使用 HttpClient 将 Content-Type 设置为“application/json”并将对象添加到正文答案

【问题标题】：use HttpClient to set the Content-Type to "application/json" and add object to the body使用 HttpClient 将 Content-Type 设置为“application/json”并将对象添加到正文
【发布时间】：2019-01-31 22:41:02
【问题描述】：

我正在尝试使用 HttpClient 创建以下帖子，使用邮递员使其正常工作，但我似乎无法在代码中复制它。我需要将标头 Content-Type 设置为 application/json 并在帖子正文中有一个对象。

发布https://mycompanyurl.com/authenticate

标题
Key：Content-Type，Value：application/json

身体 { “用户名”：“某个用户名”， “密码”：“某个密码” }

using (var client = new HttpClient())
{
    client.BaseAddress = new Uri("https://companyurl.com");

    var serializedObject = JsonConvert.SerializeObject(
                          new {username = "username", password = "password" });
    var request = new HttpRequestMessage(HttpMethod.Post, "authenticate");
    request.Content = new StringContent(serializedObject, Encoding.UTF8,"application/json");                

    var response = await client.SendAsync(request);
    response.EnsureSuccessStatusCode();

    var content = await response.Content.ReadAsStringAsync();

}

使用 fidder 中的反向代理，我可以捕获来自邮递员的原始调用，该调用有效，其余 api 按预期返回结果：

POST http://127.0.0.1:8888/v1/authenticate HTTP/1.1 Content-Type: application/json;charset=UTF-8 cache-control: no-cache Postman-Token: 4db8f2dd-cbf0-413c-ad5b-20af0543a31d User-Agent: PostmanRuntime/7.6 .0 Accept: / Host: 127.0.0.1:8888 accept-encoding: gzip, deflate content-length: 87 Connection: keep-alive

{"用户名":"用户名","密码":"密码"}

我的来自 HttpClient 并使用 fiddler 的调用如下，这不起作用，返回 200 但它不能正常工作，没有返回数据，我看不到有效负载中的任何差异，这将使其余 api 无法按预期响应.

POST http://127.0.0.1:8888/v1/authenticate HTTP/1.1 Content-Type: application/json; charset=utf-8 Host: 127.0.0.1:8888 Content-Length: 87 Expect: 100-continue 连接: Keep-Alive

{"用户名":"用户名","密码":"密码"}

【问题讨论】：

欢迎来到 Stack Overflow！这里不完全清楚你在问什么样的问题。你有任何错误吗？代码的某些部分是否不起作用？请阅读how to ask 一个问题。
标头 Content-Type 为空，未设置
你检查过这个吗？ stackoverflow.com/questions/35907642/…

标签： c# rest api

【解决方案1】：

下面的逻辑应该生成与您的示例中提供的相同的工作请求签名（作为答案发布，请改为编辑您的问题），因此应该可以工作：

var clientHandler = new HttpClientHandler
{
    AutomaticDecompression = System.Net.DecompressionMethods.GZip | System.Net.DecompressionMethods.Deflate,
    AllowAutoRedirect = false
};

using (var client = new HttpClient(clientHandler, true))
{
    client.BaseAddress = new Uri("http://127.0.0.1:8888/v1/");

    client.DefaultRequestHeaders.Add("cache-control", "no-cache");
    client.DefaultRequestHeaders.Add("Postman-Token", "db8f2dd-cbf0-413c-ad5b-20af0543a31d");
    client.DefaultRequestHeaders.Add("User-Agent", "PostmanRuntime/7.6.0");
    client.DefaultRequestHeaders.Add("Accept", "*/*");
    client.DefaultRequestHeaders.ExpectContinue = false;

    var serializedObject = JsonConvert.SerializeObject(
        new { username = "username", password = "password" }
        );

    var request = new HttpRequestMessage(HttpMethod.Post, "authenticate")
    {
        Content = new StringContent(serializedObject, Encoding.UTF8, "application/json")
    };

    var response = await client.SendAsync(request);

    response.EnsureSuccessStatusCode();

    var content = await response.Content.ReadAsStringAsync();
}

它将创建以下请求：

POST http://127.0.0.1:8888/v1/authenticate HTTP/1.1
cache-control: no-cache
Postman-Token: db8f2dd-cbf0-413c-ad5b-20af0543a31d
User-Agent: PostmanRuntime/7.6.0
Accept: */*
Content-Type: application/json; charset=utf-8
Host: 127.0.0.1:8888
Content-Length: 45
Accept-Encoding: gzip, deflate
Connection: Keep-Alive

{"username":"username","password":"password"}

希望这会有所帮助。

【讨论】：