feat: implement distributed caching

server/utils/cache.ts

@@ -0,0 +1,79 @@
+import Redis from 'ioredis';
+import type { H3Event } from 'h3';
+
+let cacher: Cacher | null = null;
+
+export type Cacher = {
+	set<T>(key: string, val: T, cacheAgeMs?: number): Promise<void>;
+	get<T>(key: string): Promise<T | null>;
+};
+
+function createCacher(event: H3Event): Cacher {
+	const config = useRuntimeConfig(event);
+	if (config.redisUrl) {
+		const redis = new Redis(config.redisUrl);
+		const prefix = `pn:website:cache`;
+		return {
+			async get(key) {
+				try {
+					const result = await redis.get(`${prefix}:${key}`);
+					if (result) {
+						return JSON.parse(result);
+					}
+				} catch {
+					// Catch connection & serialisation errors
+				}
+				return null;
+			},
+			async set(key, val, cacheAgeMs) {
+				try {
+					const fullKey = `${prefix}:${key}`;
+					await redis.set(fullKey, JSON.stringify(val));
+					if (cacheAgeMs) {
+						await redis.expire(fullKey, Math.round(cacheAgeMs / 1000));
+					}
+				} catch {
+					// Catch connection & serialisation errors
+				}
+			}
+		};
+	}
+
+	// Memory cacher
+	const store = new Map<string, { expiresAt: Date | null; value: string }>();
+	return {
+		async get(key) {
+			try {
+				const result = store.get(key);
+				if (result) {
+					if (result.expiresAt && result.expiresAt < new Date()) {
+						store.delete(key);
+						return null; // Expired
+					}
+					return JSON.parse(result.value);
+				}
+			} catch {
+				// catch Serialisation errors
+			}
+			return null;
+		},
+		async set(key, val, cacheAgeMs) {
+			try {
+				store.set(key, {
+					expiresAt: cacheAgeMs ? new Date(Date.now() + cacheAgeMs) : null,
+					value: JSON.stringify(val)
+				});
+			} catch {
+				// Catch serialisation errors
+			}
+		}
+	};
+}
+
+export function useCacher(event: H3Event): Cacher | null {
+	if (!cacher) {
+		cacher = createCacher(event);
+	}
+
+	return cacher;
+}

server/utils/getGithubProgress.ts

@@ -16,8 +16,6 @@ export type GithubProjectResponse = {
 };
 
 const orgName = 'PretendoNetwork';
-const cacheMaxAgeMs = 60 * 60 * 1000; // 1 hour
-let cache: { response: GithubProjectResponse; createdAt: Date } | null = null;
 
 const getProjectsWithItemsV2GQL = `
 query getProjectsV2($orgName: String!, $cursor: String) {
@@ -128,19 +126,24 @@ async function getGithubProjectsData(octokit: Octokit): Promise<GithubProjectRes
 	};
 }
 
-export async function getGithubProjects(octokit: Octokit | null, ignoreCache = false): Promise<GithubProjectResponse> {
-	if (!cache || new Date(cache.createdAt.getTime() + cacheMaxAgeMs) < new Date() || ignoreCache) {
-		// No github credentials, assume there are no projects
-		if (!octokit) {
-			return {
-				projects: []
-			};
-		}
+const cacheKey = 'githubProjects';
+const cacheMaxAgeMs = 60 * 60 * 1000; // 1 hour
 
-		cache = {
-			createdAt: new Date(),
-			response: await getGithubProjectsData(octokit)
+export async function getGithubProjects(cacher: Cacher, octokit: Octokit | null, ignoreCache = false): Promise<GithubProjectResponse> {
+	if (!octokit) {
+		return {
+			projects: []
 		};
 	}
-	return cache.response;
+
+	if (!ignoreCache) {
+		const cached = await cacher.get<GithubProjectResponse>(cacheKey);
+		if (cached) {
+			return cached;
+		}
+	}
+
+	const data = await getGithubProjectsData(octokit);
+	await cacher.set(cacheKey, data, cacheMaxAgeMs);
+	return data;
 }

server/utils/getStripeDonations.ts

@@ -5,9 +5,6 @@ export type StripeDonationResponse = {
 	totalDonationsCents: number;
 };
 
-const cacheMaxAgeMs = 60 * 60 * 1000; // 1 hour
-let cache: { response: StripeDonationResponse; createdAt: Date } | null = null;
-
 async function getStripeDonationData(stripe: Stripe): Promise<StripeDonationResponse> {
 	const donationData: StripeDonationResponse = {
 		donatorCount: 0,
@@ -29,21 +26,26 @@ async function getStripeDonationData(stripe: Stripe): Promise<StripeDonationResp
 	return donationData;
 }
 
-export async function getStripeDonations(stripe: Stripe | null, ignoreCache = false): Promise<StripeDonationResponse> {
-	if (!cache || new Date(cache.createdAt.getTime() + cacheMaxAgeMs) < new Date() || ignoreCache) {
-		// No credentials, fill in blank data
-		if (!stripe) {
-			return {
-				donatorCount: 0,
-				totalDonationsCents: 0
-			};
-		}
+const cacheKey = 'stripeDonations';
+const cacheMaxAgeMs = 60 * 60 * 1000; // 1 hour
 
-		cache = {
-			createdAt: new Date(),
-			response: await getStripeDonationData(stripe)
+export async function getStripeDonations(cacher: Cacher, stripe: Stripe | null, ignoreCache = false): Promise<StripeDonationResponse> {
+	if (!stripe) {
+		// No credentials, fill in blank data
+		return {
+			donatorCount: 0,
+			totalDonationsCents: 0
 		};
 	}
 
-	return cache.response;
+	if (!ignoreCache) {
+		const cached = await cacher.get<StripeDonationResponse>(cacheKey);
+		if (cached) {
+			return cached;
+		}
+	}
+
+	const data = await getStripeDonationData(stripe);
+	await cacher.set(cacheKey, data, cacheMaxAgeMs);
+	return data;
 }