C# HTTPClient 响应日志记录

Question

我有以下代码，用于使用 HTTPClient 将 JSON 数据发送到 API。我想记录 HTTP 响应/状态代码，例如 200、201、400 等。请有人帮助我如何记录响应代码？

Current code:

      public void Main()
        {
            //String filePath = @"your-path\test.json";
            String filepath = Dts.Variables["User::FileName"].Value.ToString();
            if (File.Exists(filepath))
            {
                try
                {
                    // Read the JSON file
                    string jsonData = File.ReadAllText(filepath);
                    using (var client = new HttpClient())
                    {
                        client.BaseAddress = new Uri("https://your-url.com");
                        var response = client.PostAsync("/url-path", new StringContent(jsonData, Encoding.UTF8, "application/json")).Result;
                        var responseContent = response.Content.ReadAsStringAsync();

                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"Error reading or parsing the JSON file: {ex.Message}");
                }
            }
            else
            {
                Console.WriteLine("The JSON file does not exist in the specified folder.");
            }
        }
    }

Answer 1

PostAsync 方法返回一个 HttpResponseMessage，其中包含 IsSuccessStatusCode 和 StatusCode 属性。 如果您使用它们，您的代码将如下所示：

public void Main()
{
    //String filePath = @"your-path\test.json";
    String filepath = Dts.Variables["User::FileName"].Value.ToString();
    if (File.Exists(filepath))
    {
        try
        {
            // Read the JSON file
            string jsonData = File.ReadAllText(filepath);
            using (var client = new HttpClient())
            {
                client.BaseAddress = new Uri("https://your-url.com");
                var response = client.PostAsync("/url-path", new StringContent(jsonData, Encoding.UTF8, "application/json")).Result;
                if (response.IsSuccessStatusCode)
                {
                    Console.WriteLine(response.StatusCode.ToString());

                    var responseContent = response.Content.ReadAsStringAsync();
                }


            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error reading or parsing the JSON file: {ex.Message}");
        }
    }
    else
    {
        Console.WriteLine("The JSON file does not exist in the specified folder.");
    }
}
}



   

Answer 2

HttpClient.PostAsync

方法返回

HttpResponseMessage

对象，其中包含

StatusCode

属性和有关响应的其他附加信息。

因此，您可以使用以下字符串示例在执行后将其作为“StatusCode (StatusCodeDescription)”获取：

$"{(int)response.StatusCode} ({response.ReasonPhrase})"

（输出如

"200 (OK)"

、

500 (InternalServerError)

等）：

public void Main()
{
    // ...
    using (var client = new HttpClient())
    {
        // ...
        var response = client.PostAsync(...).Result;
        // ...
        Console.WriteLine($"{(int)response.StatusCode} ({response.ReasonPhrase})"); 
        // ...
    }
}

但是，请求的执行也可能会抛出

HttpRequestException

（超时，作为最简单的例子）。而且，如果您在

HttpClient

块内同时声明

HttpResponseMessage

和

try

- 您无法在

response

块中获取

catch

信息。这就是为什么你应该在

try-catch

块中声明它：

public void Main()
{
    // ...
    var client = new HttpClient();
    var response = (HttpResponseMessage?)null;
    // ...
    try
    {
        // ...
        response = client.PostAsync(...).Result;
        // ...
        Console.WriteLine($"{(int)response.StatusCode} ({response.ReasonPhrase})");
    }
    catch (Exception ex)
    {
        // Here you have access to response object, but don't forget null-checks
        Console.WriteLine($"{(int?)response?.StatusCode} ({response?.ReasonPhrase})");
    }
}

另外，应该提到很多有关代码的内容，例如：

• 不要在方法内部声明

  HttpClient

  以避免开销（参见 这个问题）；
• 不要在可等待的

  .Result

  上使用

  Task

  以避免死锁（请参阅这个问题）；
• 别忘了

  await

  你的

  Task

  。代码中的行

  responseContent = response.Content.ReadAsStringAsync()

  会将

  Task<string>

  对象存储在

  responseContent

  变量中，而不是您所期望的纯

  string

  。你应该

  await

  这个调用来获取字符串。

假设，我建议您仅在方法之外的某个地方声明和初始化

HttpClient

一次，然后重用它。还将您的方法标记为

async

以便能够等待

HttpClient

调用。简单的例子：

private static readonly HttpClient _client = new() { BaseAddress = new Uri("SomeBaseUri") };

public static async Task Main()
{
    // ...
    var response = (HttpResponseMessage?)null;
    var responseContent = string.Empty;
    // ...
    try
    {
        // ...
        response = await _client.PostAsync(...);
        responseContent = await response.Content.ReadAsStringAsync();
        // ...
        Console.WriteLine($"Request executed with status: {(int)response.StatusCode} ({response.ReasonPhrase}). " +
                          $"Response body: {responseContent}");
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Request failed with status: {(int?)response?.StatusCode} ({response?.ReasonPhrase}). " + 
                          $"Error: {ex.Message}");
    }

    // If job with HttpClient done - don't forget to dispose it manually:
    _client.Dispose();
}