如何在F＃Async.Parallel中处理HttpWebRequest超时
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我只是花了很长时间才弄清楚为什么这段代码对于某些URL“挂起”了：
let getImage (imageUrl:string) =
async {
try
let req = WebRequest.Create(imageUrl) :?> HttpWebRequest
req.UserAgent <- \"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)\";
req.Method <- \"GET\";
req.AllowAutoRedirect <- true;
req.MaximumAutomaticRedirections <- 4;
req.Timeout <- 3000; //HAHAHA, nice try!
let! response1 = req.AsyncGetResponse()
let response = response1 :?> HttpWebResponse
use stream = response.GetResponseStream()
let ms = new MemoryStream()
let bytesRead = ref 1
let buffer = Array.create 0x1000 0uy
while !bytesRead > 0 do
bytesRead := stream.Read(buffer, 0, buffer.Length)
ms.Write(buffer, 0, !bytesRead)
return SuccessfulDownload(imageUrl, ms.ToArray())
with
ex -> return FailedDownload(imageUrl, ex.Message)
}
HttpWebRequest.Timeout
Async.Parallel |> Async.RunSynchronously
没有找到相关结果
已邀请:
1 个回复
布埃郝卞簿
type System.Net.WebRequest with member req.AsyncGetResponseWithTimeout () = let impl = async { let iar = req.BeginGetResponse (null, null) let! success = Async.AwaitIAsyncResult (iar, req.Timeout) return if success then req.EndGetResponse iar else req.Abort () raise (System.Net.WebException \"The operation has timed out\") } Async.TryCancelled (impl, fun _ -> req.Abort ())而不是。