[英]Async HttpWebRequest call using C#
我有以下代碼:
//ids are a list of strings
foreach (string id in ids)
{
string serviceurl = "https://xxx.xx.xxx/internal/v2/idsearch?id=" + id;
List<string> lst = new List<string>();
var task = WebUtil.MakeAsyncRequest("GET", serviceurl, "application/json");
string val = task.Result;
if (val != "")
lst.Add(val);
}
public static Task<string> MakeAsyncRequest(string method,string url, string contentType)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.ContentType = contentType;
request.Method = method;
request.Timeout = 20000;
request.Proxy = null;
string clientId = ConfigManager.GetClientId;
string clientSecret = ConfigManager.GetClientSecret;
request.Headers.Add(HttpRequestHeader.Authorization, ConfigManager.GetServiceKey);
request.Headers.Add("client_id", clientId);
request.Headers.Add("client_secret", clientSecret);
Task<WebResponse> task = Task.Factory.FromAsync(
request.BeginGetResponse,
asyncResult => request.EndGetResponse(asyncResult),
(object)null);
return task.ContinueWith(t => ReadStreamFromResponse(t.Result));
}
private static string ReadStreamFromResponse(WebResponse response)
{
using (Stream responseStream = response.GetResponseStream())
using (StreamReader sr = new StreamReader(responseStream))
{
//Need to return this response
string strContent = sr.ReadToEnd();
return strContent;
}
}
一切正常,但是我不確定我是否正確地實現了async
過程,因為它似乎是在同步進行。 我真的很感激任何人可以幫助我確定我在做什么錯...謝謝!
編輯:
這是我解決的方法。
var taskList = new List<Task<string>>();
foreach (string id in ids)
{
string serviceurl = "https://xxx.xx.xxx/internal/v2/idsearch?id=" + id;
taskList.Add(WebUtil.MakeAsyncRequest(serviceurl, "application/json"));
}
try
{
string[] val = await Task.WhenAll(taskList.ToArray());
}
catch (Exception)
{
throw;
}
public static async Task<string> MakeAsyncRequest(string url, string contentType)
{
using (HttpClient client = new HttpClient())
{
var requestMessage = new HttpRequestMessage()
{
RequestUri = new Uri(url),
Method = HttpMethod.Get,
};
// Add our custom headers
requestMessage.Headers.Add("client_id", ConfigManager.GetClientId);
requestMessage.Headers.Add("client_secret", ConfigManager.GetClientSecret);
requestMessage.Headers.Authorization = new AuthenticationHeaderValue(ConfigManager.GetServiceKey);
requestMessage.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue(contentType));
HttpResponseMessage response = await client.SendAsync(requestMessage);
var result = await response.Content.ReadAsStringAsync();
string res = result.ToString();
return res;
}
}
ReadToEnd
是同步的,是的。 有異步等效項。
另請注意,此處DNS解析是同步的。 這是一個一直未得到修復的錯誤。
最好的解決方法可能是使用HttpClient
,它使異步下載字符串成為一種方式。
我想發出async
請求的最佳方法是HttpClient
。 您可以這樣寫:
var client = new HttpClient();
var request = new HttpRequestMessage()
{
RequestUri = new Uri("xxxxxx"),
Method = HttpMethod.Get,
};
request.Headers.Accept.Add(new ....);
var response = await client.SendAsync(request);
//read a result from the repsonse
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