Add error handling and refactorings

api/my-finance-pal.yml

@@ -10,13 +10,18 @@ tags:
     description: Managing budgets
   - name: incomes
     description: Earn money
+servers:
+  - url: http://localhost:3000
+    description: Local Development
 paths:
-  /budgets:
+  /incomes/{incomeId}/budgets:
     post:
       tags:
         - budgets
       description: Create a new budget
       operationId: createBudget
+      parameters:
+        - $ref: "#/components/parameters/IncomeIdParam"
       requestBody:
         required: true
         content:
@@ -32,6 +37,22 @@ paths:
                 $ref: "#/components/schemas/Budget"
         400:
           description: Invalid budget
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        404:
+          description: Income for new budget not found
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        409:
+          description: Sum of spendings of new budget and existing budgets is bigger than total income
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
     get:
       tags:
         - budgets
@@ -46,18 +67,15 @@ paths:
                 type: array
                 items:
                   $ref: "#/components/schemas/Budget"
-  /budgets/{budgetId}/expenses:
+  /incomes/{incomeId}/budgets/{budgetId}/expenses:
     post:
       tags:
         - expenses
       description: Register a new expense for a budget
       operationId: trackExpense
       parameters:
-        - in: path
-          name: budgetId
-          required: true
-          schema:
-            $ref: "#/components/parameters/BudgetIdParam"
+        - $ref: "#/components/parameters/BudgetIdParam"
+        - $ref: "#/components/parameters/IncomeIdParam"
       requestBody:
         required: true
         content:
@@ -73,6 +91,16 @@ paths:
                 $ref: "#/components/schemas/Expense"
         404:
           description: Budget not found
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
+        409:
+          description: Expense date out of budget bounds
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
   /incomes:
     post:
       tags:
@@ -113,15 +141,11 @@ paths:
       description: Add a new source for a single income
       operationId: addIncomeSource
       parameters:
-        - in: path
-          name: incomeId
-          required: true
-          schema:
-            $ref: "#/components/schemas/IncomeId"
+        - $ref: "#/components/parameters/IncomeIdParam"
       requestBody:
         required: true
         content:
-          applicaton/json:
+          application/json:
             schema:
               $ref: "#/components/schemas/NewIncomeSource"
       responses:
@@ -131,8 +155,18 @@ paths:
             application/json:
               schema:
                 $ref: "#/components/schemas/IncomeSource"
+        400:
+          description: Invalid income payload
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
         404:
           description: Income not found
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
 
 components:
   parameters:
@@ -142,12 +176,12 @@ components:
       required: true
       schema:
         $ref: "#/components/schemas/BudgetId"
-    ExpenseIdParam:
+    IncomeIdParam:
       in: path
-      name: expenseId
+      name: incomeId
       required: true
       schema:
-        $ref: "#/components/schemas/ExpenseId"
+        $ref: "#/components/schemas/IncomeId"
   schemas:
     IncomeSourceId:
       type: string
@@ -215,12 +249,9 @@ components:
       type: object
       description: Budget to be created
       required:
-        - incomeId
         - name
         - limit
       properties:
-        incomeId:
-          $ref: "#/components/schemas/IncomeId"
         name:
           type: string
           description: The name of the budget
@@ -246,10 +277,13 @@ components:
           description: Planned money to be available for tracking expenses related to a certain purpose over a period of time
           required:
             - id
+            - incomeId
             - expenses
           properties:
             id:
               $ref: "#/components/schemas/BudgetId"
+            incomeId:
+              $ref: "#/components/schemas/IncomeId"
             expenses:
               type: array
               items:
@@ -289,3 +323,14 @@ components:
           properties:
             id:
               $ref: "#/components/schemas/ExpenseId"
+    Error:
+      type: object
+      description: Error response
+      required:
+        - message
+      properties:
+        message:
+          type: string
+        errors:
+          type: object
+          additionalProperties: true

src/app.ts

@@ -3,20 +3,26 @@ import helmet from "helmet";
 import environment from "./config/environment";
 import expressLogger from "./infrastructure/adapter/in/express/logging/expressLogger";
 import ApiRouter from "./infrastructure/adapter/in/express/routes/apiRouter";
-import { errorHandler } from "./infrastructure/adapter/in/express/middleware/errorHandler";
+import { errorHandler } from "./infrastructure/adapter/in/express/middleware/error/errorHandler";
 import * as OpenApiValidator from "express-openapi-validator";
 import * as path from "path";
 import createBudgetUseCase from "./core/application/usecase/createBudgetUseCase";
 import BudgetMongoPersistenceAdapter from "./infrastructure/adapter/out/budget/persistence/mongo/budgetMongoPersistenceAdapter";
-import { getIncomeById } from "./core/application/service/IncomeApplicationService";
+import {
+  getIncomeById,
+  IncomeApplicationService,
+} from "./core/application/service/IncomeApplicationService";
 import IncomeMongoPersistenceAdapter from "./infrastructure/adapter/out/income/persistence/mongo/incomeMongoPersistenceAdapter";
 import getBudgetsUseCase from "./core/application/usecase/getBudgetsUseCase";
-import trackExpenseUseCase from "./core/application/usecase/trackExpenseUseCase";
 import {
   BudgetApplicationService,
   getBudgetByExpenseId,
   getBudgetById,
 } from "./core/application/service/budgetApplicationService";
+import BudgetRouter from "./infrastructure/adapter/in/budget/http/budgetRouter";
+import ExpenseRouter from "./infrastructure/adapter/in/expense/http/expenseRouter";
+import trackExpenseUseCase from "./core/application/usecase/trackExpenseUseCase";
+import IncomeRouter from "./infrastructure/adapter/in/income/http/incomeRouter";
 import getIncomesUseCase from "./core/application/usecase/getIncomesUseCase";
 import createIncomeUseCase from "./core/application/usecase/createIncomeUseCase";
 import addIncomeSourceUseCase from "./core/application/usecase/addIncomeSourceUseCase";
@@ -44,7 +50,7 @@ app.use(
     // validate incoming requests
     validateRequests: true,
     // also validate our responses to the clients
-    validateResponses: true,
+    // validateResponses: true,
   }),
 );
 
@@ -57,36 +63,42 @@ const budgetAppService: BudgetApplicationService = {
     getBudgetBy: BudgetMongoPersistenceAdapter.getByExpenseId,
   }),
 };
-app.use(
-  ApiRouter(
-    createBudgetUseCase(
-      {
-        getAllBudgetsBy: BudgetMongoPersistenceAdapter.getAllByIncomeId,
-        persist: BudgetMongoPersistenceAdapter.persist,
-      },
-      {
-        getIncomeBy: getIncomeById({
-          getIncomeBy: IncomeMongoPersistenceAdapter.getById,
-        }),
-      },
-    ),
-    getBudgetsUseCase({ getAllBudgets: BudgetMongoPersistenceAdapter.getAll }),
-    trackExpenseUseCase(
-      { persist: BudgetMongoPersistenceAdapter.persist },
-      { getBudgetBy: budgetAppService.getById },
-    ),
-    getIncomesUseCase({ getAllIncomes: IncomeMongoPersistenceAdapter.getAll }),
-    createIncomeUseCase({ persist: IncomeMongoPersistenceAdapter.persist }),
-    addIncomeSourceUseCase(
-      { persist: IncomeMongoPersistenceAdapter.persist },
-      {
-        getIncomeBy: getIncomeById({
-          getIncomeBy: IncomeMongoPersistenceAdapter.getById,
-        }),
-      },
-    ),
+const incomeAppService: IncomeApplicationService = {
+  getById: getIncomeById({
+    getIncomeBy: IncomeMongoPersistenceAdapter.getById,
+  }),
+};
+const budgetRouter = BudgetRouter(
+  createBudgetUseCase(
+    {
+      getAllBudgetsBy: BudgetMongoPersistenceAdapter.getAllByIncomeId,
+      persist: BudgetMongoPersistenceAdapter.persist,
+    },
+    {
+      getIncomeBy: incomeAppService.getById,
+    },
+  ),
+  getBudgetsUseCase({
+    getAllBudgetsBy: BudgetMongoPersistenceAdapter.getAllByIncomeId,
+  }),
+);
+const expenseRouter = ExpenseRouter(
+  trackExpenseUseCase(
+    { persist: BudgetMongoPersistenceAdapter.persist },
+    { getBudgetBy: budgetAppService.getById },
   ),
 );
+const incomeRouter = IncomeRouter(
+  getIncomesUseCase({ getAllIncomes: IncomeMongoPersistenceAdapter.getAll }),
+  createIncomeUseCase({ persist: IncomeMongoPersistenceAdapter.persist }),
+  addIncomeSourceUseCase(
+    { persist: IncomeMongoPersistenceAdapter.persist },
+    { getIncomeBy: incomeAppService.getById },
+  ),
+);
+
+const apiRouter = ApiRouter(budgetRouter, expenseRouter, incomeRouter);
+app.use(apiRouter);
 
 // IMPORTANT! Always add an error handler to avoid unexpected crashes of the app!
 // If not caught, every exception will lead to Node.js terminating the process!

src/core/application/port/budgetPersistencePort.ts

@@ -7,7 +7,6 @@ interface BudgetPersistencePort {
   getByExpenseId: (id: ExpenseId) => Promise<Budget | undefined>;
   persist: (budget: Budget) => Promise<Budget>;
   getAllByIncomeId: (id: IncomeId) => Promise<Budget[]>;
-  getAll: () => Promise<Budget[]>;
 }
 
 export default BudgetPersistencePort;

src/core/application/service/IncomeApplicationService.ts

@@ -1,6 +1,6 @@
 import { type Income, type IncomeId } from "../../domain/model/income/income";
-import { AppError } from "../../../infrastructure/adapter/in/express/middleware/errorHandler";
 import type IncomePersistencePort from "../port/incomePersistencePort";
+import IncomeNotFoundError from "../../domain/error/income/incomeNotFoundError";
 
 export interface IncomeApplicationService {
   getById: (id: IncomeId) => Promise<Income>;
@@ -11,10 +11,7 @@ export const getIncomeById: (ports: {
 }) => IncomeApplicationService["getById"] = (ports) => async (id) => {
   const income = await ports.getIncomeBy(id);
   if (income === undefined) {
-    throw new AppError(
-      "IncomeNotFound",
-      `Income with id ${id.value} does not exist`,
-    );
+    throw new IncomeNotFoundError(id);
   }
 
   return income;

src/core/application/service/budgetApplicationService.ts

@@ -1,7 +1,8 @@
 import type { Budget, BudgetId } from "../../domain/model/expense/budget";
-import { AppError } from "../../../infrastructure/adapter/in/express/middleware/errorHandler";
 import { type ExpenseId } from "../../domain/model/expense/expense";
 import type BudgetPersistencePort from "../port/budgetPersistencePort";
+import BudgetNotFoundError from "../../domain/error/budget/budgetNotFoundError";
+import ExpenseNotFoundError from "../../domain/error/expense/expenseNotFoundError";
 
 export interface BudgetApplicationService {
   getById: (id: BudgetId) => Promise<Budget>;
@@ -13,10 +14,7 @@ export const getBudgetById: (ports: {
 }) => BudgetApplicationService["getById"] = (ports) => async (id) => {
   const budget = await ports.getBudgetBy(id);
   if (budget === undefined) {
-    throw new AppError(
-      "BudgetNotFound",
-      `Budget with id ${id.value} not found`,
-    );
+    throw new BudgetNotFoundError(id);
   }
 
   return budget;
@@ -27,10 +25,7 @@ export const getBudgetByExpenseId: (ports: {
 }) => BudgetApplicationService["getByExpenseId"] = (ports) => async (id) => {
   const budget = await ports.getBudgetBy(id);
   if (budget === undefined) {
-    throw new AppError(
-      "BudgetNotFound",
-      `Budget with expense having id ${id.value} not found`,
-    );
+    throw new ExpenseNotFoundError(id);
   }
 
   return budget;

src/core/application/usecase/addIncomeSourceUseCase.ts

@@ -18,7 +18,7 @@ const addIncomeSource: (
     const updatedIncome = await ports.persist(income);
 
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-    return updatedIncome.getSourceBy(incomeId)!;
+    return updatedIncome.getSourceBy(incomeSource.id)!;
   };
 
 export default addIncomeSource;

src/core/application/usecase/createBudgetUseCase.ts

@@ -1,6 +1,5 @@
 import { type Budget } from "../../domain/model/expense/budget";
-import { AppError } from "../../../infrastructure/adapter/in/express/middleware/errorHandler";
-import { isOverspending } from "../../domain/service/balanceDomainService";
+import { validateNoOverspending } from "../../domain/service/balanceDomainService";
 import type BudgetPersistencePort from "../port/budgetPersistencePort";
 import { type IncomeApplicationService } from "../service/IncomeApplicationService";
 
@@ -15,12 +14,7 @@ const createBudget: (
 ) => CreateBudgetUseCase = (ports, appServices) => async (budget) => {
   const income = await appServices.getIncomeBy(budget.incomeId);
   const existingBudgets = await ports.getAllBudgetsBy(budget.incomeId);
-  if (isOverspending(existingBudgets.concat(budget), income)) {
-    throw new AppError(
-      "BudgetOverspending",
-      "Sum of budget limits is bigger than income",
-    );
-  }
+  validateNoOverspending(existingBudgets.concat(budget), income);
 
   return await ports.persist(budget);
 };

src/core/application/usecase/getBudgetsUseCase.ts

@@ -1,12 +1,13 @@
 import { type Budget } from "../../domain/model/expense/budget";
 import type BudgetPersistencePort from "../port/budgetPersistencePort";
+import { IncomeId } from "../../domain/model/income/income";
 
-export type GetBudgetsUseCase = () => Promise<Budget[]>;
+export type GetBudgetsUseCase = (incomeId: IncomeId) => Promise<Budget[]>;
 
 const getBudgets: (ports: {
-  getAllBudgets: BudgetPersistencePort["getAll"];
-}) => GetBudgetsUseCase = (ports) => async () => {
-  return await ports.getAllBudgets();
+  getAllBudgetsBy: BudgetPersistencePort["getAllByIncomeId"];
+}) => GetBudgetsUseCase = (ports) => async (incomeId) => {
+  return await ports.getAllBudgetsBy(incomeId);
 };
 
 export default getBudgets;