DotNet Backend Task: Exchange rates - aseverinac

.gitignore

@@ -21,3 +21,4 @@
 node_modules
 bower_components
 npm-debug.log
+.vs/

jobs/Backend/Task/ExchangeRateUpdater.API/Controllers/ExchangeRateController.cs

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+using ExchangeRateUpdater.Core.Models;
+using ExchangeRateUpdater.Core.Services.Abstractions;
+using Microsoft.AspNetCore.Mvc;
+
+namespace ExchangeRateUpdater.API.Controllers
+{
+    [ApiController]
+    [Route("[controller]")]
+    public class ExchangeRateController : ControllerBase
+    {
+        private readonly IExchangeRateProvider _exchangeRateProvider;
+        private readonly ILogger<ExchangeRateController> _logger;
+
+        public ExchangeRateController(
+            IExchangeRateProvider exchangeRateProvider,
+            ILogger<ExchangeRateController> logger)
+        {
+            _exchangeRateProvider = exchangeRateProvider;
+            _logger = logger;
+        }
+
+        /// <summary>
+        /// Gets exchange rates for the specified currencies or all exchange rates if no currencies are specified.
+        /// </summary>
+        /// <param name="currencies">A list of currency codes to get exchange rates for. If not specified, all exchange rates are returned.</param>
+        /// <returns>A list of exchange rates.</returns>
+        /// <response code="200">Returns the list of exchange rates.</response>
+        /// <response code="204">No exchange rates available for the specified currencies.</response>
+        /// <response code="503">Error occurred while fetching exchange rates from the external service.</response>
+        /// <response code="500">An unexpected error occurred.</response>
+        [HttpGet]
+        [ProducesResponseType(typeof(IEnumerable<string>), StatusCodes.Status200OK)]
+        public IActionResult Get([FromQuery] List<string>? currencies)
+        {
+            IEnumerable<ExchangeRate> result;
+            try
+            {
+                if (currencies == null || currencies.Count == 0)
+                {
+                    _logger.LogInformation("No currencies provided, fetching all exchange rates.");
+                    currencies = new List<string>();
+                }
+                else
+                {
+                    _logger.LogInformation("Fetching exchange rates for specified currencies.");
+                }
+
+                var currencyObjects = currencies.Select(c => new Currency(c)).ToList();
+                result = _exchangeRateProvider.GetExchangeRates(currencyObjects);
+            }
+            catch (HttpRequestException ex)
+            {
+                _logger.LogError(ex, "Error occurred while fetching exchange rates from the external service.");
+                return StatusCode(StatusCodes.Status503ServiceUnavailable, "Error occurred while fetching exchange rates from the external service.");
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "An unexpected error occurred.");
+                return StatusCode(StatusCodes.Status500InternalServerError, "An unexpected error occurred.");
+            }
+
+            if (!result.Any())
+            {
+                return NoContent();
+            }
+
+            return Ok(result.Select(x => x.ToString()));
+        }
+    }
+}

jobs/Backend/Task/ExchangeRateUpdater.API/ExchangeRateUpdater.API.csproj

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+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <GenerateDocumentationFile>True</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Swashbuckle.AspNetCore" Version="7.1.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ExchangeRateUpdater.Core\ExchangeRateUpdater.Core.csproj" />
+  </ItemGroup>
+
+</Project>

jobs/Backend/Task/ExchangeRateUpdater.API/Program.cs

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+using ExchangeRateUpdater.Core.Models.Configuration;
+using ExchangeRateUpdater.Core.Services;
+using ExchangeRateUpdater.Core.Services.Abstractions;
+using Microsoft.OpenApi.Models;
+using System.Reflection;
+
+var builder = WebApplication.CreateBuilder(args);
+
+// Build configuration, include appsettings.json
+builder.Configuration
+    .SetBasePath(Directory.GetCurrentDirectory())
+    .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true);
+
+// Register services for dependency injection
+builder.Services
+    .AddSingleton<IExchangeRateProvider, CnbExchangeRateProvider>()
+    .Configure<ExchangeRateSettings>(builder.Configuration.GetSection("ExchangeRateSettings"))
+    .AddLogging(configure => configure
+        .AddConsole() // Log to console for simplicity
+        .SetMinimumLevel(LogLevel.Information))
+    .AddMemoryCache()
+    .AddHttpClient<IExchangeRateProvider, CnbExchangeRateProvider>();
+
+builder.Services.AddControllers();
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen(options =>
+{
+    options.SwaggerDoc("v1", new OpenApiInfo { Title = "Exchange Rate API", Version = "v1" });
+
+    // Set the comments path for the Swagger JSON and UI.
+    var xmlFile = $"{Assembly.GetExecutingAssembly().GetName().Name}.xml";
+    var xmlPath = Path.Combine(AppContext.BaseDirectory, xmlFile);
+    options.IncludeXmlComments(xmlPath);
+});
+
+var app = builder.Build();
+
+// Configure the HTTP request pipeline.
+if (app.Environment.IsDevelopment())
+{
+    app.UseSwagger();
+    app.UseSwaggerUI();
+}
+
+app.UseHttpsRedirection();
+
+app.UseAuthorization();
+
+app.MapControllers();
+
+await app.RunAsync();

jobs/Backend/Task/ExchangeRateUpdater.API/Properties/launchSettings.json

@@ -0,0 +1,41 @@
+{
+  "$schema": "http://json.schemastore.org/launchsettings.json",
+  "iisSettings": {
+    "windowsAuthentication": false,
+    "anonymousAuthentication": true,
+    "iisExpress": {
+      "applicationUrl": "http://localhost:9208",
+      "sslPort": 44361
+    }
+  },
+  "profiles": {
+    "http": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "applicationUrl": "http://localhost:5298",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "https": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "applicationUrl": "https://localhost:7010;http://localhost:5298",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "IIS Express": {
+      "commandName": "IISExpress",
+      "launchBrowser": true,
+      "launchUrl": "swagger",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    }
+  }
+}

jobs/Backend/Task/ExchangeRateUpdater.API/appsettings.Development.json

@@ -0,0 +1,8 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  }
+}

jobs/Backend/Task/ExchangeRateUpdater.API/appsettings.json

@@ -0,0 +1,14 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*",
+  "ExchangeRateSettings": {
+    "CnbApiUrl": "https://api.cnb.cz/cnbapi/exrates/daily",
+    "BaseCurrency": "CZK",
+    "CacheDurationInMinutes": 1
+  }
+}

jobs/Backend/Task/ExchangeRateUpdater.Console/ExchangeRateUpdater.ConsoleApp.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.FileExtensions" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Http" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Options" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="9.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\ExchangeRateUpdater.Core\ExchangeRateUpdater.Core.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="appsettings.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+</Project>

jobs/Backend/Task/ExchangeRateUpdater.Console/Program.cs

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+using ExchangeRateUpdater.Core.Models.Configuration;
+using ExchangeRateUpdater.Core.Services;
+using ExchangeRateUpdater.Core.Services.Abstractions;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using System;
+using System.IO;
+using System.Linq;
+
+namespace ExchangeRateUpdater.ConsoleApp
+{
+    public static class Program
+    {
+        /// <summary>
+        /// Main console app for testing the implementation of the exchange rate provider.
+        /// It uses the exchange rate provider to retrieve exchange rates for a list of currencies and prints them to the console.
+        /// </summary>
+        public static void Main(string[] args)
+        {
+            var serviceProvider = SetupDependencies();
+            var provider = serviceProvider.GetService<IExchangeRateProvider>();
+
+            try
+            {
+                var rates = provider.GetExchangeRates(TestData.Currencies);
+
+                Console.WriteLine($"Successfully retrieved {rates.Count()} exchange rates:");
+                foreach (var rate in rates)
+                {
+                    Console.WriteLine(rate.ToString());
+                }
+            }
+            catch (Exception e)
+            {
+                Console.WriteLine($"Could not retrieve exchange rates: '{e.Message}'.");
+            }
+
+            Console.ReadLine();
+        }
+
+        /// <summary>
+        /// Setup dependencies for the console app.
+        /// </summary>
+        private static ServiceProvider SetupDependencies()
+        {
+            // Build configuration, incude appsettings.json
+            var configuration = new ConfigurationBuilder()
+                .SetBasePath(Directory.GetCurrentDirectory())
+                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
+                .Build();
+
+            // Register services for dependency injection
+            var serviceProvider = new ServiceCollection()
+                .AddSingleton<IExchangeRateProvider, CnbExchangeRateProvider>()
+                .Configure<ExchangeRateSettings>(configuration.GetSection("ExchangeRateSettings"))
+                .AddLogging(configure => configure
+                    .AddConsole() // Log to console for simplicity
+                    .SetMinimumLevel(LogLevel.Warning))
+                .AddMemoryCache()
+                .AddHttpClient<IExchangeRateProvider, CnbExchangeRateProvider>()
+                .Services.BuildServiceProvider();
+
+            return serviceProvider;
+        }
+    }
+}

jobs/Backend/Task/ExchangeRateUpdater.Console/TestData.cs

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+using ExchangeRateUpdater.Core.Models;
+using System.Collections.Generic;
+
+namespace ExchangeRateUpdater.ConsoleApp
+{
+    internal static class TestData
+    {
+        internal static readonly IEnumerable<Currency> Currencies =
+        [
+            new Currency("USD"),
+            new Currency("EUR"),
+            new Currency("CZK"),
+            new Currency("JPY"),
+            new Currency("KES"),
+            new Currency("RUB"),
+            new Currency("THB"),
+            new Currency("TRY"),
+            new Currency("XYZ")
+        ];
+    }
+}

jobs/Backend/Task/ExchangeRateUpdater.Console/appsettings.json

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+{
+  "ExchangeRateSettings": {
+    "CnbApiUrl": "https://api.cnb.cz/cnbapi/exrates/daily",
+    "BaseCurrency": "CZK",
+    "CacheDurationInMinutes": 1
+  }
+}

jobs/Backend/Task/ExchangeRateUpdater.Core/ExchangeRateUpdater.Core.csproj

@@ -0,0 +1,15 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Caching.Abstractions" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.0" />
+    <PackageReference Include="Microsoft.Extensions.Options" Version="9.0.0" />
+  </ItemGroup>
+
+</Project>

jobs/Backend/Task/ExchangeRateUpdater.Core/Models/CnbApiResponse/CnbExchangeRate.cs

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+using System.Text.Json.Serialization;
+
+namespace ExchangeRateUpdater.Core.Models.CnbApiResponse
+{
+    /// <summary>
+    /// Class to describe exchange rates in the response from the CNB API.
+    /// </summary>
+    public class CnbExchangeRate
+    {
+        [JsonPropertyName("validFor")]
+        public DateTime ValidFor { get; set; }
+
+        [JsonPropertyName("order")]
+        public int Order { get; set; }
+
+        [JsonPropertyName("country")]
+        public string Country { get; set; } = null!;
+
+        [JsonPropertyName("currency")]
+        public string Currency { get; set; } = null!;
+
+        [JsonPropertyName("amount")]
+        public int Amount { get; set; }
+
+        [JsonPropertyName("currencyCode")]
+        public string CurrencyCode { get; set; } = null!;
+
+        [JsonPropertyName("rate")]
+        public decimal Rate { get; set; }
+    }
+}