Retrieving UIWebView cache?

Question

I'm trying to make sure that I always have an up to date cached copy of a UIWebView using the following code:

// Set URL to help file on server
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@", HELP_FILE_URL]];

// Check network reachability
 wifiReach = [Reachability reachabilityWithHostName:[NSString stringWithFormat:@"%@", SERVER_URL]];
netStatus = [wifiReach currentReachabilityStatus];

// Start activity indicators
[self startAnimation];

// Verify current help file cache if we have network connection...
if (netStatus == ReachableViaWWAN || netStatus == ReachableViaWiFi) {

    helpFileRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadRevalidatingCacheData timeoutInterval:30];

} else {

    // Network NOT reachable - show (local) cache if it exists
    helpFileRequest = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReturnCacheDataDontLoad timeoutInterval:30];
}

// Show help file in a web view
[webView loadRequest:helpFileRequest];

It works fine in most cases except for when I go to Airplane mode without terminating the app. Once in Airplane mode the cached webView shows up fine BUT the UIWebView delegate

(void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error

is also triggered which I don't want. I only want that to be triggered if the cache is empty! How can I achieve that? (If I terminate the app it works fine.) It's a small detail but I really would like it to work correctly :)

Answer 1

OK - I solved it by identifying the error code in the UIWebView delegate method - see below. I found that the error code is -1008 when the cache is empty ("resource unavailable") and -1009 with data in the cache ("The Internet connection appears to be offline."). Both cases offline, in Airplane mode.

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
    NSLog(@"%@ : %@", NSStringFromClass([self class]), NSStringFromSelector(_cmd));

    [self stopAnimation];

    // No help to display - cache is empty and no Internet connection...
    if ([error code] == -1008) {
       NSString *alertMessage = @"To make Help available offline, you need to view it at least once when connected to the Internet.";
       UIAlertView *alertView = 
       [[UIAlertView alloc] initWithTitle:@"Help Unavailable"
                               message:alertMessage
                              delegate:nil
                     cancelButtonTitle:@"OK"
                     otherButtonTitles:nil];
       [alertView show];
    }

    NSLog( @"Error code:%d, %@", [error code], [error localizedDescription]);
}