sendSynchronousRequest/connectionDidFinishLoading - ios

Question

I'm using synchronous requests for the first time and would love some help. (The code I'm writing is solely for my own use, and given its purposes synchronous requests are not a problem.)
The code gets data from a web page in a series, manipulates the data, moves on to the next page in the series, manipulates THAT data, and so on. I'm using a synchronous request because I need the connection to finish loading and the data to be manipulated before the function loops to the next page.
Here's my looping code:
-(NSData *)myMethod {
NSString *string;
NSData *data;
for (int x = 1; x<100; x++) {
string = [NSString stringWithFormat:#"http://www.blahblah.com/%d",(x)];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:string]];
NSURLResponse *response = nil;
NSError *error = nil;
data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
}
return data;
}
When I was using connectionWithRequest, I just put the code to manipulate the data in connectionDidFinishLoading and it worked fine. But with sendSynchronousRequest, even though NSLog shows that the loop code is looping, the code in connectionDidFinishLoading never runs.
How can I fix this?
(Or am I taking the wrong approach completely?)

Answer 1

Here's how to take #nhgrif's good advice to perform asynch and preserve all of the results.
- (void)doRequest:(NSInteger)requestIndex gatheringResultsIn:(NSMutableArray *)array completion:(void (^)(void))completion {
if (requestIndex < 100) {
NSString *string = [NSString stringWithFormat:#"http://www.blahblah.com/%d",(requestIndex)];
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:string]];
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if (data) [array addObject:data];
[self doRequest:requestIndex+1 gatheringResultsIn:array completion: completion];
}];
} else {
completion();
}
}
This will run 100 requests indexed 0..99 placing the results in a mutable array. Call it like this:
NSMutableArray *results = [NSMutableArray array];
[self doRequest:0 gatheringResultsIn:results completion:^{
NSLog(#"100 NSData objects should be here: %#", results);
}];

Answer 2

connectionDidFinishLoading is an NSURLConnection delegate method for when you've sent asynchronous requests. Normally, you'd implement this method to get the data that loaded, but you don't need to do this, as it's returned synchronously and assigned to your data variable.
I will note however, you are definitely taking a poor approach here.
First of all, if you'd use asynchronous requests here, you could query all 100 URLs as basically the same time and let them return in their own time.
But what's more problematic is what actually happens with your code.
We create a URL, send the synchronous request, and when it finishes, assign the return to data.
... then we loop. And do this 99 times. 99 times we make this synchronous request (to a different URL each time) and overwrite the data that the previous request loaded. And after the 100th time, we exit the loop and return the data we downloaded in the final request.