Question

我在c＃中学习web api。我想知道如何从服务器端发送的响应对象中捕获异常消息。

假设这是服务器端抛出的响应异常消息。所以我如何在客户端捕获它。通过使用正常的尝试捕捉它没有显示消息。

try
{
}
catch{Exception exception)
{

var errorMessage = new HttpResponseMessage(HttpStatusCode.BadRequest) { Content = new StringContent(exception.Message) };
                    throw new HttpResponseException(errorMessage);
}

Answer 1

这取决于谁是Web API的客户端。

C＃client＆＃34; exception＆＃34;风格 - 你不会收到直接的异常抛出。您应该自己检查返回的HttpResponseMessage。

using (var client = new HttpClient() { BaseAddress = "http://someurl.com" } )
using (var responseMessage = await client.GetAsync("resources/123")
{
    try
    {
        // EnsureSuccessStatusCode will throw HttpRequestException exception if 
        // status code is not successfull
        responseMessage.EnsureSuccessStatusCode();

        // Here you should process your response if it is successfull.
        // Something like
        // var result = await responseMessage.Content.ReadAsAsync<MyClass>();
    }
    catch (HttpRequestException)
    {
        var errorContent = await responseMessage.Content.ReadAsStringAsync();
        // "errorContent" variable will contain your exception message.
    } 
}

C＃client＆＃34; if＆＃34;风格 - 你也可以在不引发异常的情况下获得相同的结果

if (responseMessage.IsSuccessStatusCode)
{
    // Here you should process your response if it is successfull.
    // Something like
    // var result = await responseMessage.Content.ReadAsAsync<MyClass>();
}
else
{
    var errorContent = await responseMessage.Content.ReadAsStringAsync();
    // "errorContent" variable will contain your exception message.
}

JavaScript - 取决于您将用于调用服务的库，但通常它们都提供了一些错误回调参数，您可以在其中传递错误处理函数。

Answer 2

我只想添加从服务器端向客户端发送异常的整个过程：

1-在服务器端：

[HttpGet]
public HttpResponseMessage DoSomething([FromUri] string ValtoProcess)
{
    try
    {
       return ControllerContext.Request.CreateResponse(HttpStatusCode.OK, new { result, message });
    }
    catch(exception ex)
    {
       HttpResponseMessage Response =Request.CreateErrorResponse(HttpStatusCode.InternalServerError,ex.InnerException.Message);
            throw new HttpResponseException(Response);
     }

然后在客户端只是在响应状态不正常的情况下读取错误如下：

string ErrorMessage = await TaskReponse.Content.ReadAsStringAsync();

在客户端捕获异常消息

2 个答案: