我试图设置一个HttpClient对象的Content-Type头作为我调用的API所要求的。
我试着像下面这样设置内容类型:
using (var httpClient = new HttpClient())
{
httpClient.BaseAddress = new Uri("http://example.com/");
httpClient.DefaultRequestHeaders.Add("Accept", "application/json");
httpClient.DefaultRequestHeaders.Add("Content-Type", "application/json");
// ...
}
它允许我添加Accept头，但当我尝试添加Content-Type时，它会抛出以下异常:
误用头名称。确保请求头与一起使用 HttpRequestMessage，带有HttpResponseMessage的响应头，以及 内容头与HttpContent对象。
如何在HttpClient请求中设置内容类型报头?
当前回答
好吧，它不是HTTPClient，但如果你能使用它，WebClient是相当简单的:
using (var client = new System.Net.WebClient())
{
client.Headers.Add("Accept", "application/json");
client.Headers.Add("Content-Type", "application/json; charset=utf-8");
client.DownloadString(...);
}
其他回答
尝试使用TryAddWithoutValidation
var client = new HttpClient();
client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json; charset=utf-8");
我发现下面的方法最简单易懂:
async Task SendPostRequest()
{
HttpClient client = new HttpClient();
var requestContent = new StringContent(<content>);
requestContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
var response = await client.PostAsync(<url>, requestContent);
var responseString = await response.Content.ReadAsStringAsync();
}
...
SendPostRequest().Wait();
对于那些想要专门将Content-Type设置为Json的人，你可以使用扩展方法PostAsJsonAsync。
using System.Net.Http.Json; //this is needed for PostAsJsonAsync to work
//....
HttpClient client = new HttpClient();
HttpResponseMessage response = await
client.PostAsJsonAsync("http://example.com/" + "relativeAddress",
new
{
name = "John Doe",
age = 33
});
//Do what you need to do with your response
这样做的好处是代码更简洁，并且可以避免字符串化的json。更多详情请访问:https://learn.microsoft.com/en-us/previous-versions/aspnet/hh944339(v=vs.118)
你需要这样做:
HttpContent httpContent = new StringContent(@"{ the json string }");
httpContent.Headers.ContentType = new MediaTypeHeaderValue("application/json");
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage message = client.PostAsync(@"{url}", httpContent).Result;
我用RestSharp得到了答案:
private async Task<string> GetAccessTokenAsync()
{
var client = new RestClient(_baseURL);
var request = new RestRequest("auth/v1/login", Method.POST, DataFormat.Json);
request.AddHeader("Content-Type", "application/json");
request.AddHeader("x-api-key", _apiKey);
request.AddHeader("Accept-Language", "br");
request.AddHeader("x-client-tenant", "1");
...
}
这对我很管用。
