feat(server): add application layer to exchange rate service

packages/server/src/api/controllers/ExchangeRates.ts

@@ -1,16 +1,16 @@
 import { Service, Inject } from 'typedi';
 import { Router, Request, Response, NextFunction } from 'express';
-import { check, param, query } from 'express-validator';
+import { query } from 'express-validator';
 import asyncMiddleware from '@/api/middleware/asyncMiddleware';
 import BaseController from './BaseController';
 import { ServiceError } from '@/exceptions';
-import { ExchangeRatesService } from '@/services/ExchangeRates/ExchangeRatesService';
 import { EchangeRateErrors } from '@/lib/ExchangeRate/types';
+import { ExchangeRateApplication } from '@/services/ExchangeRates/ExchangeRateApplication';
 
 @Service()
 export default class ExchangeRatesController extends BaseController {
   @Inject()
-  private exchangeRatesService: ExchangeRatesService;
+  private exchangeRatesApp: ExchangeRateApplication;
 
   /**
    * Constructor method.
@@ -43,7 +43,7 @@ export default class ExchangeRatesController extends BaseController {
     const exchangeRateQuery = this.matchedQueryData(req);
 
     try {
-      const exchangeRate = await this.exchangeRatesService.latest(
+      const exchangeRate = await this.exchangeRatesApp.latest(
         tenantId,
         exchangeRateQuery
       );

packages/server/src/interfaces/ExchangeRate.ts

@@ -1,36 +1,9 @@
-import { IFilterRole } from './DynamicFilter';
+export interface ExchangeRateLatestDTO {
+  toCurrency: string;
+}
 
-export interface IExchangeRate {
-  id: number,
-  currencyCode: string,
-  exchangeRate: number,
-  date: Date,
-  createdAt: Date,
-  updatedAt: Date,
-};
-
-export interface IExchangeRateDTO {
-  currencyCode: string,
-  exchangeRate: number,
-  date: Date,
-};
-
-export interface IExchangeRateEditDTO {
-  exchangeRate: number,
-};
-
-export interface IExchangeRateFilter {
-  page: number,
-  pageSize: number,
-  filterRoles?: IFilterRole[];
-  columnSortBy: string;
-  sortOrder: string;
-};
-
-export interface IExchangeRatesService {
-  newExchangeRate(tenantId: number, exchangeRateDTO: IExchangeRateDTO): Promise<IExchangeRate>;
-  editExchangeRate(tenantId: number, exchangeRateId: number, editExRateDTO: IExchangeRateEditDTO): Promise<void>;
-
-  deleteExchangeRate(tenantId: number, exchangeRateId: number): Promise<void>;
-  listExchangeRates(tenantId: number, exchangeRateFilter: IExchangeRateFilter): Promise<void>;
-};
+export interface EchangeRateLatestPOJO {
+  baseCurrency: string;
+  toCurrency: string;
+  exchangeRate: number;
+}

packages/server/src/lib/ExchangeRate/OpenExchangeRate.ts

@@ -18,6 +18,9 @@ export class OpenExchangeRate implements IExchangeRateService {
     baseCurrency: string,
     toCurrency: string
   ): Promise<number> {
+    // Vaclidates the Open Exchange Rate api id early.
+    this.validateApiIdExistance();
+
     try {
       const result = await Axios.get(OPEN_EXCHANGE_RATE_LATEST_URL, {
         params: {
@@ -32,9 +35,25 @@ export class OpenExchangeRate implements IExchangeRateService {
     }
   }
 
+  /**
+   * Validates the Open Exchange Rate api id.
+   * @throws {ServiceError}
+   */
+  private validateApiIdExistance() {
+    const apiId = config.exchangeRate.openExchangeRate.appId;
+
+    if (!apiId) {
+      throw new ServiceError(
+        EchangeRateErrors.EX_RATE_SERVICE_API_KEY_REQUIRED,
+        'Invalid App ID provided. Please sign up at https://openexchangerates.org/signup, or contact support@openexchangerates.org.'
+      );
+    }
+  }
+
   /**
    * Handles the latest errors.
    * @param {any} error
+   * @throws {ServiceError}
    */
   private handleLatestErrors(error: any) {
     if (error.response.data?.message === 'missing_app_id') {

packages/server/src/services/ExchangeRates/ExchangeRateApplication.ts

@@ -0,0 +1,21 @@
+import { Inject } from 'typedi';
+import { ExchangeRatesService } from './ExchangeRatesService';
+import { EchangeRateLatestPOJO, ExchangeRateLatestDTO } from '@/interfaces';
+
+export class ExchangeRateApplication {
+  @Inject()
+  private exchangeRateService: ExchangeRatesService;
+
+  /**
+   * Gets the latest exchange rate.
+   * @param {number} tenantId
+   * @param {ExchangeRateLatestDTO} exchangeRateLatestDTO
+   * @returns {Promise<EchangeRateLatestPOJO>}
+   */
+  public latest(
+    tenantId: number,
+    exchangeRateLatestDTO: ExchangeRateLatestDTO
+  ): Promise<EchangeRateLatestPOJO> {
+    return this.exchangeRateService.latest(tenantId, exchangeRateLatestDTO);
+  }
+}

packages/server/src/services/ExchangeRates/ExchangeRatesService.ts

@@ -1,16 +1,7 @@
-import { Service, Inject } from 'typedi';
-import { IExchangeRatesService } from '@/interfaces';
+import { Service } from 'typedi';
 import { ExchangeRate } from '@/lib/ExchangeRate/ExchangeRate';
 import { ExchangeRateServiceType } from '@/lib/ExchangeRate/types';
-interface ExchangeRateLatestDTO {
-  toCurrency: string;
-}
-
-interface EchangeRateLatestPOJO {
-  baseCurrency: string;
-  toCurrency: string;
-  exchangeRate: number;
-}
+import { EchangeRateLatestPOJO, ExchangeRateLatestDTO } from '@/interfaces';
 
 @Service()
 export class ExchangeRatesService {