Check web server is up or down in iphone

I need a little help here!!!

If string 'url' contains the address to web server, how do i check whether my web server is up or down? I got some codes to check Internet connectivity. But even if we have internet connectivity how do we know server is up or开发者_运维百科 not? Is there any better way to do that?

Thank You

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You could do a request,

NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:url]
                                       cachePolicy:NSURLRequestUseProtocolCachePolicy
                                       timeoutInterval:20.0]; 

NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest
                                                        delegate:self];

Now if you implement (along with all other delegate methods)

-(void)connectionDidFinishLoading:(NSURLConnection *)connection

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error

you will get either succes or error.

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Post a request, get the response. If you get a response, the server is up, if not its down..