如何在C#中使用HttpClient阅读webapi响应

时间:2016-08-26 09:01:58

标签: c# asp.net-web-api httpclient

我是webapi的新手,并开发了一个小的webapi,它有一些动作并返回我的自定义类,名为Response。

Response

public class Response
{
    bool IsSuccess=false;
    string Message;
    object ResponseData;

    public Response(bool status, string message, object data)
    {
        IsSuccess = status;
        Message = message;
        ResponseData = data;
    }
}

带有操作的我的webapi

[RoutePrefix("api/customer")]
public class CustomerController : ApiController
{
    static readonly ICustomerRepository repository = new CustomerRepository();

    [HttpGet, Route("GetAll")]
    public Response GetAllCustomers()
    {
        return new Response(true, "SUCCESS", repository.GetAll());
    }

    [HttpGet, Route("GetByID/{customerID}")]
    public Response GetCustomer(string customerID)
    {
        Customer customer = repository.Get(customerID);
        if (customer == null)
        {
            throw new HttpResponseException(HttpStatusCode.NotFound);
        }
        return new Response(true, "SUCCESS", customer);
        //return Request.CreateResponse(HttpStatusCode.OK, response);
    }

    [HttpGet, Route("GetByCountryName/{country}")]
    public IEnumerable<Customer> GetCustomersByCountry(string country)
    {
        return repository.GetAll().Where(
            c => string.Equals(c.Country, country, StringComparison.OrdinalIgnoreCase));
    }
}

现在我被困住的地方是我不知道如何读取webapi操作返回的响应数据并从响应类中提取json。获得json之后我怎么能{j}到客户类deserialize

这就是我调用webapi功能的方式:

private void btnLoad_Click(object sender, EventArgs e)
{
    HttpClient client = new HttpClient();
    client.BaseAddress = new Uri("http://localhost:8010/");
    // Add an Accept header for JSON format.  
    //client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    // List all Names.  
    HttpResponseMessage response = client.GetAsync("api/customer/GetAll").Result;  // Blocking call!  
    if (response.IsSuccessStatusCode)
    {
        Console.WriteLine("Request Message Information:- \n\n" + response.RequestMessage + "\n");
        Console.WriteLine("Response Message Header \n\n" + response.Content.Headers + "\n");
    }
    else
    {
        Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
    }
    Console.ReadLine();   
}

请帮我整理一下我的代码

  

1)如何获取webapi在客户端返回的响应类   侧

     

2)我如何从响应类中提取json

     

3)如何将json反序列化到客户端的客户类

由于

修改

我使用此代码但仍然出错。

    var baseAddress = "http://localhost:8010/api/customer/GetAll";
    using (var client = new HttpClient())
    {
        using (var response =  client.GetAsync(baseAddress).Result)
        {
            if (response.IsSuccessStatusCode)
            {
                var customerJsonString = await response.Content.ReadAsStringAsync();
                var cust = JsonConvert.DeserializeObject<Response>(customerJsonString);
            }
            else
            {
                Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
            }
        }
    }

T 他的错误信息是:

  

“Newtonsoft.Json.JsonSerializationException”类型的例外   发生在Newtonsoft.Json.dll但未在用户代码中处理

     

其他信息:无法反序列化当前的JSON对象   (例如{“name”:“value”})进入'WebAPIClient.Response []'类型因为   该类型需要一个JSON数组(例如[1,2,3])来反序列化   正确。

为什么响应会导致此错误?

2 个答案:

答案 0 :(得分:16)

在客户端上,包括对内容的阅读:

    HttpResponseMessage response = client.GetAsync("api/customer/GetAll").Result;  // Blocking call!  
    if (response.IsSuccessStatusCode)
    {
        Console.WriteLine("Request Message Information:- \n\n" + response.RequestMessage + "\n");
        Console.WriteLine("Response Message Header \n\n" + response.Content.Headers + "\n");
        // Get the response
        var customerJsonString = await response.Content.ReadAsStringAsync();
        Console.WriteLine("Your response data is: " + customerJsonString);

        // Deserialise the data (include the Newtonsoft JSON Nuget package if you don't already have it)
        var deserialized = JsonConvert.DeserializeObject<IEnumerable<Customer>>(custome‌​rJsonString);
        // Do something with it
    }

更改您的WebApi,不要使用您的Response类,而是使用IEnumerable Customer。使用HttpResponseMessage响应类。

您的WebAPI应该只需要:

[HttpGet, Route("GetAll")]
public IEnumerable<Customer> GetAllCustomers()
{
    var allCustomers = repository.GetAll();
    // Set a breakpoint on the line below to confirm
    // you are getting data back from your repository.
    return allCustomers;
}

根据评论中的讨论添加了通用响应类的代码,尽管我仍然建议您不要这样做并避免调用您的类Response。您应该返回HTTP status codes而不是您自己的this post。 200 Ok,401 Unauthorized等。另外config()关于如何返回HTTP状态代码。

    public class Response<T>
    {
        public bool IsSuccess { get; set; }
        public string Message { get; set; }
        public IEnumerable<T> ResponseData { get; set; }

        public Response(bool status, string message, IEnumerable<T> data)
        {
            IsSuccess = status;
            Message = message;
            ResponseData = data;
        }
    }

答案 1 :(得分:0)

或者您可以在同一电话上进行转化

  TResponse responseobject = response.Content.ReadAsAsync<TResponse>().Result;
            responseJson += "hostResponse: " + JsonParser.ConvertToJson(responseobject);
            //_logger.Debug($"responseJson : {responseJson}", correlationId);