初心者向けC#サービスコンシューマの実装方法を徹底解説

Install-Package System.Net.Http

using System.Net.Http;

HttpClient client = new HttpClient();

client.BaseAddress = new Uri("https://api.example.com/");

client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", "your_token_here");

HttpResponseMessage response = await client.GetAsync("endpoint");
if (response.IsSuccessStatusCode)
{
    string responseData = await response.Content.ReadAsStringAsync();
    // レスポンスデータの処理
}
else
{
    // エラーハンドリング
}

HttpResponseMessage response = await client.GetAsync("endpoint");
if (response.IsSuccessStatusCode)
{
    string jsonData = await response.Content.ReadAsStringAsync();
    // JSONデータの処理
}
else
{
    // エラーハンドリング
}

Install-Package Newtonsoft.Json

using Newtonsoft.Json;

public class ApiResponse
{
    public int Id { get; set; }
    public string Name { get; set; }
    // 他のプロパティ
}

ApiResponse data = JsonConvert.DeserializeObject<ApiResponse>(jsonData);

Console.WriteLine($"ID: {data.Id}, Name: {data.Name}");

using System.Collections.Generic;
using System.Linq;

// データのリスト
List<ApiResponse> dataList = JsonConvert.DeserializeObject<List<ApiResponse>>(jsonData);

// 条件に基づいてフィルタリング
var filteredData = dataList.Where(d => d.Id > 10).ToList();

foreach (var item in filteredData)
{
    Console.WriteLine($"ID: {item.Id}, Name: {item.Name}");
}

foreach (var item in filteredData)
{
    Console.WriteLine($"ID: {item.Id}, Name: {item.Name}, Description: {item.Description}");
}

@model List<ApiResponse>

<table>
    <thead>
        <tr>
            <th>ID</th>
            <th>Name</th>
            <th>Description</th>
        </tr>
    </thead>
    <tbody>
        @foreach (var item in Model)
        {
            <tr>
                <td>@item.Id</td>
                <td>@item.Name</td>
                <td>@item.Description</td>
            </tr>
        }
    </tbody>
</table>

HttpResponseMessage response = await client.GetAsync("endpoint");
if (response.IsSuccessStatusCode)
{
    string jsonData = await response.Content.ReadAsStringAsync();
    // 正常時の処理
}
else
{
    Console.WriteLine($"Error: {response.StatusCode}");
    // エラー時の処理
}

try
{
    HttpResponseMessage response = await client.GetAsync("endpoint");
    response.EnsureSuccessStatusCode(); // ステータスコードがエラーの場合、例外をスロー

    string jsonData = await response.Content.ReadAsStringAsync();
    // 正常時の処理
}
catch (HttpRequestException e)
{
    Console.WriteLine($"Request error: {e.Message}");
    // エラー時の処理
}

try
{
    HttpResponseMessage response = await client.GetAsync("endpoint");
    response.EnsureSuccessStatusCode();

    string jsonData = await response.Content.ReadAsStringAsync();
    // 正常時の処理
}
catch (HttpRequestException e)
{
    string errorMessage = e.StatusCode switch
    {
        HttpStatusCode.NotFound => "Resource not found",
        HttpStatusCode.Unauthorized => "Access denied",
        _ => "An unexpected error occurred"
    };
    Console.WriteLine(errorMessage);
    // エラー時の処理
}

using Serilog;

// ログの設定
Log.Logger = new LoggerConfiguration()
    .WriteTo.Console()
    .WriteTo.File("logs\\myapp.txt", rollingInterval: RollingInterval.Day)
    .CreateLogger();

try
{
    HttpResponseMessage response = await client.GetAsync("endpoint");
    response.EnsureSuccessStatusCode();

    string jsonData = await response.Content.ReadAsStringAsync();
    // 正常時の処理
}
catch (HttpRequestException e)
{
    Log.Error(e, "HTTP request failed");
    Console.WriteLine("An error occurred, please check the log for details.");
}

string apiKey = "your_api_key";
string baseUrl = "http://api.openweathermap.org/data/2.5/weather";
HttpClient client = new HttpClient
{
    BaseAddress = new Uri(baseUrl)
};

string city = "Tokyo";
string requestUrl = $"?q={city}&appid={apiKey}&units=metric";

HttpResponseMessage response = await client.GetAsync(requestUrl);
if (response.IsSuccessStatusCode)
{
    string jsonData = await response.Content.ReadAsStringAsync();
    // JSONデータの処理
}
else
{
    Console.WriteLine($"Error: {response.StatusCode}");
}

public class WeatherResponse
{
    public Main Main { get; set; }
    public string Name { get; set; }
}

public class Main
{
    public float Temp { get; set; }
}

WeatherResponse weather = JsonConvert.DeserializeObject<WeatherResponse>(jsonData);
Console.WriteLine($"City: {weather.Name}, Temperature: {weather.Main.Temp}°C");

Console.WriteLine($"The current temperature in {weather.Name} is {weather.Main.Temp}°C.");

public class WeatherResponse
{
    public Main Main { get; set; }
    public Wind Wind { get; set; }
    public string Name { get; set; }
}

public class Wind
{
    public float Speed { get; set; }
}

// デシリアライズ後の処理
Console.WriteLine($"City: {weather.Name}, Temperature: {weather.Main.Temp}°C, Wind Speed: {weather.Wind.Speed} m/s");

string url = "https://api.github.com/repos/dotnet/runtime";
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.UserAgent.TryParseAdd("request");

HttpResponseMessage response = await client.GetAsync(url);
if (response.IsSuccessStatusCode)
{
    string jsonData = await response.Content.ReadAsStringAsync();
    // JSONデータの処理
}

try
{
    HttpResponseMessage response = await client.GetAsync(url);
    response.EnsureSuccessStatusCode();

    string jsonData = await response.Content.ReadAsStringAsync();
    // JSONデータの処理
}
catch (HttpRequestException e)
{
    Console.WriteLine($"Request error: {e.Message}");
}

public class WeatherResponse
{
    public Main Main { get; set; }
    public Wind Wind { get; set; }
    public string Name { get; set; }
}

public class Main
{
    public float Temp { get; set; }
    public int Humidity { get; set; }
}

public class Wind
{
    public float Speed { get; set; }
}

// デシリアライズ後の処理
Console.WriteLine($"City: {weather.Name}, Temperature: {weather.Main.Temp}°C, Wind Speed: {weather.Wind.Speed} m/s, Humidity: {weather.Main.Humidity}%");