gistfile1.m

- (NSString *)stringFromURL:(NSURL *)url
{
	NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url
                                                cachePolicy:NSURLRequestReturnCacheDataElseLoad
                                            timeoutInterval:30];
    // Fetch the response
	NSData *urlData;
	NSURLResponse *response;
	NSError *error;
    
	// Make synchronous request
    
	urlData = [NSURLConnection sendSynchronousRequest:urlRequest
                                    returningResponse:&response
                                                error:&error];
    
    if (error) {
        return @"connection error";
    } else {
        // Construct a String around the Data from the response
        return [[[NSString alloc] initWithData:urlData encoding:NSUTF8StringEncoding] autorelease];
    }
    
    
}




- (void) doRequest: (NSURL *) url {
    NSString * jsonString = [self stringFromURL:url];
    
    NSDictionary * response = (NSDictionary*)[jsonString yajl_JSON];
    
    if (response == nil) {
        if (![self.hasFailedConnection boolValue]){
            [self setHasFailedConnection:[NSNumber numberWithInt:1]];
            [delegate networkError];
        }
    } else {
        if([response valueForKey:@"num_results"] == 0){
            // TODO handle no results
        }
        else if([response valueForKey:@"latitude_delta"] && [response valueForKey:@"longitude_delta"] 
                && [response objectForKey:@"result_set"]) {
            lastResultList = [[NSArray alloc] initWithArray:[response objectForKey:@"result_set"]];
            MKCoordinateRegion region_ = region;
            region_.span.latitudeDelta = [[response valueForKey:@"latitude_delta"] floatValue];
            region_.span.longitudeDelta = [[response valueForKey:@"longitude_delta"] floatValue];
            [self setRegion:region_];
            [self performSelectorOnMainThread:@selector(receivedResults) withObject:nil waitUntilDone:NO];
            
        } else {
            if ([self.hasFailedConnection boolValue] == NO){
                [delegate networkError];
            }
        }
        
    }
}

- (BOOL) fetchesMoreResults {
    return YES;
}

- (void) fetchData: (NSURL *) url {

    NSInvocationOperation * io = [[[NSInvocationOperation alloc] initWithTarget:self selector:@selector(doRequest:) object:url] autorelease];
    [opQueue addOperation:io];
}

- (void) receivedResults {
    [locations removeAllObjects];
    for (NSDictionary * cur in lastResultList) {
        NSString * category =  [cur valueForKey:@"category"];
        BOOL meetsFilter = YES;
        if ([filters objectForKey:category]!=nil) {
            meetsFilter = [[filters objectForKey:category] boolValue];
        }
        if (meetsFilter) {
            float lat = [[cur valueForKey:@"lat"] floatValue];            
            float lon = [[cur valueForKey:@"lon"] floatValue];
            CLLocationCoordinate2D coord;
            coord.latitude = lat;
            coord.longitude = lon;
            InfoLocation * newInfoLoc = [[InfoLocation alloc] initWithCoordinate:coord info:cur];
            [locations addObject:newInfoLoc];
            [newInfoLoc release];
        }
    }
    [delegate resultsAvailable];
}