When I do let! read = from.AsyncRead buf in F#, it blocks and doesn't return until the TCP socket is dead. Why? And how do I fix it?
Its code:
module StreamUtil
open System.IO
/// copy from 'from' stream to 'toStream'
let (|>>) (from : Stream) (toStream : Stream) =
let buf = Array.zeroCreate<byte> 1024
let rec doBlock () =
async {
let! read = from.AsyncRead buf
if read <= 0 then
toStream.Flush()
return ()
else
do! toStream.AsyncWrite(buf, 0, read)
return! doBlock () }
doBlock ()
It's being called from this code:
use fs = new FileStream(targPath, FileMode.CreateNew, FileAccess.ReadWrite)
do! req.InputStream |>> fs
and requested over HTTP with this code from Windows Phone 7.1 emulator:
public void Send()
{
var b = new UriBuilder(_imageService.BaseUrl) {Path = "/images"};
var req = WebRequest.CreateHttp(b.Uri);
req.ContentType = "image/jpeg";
req.Method = "POST";
var imgLen = SelectedImage.ImageStream.Length;
req.Headers[HttpRequestHeader.ContentLength] = imgLen.ToString(CultureInfo.InvariantCulture);
req.Accept = "application/json";
req.BeginGetRequestStream(RequestReady, new ReqState(req, imgLen));
}
void RequestReady(IAsyncResult ar)
{
var state = (ReqState)ar.AsyncState;
var req = state.Request;
var reqStream = req.EndGetRequestStream(ar);
SmartDispatcher.BeginInvoke(() =>
{
using (var sw = new StreamWriter(reqStream))
using (var br = new BinaryReader(SelectedVoucher.ImageStream))
{
var readBytes = br.ReadBytes(state.ImgLen);
// tried both 2
sw.Write(readBytes);
//sw.Write(Convert.ToBase64String(readBytes));
sw.Flush();
sw.Close();
}
req.BeginGetResponse(ResponseReady, req);
});
}
// WHY IS IT YOU ARE NOT CALLED???
void ResponseReady(IAsyncResult ar)
{
try
{
var request = (HttpWebRequest)ar.AsyncState;
var response = request.EndGetResponse(ar);
SmartDispatcher.BeginInvoke(() =>
{
var rdr = new StreamReader(response.GetResponseStream());
var msg = rdr.ReadToEnd();
var imageLocation = response.Headers["Location"];
Debug.WriteLine(msg);
Debug.WriteLine(imageLocation);
});
}
catch (WebException ex)
{
Debug.WriteLine(ex.ToString());
}
catch (Exception ex)
{
Debug.WriteLine(ex.ToString());
}
}
Unsuccessfully. The ResponseReady callback is never reached.
Meanwhile, this code works excellent:
open System
open System.Net.Http // WebAPI nuget
let sync aw = Async.RunSynchronously aw
let postC<'a> (c : HttpClient) (r : Uri) (cont : HttpContent) =
let response = sync <| Async.AwaitTask( c.PostAsync(r, cont) )
let struc:'a = sync <| deserialize<'a> response
response, struc
let withContent<'a> (fVerb : (HttpClient -> Uri -> HttpContent -> _ * 'a))=
let c = new HttpClient()
fVerb c
[<Test>]
let ``POST /images 201 + Location header`` () =
let post = withContent<MyImage> postC
let bytes = IO.File.ReadAllBytes("sample.jpg")
let hash = SHA1.Create().ComputeHash(bytes) |> Convert.ToBase64String
let pic = new ByteArrayContent(bytes)
pic.Headers.Add("Content-Type", "image/jpeg")
pic.Headers.Add("X-SHA1-Hash", hash)
let resp, ri = (resource "/images", pic) ||> post
resp.StatusCode =? Code.Created
ri.sha1 =? hash
mustHaveHeaders resp
I couldn't get Fiddler2 working with WP7.
EDIT: Welcome to a yak. I've moved onto greener pastures myself ;)
