I want to receive data from elm327 device.
in line 7 I receive AT+BRSF=24\r string instead of string with the speed.
1.private async Task<string> GetSpeed()
2. {
3. string retVal;
4. _dataWriter.WriteString("010D\r"); // send pid for speed information
5. await _dataWriter.FlushAsync();
6. await _dataReader.LoadAsync(30); // get answer
7. String Message = _dataReader.ReadString(11);
8. retVal = Message;
9. if (retVal.Contains('<'))
10. {
11. retVal.Substring(0, retVal.IndexOf("<"));
12. }
13. return retVal.Replace("\n", "");
14. }
I'm using SDP Bluetooth protocol:
PeerFinder.AlternateIdentities["Bluetooth:SDP"] = "{00001101-0000-1000-8000-00805F9B34FB}";
the problem is with the connecting channel,
I first tried with the next line:
_stream = await socket.ConnectAsync(selectedDevice.HostName,"1");
but the working channel is 16 and not 1, and the working line is:
_stream = await socket.ConnectAsync(selectedDevice.HostName,"16"):
Related
Tested with: Chrome on Linux 70.0.3538.110
Bug: Previously failed textDecoder.decode call will cause failure of successive calls.
const log = console.log
let string = 'Hello ♥ world! ♥'
let textEncoder = new TextEncoder()
let bytes = textEncoder.encode(string)
let textDecoder = new TextDecoder('utf-8', {fatal: true})
try {
// Comment away this line and the code below will work
log(textDecoder.decode(new DataView(bytes.buffer, 0, 19)))
} catch (e) {
log('After this failed the next try will also fail')
}
log(textDecoder.decode(new DataView(bytes.buffer, 0, 20)))
I got the following code:
using (var client = new HttpClient(new NativeMessageHandler()))
{
client.Timeout = TimeSpan.FromSeconds(30.0);
var response = await client.PostAsync(requestString, content);
json = await response.Content.ReadAsStringAsync();
var tk = JObject.Parse(json);
if ((string)tk.GetValue("Ident") == "Message" && (int)tk.GetValue("Status") == 401)
throw new AuthenticationException();
return tk;
}
This is the base for calling a webservice for the app I'm working on. The thing is: Every time I step over this one line:
var response = await client.PostAsync(requestString, content);
I get an error message from Visual Studio saying "The network connection to {IP:PORT} has been lost. Debugging will be aborted."
And so I get disconnected (happens with Emulator and WP device). This is really annoying since I would like to debug the result, but no chance. As I just have noticed the connection breaks even if you continue. Once it hit's it, the connection get lost.
This is a very weird behavior. Any clues why this happens or what could trigger connection loss?
FYI I'm using Newtonsoft.Json for that.
I have a spec in which there is a need to ignore HTTPS certificates and also to get the status of Upload/Download.
I am using HttpClient to ignore the certificate but i could not find the way to get the status of downloading/Uploading.
I know it was there in WebClient Windows Phone 8 and Webclient not there in Windows 8.1.
So please guide me to accomplish both these things.
For Download progress, You can return response stream from your Http request and can use below code to write to file which also display progress status
IInputStream inputStream = null;
IRandomAccessStream fs = null;
try
{
inputStream = responseStream.AsInputStream();
ulong totalBytesRead = 0;
fs = await file.OpenAsync(FileAccessMode.ReadWrite);
ulong fileSize = Convert.ToUInt64(Size);
while (true)
{
// Read from the web.
if (!cancellationToken.IsCancellationRequested)
{
IBuffer buffer = new Windows.Storage.Streams.Buffer(512);
buffer = await inputStream.ReadAsync(
buffer,
buffer.Capacity,
InputStreamOptions.None);
if (buffer.Length == 0)
{
// There is nothing else to read.
break;
}
// Report progress.
totalBytesRead += buffer.Length;
double progress = ((double)totalBytesRead / fileSize);
double Value = progress * 100;
System.Diagnostics.Debug.WriteLine("Bytes read: {0}", totalBytesRead);
await fs.WriteAsync(buffer);
}
else
{
inputStream.Dispose();
fs.Dispose();
await file.DeleteAsync();
break;
}
}
inputStream.Dispose();
fs.Dispose();
}
catch
{
}
For upload Progress, there is no in built support to do that, but you can use
ProgressMessageHandler found in System.Net.Http.Handler which you can found on Nuget and than hook that to your HttpClient Object.
I am building my first windowsPhone 8.1 application ,the role of my application is to create connection with server to get information from it, so I am writing the code to do this process by sending json-rpc request to server to get some information ,I am successful to get it in first time but when I send the second request I am receiving an empty response with 404 error (page not found).
But when I call the service without https (http only) it works fine regardless how many time I call it !
public async Task<string> GetDataFromServer(string urlToCall, string JSONData,string RR)
{
string UserName = “XXXXXXX”
string Password = "XXX";
using ( var handler = new HttpClientHandler())
{
handler.Credentials = new NetworkCredential(UserName, Password);
HttpClient client = new HttpClient(handler);
HttpResponseMessage response = null;
try
{
response = await client.PostAsync(urlToCall, new StringContent(JSONData.ToString(), Encoding.UTF8, " application/json"));
string res = response.Content.ReadAsStringAsync().Result;
Windows.UI.Popups.MessageDialog g = new Windows.UI.Popups.MessageDialog(res);
await g.ShowAsync();
return res;
}
catch (Exception ex)
{
Windows.UI.Popups.MessageDialog g = new Windows.UI.Popups.MessageDialog("Error is : " + ex.Message);
g.ShowAsync();
return "Error";
}
finally
{
response.Dispose();
client.CancelPendingRequests();
client.Dispose();
handler.Dispose();
}
}
}
Again, when call the URL of service (start with https) on first time I got response with seeked data, but second time I receive an empty response with 404 error (page not found) !!
Any help please
Please try to use this solution.
public async Task<string> SendJSONData3(string urlToCall, string JSONData)
{
string UserName = "XXXXXXXXX";
string Password = "XXXXXXXXX";
var httpWebRequest = (HttpWebRequest)WebRequest.Create(urlToCall);
httpWebRequest.Credentials = new NetworkCredential(UserName, Password);
httpWebRequest.ContentType = "text/json";
httpWebRequest.Method = "POST";
using (var streamWriter = new StreamWriter(await httpWebRequest.GetRequestStreamAsync()))
{
string json = JSONData;
streamWriter.Write(json);
streamWriter.Flush();
}
var httpResponse = (HttpWebResponse)await httpWebRequest.GetResponseAsync();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
var result = streamReader.ReadToEnd();
return result;
}
}
A couple of ideas:
Do not use the .Result property. Just use await instead to avoid deadlocks.
Remove the additional space in front of the media type parameter " application/json"
Enable logging on the webserver and see if the second request arrives on the server.
Get a network trace, for example with Wireshark or Fiddler.
Try puting WebRequest.RegisterPrefix("https://", WebRequestCreator.ClientHttp); in your initialization code, as proposed in this answer.
I am trying to get a reference to a response stream before its complete in windows phone 8.
In other .Net platforms you can do
HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(myUri);
WebResponse subscribeWebResponse = null;
Stream subscribeStream = null;
subscribeWebResponse = httpRequest.GetResponse();
subscribeStream = subscribeWebResponse.GetResponseStream();
For the purpose of creating Portable class libraries I've used the HttpClientLibrary from nuget.
This Adds ref to extensions assembly Microsoft.Net.Http
this allows me to return the async request at the time the headers have been read instead of waiting for the content transfer to be complete with
var clientResponse = await httpClient.SendAsync(requestmessage, HttpCompletionOption.ResponseHeadersRead);
The problem I'm having is that in windows phone 8 it doesn't work correctly, and still awaits the completion of the content stream to return.
Additionally
await httpWebRequest.BeginGetResponse(callback, request)
has the same behavior as these async methods are actually waiting for the completion of the web's response to continue execution.
So, is there any way to achieve the returning the response/stream at the point that i have received the response headers without Microsoft.Http.Net package?
Even if it has to be a Windows Phone 8 Platform Specific Solution?
Possibly an extension of HttpWebRequest?
From what I can tell, ResponseHeadersRead works on the WP8 emulator as it does on the desktop.
I installed the Win8 SDK. Created a windows phone app. I added this code to the MainPage ctor. This demonstrates a very rudimentary long polling example.
var client = new HttpClient();
var request = new HttpRequestMessage()
{
RequestUri = new Uri("http://oak:1001/longpolling")
};
client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, new CancellationToken())
.ContinueWith((t) =>
{
var response = t.Result;
response.Content.ReadAsStreamAsync()
.ContinueWith(s =>
{
var st = s.Result;
while (true)
{
var message= ReadNextMessage(st);
}
});
});
}
private static string ReadNextMessage(Stream stream)
{
int chr = 0;
string output = "";
while (chr != 10)
{
chr = stream.ReadByte();
output += Convert.ToChar(chr);
}
return output;
}
On my host dev machine I have a web api with a controller that looks like this...
public class LongPollingController : ApiController
{
public HttpResponseMessage Get()
{
Thread.Sleep(2000);
var content = new PushStreamContent( (s,c,t) =>
{
int i = 0;
while (true)
{
try
{
var message = String.Format("The current count is {0} " + Environment.NewLine, i++);
var buffer = Encoding.UTF8.GetBytes(message);
s.Write(buffer, 0, buffer.Length);
}
catch (IOException exception)
{
s.Close();
return;
}
Thread.Sleep(1000);
}
});
return new HttpResponseMessage(HttpStatusCode.OK)
{
RequestMessage = Request,
Content = content
};
}
}
So here's the deal. I would say that what you want to do is not possible, due to platform limitations... But SignalR has a WP client and is able to manage it. So it seems to me you have two options:
1) Dig into the SignalR source code to see how they do it (I'm on my phone right now so I can't provide a link).
UPDATE: Here is the link. They do some pretty neat tricks, like setting the Timeout to -1 for long-running clients. I think you should definitely use the techniques here.
OR
2) You can move whatever you're doing over to SignalR, which would gain the benefit of having a robust infrastructure and being cross-platform compatible.
HTH