Im trying to write to a form from an asynchronous call. The examples I seen on line show that this should work but I keep getting an error.
First the call that is made though the Disbatcher never calls p. Second i get a System.Security.SecurityException on the call req.EndGetResponse(a);
What could be causing the problem?
public partial class Page : UserControl
{
Uri url = new Uri("http://www.google.com", UriKind.Absolute);
HttpWebRequest req;
private delegate void PrintToUIThread(string text);
PrintToUIThread p;
public Page()
{
InitializeComponent();
req = (HttpWebRequest)WebRequest.Create(url);
p = new PrintToUIThread(print);
req.BeginGetResponse(new AsyncCallback(WebComplete), req);
}
void WebComplete(IAsyncResult a)
{
try
{
Dispatcher.BeginInvoke(p);
HttpWebRequest req = (HttpWebRequest)a.AsyncState;
HttpWebResponse res = (HttpWebResponse)req.EndGetResponse(a);
Dispatcher.BeginInvoke(p);
}
catch (Exception ex)
{
print(ex.ToString());
}
}
private void print(string text)
{
PageTextBox.Text = text;
}
private void print()
{
PageTextBox.Text = "Call From Invoke";
}
}
There's nothing inherently wrong with your request/response code from what I can see. You're probably running into the security exception because of the cross-domain restrictions implied by google's crossdomain.xml file.
This is Google's crossdomain.xml:
<?xml version="1.0"?>
<!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<site-control permitted-cross-domain-policies="by-content-type" />
</cross-domain-policy>
All this is really saying is "Hey, RIA app, use a proxy". Basically, set up a WCF or ASMX web service call with your "friendly" server with a clientaccesspolicy.xml file in place, use your server to make the http request, then deliver the results back. I'm not not sure if google supports JSONP, but you could try that as well.
Related
I am trying to integrate Twilio to my AngularJS and spring MVC application. After following Twilio documentation I set up at front end device setup and calling etc. In Java class I am generating a token, and passing that token while making the call. In java the code is:
#RequestMapping(value = "/phoneCalling", method {
RequestMethod.GET, RequestMethod.POST
})
public #ResponseBody Phone phoneCalling(HttpServletRequest request, HttpServletResponse response, #RequestParam String leadPhone) {
try {
Number number = new Number.Builder(leadPhone).build();
Dial dial = new Dial.Builder().number(number).build();
VoiceResponse responseVR = new VoiceResponse.Builder().dial(dial).build();
System.out.println(responseVR.toXml());
} catch (TwiMLException e) {
e.printStackTrace();
}
return null;
}
At twilio TwiML, I set request URL as:
https://865c048b.ngrok.io/ZingyCRM/phoneCalling/
As I am testing locally, so used ngrok. But after clicking on make a call, it gives me voice message as application error occurred. I believe the TwiML request URL I might be setting wrong, can some one help here?
tl;dr What is the best way to pass binary data (up to 1MBish) from a WPF application to a WebAPI service method?
I'm currently trying to pass binary data from a WPF application to a WebAPI web service, with variable results. Small files (< 100k) generally work fine, but any larger and the odds of success reduce.
A standard OpenFileDialog, and then File.ReadAllBytes pass the byte[] parameter into the client method in WPF. This always succeeds, and I then post the data to WebAPI via a PostAsync call and a ByteArrayContent parameter.
Is this the correct way to do this? I started off with a PostJSONAsync call, and passed the byte[] into that, but thought the ByteArrayContent seemed more appropriate, but neither work reliably.
Client Method in WPF
public static async Task<bool> UploadFirmwareMCU(int productTestId, byte[] mcuFirmware)
{
string url = string.Format("productTest/{0}/mcuFirmware", productTestId);
ByteArrayContent bytesContent = new ByteArrayContent(mcuFirmware);
HttpResponseMessage response = await GetClient().PostAsync(url, bytesContent);
....
}
WebAPI Method
[HttpPost]
[Route("api/productTest/{productTestId}/mcuFirmware")]
public async Task<bool> UploadMcuFirmware(int productTestId)
{
bool result = false;
try
{
Byte[] mcuFirmwareBytes = await Request.Content.ReadAsByteArrayAsync();
....
}
Web Config Settings
AFAIK these limits in web.config should be sufficient to allow 1MB files through to the service?
<security>
<requestFiltering>
<requestLimits maxAllowedContentLength="1073741824" />
</requestFiltering>
</security>
<httpRuntime targetFramework="4.5" maxRequestLength="2097152"/>
I receive errors in WebAPI when calling ReadAsByteArrayAsync(). These vary, possibly due to the app pool in IIS Express having crashed / getting into a bad state, but they include the following (None of which have lead to any promising leads via google):
Specified argument was out of the range of valid values. Parameter name: offset
at System.Web.HttpInputStream.Seek(Int64 offset, SeekOrigin origin)\r\n
at System.Web.HttpInputStream.set_Position(Int64 value)\r\n at System.Web.Http.WebHost.SeekableBufferedRequestStream.SwapToSeekableStream()\r\n at System.Web.Http.WebHost.Seek
OR
Message = "An error occurred while communicating with the remote host. The error code is 0x800703E5."
InnerException = {"Overlapped I/O operation is in progress. (Exception from HRESULT: 0x800703E5)"}
at System.Web.Hosting.IIS7WorkerRequest.RaiseCommunicationError(Int32 result, Boolean throwOnDisconnect)\r\n
at System.Web.Hosting.IIS7WorkerRequest.ReadEntityCoreSync(Byte[] buffer, Int32 offset, Int32 size)\r\n
at System.Web.Hosting.IIS7WorkerRequ...
Initially I thought this was most likely down to IIS Express limitations (running on Windows 7 on my dev pc) but we've had the same issues on a staging server running Server 2012.
Any advice on how I might get this working would be great, or even just a basic example of uploading files to WebAPI from WPF would be great, as most of the code I've found out there relates to uploading files from multipart forms web pages.
Many thanks in advance for any help.
tl;dr It was a separate part of our code in the WebApi service that was causing it to go wrong, duh!
Ah, well, this is embarrassing.
It turns out our problem was down to a Request Logger class we'd registered in WebApiConfig.Register(HttpConfiguration config), and that I'd forgotten about.
It was reading the request content via async as StringContent, and then attempting to log it to the database in an ncarchar(max) field. This itself is probably OK, but I'm guessing all the weird problems started occurring when the LoggingHandler as well as the main WebApi controller, were both trying to access the Request content via async?
Removing the LoggingHandler fixed the problem immediately, and we're now able to upload files of up to 100MB without any problems. To fix it more permanently, I guess I rewrite of the LoggingHandler is required to set a limit on the maximum content size it tries to log / to ignore certain content types.
It's doubtful, but I hope this may be of use for someone one day!
public class LoggingHandler : DelegatingHandler
{
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
LogRequest(request);
return base.SendAsync(request, cancellationToken).ContinueWith(task =>
{
var response = task.Result;
// ToDo: Decide if/when we need to log responses
// LogResponse(response);
return response;
}, cancellationToken);
}
private void LogRequest(HttpRequestMessage request)
{
(request.Content ?? new StringContent("")).ReadAsStringAsync().ContinueWith(x =>
{
try
{
var callerId = CallerId(request);
var callerName = CallerName(request);
// Log request
LogEntry logEntry = new LogEntry
{
TimeStamp = DateTime.Now,
HttpVerb = request.Method.ToString(),
Uri = request.RequestUri.ToString(),
CorrelationId = request.GetCorrelationId(),
CallerId = callerId,
CallerName = callerName,
Controller = ControllerName(request),
Header = request.Headers.ToString(),
Body = x.Result
};
...........
I'm having trouble following the second step here.
I really don't understand how this sample does anything other than return a simple toast message. How does it utilize the API to display that message?
class EndpointsAsyncTask extends AsyncTask<Pair<Context, String>, Void, String> {
private static MyApi myApiService = null;
private Context context;
#Override
protected String doInBackground(Pair<Context, String>... params) {
if(myApiService == null) { // Only do this once
MyApi.Builder builder = new MyApi.Builder(AndroidHttp.newCompatibleTransport(),
new AndroidJsonFactory(), null)
// options for running against local devappserver
// - 10.0.2.2 is localhost's IP address in Android emulator
// - turn off compression when running against local devappserver
.setRootUrl("http://10.0.2.2:8080/_ah/api/")
.setGoogleClientRequestInitializer(new GoogleClientRequestInitializer() {
#Override
public void initialize(AbstractGoogleClientRequest<?> abstractGoogleClientRequest) throws IOException {
abstractGoogleClientRequest.setDisableGZipContent(true);
}
});
// end options for devappserver
myApiService = builder.build();
}
context = params[0].first;
String name = params[0].second;
try {
return myApiService.sayHi(name).execute().getData();
} catch (IOException e) {
return e.getMessage();
}
}
#Override
protected void onPostExecute(String result) {
Toast.makeText(context, result, Toast.LENGTH_LONG).show();
}
I'm afraid my this sample is too complex for my limited knowledge. How exactly do I "talk" to the Google Endpoints Module when running an app? Specifically, What is EndpointsAsyncTask();?
Are there any resources listing all the methods available to me? Is there a simpler example of an app communicating with a Google Cloud Endpoint?
The service methods available to you are defined by the backend source in section 1.
In the example you posted, this line: myApiService.sayHi(name).execute()
is an actual invocation call to the backend that you defined by annotating #ApiMethod("sayHi") on the method in the MyEndpoint.java class of your backend module.
The reason your Android app defines an EndpointsAsyncTask is because slow operations such as calls that hit the network need to happen off of the UI thread to avoid locking the UI. The demo simply puts the returned value into a Toast but you could modify onPostExecute() to do whatever you'd like with the result.
For more info on Google Endpoints check out:
https://cloud.google.com/appengine/docs/java/endpoints/
And for info about using an Android AsyncTask look here:
http://developer.android.com/reference/android/os/AsyncTask.html
I've got a Silverlight enabled WCF web service set up and I'm connecting to it from my Silverlight application.
The Service is not written using the ASync pattern but Silverlight generates the async methods automatically.
I have a method that within my service that has a chance of throwing an exception I can catch this exception but I'm not sure of the best way of handling this exception, I've noticed that the event args of the completed method contain an error property.
Is is possible to set the value of this error property?
Example Method
public class service
{
[OperationContract]
public Stream getData(string filename)
{
string filepath = HostingEnvironment.MapPath(filename);
FileInfo fi = new FileInfo(filenpath);
try
{
Stream s = fi.Open(FileMode.Open);
return s;
}
catch (IOException e)
{
return null;
}
}
}
Silverlight Code
btnFoo_Click(object sender, RoutedEventArgs e)
{
ServiceClient svc = new ServiceClient();
svc.getDataCompleted += new EventHandler<getDataCompletedEventArgs>(getData_Completed);
svc.getDataAsync("text.txt");
}
void getData_Completed(object sender, getDataCompletedEventArgs e)
{
e.Error //how can i set this value on the service?
}
Finally if the service is offline or times out is there anyway to catch this exception before it reaches the UnhandledException method within App.xaml?
Thanks
Since silverlight is using services asyncronously you dont get a synchronous exception throw, but instead it is stored in e.Error property, that you need to check in your ServiceCallCompleted method.
To answer your question
how can i set this value on the service?
Simply throw an exception on server and it can be enough given several other conditions.
You may want to introduce FaultContract on your WCF service method, and throw FaultException<T> which is a common way to deal with errors in WCF.
However fault result in return code 500 and silverlight won't be able to get response with such status code and have access to Fault object, even if you add that attribute to service.
This can be solved using several approaches.
Use the alternative client HTTP stack: You can register an alternative HTTP stack by using the RegisterPrefix method. See below for an outline of how to do this. Silverlight 4 provides the option of using a client HTTP stack which, unlike the default browser HTTP stack, allows you to process SOAP-compliant fault messages. However, a potential problem of switching to the alternative HTTP stack is that information stored by the browser (such as authentication cookies) will no longer be available to Silverlight, and thus certain scenarios involving secure services might stop working, or require additional code to work.
Modify the HTTP status code: You can modify your service to return SOAP faults with an HTTP status code of 200, Silverlight 4 so that faults will be processed successfully. How to do this is outlined below. Note that this will make the service non-compliant with the SOAP protocol, because SOAP requires a response code in the 400 or 500 range for faults. If the service is a WCF service, you can create an endpoint behavior that plugs in a message inspector that changes the status code to 200. Then you can create an endpoint specifically for Silverlight consumption, and apply the behavior there. Your other endpoints will still remain SOAP-compliant.
Faults in silverlight
Creating and Handling Faults in Silverlight
OR
[DataContract]
public class MyError
{
[DataMember]
public string Code { get; set; }
[DataMember]
public string Message { get; set; }
[DataMember]
public DateTime Time { get; set; }
}
public class service
{
[OperationContract]
public Stream getData(string filename, out MyError myError)
{
myError = null;
string filepath = HostingEnvironment.MapPath(filename);
FileInfo fi = new FileInfo(filenpath);
try
{
Stream s = fi.Open(FileMode.Open);
return s;
}
catch (IOException e)
{
myError = new MyError() { Code = "000", Message = ex.Message, Time = DateTime.Now };
return null;
}
}
}
I wish successful projects
I have a Windows Phone 7 application built with silverlight. This application has been deployed. I've noticed in the log files that occasionally, my user's actions throw a "NotSupportedException". I have not been able to produce this. However, because of my logs, I know that it is happening in the Execute method shown here:
public void Execute()
{
try
{
// 1. Build the query
string serviceUrl = GetServiceUrl;
// 2. Asynchronously execute the query using HttpWebRequest
WebRequest request = HttpWebRequest.Create(serviceUrl);
request.BeginGetResponse(new AsyncCallback(ServiceRequest_Completed), request);
} catch (Exception ex)
{
LogException(ex, "1");
}
}
private void ServiceRequest_Completed(IAsyncResult result)
{
try
{
// 1. Get the response from the service call
WebRequest request = (WebRequest)(result.AsyncState);
WebResponse response = request.EndGetResponse(result);
// 2. Do stuff with response
}
catch (Exception ex)
{
LogException(ex, "2");
}
}
I know it is happening in the Execute method because the "1" is written in the log file instead of the "2" My question is, what would cause this? I looked at the MSDN documentation and it looks like I'm doing what I should be doing. Like I said, I can't reproduce it locally. But I do know that it is happening regularly by different users because of the log files.
There is a previous question with a very similar title - https://stackoverflow.com/questions/4053197/httpwebrequest-leads-me-to-system-notsupportedexception
The answer to that problem seems to have been using ServiceRequest_Completed instead of new AsyncCallback(ServiceRequest_Completed)