How to detect and handle HTTP error codes in UIWebView?

Question

I want to inform user when HTTP error 404 etc is received. How can I detect that? I've already tried to implement

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

but it is not called when I receive 404 error.

Answer 1

My implementation inspired by Radu Simionescu's response :

- (void)webViewDidFinishLoad:(UIWebView *)webView {
    NSCachedURLResponse *urlResponse = [[NSURLCache sharedURLCache] cachedResponseForRequest:webView.request];
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse*) urlResponse.response;
    NSInteger statusCode = httpResponse.statusCode;
    if (statusCode > 399) {
        NSError *error = [NSError errorWithDomain:@"HTTP Error" code:httpResponse.statusCode userInfo:@{@"response":httpResponse}];
        // Forward the error to webView:didFailLoadWithError: or other
    }
    else {
        // No HTTP error
    }
}

It manages HTTP client errors (4xx) and HTTP server errors (5xx).

Note that cachedResponseForRequest returns nil if the response is not cached, in that case statusCode is assigned to 0 and the response is considered errorless.