NSURLConnection returns data but I cannot read it - iphone

Question

This is another simple question who'se answer escapes me after a hour on Google...
A user is typing something into a text field and upon this field loosing focus, I launch an NSURLConnection....
NSString *usernameTry = [sender text];
NSLog(#"username field = %#",usernameTry);
NSString *content = [#"http://www.siebenware.de/Rhythm/user/checkusername.php?username=" stringByAppendingString:usernameTry];
content = [content stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:content] cachePolicy:NSURLRequestReloadIgnoringLocalCacheData timeoutInterval:5.0];
NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
[connection start];
NSLog(#"%#",content);
Then I wait for the response....
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
NSLog(#"Received Response");
if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response;
int status = [httpResponse statusCode];
if (!((status >= 200) && (status < 300))) {
NSLog(#"Connection failed with status %#", status);
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
}
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[resultsData appendData:data];
NSString *resultsString = [[NSString alloc] initWithData:resultsData encoding:NSUTF8StringEncoding];
NSLog(#"received data %# %i",resultsString,[resultsString length]);
if ([resultsString isEqualToString: #"FAIL"]){
NSLog(#"failed to retrieve data");
}else{
resultsObjects = [[resultsString componentsSeparatedByString:#":"] mutableCopy];
if([resultsObjects objectAtIndex:0]==#"usernamecheck"){
if ([resultsObjects objectAtIndex:1]==username.text) {
if ([resultsObjects objectAtIndex:2]==#"NG"){
//set the check marker to bad
[usernameVer setImage:[UIImage imageNamed:#"redcross.png"]];
}else{
//set the check market to good
[usernameVer setImage:[UIImage imageNamed:#"greentick.png"]];
}
}
}
}
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
NSLog([NSString stringWithFormat:#"Connection failed: %#", [error description]]);
UIAlertView *errorAlert = [[UIAlertView alloc] initWithTitle:#"Unable to retrieve data" message:[NSString stringWithFormat:#"Error code %i",[error code]] delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil];
}
I see the response arrive in didReceiveResponse and am getting 18 bytes of data (which is correct).
However didReceiveData says that the 'data' is null. I know I am missing something exceptionally simple, and I promise to kick myself once this is cleared up.
Regards
Chris H

Answer 1

if you want to change the data into an NSString you can do this:
NSString *responsestring = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
NSLog(#"%#", responsestring);

Answer 2

You need work with your data in:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection;
Because
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data;
can be called many times
You can do that:
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
[myData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// TODO: work with data
}
NSMutableData* myData must be instance var.

Answer 3

You need to convert the NSMutableData received by the NSURLConnection delegate method to readable NSString by using the below code
NSString *finalString = [[NSString alloc]initWithData:responseData encoding:NSUTF8StringEncoding];
and that should do it.

Answer 4

Try with other encoding..May be ASCII encoding instead of UTF-8..It may work out