How to waiting asynchronous NSURLConnection response - ios

Question

I am trying to fill a UITableView by fetching an URL. To avoid freeze UI I using dispatch_async(dispatch_queue_t queue, ^(void)block) making asynchronous fetching.
In the asynchronous block using NSRunLoop to waiting response.
Here's my fetching code:
- (BOOL)isFinished {
return _finished;
}
- (void)startReceive {
NSURLRequest* request = [NSURLRequest requestWithURL:self.baseURL];
self.connection = [NSURLConnection connectionWithRequest:request delegate:self];
assert(self.connection);
}
- (void)stopReceiveWithStatus:(NSString*)statusCode {
if (self.connection) {
[self.connection cancel];
self.connection = nil;
}
self.finished = YES;
NSLog(#"Stop Receive with status code %#", statusCode);
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
assert(connection == self.connection);
NSHTTPURLResponse* httpResponse = nil;
if ([response isKindOfClass:[NSHTTPURLResponse class]]) {
httpResponse = (NSHTTPURLResponse*) response;
if (httpResponse.statusCode != 409) {
// I need 409 to fetch some data
[self stopReceiveWithStatus:[NSString stringWithFormat:#"HTTP error %2d", httpResponse.statusCode]];
}
}
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
assert(connection == self.connection);
self.sessionID = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
assert(connection == self.connection);
[self stopReceiveWithStatus:#"Connection failed"];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
assert(connection == self.connection);
[self stopReceiveWithStatus:nil];
}
UITableViewController:
// refreshControl handler
- (IBAction)refresh {
[self startRefreshingAnimation];
dispatch_queue_t loaderQ = dispatch_queue_create("loading transmission data", NULL);
dispatch_async(loaderQ, ^{
[self foo];
while(!self.t.finished) {
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
}
dispatch_async(dispatch_get_main_queue(), ^{
[self endRefreshingAnimation]; // end
});
});
}
- (void)foo {
NSLog(#"session id: %#", self.t.sessionID);
}
That sessionID will be filled when HTTP request has done. Now the problem is I can not get the sessionID when first call because the first time it not be filled and second time it works good. How can I get it when first call?
I'm new to iOS. If you have a better solution to solve this problem please tell me, thanks.

Answer 1

There is a good framework, don't waste your time.
https://github.com/AFNetworking/AFNetworking/wiki/Getting-Started-with-AFNetworking
Upd.
You can do your request like:
NSURL *url = self.baseURL;
AFHTTPClient *httpClient = [[AFHTTPClient alloc] initWithBaseURL:url];
NSDictionary *params = [NSDictionary dictionaryWithObjectsAndKeys:
height, #"user[height]",
weight, #"user[weight]",
nil];
[httpClient postPath:#"/myobject" parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSString *responseStr = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];
NSLog(#"Request Successful, response '%#'", responseStr);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"[HTTPClient Error]: %#", error.localizedDescription);
}];

Answer 2

You should use an third-party library to handle network connections, such as STHTTPRequest:
STHTTPRequest *r = [STHTTPRequest requestWithURLString:#"http://www.apple.com"];
r.completionBlock = ^(NSDictionary *headers, NSString *body) {
// ...
};
r.errorBlock = ^(NSError *error) {
// ...
};
[r startAsynchronous];