refine outbound request caching

src/http-web/root-page.ts

@@ -28,11 +28,7 @@ export function register_root_page_endpoint(http_server: FastifyInstance, conf:
 			longitude: -122.6714,
 		};
 
-		const [
+		const [ forecast, alerts, weather ] = await Promise.all([
-			{ value: forecast },
-			{ value: alerts },
-			{ value: weather }
-		] = await Promise.all([
 			services.weather_gov.get_forecast_for_location(location, 'us'),
 			services.weather_gov.get_alerts_for_location(location),
 			services.weatherapi_com.get_current_for_location(location),

src/http/outbound.ts

@@ -103,7 +103,7 @@ export function create_outbound_http_provider(conf: OutboundHttpConfig, logger:
 		if (cached) {
 			const revalidation = response_cache.determine_revalidation_needed(cached);
 
-			if (! revalidation.must_revalidate) {
+			if (! revalidation.should_revalidate) {
 				log.info('serving request from cache (no revalidation required)');
 				result.status = cached.status;
 				result.body = cached.body;
@@ -111,6 +111,10 @@ export function create_outbound_http_provider(conf: OutboundHttpConfig, logger:
 				return Promise.resolve(result);
 			}
 
+			// if (! revalidation.must_revalidate) {
+			// 	// todo: lazy revalidation option
+			// }
+
 			log.info('cached response found, but requires revalidation');
 			Object.assign(req_headers, revalidation.headers);
 		}

src/http/request-cache.ts

@@ -7,6 +7,8 @@ import { parse_cache_headers, ParsedCacheHeaders } from './parse-cache-headers';
 import type { HttpURL } from '../utilities/types';
 import type { HttpResult } from './outbound';
 
+// todo: second implementation that stores to disk / db
+
 export interface RequestCacheConfig {
 	// todo: support for configurable limits:
 	max_records?: number;  // max number of cached responses
@@ -67,6 +69,7 @@ export function create_request_cache_provider(conf: RequestCacheConfig, logger:
 			const { cache_control, etag, date, last_modified } = cached.cache_info;
 
 			const must_revalidate = Boolean(cache_control?.must_revalidate || cache_control?.no_cache);
+			const should_revalidate = must_revalidate || cached.is_stale;
 			const headers: OutgoingHttpHeaders = { };
 
 			if (etag) {
@@ -83,6 +86,7 @@ export function create_request_cache_provider(conf: RequestCacheConfig, logger:
 
 			return {
 				must_revalidate,
+				should_revalidate,
 				headers,
 			};
 		},

src/services/weather.gov/index.ts

@@ -1,6 +1,5 @@
 
 import pino from 'pino';
-import { memo } from '../../utilities/memo';
 import { deep_freeze } from '../../utilities/deep';
 import { render_forecast } from './render-forecast';
 import type { NamedLocation } from '../../storage/named-location';
@@ -22,15 +21,6 @@ export type WeatherGovProvider = ReturnType<typeof create_weather_gov_provider>;
 export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino.Logger, outbound_http: OutboundHttpProvider) {
 	const log = logger.child({ logger: 'weather.gov' });
 
-	const get_points_ttl = 1000 * 60 * 60 * 24;
-	const get_points = memo(get_points_ttl, get_points_nocache, { });
-
-	const get_forecast_ttl = 1000 * 60 * 30;
-	const get_forecast = memo(get_forecast_ttl, get_forecast_nocache, { });
-
-	const get_alerts_ttl = 1000 * 30;
-	const get_alerts = memo(get_alerts_ttl, get_alerts_nocache, { });
-
 	return {
 		ready: Promise.resolve(),
 
@@ -43,22 +33,22 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 		get_alerts: if_enabled(get_alerts),
 
 		async get_forecast_for_lat_long(latitude: number, longitude: number, units: 'us' | 'si') {
-			const { value: points } = await get_points(latitude, longitude);
+			const points = await get_points(latitude, longitude);
 			return get_forecast(points.gridId, points.gridX, points.gridY, units, false);
 		},
 
 		async get_hourly_forecast_for_lat_long(latitude: number, longitude: number, units: 'us' | 'si') {
-			const { value: points } = await get_points(latitude, longitude);
+			const points = await get_points(latitude, longitude);
 			return get_forecast(points.gridId, points.gridX, points.gridY, units, true);
 		},
 
 		async get_forecast_for_location(location: NamedLocation, units: 'us' | 'si') {
-			const { value: points } = await get_points(location.latitude, location.longitude);
+			const points = await get_points(location.latitude, location.longitude);
 			return get_forecast(points.gridId, points.gridX, points.gridY, units, false);
 		},
 
 		async get_hourly_forecast_for_location(location: NamedLocation, units: 'us' | 'si') {
-			const { value: points } = await get_points(location.latitude, location.longitude);
+			const points = await get_points(location.latitude, location.longitude);
 			return get_forecast(points.gridId, points.gridX, points.gridY, units, true);
 		},
 
@@ -79,7 +69,7 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 		}) as T;
 	}
 	
-	async function get_points_nocache(latitude: number, longitude: number) : Promise<Cachable<WeatherGovPoints>> {
+	async function get_points(latitude: number, longitude: number) : Promise<WeatherGovPoints> {
 		log.info({ latitude, longitude }, 'fetching points data');
 
 		let { status, headers, body } = await outbound_http.get(`https://api.weather.gov/points/${latitude},${longitude}`, {
@@ -97,7 +87,7 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 
 		if (status === 200) {
 			const data = JSON.parse(body);
-			return cacheable(get_points_ttl, data as WeatherGovPoints);
+			return data as WeatherGovPoints;
 		}
 
 		const data = headers['content-type'].startsWith('application/problem+json')
@@ -108,7 +98,7 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 		throw new Error('failed to fetch points data');
 	}
 	
-	async function get_forecast_nocache(gridId: string, gridX: number, gridY: number, units: 'us' | 'si', hourly = false) : Promise<Cachable<WeatherGovForecast>> {
+	async function get_forecast(gridId: string, gridX: number, gridY: number, units: 'us' | 'si', hourly = false) : Promise<WeatherGovForecast> {
 		log.info({ gridId, gridX, gridY }, 'fetching forecast info');
 
 		const url = `https://api.weather.gov/gridpoints/${gridId}/${gridX},${gridY}/forecast${hourly ? '/hourly' : ''}?units=${units}`;
@@ -127,7 +117,7 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 
 		if (status === 200) {
 			const data = JSON.parse(body);
-			return cacheable(get_forecast_ttl, data as WeatherGovForecast);
+			return data as WeatherGovForecast;
 		}
 
 		const data = headers['content-type'].startsWith('application/problem+json')
@@ -138,7 +128,7 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 		throw new Error('failed to fetch forecast data');
 	}
 	
-	async function get_alerts_nocache(latitude: number, longitude: number) : Promise<Cachable<WeatherGovAlerts>> {
+	async function get_alerts(latitude: number, longitude: number) : Promise<WeatherGovAlerts> {
 		log.info({ latitude, longitude }, 'fetching alerts info');
 
 		let { status, headers, body } = await outbound_http.get(`https://api.weather.gov/alerts?active=1&point=${latitude},${longitude}`, {
@@ -156,7 +146,7 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 
 		if (status === 200) {
 			const data = JSON.parse(body);
-			return cacheable(get_alerts_ttl, data as WeatherGovAlerts);
+			return data as WeatherGovAlerts;
 		}
 
 		const data = headers['content-type'].startsWith('application/problem+json')
@@ -167,18 +157,3 @@ export function create_weather_gov_provider(conf: WeatherGovConfig, logger: pino
 		throw new Error('failed to fetch alerts data');
 	}
 }
-
-function cacheable<T>(ttl: number, value: T) : Cachable<T> {
-	const now = new Date();
-	return deep_freeze({
-		fetched: now,
-		expires: new Date(now.getTime() + ttl),
-		value,
-	});
-}
-
-interface Cachable<T> {
-	readonly fetched: Date;
-	readonly expires: Date;
-	readonly value: Readonly<T>;
-}

src/services/weatherapi.com/index.ts

@@ -1,13 +1,10 @@
 
 import pino from 'pino';
-import { memo } from '../../utilities/memo';
-import { deep_freeze } from '../../utilities/deep';
-// import { render_forecast } from './render-forecast';
 import { render_current_weather } from './render-current-weather';
 import { SecretValue, resolve_secret_value } from '../../conf';
-import type { OutboundHttpProvider } from '../../http/outbound';
-import type { WeatherAPIComCurrentWeather, WeatherAPIComLocation } from './interface';
 import type { NamedLocation } from '../../storage/named-location';
+import type { OutboundHttpProvider } from '../../http/outbound';
+import type { WeatherAPIComCurrentWeather } from './interface';
 
 export interface WeatherAPIComConfig {
 	enabled: boolean;
@@ -24,16 +21,6 @@ export function create_weatherapi_com_provider(conf: WeatherAPIComConfig, logger
 	const log = logger.child({ logger: 'weatherapi.com' });
 	const api_key = resolve_secret_value(conf.api_key);
 
-	const get_current_ttl = 1000;
-	// const get_current_ttl = 1000 * 60 * 3;
-	const get_current = memo(get_current_ttl, get_current_nocache, { });
-
-	// const get_forecast_ttl = 1000 * 60 * 30;
-	// const get_forecast = memo(get_forecast_ttl, get_forecast_nocache, { });
-
-	// const get_alerts_ttl = 1000 * 30;
-	// const get_alerts = memo(get_alerts_ttl, get_alerts_nocache, { });
-
 	return {
 		ready: Promise.resolve(),
 
@@ -59,7 +46,7 @@ export function create_weatherapi_com_provider(conf: WeatherAPIComConfig, logger
 		}) as T;
 	}
 	
-	async function get_current_nocache(query: string) : Promise<Cachable<WeatherAPIComCurrentWeather>> {
+	async function get_current(query: string) : Promise<WeatherAPIComCurrentWeather> {
 		log.info({ query }, 'fetching current weather');
 
 		let { status, headers, body } = await outbound_http.get(`https://api.weatherapi.com/v1/current.json?key=${api_key}&q=${query}`, {
@@ -68,7 +55,7 @@ export function create_weatherapi_com_provider(conf: WeatherAPIComConfig, logger
 
 		if (status === 200) {
 			const data = JSON.parse(body);
-			return cacheable(get_current_ttl, data as WeatherAPIComCurrentWeather);
+			return data as WeatherAPIComCurrentWeather;
 		}
 
 		const data = headers['content-type'].startsWith('application/json')
@@ -79,18 +66,3 @@ export function create_weatherapi_com_provider(conf: WeatherAPIComConfig, logger
 		throw new Error('failed to fetch current weather');
 	}
 }
-
-function cacheable<T>(ttl: number, value: T) : Cachable<T> {
-	const now = new Date();
-	return deep_freeze({
-		fetched: now,
-		expires: new Date(now.getTime() + ttl),
-		value,
-	});
-}
-
-interface Cachable<T> {
-	readonly fetched: Date;
-	readonly expires: Date;
-	readonly value: Readonly<T>;
-}