I am using ConnectionRequest and downloadImageToStorage to download an image from a web server. The webserver is returning a 307 with a location, that next url returns a 301 with another location, that location finally returns the actual image.
I defined a FailureCallback, but it is not getting called at all. All I can see is a message on the device screen that indicates the error and has a retry/cancel buttons.
Here is my code
FailureCallback<Image> failure = new FailureCallback<Image>() {
public void onError(Object sender, Throwable err, int errorCode, String errorMessage) {
System.out.println(errorCode);
if (errorCode == 307 || errorCode == 301) {
System.out.println(sender.getClass().getName());
}
}
};
ConnectionRequest request = new ConnectionRequest();
request.setUrl(url);
request.setHttpMethod("GET");
request.downloadImageToStorage("img_" + imgCount, (img) -> {
SpanLabel t = new SpanLabel();
t.add(BorderLayout.CENTER, img);
myform.add(t);
}, failure);
++imgCount;
How can I capture these errors so I can get the Location from the Response objects and call those with new ConnectionRequests?
Note that I can see the chain of error codes and locations when I use the debugger in Chrome to get the image that I am trying to load.
Thanks
To capture error code and error message setReadResponseForErrors method should be called and override handleErrorResponseCode method of ConnectionRequest as shown in below code
request .setReadResponseForErrors(true);
#Override
protected void handleErrorResponseCode(int code, String message) {
Dialog.show("Message", " code "+ code+" msg "+message, "ok", null);
}
As Shai mentioned in his comment, there was a bug that caused 307 to be interpreted as an error response, rather than a redirect. This should now be fixed in the latest, and this should cause your example to work.
There is also another bug which has not been fixed that prevents the onError() callback from being called when there is an error response code. This will be fixed soon. In the mean time, your example should work (and the onError() will not be called) with 301 and 307 response codes.
Related
My app tries to do an async network request at app launch, using RequestBuilder request = Rest.get, as described in this article: https://www.codenameone.com/blog/rest-api-error-handling.html. If I power off my testing server, at the app launch I have this exception:
[Network Thread] 0:0:0,586 - Exception: java.net.ConnectException - Connection refused
but no info, message or dialog is shown to the user. The following boilerplate code in the init() is not called:
addNetworkErrorListener(err -> {
// prevent the event from propagating
err.consume();
if (err.getError() != null) {
Log.e(err.getError());
}
Log.sendLogAsync();
Dialog.show("Connection Error", "There was a networking error in the connection to " + err.getConnectionRequest().getUrl(), "OK", null);
});
If I provide a custom network error handler, with request.onError(networkError);, the issue is the same: my network error handler is not called. I tried to implement it so (it's very similar to the above boilerplate code):
private static final ActionListener<NetworkEvent> networkError = new ActionListener<NetworkEvent>() {
#Override
public void actionPerformed(NetworkEvent err) {
Log.p("NETWORK ERROR connecting to the server");
err.consume();
if (err.getError() != null) {
Log.e(err.getError());
}
Log.sendLogAsync();
DialogUtilities.genericNetworkError();
}
};
I tried using the Simulator with the server offline. Then I tried with Android and iOS app, disconnecting the device from the Internet, but also in this case there is no message to the user. What's wrong?
Note that the error code handlers used with onErrorCodeBytes, onErrorCodeJSON and onErrorCodeString seem to work correctly (they are invoked, for example, if I have a 404 http code).
Did you define onError?
It should be invoked for exceptions and might override the global error handling logic once defined.
I tried this case with wifi turned off and it seems to have worked correctly:
Button test = new Button("Test");
test.addActionListener(e -> {
Rest.get("https://www.codenameone.com/").
onError(ee -> {
if(ee.getError() != null) {
Log.e(ee.getError());
}
}).
fetchAsBytes(call -> {});
});
codenameone: how to handle exception java.net.ConnectionException explicitly
I want to handle exception explicitly.Currently when I am handling exception It handled implicitly first in which shows the exception message on screen in detail.I don't want to show in detail error message on screen(pop up dialog).
right now it shows the exception Java.net.Connection Exception: Connection refused for URL http:localhost/login connection refused.instead of this message i just want to show "connection refused" message on pop-up dialog
Can you please let me know how to resolve it.
On mobile devices the error might be quite different to the one on the simulator since we are dealing with native API's under the surface. See the error handling section of the networking section in the developer guide:
There are two distinct placed where you can handle a networking error:
The ConnectionRequest - by overriding callback methods
The NetworkManager error handler
Notice that the NetworkManager error handler takes precedence thus allowing you to define a global policy for network error handling by consuming errors.
E.g. if I would like to block all network errors from showing anything to the user I could do something like this:
NetworkManager.getInstance().addToQueue(request);
NetworkManager.getInstance().addErrorListener((e) -> e.consume());
The error listener is invoked first with the NetworkEvent matching the error. Consuming the event prevents it from propagating further down the chain into the ConnectionRequest callbacks.
We can also override the error callbacks of the various types in the request e.g. in the case of a server error code we can do:
ConnectionRequest request = new ConnectionRequest(url, false) {
protected void handleErrorResponseCode(int code, String message) {
if(code == 444) {
// do something
}
}
protected void handleException(Exception err) {
// handle exception that occurred. Notice you can either have this or have the listener on the NetworkManager
}
protected void readResponse(InputStream input) {
// just read from the response input stream
}
};
NetworkManager.getInstance().addToQueue(request);
I am getting a strange situation at the code below which simply routes request to Google and returns response.
It works well but when I activate the line commented out as "//Activating this line causes empty response on browser" to print out returned response from http endpoint (Google), response is disappear, nothing is displayed on browser. I thought it might be related with input stream of http response which can be consumed only once and I activated Stream Caching on context but nothing changed.
Apache Camel version is 2.11.0
Any suggestions are greatly appreciated, thanks in advance.
public class GoogleCaller {
public static void main(String[] args) throws Exception {
CamelContext context = new DefaultCamelContext();
context.addRoutes(new RouteBuilder() {
public void configure() {
from("jetty:http://0.0.0.0:8081/myapp/")
.to("jetty://http://www.google.com?bridgeEndpoint=true&throwExceptionOnFailure=false")
.process(new Processor() {
public void process(Exchange exchange) throws Exception {
System.out.println("Response received from Google, is streamCaching = " + exchange.getContext().isStreamCaching());
System.out.println("----------------------------------------------IN MESSAGE--------------------------------------------------------------");
System.out.println(exchange.getIn().getBody(String.class));
System.out.println("----------------------------------------------OUT MESSAGE--------------------------------------------------------------");
//System.out.println(exchange.getOut().getBody(String.class)); //Activating this line causes empty response on browser
}
});
}
});
context.setTracing(true);
context.setStreamCaching(true);
context.start();
}
}
As you use a custom processor to process the message, you should keep it in mind the in message of the exchange has response message from the google, if you are using exchange.getOut(), camel will create a new empty out message for you and treat it as response message.
Because you don't set the out message body in the processor, it makes sense that you get the empty response in the browser.
I realise that similar questions have been asked before however none of the solutions provided worked.
Examining the token returned from the BeginGetResponse method I see that the following exception is thrown there:
'token.AsyncWaitHandle' threw an exception of type 'System.NotSupportedException'
This page tells me that this exception means the Callback parameter is Nothing, however I'm passing the callback - and the debugger breaks into the callback method when I insert a breakpoint. However the request object in the callback is always null. I can view the same exception detail in the result object in the callback method.
I've tried using new AsyncCallback(ProcessResponse) when calling BeginGetResponse
I've tried adding request.AllowReadStreamBuffering = true;
I've tried this in-emulator and on-device, with no luck on either.
public static void GetQuakes(int numDays)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://magma.geonet.org.nz/services/quake/geojson/quake?numberDays=" + numDays);
// Examining this token reveals the exception.
var token = request.BeginGetResponse(ProcessResponse, request);
}
static void ProcessResponse(IAsyncResult result)
{
HttpWebRequest request = result.AsyncState as HttpWebRequest;
if (request != null)
{
// do stuff...
}
}
So I'm at a bit of a loss as to where to look next.
'token.AsyncWaitHandle' threw an exception of type
'System.NotSupportedException'
This page tells me that this exception means the Callback parameter is
Nothing
The documentation you are looking at http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.begingetresponse%28v=vs.95%29.aspx is for BeginGetResponse. Silverlight does not use the AsyncWaitHandle, and correctly throws a NotSupportedException. You are seeing the exception System.NotSupportedException is for call to IAsyncResult.AsyncWaitHandle you are making when you inspect token.
The documentation on IAsyncResult.AsyncWaitHandle says explicitly that it is up to the implementation of IAsyncResult whether they create a wait handle http://msdn.microsoft.com/en-us/library/system.iasyncresult.asyncwaithandle(v=vs.95).aspx. Worrying about this is sending you down th wrong path.
I think you need to descibe the actual problem you are seeing. It is great to know what you have investigated, but in this case it does help resolve the problem.
The code should work and in ProcessResponse request should not be null when you test it in the if statement. I just copied the code you have provided into a windows phone application and ran it with no problems.
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)