NSURLConnection not responding

问题

I'm trying to get some data from an URL, but for some reason, nothing happens when I do the following. Neither didReceiveResponse:, didReceiveData:, didFailWithError: or connectionDidFinishLoading: are reached, except when I add a timeout to my request by doing this: [request setTimeoutInterval:10.0]

Here's what I'm doing :

-(void)getConfigFromServer{
    [self getContentAtURL:kUrlGetUser];
}

//Va chercher le contenu à l'URL passée en paramètre
- (void)getContentAtURL: (NSURL *)url {

    [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;

    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    NSString * userLogin = [userDefaults objectForKey:@"UserLogin"];
    NSString * userPassword = [userDefaults objectForKey:@"UserPassword"];
    NSURL * urlFinal = [NSURL URLWithString:[NSString stringWithFormat:@"%@", url]];
    NSLog(@"Request : %@", [NSString stringWithFormat:@"%@", url]);
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setURL:urlFinal];  
    [request setHTTPShouldHandleCookies:NO];
    [request setTimeoutInterval:10.0];

    NSString *sourceString = [NSString stringWithFormat:@"%@:%@", userLogin, userPassword]; 
    NSData * sourceData = [sourceString dataUsingEncoding:NSUTF8StringEncoding];  
    NSString *authString = [sourceData base64EncodedString];  

    authString = [NSString stringWithFormat: @"Basic %@", authString];
    [request setValue:authString forHTTPHeaderField:@"Authorization"];
    [request setValue:@"text/xml" forHTTPHeaderField:@"Accept"];
    NSURLConnection * connection=[NSURLConnection connectionWithRequest:request delegate:self];

    if(connection){
        NSLog(@"Connection started");
        receivedData = [NSMutableData data];
    }else{
        NSLog(@"Error while trying to initiate the connection");
    }
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
    [receivedData setLength:0];
    if ([response respondsToSelector:@selector(statusCode)])
    {
        int statusCode = [((NSHTTPURLResponse *)response) statusCode];
        if (statusCode >= 400)
        {
            [connection cancel];  // stop connecting; no more delegate messages
            NSDictionary *errorInfo
                = [NSDictionary dictionaryWithObject:[NSString stringWithFormat:
                NSLocalizedString(@"Server returned status code %d",@""),
                statusCode]
                    forKey:NSLocalizedDescriptionKey];
            NSError *statusError = [NSError errorWithDomain:@"Error"
                code:statusCode
                userInfo:errorInfo];
            [self connection:connection didFailWithError:statusError];
        }
    }
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
    [receivedData appendData:data];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    NSLog(@"Connection failed! Error - %@ %@",[error localizedDescription],[[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
    [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
    [self fetchedData:receivedData];
}

EDIT : I'm still having this problem, and now have it on the actual device too. As I said it in the comments, I use ARC on this app for the first time, and I'm using XCode 4.2.

Any idea?

回答1:

This is old thread but still this answer might help someone out there.

If you are calling this in background thread, check whether you thread is exiting before delegates is called.

Try doing this.

NSURLConnection * connection = [[NSURLConnection alloc] 
                                initWithRequest:request
                                       delegate:self startImmediately:NO];

[connection scheduleInRunLoop:[NSRunLoop mainRunLoop] 
                      forMode:NSDefaultRunLoopMode];
[connection start];

回答2:

Error message, as you have told in comments, is saying that the request has timed out. I am sure that if you remove the line with timeout, you will get either the same response or actual data, after 60 seconds. Make sure you wait enough, because if your connection is very weak for some reason, the request may not time out after 60 seconds because it keeps downloading data.

Is your app in foreground while you launch this? Make sure you don't suspend it.

Furthermore, you say that the server is online, but your code is timing out. Means something is probably wrong with your connection after all.

In another comment you say that sometimes it works. Even more points to the fact that the connection is weak/unreliable or breaking up.

回答3:

You're passing an NSURL to your getContentAtURL but then treating it as though it was a string in :

NSURL * urlFinal = [NSURL URLWithString:[NSString stringWithFormat:@"%@", url]];

try changing it to:

NSURL * urlFinal = [NSURL URLWithString:[NSString stringWithFormat:@"%@", [url absoluteString]]];

btw, you know you're not using your login and password don't you?

EDIT:

When you say receivedData = [NSMutableData data]; what is data?

I think that might be the problem.

I tend to use the following to setup the data object when data first arrives:

- (void)connection:(NSURLConnection *)theConnection didReceiveData:(NSData *)incrementalData {
    if (receivedData ==nil) { receivedData = [[NSMutableData alloc] initWithCapacity:2048]; } 
    [receivedData appendData:incrementalData];
}

回答4:

Some thoughts here:

Please do not store passwords in UserDefaults, use the keychain for that (maybe you are only testing, I just wanted to have this mentioned)
Why do you convert your NSURL url to a new NSURL by calling stringWithFormat: on the url? (Oh, I see @ade already mentioned that)
Is this an ARC-enabled App? If not, your NSMutableData will be autoreleased too soon, use self.receivedData = [NSMutableData data] and you will see a crash.
Try making your NSURLConnection an instance variable and hold on to it. I think it should work the way you do it right now, but I tend to hold on to it and never had the problem you mention here.
Weird that your 10 seconds timeout seems to work, I had trouble getting this to work and found that on iPhone, the timeout can not be lower than 240 seconds. Yes, I was confused about this as well, but: https://stackoverflow.com/a/3611383/148335

回答5:

I think the problem will be with server side. Try to increase TimeoutInterval to 60 so there will be more time to fetch data from server. Didn't you get "connection timed out" message after 10 seconds?

EDIT

Hi, I think still you are not reached a solution. When I read the code in detail, I found some statements are confusing.

1) [request setValue:@"text/xml" forHTTPHeaderField:@"Accept"]; replace with

    [request setValue:@"text/plain" forHTTPHeaderField:@"Accept"];

Also include,

    [request setValue:@"text/plain" forHTTPHeaderField:@"Content-Type"];

And finally...

The error "connection timed out" indicates that the iPhone does not receiving any data from server. As soon as iPhone gets a bye of data it will call - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data. Try to put NSLog after each statements to verify variables hold desired value. Try to check the length of data --sourceData-- before sending ...

来源：https://stackoverflow.com/questions/9363286/nsurlconnection-not-responding

标签

iphone

objective-c

ios5

nsurlconnection

nsurlrequest