[英]Getting HttpClient to POST/PUT Async
我正在尝试使用C#中的HttpClient将和输入到POST。 我需要异步进行缩放。 但是,我只能使我的PUT和POST同步工作。 以下是我用于将JSON格式的ZoomData对象放入URL的代码:
// takes the dataset to PUT and PUTs to server
public async Task<HttpResponseMessage> JsonPUTcall(ZoomData toPut)
{
string jsonString = JsonConvert.SerializeObject(toPut);
return await client.PutAsync(InsiteDatasetPutURL.Replace("sys_id", toPut.sys_id), new StringContent(jsonString, UnicodeEncoding.UTF8, "application/json"));
}
这是我用来将队列中的ZoomData对象实际传递给JsonPUTcall的代码:
public async void JsonPUTqueueCall(Queue<ZoomData> toPut)
{
if (toPut.Count == 0)
return;
foreach (var zoomData in toPut)
{
var result = await this.JsonPUTcall(zoomData);
}
}
但是,当我尝试这样做时,它只是挂起。 因此,作为测试,我替换为“ var result = await this.JsonPUTcall(zoomData);” 具有以下内容:
public async void JsonPUTqueueCall(Queue<ZoomData> toPut)
{
if (toPut.Count == 0)
return;
foreach (var zoomData in toPut)
{
var result = this.JsonPUTcall(zoomData);
result.Wait();
}
}
那是可行的,但是由于它是同步的,因此无法达到使用异步的目的。 我想念什么?
这是我的API客户端,可以高效地使用资源,并且方法是异步的
using System;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
//You need to install package Newtonsoft.Json > https://www.nuget.org/packages/Newtonsoft.Json/
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
public class MyApiClient : IDisposable
{
private readonly TimeSpan _timeout;
private HttpClient _httpClient;
private HttpClientHandler _httpClientHandler;
private readonly string _baseUrl;
private const string ClientUserAgent = "my-api-client-v1";
private const string MediaTypeJson = "application/json";
public MyApiClient(string baseUrl, TimeSpan? timeout = null)
{
_baseUrl = NormalizeBaseUrl(baseUrl);
_timeout = timeout ?? TimeSpan.FromSeconds(90);
}
public async Task<string> PostAsync(string url, object input)
{
EnsureHttpClientCreated();
using (var requestContent = new StringContent(ConvertToJsonString(input), Encoding.UTF8, MediaTypeJson))
{
using (var response = await _httpClient.PostAsync(url, requestContent))
{
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsStringAsync();
}
}
}
public async Task<TResult> PostAsync<TResult>(string url, object input) where TResult : class, new()
{
var strResponse = await PostAsync(url, input);
return JsonConvert.DeserializeObject<TResult>(strResponse, new JsonSerializerSettings
{
ContractResolver = new CamelCasePropertyNamesContractResolver()
});
}
public async Task<TResult> GetAsync<TResult>(string url) where TResult : class, new()
{
var strResponse = await GetAsync(url);
return JsonConvert.DeserializeObject<TResult>(strResponse, new JsonSerializerSettings
{
ContractResolver = new CamelCasePropertyNamesContractResolver()
});
}
public async Task<string> GetAsync(string url)
{
EnsureHttpClientCreated();
using (var response = await _httpClient.GetAsync(url))
{
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsStringAsync();
}
}
public async Task<string> PutAsync(string url, object input)
{
return await PutAsync(url, new StringContent(JsonConvert.SerializeObject(input), Encoding.UTF8, MediaTypeJson));
}
public async Task<string> PutAsync(string url, HttpContent content)
{
EnsureHttpClientCreated();
using (var response = await _httpClient.PutAsync(url, content))
{
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsStringAsync();
}
}
public async Task<string> DeleteAsync(string url)
{
EnsureHttpClientCreated();
using (var response = await _httpClient.DeleteAsync(url))
{
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsStringAsync();
}
}
public void Dispose()
{
_httpClientHandler?.Dispose();
_httpClient?.Dispose();
}
private void CreateHttpClient()
{
_httpClientHandler = new HttpClientHandler
{
AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip
};
_httpClient = new HttpClient(_httpClientHandler, false)
{
Timeout = _timeout
};
_httpClient.DefaultRequestHeaders.UserAgent.ParseAdd(ClientUserAgent);
if (!string.IsNullOrWhiteSpace(_baseUrl))
{
_httpClient.BaseAddress = new Uri(_baseUrl);
}
_httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(MediaTypeJson));
}
private void EnsureHttpClientCreated()
{
if (_httpClient == null)
{
CreateHttpClient();
}
}
private static string ConvertToJsonString(object obj)
{
if (obj == null)
{
return string.Empty;
}
return JsonConvert.SerializeObject(obj, new JsonSerializerSettings
{
ContractResolver = new CamelCasePropertyNamesContractResolver()
});
}
private static string NormalizeBaseUrl(string url)
{
return url.EndsWith("/") ? url : url + "/";
}
}
用法 ;
using ( var client = new MyApiClient("http://localhost:8080"))
{
var response = client.GetAsync("api/users/findByUsername?username=alper").Result;
var userResponse = client.GetAsync<MyUser>("api/users/findByUsername?username=alper").Result;
}
这2行是为了使其同步:
var result = this.JsonPUTcall(zoomData);
result.Wait();
为了使其异步,您不希望这样做:
var result = await this.JsonPUTcall(zoomData);
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