implemented exchange rates fetching and caching

.gitignore

@@ -0,0 +1 @@
+.DS_Store

fullstack/task/packages/client/project.json

@@ -9,7 +9,7 @@
         "start": {
             "executor": "nx:run-commands",
             "options": {
-                "command": "yarn vite",
+                "command": "yarn vite --host 0.0.0.0",
                 "cwd": "packages/client"
             }
         },

fullstack/task/packages/client/src/App.tsx

@@ -1,5 +1,49 @@
+import React from 'react';
+import { useQuery } from '@apollo/client';
+import { GET_EXCHANGE_RATES } from './graphql/queries';
+import { ExchangeRate } from './types/ExchangeRate';
+
+interface ExchangeRateResponse {
+  exchangeRatesList: ExchangeRate[];
+}
+
 function App() {
-    return <p>TODO</p>;
+  const { data, loading, error } = useQuery<ExchangeRateResponse>(GET_EXCHANGE_RATES);
+
+  if (loading) return <div>Loading...</div>;
+  if (error) return <div>Error: {error.message}</div>;
+
+  const exchangeRates = data?.exchangeRatesList || [];
+
+  return (
+    <div>
+      <h1>Exchange Rates</h1>
+      <table border="1">
+        <thead>
+          <tr>
+            <th>Country</th>
+            <th>Currency</th>
+            <th>Amount</th>
+            <th>Code</th>
+            <th>Rate</th>
+            <th>Last updated at</th>
+          </tr>
+        </thead>
+        <tbody>
+          {exchangeRates.map((rate) => (
+            <tr key={rate.currencyCode}>
+              <td>{rate.country}</td>
+              <td>{rate.currency}</td>
+              <td>{rate.amount}</td>
+              <td>{rate.currencyCode}</td>
+              <td>{rate.rate}</td>
+              <td>{rate.updatedAtUtc}</td>
+            </tr>
+          ))}
+        </tbody>
+      </table>
+    </div>
+  );
 }
 
 export default App;

fullstack/task/packages/client/src/graphql/queries.ts

@@ -0,0 +1,14 @@
+import { gql } from '@apollo/client';
+
+export const GET_EXCHANGE_RATES = gql`
+  query GetExchangeRates {
+    exchangeRatesList {
+      country
+      currency
+      currencyCode
+      amount
+      rate
+      updatedAtUtc
+    }
+  }
+`;

fullstack/task/packages/client/src/main.tsx

@@ -4,8 +4,10 @@ import { ApolloClient, ApolloProvider, InMemoryCache } from '@apollo/client';
 import App from './App';
 
 const client = new ApolloClient({
-    uri: 'http://localhost:4000/graphql',
-    cache: new InMemoryCache(),
+    uri: 'http://localhost:4001/graphql',
+    cache: new InMemoryCache({
+        addTypename: false
+    }),
 });
 
 ReactDOM.createRoot(document.getElementById('root') as HTMLElement).render(

fullstack/task/packages/client/src/types/ExchangeRate.ts

@@ -0,0 +1,8 @@
+export interface ExchangeRate {
+  country: string;
+  currency: string;
+  amount: number;
+  currencyCode: string;
+  rate: number;
+  updatedAtUtc?: string;
+}

fullstack/task/packages/server/project.json

@@ -42,16 +42,16 @@
             },
             "configurations": {
                 "run": {
-                    "command": "yarn typeorm-ts-node-commonjs migration:run -d ./src/config/typeorm/data-source.ts"
+                    "command": "yarn typeorm-ts-node-commonjs migration:run --dataSource ./src/config/typeorm/data-source.ts"
                 },
                 "revert": {
-                    "command": "yarn typeorm-ts-node-commonjs migration:revert -d ./src/config/typeorm/data-source.ts"
+                    "command": "yarn typeorm-ts-node-commonjs migration:revert --dataSource ./src/config/typeorm/data-source.ts"
                 },
                 "generate": {
-                    "command": "yarn typeorm-ts-node-commonjs migration:generate -d ./src/config/typeorm/data-source.ts ./src/migrations/{args.name}"
+                    "command": "yarn typeorm-ts-node-commonjs migration:generate --dataSource ./src/config/typeorm/data-source.ts ./src/migrations/{args.name}"
                 },
                 "create": {
-                    "command": "yarn typeorm-ts-node-commonjs migration:create -d ./src/config/typeorm/data-source.ts ./src/migrations/{args.name}"
+                    "command": "yarn typeorm-ts-node-commonjs migration:create ./src/migrations/{args.name}"
                 }
             }
         }

fullstack/task/packages/server/schema.gql

@@ -17,8 +17,21 @@ A date-time string at UTC, such as 2019-12-03T09:54:33Z, compliant with the date
 """
 scalar DateTime
 
+type ExchangeRate {
+  id: ID!
+  createdAtUtc: DateTime!
+  updatedAtUtc: DateTime
+  deleteDateUtc: DateTime
+  version: Int!
+  country: String!
+  currency: String!
+  amount: Float!
+  currencyCode: String!
+  rate: Float!
+}
+
 type Query {
-  exchangeRates: String!
+  exchangeRatesList: [ExchangeRate!]!
   exampleByName(name: String!): Example
 }
 

fullstack/task/packages/server/src/app.module.ts

@@ -5,6 +5,7 @@ import { TypeOrmModule } from '@nestjs/typeorm';
 import { graphqlConfig, typeormConfig } from './config';
 import { modules } from './entity-modules';
 import { ExchangeRateModule } from './services/exchange-rate/exchange-rate.module';
+import { CurrencyFetchModule } from './services/currency-fetch/currency-fetch.module';
 
 @Module({
     imports: [
@@ -14,6 +15,7 @@ import { ExchangeRateModule } from './services/exchange-rate/exchange-rate.modul
         TypeOrmModule.forRoot(typeormConfig),
         GraphQLModule.forRoot(graphqlConfig),
         ExchangeRateModule,
+        CurrencyFetchModule,
         ...modules,
     ],
     controllers: [],

fullstack/task/packages/server/src/entities/cache-metadata.entity.ts

@@ -0,0 +1,16 @@
+import { Field, ObjectType } from '@nestjs/graphql';
+import { IsString } from 'class-validator';
+import { Column, Entity, PrimaryColumn } from 'typeorm';
+
+@ObjectType()
+@Entity('cache_metadata')
+export class CacheMetadata {
+    @IsString()
+    @Field(() => String)
+    @PrimaryColumn({ type: 'varchar', length: 50 })
+    public cacheKey!: string;
+
+    @Field(() => Date)
+    @Column({ type: 'timestamptz' })
+    public lastFetchedAt!: Date;
+}

fullstack/task/packages/server/src/entities/exchange-rate.entity.ts

@@ -0,0 +1,36 @@
+import { Field, Float, ObjectType } from '@nestjs/graphql';
+import { IsDecimal, IsString, Length } from 'class-validator';
+import { Column, Entity, Index } from 'typeorm';
+import { EntityWithMeta } from '../common';
+import { VAR_CHAR } from './constants';
+
+@ObjectType()
+@Entity('exchange_rates')
+@Index('IDX_exchange_rates_currency_code', ['currencyCode'], { unique: true })
+export class ExchangeRate extends EntityWithMeta {
+    @IsString()
+    @Field(() => String)
+    @Column({ ...VAR_CHAR })
+    public country!: string;
+
+    @IsString()
+    @Field(() => String)
+    @Column({ ...VAR_CHAR })
+    public currency!: string;
+
+    @IsDecimal()
+    @Field(() => Float)
+    @Column({ type: 'decimal', precision: 10, scale: 0 })
+    public amount!: number;
+
+    @IsString()
+    @Length(3, 3)
+    @Field(() => String)
+    @Column({ type: 'varchar', length: 3 })
+    public currencyCode!: string;
+
+    @IsDecimal()
+    @Field(() => Float)
+    @Column({ type: 'decimal', precision: 10, scale: 6 })
+    public rate!: number;
+}

fullstack/task/packages/server/src/entities/index.ts

@@ -1 +1,3 @@
 export * from './example.entity';
+export * from './exchange-rate.entity';
+export * from './cache-metadata.entity';

fullstack/task/packages/server/src/main.ts

@@ -7,6 +7,7 @@ import { AppModule } from './app.module';
 async function bootstrap() {
     const app = await NestFactory.create<NestApplication>(AppModule);
 
+    app.enableCors();
     app.useGlobalPipes(new ValidationPipe({ whitelist: false, transform: false }));
 
     useContainer(app.select(AppModule), { fallbackOnErrors: true });

fullstack/task/packages/server/src/migrations/1758100643630-create-table-exchange_rates.ts

@@ -0,0 +1,32 @@
+import { MigrationInterface, QueryRunner } from "typeorm"
+
+export class createTableExchangeRates1758100643630 implements MigrationInterface {
+
+    public async up(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`
+            CREATE TABLE "exchange_rates" 
+            (
+                "id" uuid NOT NULL DEFAULT uuid_generate_v4(), 
+                "createdAtUtc" TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT now(), 
+                "updatedAtUtc" TIMESTAMP WITH TIME ZONE DEFAULT now(), 
+                "deleteDateUtc" TIMESTAMP WITH TIME ZONE, 
+                "version" integer NOT NULL, 
+                "country" character varying(255) NOT NULL, 
+                "currency" character varying(255) NOT NULL, 
+                "amount" numeric(10, 2) NOT NULL, 
+                "currencyCode" character varying(255) NOT NULL, 
+                "rate" numeric(10, 2) NOT NULL,
+                CONSTRAINT "PK_876duygd68as6d8a6d8as768" PRIMARY KEY ("id")
+            )`);
+
+            await queryRunner.query(`
+                CREATE UNIQUE INDEX "IDX_exchange_rates_currency_code" ON "exchange_rates" ("currencyCode")
+            `);
+    }
+
+    public async down(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`DROP INDEX "IDX_exchange_rates_currency_code"`);
+        await queryRunner.query(`DROP TABLE "exchange_rates"`);
+    }
+
+}

fullstack/task/packages/server/src/migrations/1758102061344-create-cache-metadata-table.ts

@@ -0,0 +1,16 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class CreateCacheMetadataTable1758102061344 implements MigrationInterface {
+    public async up(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`
+            CREATE TABLE cache_metadata (
+                "cacheKey" VARCHAR(50) PRIMARY KEY,
+                "lastFetchedAt" TIMESTAMPTZ NOT NULL
+            )
+        `);
+    }
+
+    public async down(queryRunner: QueryRunner): Promise<void> {
+        await queryRunner.query(`DROP TABLE IF EXISTS cache_metadata`);
+    }
+}

fullstack/task/packages/server/src/services/currency-fetch/currency-fetch.module.ts

@@ -0,0 +1,11 @@
+import { Module } from '@nestjs/common';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { CurrencyFetchService } from './currency-fetch.service';
+import { ExchangeRate, CacheMetadata } from '../../entities';
+
+@Module({
+    imports: [TypeOrmModule.forFeature([ExchangeRate, CacheMetadata])],
+    providers: [CurrencyFetchService],
+    exports: [CurrencyFetchService],
+})
+export class CurrencyFetchModule {}