feat(cache): implement a simple caching mechanism with TTL and prefix invalidation

refactor(expenses): integrate caching for periodic expenses and related operations
refactor(quotes): add caching for quotes retrieval and history endpoints

apps/backend/src/index.ts

@@ -7,6 +7,8 @@ import { startQuoteJob } from "./modules/quotes/quote.job";
 import quotesRouter from "./modules/quotes/quotes.routes";
 import expensesRouter from "./modules/expenses/expenses.routes";
 import { startExpenseJob } from "./modules/expenses/expense.job";
+import { cache } from "./lib/cache";
+import { eventBus } from "./lib/event-bus";
 import { logger } from "./lib/logger";
 
 const app = new Hono();
@@ -32,6 +34,10 @@ app.route("/api", expensesRouter);
 app.use("/assets/*", serveStatic({ root: "./web" }));
 app.get("*", serveStatic({ path: "./web/index.html" }));
 
+eventBus.on("quotes-updated", () => {
+  cache.invalidateByPrefix("quotes:");
+});
+
 startQuoteJob();
 startExpenseJob();
 

apps/backend/src/lib/cache.ts

@@ -0,0 +1,42 @@
+const TEN_MINUTES = 10 * 60 * 1000;
+
+interface CacheEntry<T> {
+  data: T;
+  expiresAt: number;
+}
+
+class SimpleCache {
+  private store = new Map<string, CacheEntry<unknown>>();
+
+  get<T>(key: string): T | undefined {
+    const entry = this.store.get(key);
+    if (!entry) return undefined;
+    if (Date.now() > entry.expiresAt) {
+      this.store.delete(key);
+      return undefined;
+    }
+    return entry.data as T;
+  }
+
+  set<T>(key: string, data: T, ttlMs: number = TEN_MINUTES): void {
+    this.store.set(key, { data, expiresAt: Date.now() + ttlMs });
+  }
+
+  delete(key: string): void {
+    this.store.delete(key);
+  }
+
+  invalidateByPrefix(prefix: string): void {
+    for (const key of this.store.keys()) {
+      if (key.startsWith(prefix)) {
+        this.store.delete(key);
+      }
+    }
+  }
+
+  clear(): void {
+    this.store.clear();
+  }
+}
+
+export const cache = new SimpleCache();

apps/backend/src/modules/expenses/expenses.service.ts

@@ -1,5 +1,6 @@
 import { z } from "zod";
 import { prisma } from "../../lib/prisma";
+import { cache } from "../../lib/cache";
 import { PaymentStatus } from "../../generated/prisma/client";
 
 export const createPeriodicExpenseSchema = z.object({
@@ -37,28 +38,38 @@ export function getCurrentYearMonthUTC(): { year: number; month: number } {
 }
 
 export async function listPeriodicExpenses() {
-  return prisma.periodicExpense.findMany({
+  const cached = cache.get("expenses:periodic");
+  if (cached) return cached;
+
+  const data = await prisma.periodicExpense.findMany({
     where: { isDeleted: false },
     orderBy: { description: "asc" },
   });
+  cache.set("expenses:periodic", data);
+  return data;
 }
 
 export async function createPeriodicExpense(data: z.infer<typeof createPeriodicExpenseSchema>) {
   const result = await prisma.periodicExpense.create({ data });
   const { year, month } = getCurrentYearMonthUTC();
   const currentMonthApplicable = data.periods.includes(month);
+  cache.invalidateByPrefix("expenses:");
   return { ...result, currentMonthApplicable };
 }
 
 export async function updatePeriodicExpense(id: number, data: z.infer<typeof updatePeriodicExpenseSchema>) {
-  return prisma.periodicExpense.update({ where: { id }, data });
+  const result = await prisma.periodicExpense.update({ where: { id }, data });
+  cache.invalidateByPrefix("expenses:");
+  return result;
 }
 
 export async function softDeletePeriodicExpense(id: number) {
-  return prisma.periodicExpense.update({
+  const result = await prisma.periodicExpense.update({
     where: { id },
     data: { isDeleted: true },
   });
+  cache.invalidateByPrefix("expenses:");
+  return result;
 }
 
 export async function generateMonthlyExpense(id: number) {
@@ -71,7 +82,7 @@ export async function generateMonthlyExpense(id: number) {
   if (existing) return existing;
 
   const dueDate = buildDueDate(year, month, periodic.defaultDueDay);
-  return prisma.expense.create({
+  const result = await prisma.expense.create({
     data: {
       description: periodic.description,
       periodicExpenseId: id,
@@ -82,6 +93,8 @@ export async function generateMonthlyExpense(id: number) {
       status: PaymentStatus.PENDING,
     },
   });
+  cache.invalidateByPrefix("expenses:");
+  return result;
 }
 
 export async function listExpenses(params: {
@@ -92,6 +105,11 @@ export async function listExpenses(params: {
   search?: string;
 }) {
   const { status, page = 1, pageSize = 10, periodicExpenseId, search } = params;
+
+  const cacheKey = `expenses:list:${status ?? "all"}:${page}:${pageSize}:${periodicExpenseId ?? "none"}:${search ?? ""}`;
+  const cached = cache.get(cacheKey);
+  if (cached) return cached;
+
   const where: Record<string, unknown> = {};
   if (status === "PENDING" || status === "PAYED") {
     where.status = status;
@@ -112,14 +130,16 @@ export async function listExpenses(params: {
     }),
     prisma.expense.count({ where }),
   ]);
-  return { data, total, page, pageSize };
+  const result = { data, total, page, pageSize };
+  cache.set(cacheKey, result);
+  return result;
 }
 
 export async function createNonPeriodicExpense(data: z.infer<typeof createNonPeriodicExpenseSchema>) {
   const dueDate = new Date(data.dueDate);
   const year = dueDate.getUTCFullYear();
   const month = dueDate.getUTCMonth() + 1;
-  return prisma.expense.create({
+  const result = await prisma.expense.create({
     data: {
       description: data.description,
       amount: data.amount,
@@ -131,11 +151,13 @@ export async function createNonPeriodicExpense(data: z.infer<typeof createNonPer
       status: PaymentStatus.PAYED,
     },
   });
+  cache.invalidateByPrefix("expenses:");
+  return result;
 }
 
 export async function payExpense(id: number, data: z.infer<typeof payExpenseSchema>) {
   const paymentDate = data.paymentDate ? new Date(data.paymentDate) : new Date();
-  return prisma.expense.update({
+  const result = await prisma.expense.update({
     where: { id },
     data: {
       status: PaymentStatus.PAYED,
@@ -143,36 +165,55 @@ export async function payExpense(id: number, data: z.infer<typeof payExpenseSche
       paymentDate,
     },
   });
+  cache.invalidateByPrefix("expenses:");
+  return result;
 }
 
 export async function getMonthlyPayedTotal(year: number, month: number) {
+  const cacheKey = `expenses:monthly-total:${year}:${month}`;
+  const cached = cache.get(cacheKey);
+  if (cached) return cached;
+
   const result = await prisma.$queryRaw<Array<{ total: string | null }>>`
     SELECT CAST(SUM("amountPayed") AS NUMERIC) as total
     FROM expenses
     WHERE year = ${year} AND month = ${month} AND status = ${PaymentStatus.PAYED}::"PaymentStatus"
   `;
-  return { total: Number(result[0]?.total ?? 0) };
+  const data = { total: Number(result[0]?.total ?? 0) };
+  cache.set(cacheKey, data);
+  return data;
 }
 
 export async function getMonthlyTotals(year: number, month: number) {
+  const cacheKey = `expenses:totals:${year}:${month}`;
+  const cached = cache.get(cacheKey);
+  if (cached) return cached;
+
   const result = await prisma.$queryRaw<Array<{ payed: string | null; pending: string | null }>>`
     SELECT
       (SELECT CAST(SUM("amountPayed") AS NUMERIC) FROM expenses WHERE year = ${year} AND month = ${month} AND status = ${PaymentStatus.PAYED}::"PaymentStatus") as payed,
       (SELECT CAST(SUM(amount) AS NUMERIC) FROM expenses WHERE year = ${year} AND month = ${month} AND status = ${PaymentStatus.PENDING}::"PaymentStatus") as pending
   `;
-  return {
+  const data = {
     payed: Number(result[0]?.payed ?? 0),
     pending: Number(result[0]?.pending ?? 0),
   };
+  cache.set(cacheKey, data);
+  return data;
 }
 
 export async function getTotalPending() {
+  const cached = cache.get("expenses:pending-total");
+  if (cached) return cached;
+
   const result = await prisma.$queryRaw<Array<{ total: string | null }>>`
     SELECT CAST(SUM(amount) AS NUMERIC) as total
     FROM expenses
     WHERE status = ${PaymentStatus.PENDING}::"PaymentStatus"
   `;
-  return { total: Number(result[0]?.total ?? 0) };
+  const data = { total: Number(result[0]?.total ?? 0) };
+  cache.set("expenses:pending-total", data);
+  return data;
 }
 
 export async function generateExpensesForCurrentMonth() {
@@ -205,5 +246,6 @@ export async function generateExpensesForCurrentMonth() {
     });
     results.push({ id: periodic.id, status: "created" });
   }
+  cache.invalidateByPrefix("expenses:");
   return results;
 }

apps/backend/src/modules/expenses/handlers/importExpenses.ts

@@ -1,5 +1,6 @@
 import type { Context } from "hono";
 import { prisma } from "../../../lib/prisma";
+import { cache } from "../../../lib/cache";
 import { logger } from "../../../lib/logger";
 import { PaymentStatus } from "../../../generated/prisma/client";
 
@@ -113,6 +114,8 @@ export async function importExpensesHandler(c: Context) {
     }
   }
 
+  cache.invalidateByPrefix("expenses:");
+
   return c.json({
     imported,
     skipped,

apps/backend/src/modules/expenses/handlers/importPeriodicExpenses.ts

@@ -1,5 +1,6 @@
 import type { Context } from "hono";
 import { prisma } from "../../../lib/prisma";
+import { cache } from "../../../lib/cache";
 import { logger } from "../../../lib/logger";
 
 function parseArgentineAmount(raw: string): number {
@@ -84,6 +85,8 @@ export async function importPeriodicExpensesHandler(c: Context) {
     }
   }
 
+  cache.invalidateByPrefix("expenses:");
+
   return c.json({
     imported,
     skipped: skippedNoPeriods + skippedDuplicate,

apps/backend/src/modules/quotes/handlers/getCurrentQuotes.ts

@@ -1,7 +1,12 @@
 import type { Context } from "hono";
 import { prisma } from "../../../lib/prisma";
+import { cache } from "../../../lib/cache";
 
 export async function getCurrentQuotes(c: Context) {
+  const cached = cache.get("quotes:current");
+  if (cached) return c.json(cached);
+
   const quotes = await prisma.quote.findMany();
+  cache.set("quotes:current", quotes);
   return c.json(quotes);
 }

apps/backend/src/modules/quotes/handlers/getDailyMinMax.ts

@@ -1,5 +1,6 @@
 import type { Context } from "hono";
 import { prisma } from "../../../lib/prisma";
+import { cache } from "../../../lib/cache";
 import type { QuoteType } from "../../../generated/prisma/client";
 
 const VALID_TYPES = ["BLUE", "BNA", "BELO"] as const;
@@ -26,6 +27,10 @@ export async function getDailyMinMax(c: Context) {
     return c.json({ error: "Invalid date format. Use ISO 8601." }, 400);
   }
 
+  const cacheKey = `quotes:minmax:${rawType}:${startDate.toISOString()}:${endDate.toISOString()}`;
+  const cached = cache.get(cacheKey);
+  if (cached) return c.json(cached);
+
   const rows = await prisma.$queryRaw<Array<{
     date: string;
     minBuy: number;
@@ -67,5 +72,6 @@ export async function getDailyMinMax(c: Context) {
     }
   }
 
+  cache.set(cacheKey, rows);
   return c.json(rows);
 }

apps/backend/src/modules/quotes/handlers/getDailyQuotes.ts

@@ -1,5 +1,6 @@
 import type { Context } from "hono";
 import { prisma } from "../../../lib/prisma";
+import { cache } from "../../../lib/cache";
 
 const VALID_TYPES = ["BLUE", "BNA", "BELO"] as const;
 
@@ -25,6 +26,10 @@ export async function getDailyQuotes(c: Context) {
     return c.json({ error: "Invalid date format. Use ISO 8601." }, 400);
   }
 
+  const cacheKey = `quotes:daily:${rawType}:${startDate.toISOString()}:${endDate.toISOString()}`;
+  const cached = cache.get(cacheKey);
+  if (cached) return c.json(cached);
+
   const rows = await prisma.$queryRaw<Array<{
     date: string;
     buy: number;
@@ -41,5 +46,6 @@ export async function getDailyQuotes(c: Context) {
     ORDER BY DATE("timeStamp") ASC
   `;
 
+  cache.set(cacheKey, rows);
   return c.json(rows);
 }

apps/backend/src/modules/quotes/handlers/getQuoteHistory.ts

@@ -1,5 +1,6 @@
 import type { Context } from "hono";
 import { prisma } from "../../../lib/prisma";
+import { cache } from "../../../lib/cache";
 import type { QuoteType } from "../../../generated/prisma/client";
 
 const VALID_TYPES = ["BLUE", "BNA", "BELO"] as const;
@@ -27,6 +28,10 @@ export async function getQuoteHistory(c: Context) {
     return c.json({ error: "Invalid date format. Use ISO 8601." }, 400);
   }
 
+  const cacheKey = `quotes:history:${type}:${startDate.toISOString()}:${endDate.toISOString()}`;
+  const cached = cache.get(cacheKey);
+  if (cached) return c.json(cached);
+
   const history = await prisma.quoteHistory.findMany({
     where: {
       type,
@@ -35,5 +40,6 @@ export async function getQuoteHistory(c: Context) {
     orderBy: { timeStamp: "asc" },
   });
 
+  cache.set(cacheKey, history);
   return c.json(history);
 }