使用 HttpClient 时记录请求/响应消息 [英] Logging request/response messages when using HttpClient

问题描述

我有一个像下面这样的 POST 方法

I have a method that does a POST like below

var response = await client.PostAsJsonAsync(url, entity);

if (response.IsSuccessStatusCode)
{
        // read the response as strongly typed object
        return await response.Content.ReadAsAsync<T>();
}

我的问题是如何获取从实体对象发布的实际 JSON.我想记录被发布的 JSON，所以不用我自己做一个 json 序列化就可以了.

My question is how can I obtain the actual JSON that got posted from the entity object. I would like to log the JSON that gets POSTED, so it will be nice to have that without me having to do a json serialize myself.

推荐答案

您可以如何执行此操作的示例:

An example of how you could do this:

一些注意事项:

• LoggingHandler 在将请求处理到 HttpClientHandler 之前拦截请求，后者最终写入线路.

• LoggingHandler intercepts the request before it handles it to HttpClientHandler which finally writes to the wire.

PostAsJsonAsync 扩展在内部创建一个 ObjectContent，当 ReadAsStringAsync() 在 LoggingHandler 中被调用时，它会导致格式化程序在 ObjectContent 中序列化对象，这就是您在 json 中看到内容的原因.

PostAsJsonAsync extension internally creates an ObjectContent and when ReadAsStringAsync() is called in the LoggingHandler, it causes the formatter inside ObjectContent to serialize the object and that's the reason you are seeing the content in json.

日志处理程序:

public class LoggingHandler : DelegatingHandler
{
    public LoggingHandler(HttpMessageHandler innerHandler)
        : base(innerHandler)
    {
    }

    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        Console.WriteLine("Request:");
        Console.WriteLine(request.ToString());
        if (request.Content != null)
        {
            Console.WriteLine(await request.Content.ReadAsStringAsync());
        }
        Console.WriteLine();

        HttpResponseMessage response = await base.SendAsync(request, cancellationToken);

        Console.WriteLine("Response:");
        Console.WriteLine(response.ToString());
        if (response.Content != null)
        {
            Console.WriteLine(await response.Content.ReadAsStringAsync());
        }
        Console.WriteLine();

        return response;
    }
}

将上述 LoggingHandler 与 HttpClient 链接起来:

HttpClient client = new HttpClient(new LoggingHandler(new HttpClientHandler()));
HttpResponseMessage response = client.PostAsJsonAsync(baseAddress + "/api/values", "Hello, World!").Result;

输出:

Request:
Method: POST, RequestUri: 'http://kirandesktop:9095/api/values', Version: 1.1, Content: System.Net.Http.ObjectContent`1[
[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]], Headers:
{
  Content-Type: application/json; charset=utf-8
}
"Hello, World!"

Response:
StatusCode: 200, ReasonPhrase: 'OK', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
  Date: Fri, 20 Sep 2013 20:21:26 GMT
  Server: Microsoft-HTTPAPI/2.0
  Content-Length: 15
  Content-Type: application/json; charset=utf-8
}
"Hello, World!"

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