Objective-C Asynchronous Web Request with Cookies - objective-c

Question

I am writing a program in Objective-C and I need to make web requests to web server, but asynchronously and I am fairly new on mac, I am very good at windows technologies, but I need to know that if I use NSOperation (introduced in 10.5, i am assuming that it will not run in 10.4 MAC?), or if it was implemented such that it utilizes system threading which will be available on 10.4?
Or I should create a new thread and create a new runloop, also how to use cookies etc, if anyone can give me one small example, that will be of great help. I want this sample to run on mac 10.4 too if possible.

Answer 1

There's a good example of using NSURLRequest and NSHTTPCookies to do a full web application example of logging into a website, storing the SessionID cookie and resubmitting it in future requests.
NSURLConnection, NSHTTPCookie
By logix812:
NSHTTPURLResponse * response;
NSError * error;
NSMutableURLRequest * request;
request = [[[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:#"http://temp/gomh/authenticate.py?setCookie=1"]
cachePolicy:NSURLRequestReloadIgnoringCacheData
timeoutInterval:60] autorelease];
[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSLog(#"RESPONSE HEADERS: \n%#", [response allHeaderFields]);
// If you want to get all of the cookies:
NSArray * all = [NSHTTPCookie cookiesWithResponseHeaderFields:[response allHeaderFields] forURL:[NSURL URLWithString:#"http://temp"]];
NSLog(#"How many Cookies: %d", all.count);
// Store the cookies:
// NSHTTPCookieStorage is a Singleton.
[[NSHTTPCookieStorage sharedHTTPCookieStorage] setCookies:all forURL:[NSURL URLWithString:#"http://temp"] mainDocumentURL:nil];
// Now we can print all of the cookies we have:
for (NSHTTPCookie *cookie in all)
NSLog(#"Name: %# : Value: %#, Expires: %#", cookie.name, cookie.value, cookie.expiresDate);
// Now lets go back the other way. We want the server to know we have some cookies available:
// this availableCookies array is going to be the same as the 'all' array above. We could
// have just used the 'all' array, but this shows you how to get the cookies back from the singleton.
NSArray * availableCookies = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:[NSURL URLWithString:#"http://temp"]];
NSDictionary * headers = [NSHTTPCookie requestHeaderFieldsWithCookies:availableCookies];
// we are just recycling the original request
[request setAllHTTPHeaderFields:headers];
request.URL = [NSURL URLWithString:#"http://temp/gomh/authenticate.py"];
error = nil;
response = nil;
NSData * data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSLog(#"The server saw:\n%#", [[[NSString alloc] initWithData:data encoding: NSASCIIStringEncoding] autorelease]);

Answer 2

For asynchronous requests, you need to use NSURLConnection.
For cookies, see NSHTTPCookie and NSHTTPCookieStorage.
UPDATE:
The code below is real, working code from one of my applications. responseData is defined as NSMutableData* in the class interface.
- (void)load {
NSURL *myURL = [NSURL URLWithString:#"http://stackoverflow.com/"];
NSURLRequest *request = [NSURLRequest requestWithURL:myURL
cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
timeoutInterval:60];
[[NSURLConnection alloc] initWithRequest:request delegate:self];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
responseData = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[responseData appendData:data];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
[responseData release];
[connection release];
// Show error message
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
// Use responseData
[responseData release];
[connection release];
}

Answer 3

I am able to fetch cookie in such way:
NSArray* arr = [[NSHTTPCookieStorage sharedHTTPCookieStorage] cookiesForURL:[NSURL URLWithString: #"http://google.com" ]];
This one works fine for asynchronous request as well.