How to recreate the following code in Silverlight? I'm pretty lost when it comes to async.
public class StringGet
{
public static string GetPageAsString(Uri address)
{
string result = "";
// Create the web request
HttpWebRequest request = WebRequest.Create(address) as HttpWebRequest;
// Get response
using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
{
// Get the response stream
StreamReader reader = new StreamReader(response.GetResponseStream());
// Read the whole contents and return as a string
result = reader.ReadToEnd();
}
return result;
}
public void DownloadHtml(Uri address){
WebClient webClient = new WebClient();
webClient.DownloadStringCompleted += WebClientDownloadString_Complete;
webClient.DownloadStringAsync(address)
}
private void WebClientDownloadString_Complete(object sender, DownloadStringCompletedEventArgs e) {
if (e.Error == null) {
string html = e.Result;
}
}
Related
In my Mainpage.xaml.cs file I have a function that creates an instance of another class and tries to download a webpage using a HttpWebRequest from that instance. The problem is, once I've managed to download the webpage I can't send it back to the main UI thread. I've tried using Deployment.Current.Dispatcher.BeginInvoke to send the webpage back to a TextBlock I have waiting, but when I try I get an error telling me that I can't access the TextBlock from the other class. Is there any way to pass data between two threads without using LocalStorage?
EDIT: code below:
MainPage:
private void button1_Click(object sender, RoutedEventArgs e)
{
Member m = new Member(name, id);
}
Member class:
public Member(String Member, String API)
{
APIKey = API;
MemberName = Member;
this.super = super;
DoSend(method, string, "", null);
}
public void DoSend(string method, string url, string body, string mimetype)
{
if (WebRequest.RegisterPrefix("https://",System.Net.Browser.WebRequestCreator.ClientHttp)) {
HttpWebRequest request = WebRequest.Create(makeURI(url)) as HttpWebRequest;
request.Method = method;
request.Headers["X-NFSN-Authentication"] = MakeAuthHeader(url,body);
if (body != "")
{
byte[] bodyData = Encoding.UTF8.GetBytes(body);
request.ContentType = mimetype;
//Stuff Should Happen Here
}
else
doStuff(request);
}
public void doStuff(HttpWebRequest httpReq)
{
httpReq.BeginGetResponse(r =>
{
var httpRequest = (HttpWebRequest)r.AsyncState;
var httpResponse = (HttpWebResponse)httpRequest.EndGetResponse(r);
using (var reader = new StreamReader(httpResponse.GetResponseStream()))
{
var response = reader.ReadToEnd();
ResponseBlock.Text = response; //Invalid cross-thread reference
}
}, httpReq);
}
MainPage:
customClass.DownloadPage((result) =>
{
textBlock.Text = result;
},
(exception) =>
{
MessageBox.Show(exception.Message);
});
CustomClass:
public void DownloadPage(Action<string> callback, Action<Exception> exception)
{
WebClient webClient = new WebClient();
webClient.DonwloadStringCompleted += (s, e) =>
{
if (e.Error == null)
{
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
callback(e.Result);
});
}
else
{
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
exception(e.Error);
});
}
};
webClient.DonwloadStringAsync();
}
I've been dying for about 6 hours trying to figure out how to make a regular POST request in WP7 , I tried the answers of similar questions posted here and on many other places, I also tried many different APIs POST request, they all lead to one certain problem,
The remote server returned an error: NotFound.
it seems like everytime there's something missing.
So, if you please someone show us how to properly get a POST request right in this WP7
I use this to post to facebook without any problem:
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(requestUrl);
request.Method = "POST";
request.BeginGetResponse((e) =>
{
try
{
WebResponse response = request.EndGetResponse(e);
// Do Stuff
}
catch (WebException ex)
{
// Handle
}
catch (Exception ex)
{
// Handle
}
}, null);
I assume you would have tried this already so it may be something to do with the post data (which isn't in the above example as facebook uses the query string). Can you give us any more info?
EDIT: This is an (untested) example for writing post data:
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(requestUrl);
request.Method = "POST";
request.BeginGetRequestStream((e) =>
{
using (Stream stream = request.EndGetRequestStream(e))
{
// Write data to the request stream
}
request.BeginGetResponse((callback) =>
{
try
{
WebResponse response = request.EndGetResponse(callback);
// Do Stuff
}
catch (WebException ex)
{
// Handle
}
catch (Exception ex)
{
// Handle
}
}, null);
}, null);
I use the following class for making POST requests with WP7:
public class PostMultiPartFormData
{
private Dictionary<string, object> Parameters;
private Encoding ENCODING = Encoding.UTF8;
private string BOUNDARY = "-----------------------------wp7postrequest";
public event EventHandler PostComplete;
public void Post(string postbackURL,
Dictionary<string, object> parameters)
{
Parameters = parameters;
Uri url = null;
url = new Uri(postbackURL);
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
request.Method = "POST";
request.ContentType = "multipart/form-data; boundary=" + BOUNDARY;
request.BeginGetRequestStream(new AsyncCallback(SendStatusUpdate), request);
}
private void SendStatusUpdate(IAsyncResult ar)
{
HttpWebRequest request = (HttpWebRequest)ar.AsyncState;
Stream stream = request.EndGetRequestStream(ar);
byte[] byteArray = GetMultipartFormData(Parameters, BOUNDARY);
stream.Write(byteArray, 0, byteArray.Length);
stream.Close();
stream.Dispose();
request.BeginGetResponse(new AsyncCallback(StatusUpdateCompleted), request);
}
private byte[] GetMultipartFormData(Dictionary<string, object> postParameters, string boundary)
{
Stream formDataStream = new System.IO.MemoryStream();
foreach (var param in postParameters)
{
if (param.Value is byte[])
{
byte[] fileData = param.Value as byte[];
string header = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"; filename=\"{2}.jpg\";\r\nContent-Type: application/octet-stream\r\n\r\n", boundary, param.Key, param.Key);
formDataStream.Write(ENCODING.GetBytes(header), 0, header.Length);
formDataStream.Write(fileData, 0, fileData.Length);
}
else
{
string postData = string.Format("--{0}\r\nContent-Disposition: form-data; name=\"{1}\"\r\n\r\n{2}\r\n", boundary, param.Key, param.Value);
byte[] b = ENCODING.GetBytes(postData);
foreach (var item in b)
{
formDataStream.WriteByte(item);
}
}
}
string footer = "\r\n--" + boundary + "--\r\n";
byte[] footerbytes = ENCODING.GetBytes(footer);
formDataStream.Write(footerbytes, 0, footerbytes.Length);
formDataStream.Position = 0;
byte[] formData = new byte[formDataStream.Length];
formDataStream.Read(formData, 0, formData.Length);
formDataStream.Flush();
formDataStream.Close();
return formData;
}
private void StatusUpdateCompleted(IAsyncResult ar)
{
if (PostComplete != null)
{
PostComplete(ar, null);
}
}
}
Example:
PostMultiPartFormData postRequest = new PostMultiPartFormData();
postRequest.PostComplete += new EventHandler( (sender, e) =>
{
IAsyncResult ar = ((IAsyncResult)sender);
using (WebResponse resp = ((HttpWebRequest)ar.AsyncState).EndGetResponse(ar))
{
using (StreamReader sr = new StreamReader(resp.GetResponseStream()))
{
string responseString = sr.ReadToEnd();
this.Dispatcher.BeginInvoke(() =>
{
textBlock.Text = responseString;
});
}
}
});
postRequest.Post("http://localhost:50624/SSLProxy.ashx",
new Dictionary<string, object>() { { "param1", "value1" } });
This should work...
If it doesn't let me know! :-)
For easier access to advanced http features check out these http classes:
http://mytoolkit.codeplex.com/wikipage?title=Http
It encapsulates GET, POST, FILES (using path or Stream objects) and GZIP (not directly supported by WP7) requests.
To add post data just call BeginGetRequestStream method (also, BeginGetResponse move to GetRequestStreamCallback)
request.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), request);
void GetRequestStreamCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest webRequest = (HttpWebRequest)asynchronousResult.AsyncState;
// End the stream request operation
Stream postStream = webRequest.EndGetRequestStream(asynchronousResult);
// Create the post data
string postData = "post data";
byte[] byteArray = Encoding.Unicode.GetBytes(postData);
// Add the post data to the web request
postStream.Write(byteArray, 0, byteArray.Length);
postStream.Close();
// Start the web request
webRequest.BeginGetResponse(new AsyncCallback(GetResponseCallback), webRequest);
}
I recommend you to use the postclient. It is pretty simple. You just need to add reference to dll file into your project, and then write something like:
public void authorize(string login, string password)
{
Dictionary<string, object> parameters = new Dictionary<string, object>();
parameters.Add("command", "login");
parameters.Add("username", login);
parameters.Add("password", password);
PostClient proxy = new PostClient(parameters);
proxy.DownloadStringCompleted += (sender, e) =>
{
if (e.Error == null)
{
MessageBox.Show(e.Result);
}
};
proxy.DownloadStringAsync(new Uri("http://address.com/service", UriKind.Absolute));
}
Friends!
Help me, please!
I try to post file from Silverlight. I use such class:
public class HttpHelper
{
public WebRequest Request { get; set; }
public Stream Filestream { get; private set; }
public HttpHelper(Stream filestream)
{
Request = WebRequest.Create("http://www.mysite.com/recieve");
Request.Method = "POST";
Request.ContentType = "application/octet-stream";
Filestream = filestream;
}
private static void BeginFilePostRequest(IAsyncResult ar)
{
HttpHelper helper = ar.AsyncState as HttpHelper;
if (helper != null)
{
byte[] bytes = new byte[helper.Filestream.Length];
int sf = helper.Filestream.Read(bytes, 0, (int)helper.Filestream.Length);
//helper.Request.ContentLength = bytes.Length; //It doesn't work in SL
using (StreamWriter writer = new StreamWriter(helper.Request.EndGetRequestStream(ar)))
{
writer.Write(bytes);
}
helper.Request.BeginGetResponse(new AsyncCallback(HttpHelper.BeginResponse), helper);
}
}
private static void BeginResponse(IAsyncResult ar)
{
HttpHelper helper = ar.AsyncState as HttpHelper;
if (helper != null)
{
HttpWebResponse response = (HttpWebResponse)helper.Request.EndGetResponse(ar);
if (response != null)
{
Stream stream = response.GetResponseStream();
if (stream != null)
{
using (StreamReader reader = new StreamReader(stream))
{
//anything...
}
}
}
}
}
public void PostFile()
{
this.Request.BeginGetRequestStream(new AsyncCallback(HttpHelper.BeginFilePostRequest), this);
}
}
I have Stream in my silverlight application and try to call PostFile by click submit button:
private void submit_button_Click(object sender, RoutedEventArgs e)
{
//...
HttpHelper helper = new HttpHelper(memory_stream);
helper.PostFile();
}
But mysite recieve request without file. It just has ContentLength 13. What's problem?
Try Flush on your writer before exiting the using block, you should also call Close on the stream retrieved from EndGetRequestStream.
you HAVE TO Flush and Dispose HTTP request stream and all downstream streams, then it works.
I'm having trouble with a basic HttpWebRequest in a WP7 application. As soon as I call BeginGetRequestStream, it starts to go wrong. The callback method then receives an IAsyncResult with no AsyncWaitHandle.
AsyncWaitHandle = 'ar.AsyncWaitHandle' threw an exception of type 'System.NotSupportedException'
I've created a sample below that produces the error. To create this I have just taken the sample pivot application and attempted to post some data to a server in the constructor of the MainViewModel.
public MainViewModel()
{
this.Items = new ObservableCollection<ItemViewModel>();
HttpWebRequest webRequest = WebRequest.CreateHttp("http://www.google.co.uk");
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.BeginGetRequestStream(BeginGetRequestStreamCallBack, webRequest);
}
private void BeginGetRequestStreamCallBack(IAsyncResult ar)
{
HttpWebRequest webRequest = (HttpWebRequest) ar.AsyncState;
Stream requestStream = webRequest.EndGetRequestStream(ar);
using(StreamWriter sw = new StreamWriter(requestStream))
{
sw.Write("{ test: \"test\" }");
}
webRequest.BeginGetResponse(BeginGetResponseCallback, webRequest);
}
private void BeginGetResponseCallback(IAsyncResult ar)
{
HttpWebRequest webRequest = (HttpWebRequest)ar.AsyncState;
WebResponse webResponse = webRequest.EndGetResponse(ar);
Stream responseStream = webResponse.GetResponseStream();
string whatCameBack = new StreamReader(responseStream).ReadToEnd();
}
Any help would as always, be greatly appreciated.
I've looked into this a little deeper, I just can't seem to POST data using BeginGetRequestStream.
public MainViewModel()
{
this.Items = new ObservableCollection<ItemViewModel>();
HttpWebRequest webRequest = WebRequest.CreateHttp("http://www.google.co.uk");
//webRequest.Method = "POST";
//webRequest.ContentType = "application/x-www-form-urlencoded";
//webRequest.BeginGetRequestStream(BeginGetRequestStreamCallBack, webRequest);
webRequest.BeginGetResponse(BeginGetResponseCallback, webRequest);
}
private void BeginGetRequestStreamCallBack(IAsyncResult ar)
{
HttpWebRequest webRequest = (HttpWebRequest) ar.AsyncState;
Stream requestStream = webRequest.EndGetRequestStream(ar);
using(StreamWriter sw = new StreamWriter(requestStream))
{
sw.Write("{ test: \"test\" }");
}
webRequest.BeginGetResponse(BeginGetResponseCallback, webRequest);
}
private void BeginGetResponseCallback(IAsyncResult ar)
{
HttpWebRequest webRequest = (HttpWebRequest)ar.AsyncState;
WebResponse webResponse = webRequest.EndGetResponse(ar);
Stream responseStream = webResponse.GetResponseStream();
string whatCameBack = new StreamReader(responseStream).ReadToEnd();
}
This works okay, but it is not what I want.
Any ideas?
I was being a naughty boy and not Closing the stream correctly.
using(Stream requestStream = webRequest.EndGetRequestStream(ar))
{}
All is well.
in a Silverlight-Windows Phone 7-project I am creating an HttpWebRequest, get the RequestStream, write something into the Stream and try to get the response, but I always get a NotSupportedException:
"System.Net.Browser.OHWRAsyncResult.AsyncWaitHandle threw an exception of type 'System.NotSupportedException'
My production code is far more complicated, but I can narrow it down to this small piece of code:
public class HttpUploadHelper
{
private HttpWebRequest request;
private RequestState state = new RequestState();
public HttpUploadHelper(string url)
{
this.request = WebRequest.Create(url) as HttpWebRequest;
state.Request = request;
}
public void Execute()
{
request.Method = "POST";
this.request.BeginGetRequestStream(
new AsyncCallback(BeginRequest), state);
}
private void BeginRequest(IAsyncResult ar)
{
Stream stream = state.Request.EndGetRequestStream(ar);
state.Request.BeginGetResponse(
new AsyncCallback(BeginResponse), state);
}
private void BeginResponse(IAsyncResult ar)
{
// BOOM: NotSupportedException was unhandled;
// {System.Net.Browser.OHWRAsyncResult}
// AsyncWaitHandle = 'ar.AsyncWaitHandle' threw an
// exception of type 'System.NotSupportedException'
HttpWebResponse response = state.Request.EndGetResponse(ar) as HttpWebResponse;
Debug.WriteLine(response.StatusCode);
}
}
public class RequestState
{
public WebRequest Request;
}
}
Does anybody know what is wrong with this code?
The NotSupportedException can be thrown when the request stream isn't closed before the call to EndGetResponse. The WebRequest stream is still open and sending data to the server when you're attempting to get the response. Since stream implements the IDisposable interface, a simple solution is to wrap your code using the request stream in a using block:
private void BeginRequest(IAsyncResult ar)
{
using (Stream stream = request.EndGetRequestStream(ar))
{
//write to stream in here.
}
state.Request.BeginGetResponse(
new AsyncCallback(BeginResponse), state);
}
The using block will ensure that the stream is closed before you attempt to get the response from the web server.
The issue is with how you're dealing with the accessing the original requests in the callback from BeginGetResponse.
Rather than holding a reference ot the state, get a reference back to the original request with:
var request = (HttpWebRequest)asynchronousResult.AsyncState;
Have a look at this very basic (but working) example of implementing logging in by posting email and password credentials to a website.
public static string Email;
public static string Password;
private void LoginClick(object sender, RoutedEventArgs e)
{
Email = enteredEmailAddress.Text.Trim().ToLower();
Password = enteredPassword.Password;
var request = (HttpWebRequest)WebRequest.Create(App.Config.ServerUris.Login);
request.ContentType = "application/x-www-form-urlencoded";
request.Method = "POST";
request.BeginGetRequestStream(ReadCallback, request);
}
private void ReadCallback(IAsyncResult asynchronousResult)
{
var request = (HttpWebRequest)asynchronousResult.AsyncState;
using (var postStream = request.EndGetRequestStream(asynchronousResult))
{
using (var memStream = new MemoryStream())
{
var content = string.Format("Password={0}&Email={1}",
HttpUtility.UrlEncode(Password),
HttpUtility.UrlEncode(Email));
var bytes = System.Text.Encoding.UTF8.GetBytes(content);
memStream.Write(bytes, 0, bytes.Length);
memStream.Position = 0;
var tempBuffer = new byte[memStream.Length];
memStream.Read(tempBuffer, 0, tempBuffer.Length);
postStream.Write(tempBuffer, 0, tempBuffer.Length);
}
}
request.BeginGetResponse(ResponseCallback, request);
}
private void ResponseCallback(IAsyncResult asynchronousResult)
{
var request = (HttpWebRequest)asynchronousResult.AsyncState;
using (var resp = (HttpWebResponse)request.EndGetResponse(asynchronousResult))
{
using (var streamResponse = resp.GetResponseStream())
{
using (var streamRead = new StreamReader(streamResponse))
{
string responseString = streamRead.ReadToEnd();
// do something with responseString to check if login was successful
}
}
}
}
NotSupportedException can also be thrown when string url is too long. I had messed up and attached post data to url instead of post body. When the data was short, it worked just fine, but once it grew too large - EndGetResponse crashed.
Change this:
state.Request.BeginGetResponse(
new AsyncCallback(BeginResponse), state);
To this:
state.Request.BeginGetResponse(BeginResponse, state);