How to check if a file exists at particular URL?

Question

Dumb question, but how do I check if a file exists on a web site. I am using NSURLConnection with my NSURLRequest and an NSMutableData object to store what comes back in the didReceiveData delegate method. In the connectionDidFinishingLoading method I then save the NSMutableData object to the file system. All good. Except if the file does not exist at the website, my code still runs, gets data and saves a file.

How can I check the file is there before I make download request?

Regards

Dave

Answer 1

Implement connection:didReceiveResponse:, which will be called before connection:didReceiveData:.

The response should be an NSHTTPURLResponse object — suppose you're issuing an HTTP request. You can therefore check [response statusCode] == 404 to determine if the file exists or not.

See also http://stackoverflow.com/questions/1404366/check-if-nsurl-returns-404.