Re: [xmlvm-users] Bug in NSData?

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Ah yes, take out the sleep and finished flag. Sorry that was mistakenly left
in from other tests I had been trying. Without the sleep and finished flag
the system output is still (when using the google url)...

Received data [<!doctype html><html><head]
Finish loading

So looking at the implementation of NSURLConnection calling
"connectionWithRequest" starts a new thread so the method calls should be
asynchronous back to the delegate? So I would expect the
"applicationDidFinishLaunching" method to finish quickly but whilst the
NSURLConnection thread is running to get the output generated by the
delegate. Looking at the code again I see there should be just the one
"Received data" message followed by the "Finish Loading" message but there
should be a lot more data in NSData's byte array.

Thanks,
Alex

Just in case here's the modified code...

@Override
    public void applicationDidFinishLaunching(UIApplication app) {
        try {
        final NSURL url = NSURL.URLWithString("http://www.google.com");
        final NSMutableURLRequest req = new NSMutableURLRequest(url);

        NSURLConnectionDelegate delegate = new NSURLConnectionDelegate() {
        @Override
        public void connectionDidFailWithError(
        NSURLConnection connection, NSError error) {
        super.connectionDidFailWithError(connection, error);
        System.out.println("Error [" + error + "]");
        }

        @Override
        public void connectionDidFinishLoading(
        NSURLConnection connection) {
        super.connectionDidFinishLoading(connection);
        System.out.println("Finish loading");
        }

        @Override
        public void connectionDidReceiveData(
        NSURLConnection connection, NSData data) {
        super.connectionDidReceiveData(connection, data);
        System.out.println("Received data [" + new String(data.getBytes()) +
"]");
        }
        };

        NSURLConnection.connectionWithRequest(req, delegate);
        }
        catch (Exception e) {
        System.err.println("Exception doing HTTP" + e);
        }
    }

On 19 May 2011 18:05, Arno Puder <ar...@pu...> wrote:

>
> I'm not sure if you should do that sleep() in your code. The
> NSURLConnection delegate will most likely be executed in the context of
> the same thread that created it, but if you put that thread to sleep,
> problems will occur. Basically you implemented a busy wait which is
> never a good idea. This in not an XMLVM problem, IMHO.
>
> Arno
>
>
> On 5/19/11 6:53 AM, Alex Lewis wrote:
> > Hi,
> >    I wrote a very simple Java->iPhone application to open a connection
> > and read the data in the response, but I found I only ever got back 26
> > bytes of data. Here's the simplest code I could put together which
> > exhibits the problem...
> >
> > private boolean finished = false;
> >      @Override
> >      public void applicationDidFinishLaunching(UIApplication app) {
> >          try {
> > final NSURL url = NSURL.URLWithString("http://www.google.com");
> > final NSMutableURLRequest req = new NSMutableURLRequest(url);
> > NSURLConnectionDelegate delegate = new NSURLConnectionDelegate() {
> > @Override
> > public void connectionDidFailWithError(
> > NSURLConnection connection, NSError error) {
> > super.connectionDidFailWithError(connection, error);
> > System.out.println("Error [" + error + "]");
> > }
> > @Override
> > public void connectionDidFinishLoading(
> > NSURLConnection connection) {
> > super.connectionDidFinishLoading(connection);
> > finished = true;
> > System.out.println("Finish loading");
> > }
> > @Override
> > public void connectionDidReceiveData(
> > NSURLConnection connection, NSData data) {
> > super.connectionDidReceiveData(connection, data);
> > System.out.println("Received data [" + new String(data.getBytes()) +
> "]");
> > }
> > };
> > NSURLConnection.connectionWithRequest(req, delegate);
> >                 // Wait until all the data has been received or we hit a
> > 20s limit.
> > int i = 0;
> > while (!finished && i < 20) {
> > Thread.sleep(1000);
> > i++;
> > }
> >          }
> >          catch (Exception e) {
> > System.err.println("Exception doing HTTP" + e);
> >          }
> >      }
> >
> > I would have expected multiple "Received Data[.......]" messages but I
> > only ever get one of 26 characters. I took a look at the NSData java
> > class, specifically the readData method and I can see why it is failing.
> > The do/while loop in there only continues to read data if its buffer has
> > been filled and assumes that if the read() method returns a read count
> > of less than the buffer size that all the data has been read. Using the
> > code above the response contains an initial 26 bytes and consequently
> > stops as the buffer in NSData has not been completely filled. I wrote an
> > equivalent pure java application and it exhibits the same behaviour
> > using the readData code. Rewriting the readData method so it keeps
> > reading until -1 is returned and buffering the code appropriately
> > retrieves all the data which is approximately 9k bytes.
> >
> > Is this a bug or have I done something wrong? Would the code work
> > properly if the application were running on an iPhone rather than in the
> > Emulator?
> >
> > Thanks,
> > Alex
> >
> >
> >
> >
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