Save bisq aggregate exchange rates in the database for each new block

backend/src/repositories/RatesRepository.ts

@@ -0,0 +1,21 @@
+import DB from '../database';
+import logger from '../logger';
+import { IConversionRates } from '../mempool.interfaces';
+
+class RatesRepository {
+  public async $saveRate(height: number, rates: IConversionRates) {
+    try {
+      await DB.query(`INSERT INTO rates(height, bisq_rates) VALUE (?, ?)`, [height, JSON.stringify(rates)]);
+    } catch (e: any) {
+      if (e.errno === 1062) { // ER_DUP_ENTRY - This scenario is possible upon node backend restart
+        logger.debug(`Rate already exists for block ${height}, ignoring`);
+      } else {
+        logger.err(`Cannot save exchange rate into db for block ${height} Reason: ` + (e instanceof Error ? e.message : e));
+        throw e;
+      }
+    }
+  }
+}
+
+export default new RatesRepository();
+