the watering scale calculation, or undefined if no values were cached.
+	 */
+	public getWateringScale(
+		adjustmentMethodId: number,
+		coordinates: GeoCoordinates,
+		pws: PWS,
+		adjustmentOptions: AdjustmentOptions
+	): CachedScale | undefined {
+		const key = this.makeKey( adjustmentMethodId, coordinates, pws, adjustmentOptions );
+		return this.cache.get( key );
+	}
+
+	private makeKey(
+		adjustmentMethodId: number,
+		coordinates: GeoCoordinates,
+		pws: PWS,
+		adjustmentOptions: AdjustmentOptions
+	): string {
+		return `${ adjustmentMethodId }#${ coordinates.join( "," ) }#${ pws ? pws.id : "" }#${ JSON.stringify( adjustmentOptions ) }`
+	}
+}
+
+export interface CachedScale {
+	scale: number;
+	rawData: object;
+	rainDelay: number;
+}

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "os-weather-service",
-  "version": "1.0.2",
+  "version": "1.0.4",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
@@ -127,6 +127,15 @@
       "integrity": "sha512-Fvm24+u85lGmV4hT5G++aht2C5I4Z4dYlWZIh62FAfFO/TfzXtPpoLI6I7AuBWkIFqZCnhFOoTT7RjjaIL5Fjg==",
       "dev": true
     },
+    "@types/node-cache": {
+      "version": "4.1.3",
+      "resolved": "https://registry.npmjs.org/@types/node-cache/-/node-cache-4.1.3.tgz",
+      "integrity": "sha512-3hsqnv3H1zkOhjygJaJUYmgz5+FcPO3vejBX7cE9/cnuINOJYrzkfOnUCvpwGe9kMZANIHJA7J5pOdeyv52OEw==",
+      "dev": true,
+      "requires": {
+        "@types/node": "*"
+      }
+    },
     "@types/range-parser": {
       "version": "1.2.3",
       "resolved": "https://registry.npmjs.org/@types/range-parser/-/range-parser-1.2.3.tgz",
@@ -571,6 +580,11 @@
       "integrity": "sha1-T6kXw+WclKAEzWH47lCdplFocUM=",
       "dev": true
     },
+    "clone": {
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/clone/-/clone-2.1.2.tgz",
+      "integrity": "sha1-G39Ln1kfHo+DZwQBYANFoCiHQ18="
+    },
     "collection-visit": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/collection-visit/-/collection-visit-1.0.0.tgz",
@@ -1126,8 +1140,7 @@
         "ansi-regex": {
           "version": "2.1.1",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "aproba": {
           "version": "1.2.0",
@@ -1148,14 +1161,12 @@
         "balanced-match": {
           "version": "1.0.0",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "brace-expansion": {
           "version": "1.1.11",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "balanced-match": "^1.0.0",
             "concat-map": "0.0.1"
@@ -1170,20 +1181,17 @@
         "code-point-at": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "concat-map": {
           "version": "0.0.1",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "console-control-strings": {
           "version": "1.1.0",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "core-util-is": {
           "version": "1.0.2",
@@ -1300,8 +1308,7 @@
         "inherits": {
           "version": "2.0.3",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "ini": {
           "version": "1.3.5",
@@ -1313,7 +1320,6 @@
           "version": "1.0.0",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "number-is-nan": "^1.0.0"
           }
@@ -1328,7 +1334,6 @@
           "version": "3.0.4",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "brace-expansion": "^1.1.7"
           }
@@ -1336,14 +1341,12 @@
         "minimist": {
           "version": "0.0.8",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "minipass": {
           "version": "2.3.5",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "safe-buffer": "^5.1.2",
             "yallist": "^3.0.0"
@@ -1362,7 +1365,6 @@
           "version": "0.5.1",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "minimist": "0.0.8"
           }
@@ -1443,8 +1445,7 @@
         "number-is-nan": {
           "version": "1.0.1",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "object-assign": {
           "version": "4.1.1",
@@ -1456,7 +1457,6 @@
           "version": "1.4.0",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "wrappy": "1"
           }
@@ -1542,8 +1542,7 @@
         "safe-buffer": {
           "version": "5.1.2",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "safer-buffer": {
           "version": "2.1.2",
@@ -1579,7 +1578,6 @@
           "version": "1.0.2",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "code-point-at": "^1.0.0",
             "is-fullwidth-code-point": "^1.0.0",
@@ -1599,7 +1597,6 @@
           "version": "3.0.1",
           "bundled": true,
           "dev": true,
-          "optional": true,
           "requires": {
             "ansi-regex": "^2.0.0"
           }
@@ -1643,14 +1640,12 @@
         "wrappy": {
           "version": "1.0.2",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         },
         "yallist": {
           "version": "3.0.3",
           "bundled": true,
-          "dev": true,
+          "dev": true
-          "optional": true
         }
       }
     },
@@ -2091,8 +2086,7 @@
     "lodash": {
       "version": "4.17.11",
       "resolved": "https://registry.npmjs.org/lodash/-/lodash-4.17.11.tgz",
-      "integrity": "sha512-cQKh8igo5QUhZ7lg38DYWAxMvjSAKG0A8wGSVimP07SIUEK2UO+arSRKbRZWtelMtN5V0Hkwh5ryOto/SshYIg==",
+      "integrity": "sha512-cQKh8igo5QUhZ7lg38DYWAxMvjSAKG0A8wGSVimP07SIUEK2UO+arSRKbRZWtelMtN5V0Hkwh5ryOto/SshYIg=="
-      "dev": true
     },
     "lowercase-keys": {
       "version": "1.0.1",
@@ -2465,6 +2459,15 @@
         }
       }
     },
+    "node-cache": {
+      "version": "4.2.0",
+      "resolved": "https://registry.npmjs.org/node-cache/-/node-cache-4.2.0.tgz",
+      "integrity": "sha512-obRu6/f7S024ysheAjoYFEEBqqDWv4LOMNJEuO8vMeEw2AT4z+NCzO4hlc2lhI4vATzbCQv6kke9FVdx0RbCOw==",
+      "requires": {
+        "clone": "2.x",
+        "lodash": "4.x"
+      }
+    },
     "node-watch": {
       "version": "0.6.2",
       "resolved": "https://registry.npmjs.org/node-watch/-/node-watch-0.6.2.tgz",

package.json

@@ -19,6 +19,7 @@
     "geo-tz": "^5.0.4",
     "mockdate": "^2.0.2",
     "moment-timezone": "^0.5.25",
+    "node-cache": "^4.2.0",
     "suncalc": "^1.8.0"
   },
   "devDependencies": {
@@ -30,6 +31,7 @@
     "@types/mocha": "^5.2.6",
     "@types/moment-timezone": "^0.5.12",
     "@types/node": "^10.14.6",
+    "@types/node-cache": "^4.1.3",
     "@types/suncalc": "^1.8.0",
     "chai": "^4.2.0",
     "mocha": "^5.2.0",

routes/adjustmentMethods/AdjustmentMethod.ts

@@ -56,4 +56,9 @@ export interface AdjustmentMethodResponse {
 	wateringData: BaseWateringData;
 }
 
-export interface AdjustmentOptions {}
+export interface AdjustmentOptions {
+	/** The ID of the PWS to use, prefixed with "pws:". */
+	pws?: string;
+	/** The API key to use to access PWS data. */
+	key?: string;
+}

routes/weather.spec.ts

@@ -4,6 +4,10 @@ import * as MockExpressRequest from 'mock-express-request';
 import * as MockExpressResponse from 'mock-express-response';
 import * as MockDate from 'mockdate';
 
+// The tests don't use OWM, but the WeatherProvider API key must be set to prevent an error from being thrown on startup.
+process.env.WEATHER_PROVIDER = "OWM";
+process.env.OWM_API_KEY = "NO_KEY";
+
 import { getWateringData } from './weather';
 import { GeoCoordinates, WeatherData, ZimmermanWateringData } from "../types";
 import { WeatherProvider } from "./weatherProviders/WeatherProvider";

routes/weather.ts

@@ -8,6 +8,7 @@ import * as geoTZ from "geo-tz";
 import { BaseWateringData, GeoCoordinates, PWS, TimeData, WeatherData } from "../types";
 import { WeatherProvider } from "./weatherProviders/WeatherProvider";
 import { AdjustmentMethod, AdjustmentMethodResponse, AdjustmentOptions } from "./adjustmentMethods/AdjustmentMethod";
+import WateringScaleCache, { CachedScale } from "../WateringScaleCache";
 import ManualAdjustmentMethod from "./adjustmentMethods/ManualAdjustmentMethod";
 import ZimmermanAdjustmentMethod from "./adjustmentMethods/ZimmermanAdjustmentMethod";
 import RainDelayAdjustmentMethod from "./adjustmentMethods/RainDelayAdjustmentMethod";
@@ -32,6 +33,8 @@ const ADJUSTMENT_METHOD: { [ key: number ] : AdjustmentMethod } = {
 	3: EToAdjustmentMethod
 };
 
+const cache = new WateringScaleCache();
+
 /**
  * Resolves a location description to geographic coordinates.
  * @param location A partial zip/city/country or a coordinate pair.
@@ -184,7 +187,6 @@ export const getWateringData = async function( req: express.Request, res: expres
 		location: string | GeoCoordinates	= getParameter(req.query.loc),
 		outputFormat: string				= getParameter(req.query.format),
 		remoteAddress: string				= getParameter(req.headers[ "x-forwarded-for" ]) || req.connection.remoteAddress,
-		pwsString: string					= getParameter( req.query.pws ),
 		adjustmentOptions: AdjustmentOptions;
 
 	// X-Forwarded-For header may contain more than one IP address and therefore
@@ -224,67 +226,108 @@ export const getWateringData = async function( req: express.Request, res: expres
 
 	// Parse the PWS information.
 	let pws: PWS | undefined = undefined;
-	if ( pwsString ) {
+	if ( adjustmentOptions.pws ) {
-		try {
+		if ( !adjustmentOptions.key ) {
-			pws = parsePWS( pwsString );
+			res.send("Error: An API key must be provided when using a PWS.");
-		} catch ( err ) {
-			res.send( `Error: ${ err }` );
 			return;
 		}
+
+		const idMatch = adjustmentOptions.pws.match( /^pws:([a-zA-Z\d]+)$/ );
+		const pwsId = idMatch ? idMatch[ 1 ] : undefined;
+		const keyMatch = adjustmentOptions.key.match( /^[a-f\d]{32}$/ );
+		const apiKey = keyMatch ? keyMatch[ 0 ] : undefined;
+
+		// Make sure that the PWS ID and API key look valid.
+		if ( !pwsId ) {
+			res.send("Error: PWS ID does not appear to be valid.");
+			return;
+		}
+		if ( !apiKey ) {
+			res.send("Error: PWS API key does not appear to be valid.");
+			return;
+		}
+
+		pws = { id: pwsId, apiKey: apiKey };
 	}
 
 	const weatherProvider = pws ? PWS_WEATHER_PROVIDER : WEATHER_PROVIDER;
-	let adjustmentMethodResponse: AdjustmentMethodResponse;
-	try {
-		adjustmentMethodResponse = await adjustmentMethod.calculateWateringScale(
-			adjustmentOptions, coordinates, weatherProvider, pws
-		);
-	} catch ( err ) {
-		if ( typeof err != "string" ) {
-			/* If an error occurs under expected circumstances (e.g. required optional fields from a weather API are
-			missing), an AdjustmentOption must throw a string. If a non-string error is caught, it is likely an Error
-			thrown by the JS engine due to unexpected circumstances. The user should not be shown the error message
-			since it may contain sensitive information. */
-			res.send( "Error: an unexpected error occurred." );
-			console.error( `An unexpected error occurred for ${ req.url }: `, err );
-		} else {
-			res.send( "Error: " + err );
-		}
-
-		return;
-	}
-
-	let scale = adjustmentMethodResponse.scale;
-
-	if ( checkRestrictions ) {
-		let wateringData: BaseWateringData = adjustmentMethodResponse.wateringData;
-		// Fetch the watering data if the AdjustmentMethod didn't fetch it and restrictions are being checked.
-		if ( checkRestrictions && !wateringData ) {
-			try {
-				wateringData = await weatherProvider.getWateringData( coordinates );
-			} catch ( err ) {
-				res.send( "Error: " + err );
-				return;
-			}
-		}
-
-		// Check for any user-set restrictions and change the scale to 0 if the criteria is met
-		if ( checkWeatherRestriction( req.params[ 0 ], wateringData ) ) {
-			scale = 0;
-		}
-	}
 
 	const data = {
-		scale:		scale,
+		scale:		undefined,
-		rd:			adjustmentMethodResponse.rainDelay,
+		rd:			undefined,
 		tz:			getTimezone( timeData.timezone, undefined ),
 		sunrise:	timeData.sunrise,
 		sunset:		timeData.sunset,
 		eip:		ipToInt( remoteAddress ),
-		rawData:	adjustmentMethodResponse.rawData,
+		rawData:	undefined,
-		error:		adjustmentMethodResponse.errorMessage
+		error:		undefined
 	};
 
+	let cachedScale: CachedScale;
+	if ( weatherProvider.shouldCacheWateringScale() ) {
+		cachedScale = cache.getWateringScale( req.params[ 0 ], coordinates, pws, adjustmentOptions );
+	}
+
+	if ( cachedScale ) {
+		// Use the cached data if it exists.
+		data.scale = cachedScale.scale;
+		data.rawData = cachedScale.rawData;
+		data.rd = cachedScale.rainDelay;
+	} else {
+		// Calculate the watering scale if it wasn't found in the cache.
+		let adjustmentMethodResponse: AdjustmentMethodResponse;
+		try {
+			adjustmentMethodResponse = await adjustmentMethod.calculateWateringScale(
+				adjustmentOptions, coordinates, weatherProvider, pws
+			);
+		} catch ( err ) {
+			if ( typeof err != "string" ) {
+				/* If an error occurs under expected circumstances (e.g. required optional fields from a weather API are
+				missing), an AdjustmentOption must throw a string. If a non-string error is caught, it is likely an Error
+				thrown by the JS engine due to unexpected circumstances. The user should not be shown the error message
+				since it may contain sensitive information. */
+				res.send( "Error: an unexpected error occurred." );
+				console.error( `An unexpected error occurred for ${ req.url }: `, err );
+			} else {
+				res.send( "Error: " + err );
+			}
+
+			return;
+		}
+
+		data.scale = adjustmentMethodResponse.scale;
+		data.error = adjustmentMethodResponse.errorMessage;
+		data.rd = adjustmentMethodResponse.rainDelay;
+		data.rawData = adjustmentMethodResponse.rawData;
+
+		if ( checkRestrictions ) {
+			let wateringData: BaseWateringData = adjustmentMethodResponse.wateringData;
+			// Fetch the watering data if the AdjustmentMethod didn't fetch it and restrictions are being checked.
+			if ( checkRestrictions && !wateringData ) {
+				try {
+					wateringData = await weatherProvider.getWateringData( coordinates );
+				} catch ( err ) {
+					res.send( "Error: " + err );
+					return;
+				}
+			}
+
+			// Check for any user-set restrictions and change the scale to 0 if the criteria is met
+			if ( checkWeatherRestriction( req.params[ 0 ], wateringData ) ) {
+				data.scale = 0;
+			}
+		}
+
+		// Cache the watering scale if caching is enabled and no error occurred.
+		if ( weatherProvider.shouldCacheWateringScale() && !data.error ) {
+			cache.storeWateringScale( req.params[ 0 ], coordinates, pws, adjustmentOptions, {
+				scale: data.scale,
+				rawData: data.rawData,
+				rainDelay: data.rd
+			} );
+		}
+	}
+
 	// Return the response to the client in the requested format
 	if ( outputFormat === "json" ) {
 		res.json( data );
@@ -452,21 +495,3 @@ export function getParameter( parameter: string | string[] ): string {
 	// Return an empty string if the parameter is undefined.
 	return parameter || "";
 }
-
-/**
- * Creates a PWS object from a string.
- * @param pwsString Information about the PWS in the format "pws:API_KEY@PWS_ID".
- * @return The PWS specified by the string.
- * @throws Throws an error message if the string is in an invalid format and cannot be parsed.
- */
-function parsePWS( pwsString: string): PWS {
-	const match = pwsString.match( /^pws:([a-f\d]{32})@([a-zA-Z\d]+)$/ );
-	if ( !match ) {
-		throw "Invalid PWS format.";
-	}
-
-	return {
-		apiKey: match[ 1 ],
-		id: match[ 2 ]
-	};
-}

routes/weatherProviders/DarkSky.ts

@@ -7,38 +7,36 @@ import { approximateSolarRadiation, CloudCoverInfo, EToData } from "../adjustmen
 
 export default class DarkSkyWeatherProvider extends WeatherProvider {
 
+	private readonly API_KEY: string;
+
+	public constructor() {
+		super();
+		this.API_KEY = process.env.DARKSKY_API_KEY;
+		if (!this.API_KEY) {
+			throw "DARKSKY_API_KEY environment variable is not defined.";
+		}
+	}
+
 	public async getWateringData( coordinates: GeoCoordinates ): Promise< ZimmermanWateringData > {
 		// The Unix timestamp of 24 hours ago.
 		const yesterdayTimestamp: number = moment().subtract( 1, "day" ).unix();
-		const todayTimestamp: number = moment().unix();
 
-		const DARKSKY_API_KEY = process.env.DARKSKY_API_KEY,
+		const yesterdayUrl = `https://api.darksky.net/forecast/${ this.API_KEY }/${ coordinates[ 0 ] },${ coordinates[ 1 ] },${ yesterdayTimestamp }?exclude=currently,minutely,daily,alerts,flags`;
-			yesterdayUrl = `https://api.darksky.net/forecast/${ DARKSKY_API_KEY }/${ coordinates[ 0 ] },${ coordinates[ 1 ] },${ yesterdayTimestamp }?exclude=currently,minutely,daily,alerts,flags`,
-			todayUrl = `https://api.darksky.net/forecast/${ DARKSKY_API_KEY }/${ coordinates[ 0 ] },${ coordinates[ 1 ] },${ todayTimestamp }?exclude=currently,minutely,daily,alerts,flags`;
 
-		let yesterdayData, todayData;
+		let yesterdayData;
 		try {
 			yesterdayData = await httpJSONRequest( yesterdayUrl );
-			todayData = await httpJSONRequest( todayUrl );
 		} catch ( err ) {
 			console.error( "Error retrieving weather information from Dark Sky:", err );
 			throw "An error occurred while retrieving weather information from Dark Sky."
 		}
 
-		if ( !todayData.hourly || !todayData.hourly.data || !yesterdayData.hourly || !yesterdayData.hourly.data ) {
+		if ( !yesterdayData.hourly || !yesterdayData.hourly.data ) {
 			throw "Necessary field(s) were missing from weather information returned by Dark Sky.";
 		}
 
-		/* The number of hourly forecasts to use from today's data. This will only include elements that contain historic
-			data (not forecast data). */
-		// Find the first element that contains forecast data.
-		const todayElements = Math.min( 24, todayData.hourly.data.findIndex( ( data ) => data.time > todayTimestamp - 60 * 60 ) );
-
-		/* Take as much data as possible from the first elements of today's data and take the remaining required data from
-			the remaining data from the last elements of yesterday's data. */
 		const samples = [
-			...yesterdayData.hourly.data.slice( todayElements - 24 ),
+			...yesterdayData.hourly.data
-			...todayData.hourly.data.slice( 0, todayElements )
 		];
 
 		// Fail if not enough data is available.
@@ -70,8 +68,7 @@ export default class DarkSkyWeatherProvider extends WeatherProvider {
 	}
 
 	public async getWeatherData( coordinates: GeoCoordinates ): Promise< WeatherData > {
-		const DARKSKY_API_KEY = process.env.DARKSKY_API_KEY,
+		const forecastUrl = `https://api.darksky.net/forecast/${ this.API_KEY }/${ coordinates[ 0 ] },${ coordinates[ 1 ] }?exclude=minutely,alerts,flags`;
-			forecastUrl = `https://api.darksky.net/forecast/${ DARKSKY_API_KEY }/${ coordinates[ 0 ] },${ coordinates[ 1 ] }?exclude=minutely,alerts,flags`;
 
 		let forecast;
 		try {
@@ -163,4 +160,8 @@ export default class DarkSkyWeatherProvider extends WeatherProvider {
 			precip: ( historicData.daily.data[ 0 ].precipIntensity || 0 ) * 24
 		};
 	}
+
+	public shouldCacheWateringScale(): boolean {
+		return true;
+	}
 }

routes/weatherProviders/OWM.ts

@@ -6,9 +6,18 @@ import * as moment from "moment";
 
 export default class OWMWeatherProvider extends WeatherProvider {
 
+	private readonly API_KEY: string;
+
+	public constructor() {
+		super();
+		this.API_KEY = process.env.OWM_API_KEY;
+		if (!this.API_KEY) {
+			throw "OWM_API_KEY environment variable is not defined.";
+		}
+	}
+
 	public async getWateringData( coordinates: GeoCoordinates ): Promise< ZimmermanWateringData > {
-		const OWM_API_KEY = process.env.OWM_API_KEY,
+		const forecastUrl = `http://api.openweathermap.org/data/2.5/forecast?appid=${ this.API_KEY }&units=imperial&lat=${ coordinates[ 0 ] }&lon=${ coordinates[ 1 ] }`;
-			forecastUrl = "http://api.openweathermap.org/data/2.5/forecast?appid=" + OWM_API_KEY + "&units=imperial&lat=" + coordinates[ 0 ] + "&lon=" + coordinates[ 1 ];
 
 		// Perform the HTTP request to retrieve the weather data
 		let forecast;
@@ -45,9 +54,8 @@ export default class OWMWeatherProvider extends WeatherProvider {
 	}
 
 	public async getWeatherData( coordinates: GeoCoordinates ): Promise< WeatherData > {
-		const OWM_API_KEY = process.env.OWM_API_KEY,
+		const currentUrl = `http://api.openweathermap.org/data/2.5/weather?appid=${ this.API_KEY }&units=imperial&lat=${ coordinates[ 0 ] }&lon=${ coordinates[ 1 ] }`,
-			currentUrl = "http://api.openweathermap.org/data/2.5/weather?appid=" + OWM_API_KEY + "&units=imperial&lat=" + coordinates[ 0 ] + "&lon=" + coordinates[ 1 ],
+			forecastDailyUrl = `http://api.openweathermap.org/data/2.5/forecast/daily?appid=${ this.API_KEY }&units=imperial&lat=${ coordinates[ 0 ] }&lon=${ coordinates[ 1 ] }`;
-			forecastDailyUrl = "http://api.openweathermap.org/data/2.5/forecast/daily?appid=" + OWM_API_KEY + "&units=imperial&lat=" + coordinates[ 0 ] + "&lon=" + coordinates[ 1 ];
 
 		let current, forecast;
 		try {

routes/weatherProviders/WeatherProvider.ts

@@ -36,4 +36,13 @@ export class WeatherProvider {
 	getEToData( coordinates: GeoCoordinates ): Promise< EToData > {
 		throw "Selected WeatherProvider does not support getEToData";
 	};
+
+	/**
+	 * Returns a boolean indicating if watering scales calculated using data from this WeatherProvider should be cached
+	 * until the end of the day in timezone the data was for.
+	 * @return a boolean indicating if watering scales calculated using data from this WeatherProvider should be cached.
+	 */
+	shouldCacheWateringScale(): boolean {
+		return false;
+	}
 }