HttpClient在API控制器上返回带有参数化构造函数的内部服务器错误(500)

时间:2015-08-11 15:29:10

标签: asp.net asp.net-web-api asp.net-web-api2 dotnet-httpclient asp.net-web-api-routing

使用以下示例代码,

public class RolesController : ApiController
{
    private readonly IRoleService _roleService;

    public RolesController(IRoleService roleService)
    {
        _roleService = roleService;
    }

    public async Task<IHttpActionResult> Get()
    {
        return Ok(await Task.FromResult(new[] { "value1", "value2" }));
    }
}


public static class TestExtensions
{
    public static async Task<HttpResponseMessage> ExecuteRequestAsync<C, A>(this C controller, Expression<Func<C, A>> methodExpressionCall)
    {
        var methodCall = methodExpressionCall.Body as MethodCallExpression;
        var routeAttributes = methodCall.Method.GetCustomAttributes(typeof(RouteAttribute), true);

        var routeName = string.Empty;
        if (routeAttributes.Count() == 0 || string.IsNullOrEmpty(((RouteAttribute)routeAttributes[0]).Name))
            routeName = methodCall.Method.Name.ToLower();
        else
            routeName = ((RouteAttribute)routeAttributes[0]).Name;

        var config = new HttpConfiguration();
        config.Routes.MapHttpRoute("DefaultApi", "api/{controller}/{action}/{id}", new { id = RouteParameter.Optional });
        config.IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Always;

        using (var client = new HttpClient(new HttpServer(config)))
        {
            return await client.GetAsync("http://localhost/api/roles/" + routeName);
        }
    }
}


[Fact]
public void OnCreate_ReturnTrue_IfInputDataAreValid()
{
    var roleController = new RolesController(new RoleService());

    //Act
    var response = roleController.ExecuteRequestAsync(c => c.Get());

    //Assert
    Assert.Equal(HttpStatusCode.OK, response.Result.StatusCode);
}

为什么HttpClient在API控制器上使用参数化构造函数返回内部服务器错误(500)?请参阅此代码“roleController.ExecuteRequestAsync()”。

请注意IoC已经配置好并且工作正常。

1 个答案:

答案 0 :(得分:1)

我终于找到了答案How can I debug a 500 Internal Server Error when calling a WebApi from ajax?

我通过在 ExecuteRequestAsync 方法中添加 Expression 参数来更新示例代码。事实证明,Expression类要求我的控制器显式定义默认构造函数。 Expression类在NewExpression New(Type type)中抛出ArgumentException。显然,类型应该有一个不带参数的构造函数。

因此,每当您感到迷失(500)内部服务器错误时,只需尝试上面引用的SO链接上的建议步骤。不是最好的方式,但它的工作原理。通常抛出的第一个异常是根本原因,然后您可以取消选中“在抛出此异常类型时中断”,因为它可能会引发很多异常。