feat: get latest exchange rate from third party services

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

@@ -0,0 +1,62 @@
+import Axios, { AxiosError } from 'axios';
+import {
+  EchangeRateErrors,
+  IExchangeRateService,
+  OPEN_EXCHANGE_RATE_LATEST_URL,
+} from './types';
+import config from '@/config';
+import { ServiceError } from '@/exceptions';
+
+export class OpenExchangeRate implements IExchangeRateService {
+  /**
+   * Gets the latest exchange rate.
+   * @param {string} baseCurrency
+   * @param {string} toCurrency
+   * @returns {Promise<number}
+   */
+  public async latest(
+    baseCurrency: string,
+    toCurrency: string
+  ): Promise<number> {
+    try {
+      const result = await Axios.get(OPEN_EXCHANGE_RATE_LATEST_URL, {
+        params: {
+          app_id: config.exchangeRate.openExchangeRate.appId,
+          base: baseCurrency,
+          symbols: toCurrency,
+        },
+      });
+      return result.data.rates[toCurrency] || (1 as number);
+    } catch (error) {
+      this.handleLatestErrors(error);
+    }
+  }
+
+  /**
+   * Handles the latest errors.
+   * @param {any} error
+   */
+  private handleLatestErrors(error: any) {
+    if (error.response.data?.message === 'missing_app_id') {
+      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.'
+      );
+    } else if (error.response.data?.message === 'invalid_app_id') {
+      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.'
+      );
+    } else if (error.response.data?.message === 'not_allowed') {
+      throw new ServiceError(
+        EchangeRateErrors.EX_RATE_SERVICE_NOT_ALLOWED,
+        'Getting the exchange rate from the given base currency to the given currency is not allowed.'
+      );
+    } else if (error.response.data?.message === 'invalid_base') {
+      throw new ServiceError(
+        EchangeRateErrors.EX_RATE_INVALID_BASE_CURRENCY,
+        'The given base currency is invalid.'
+      );
+    }
+  }
+}