ASIHTTPRequest Download cache problem - unable to save/load date in cache

Question

I am trying to save data into cache using ASIHTTP (http://allseeing-i.com/ASIHTTPRequest/How-to-use#using_a_download_cache). I am not sure what I am doing wrong but it seems not to be storing data into cache. The output of the following code is this:

2010-08-12 15:44:13.801 TabBar[51728:207] Success is YES
2010-08-12 15:44:13.802 TabBar[51728:207] Success is NO
2010-08-12 15:44:13.804 TabBar[51728:207] Success is YES
2010-08-12 15:44:13.805 TabBar[51728:207] S-----------
2010-08-12 15:44:13.874 TabBar[51728:207] Success is YES
2010-08-12 15:44:13.874 TabBar[51728:207] Success is NO
2010-08-12 15:44:13.876 TabBar[51728:207] Success is YES

Here is the code:

[[ASIDownloadCache sharedCache] clearCachedResponsesForStoragePolicy:
                              ASICacheForSessionDurationCacheStoragePolicy];
[[ASIDownloadCache sharedCache] 
                    setDefaultCachePolicy:ASIOnlyLoadIfNotCachedCachePolicy];
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL 
                                URLWithString:@"http://www.nytimes.com/"]];
[request setDownloadCache:[ASIDownloadCache sharedCache]];
[request startSynchronous];

request = [ASIHTTPRequest requestWithURL:[NSURL 
                                URLWithString:@"http://www.nytimes.com/"]];
[request setDownloadCache:[ASIDownloadCache sharedCache]];
[request startSynchronous];
BOOL success = ([request responseStatusCode] == 200);
NSLog(@"Success is %@\n", (success ? @"YES" : @"NO"));

success = [request didUseCachedResponse];
NSLog(@"Success is %@\n", (success ? @"YES" : @"NO"));

success = ([[request responseData] length]);
NSLog(@"Success is %@\n", (success ? @"YES" : @"NO"));

NSLog(@"S-----------");
request = [ASIHTTPRequest requestWithURL:[NSURL 
                    URLWithString:@"http://www.nytimes.com/"]];
[request setDownloadCache:[ASIDownloadCache sharedCache]];
[request startSynchronous];
success = ([request responseStatusCode] == 200);
NSLog(@"Success is %@\n", (success ? @"YES" : @"NO"));

success = [request didUseCachedResponse];
NSLog(@"Success is %@\n", (success ? @"YES" : @"NO"));

success = ([[request responseData] length]);
NSLog(@"Success is %@\n", (success ? @"YES" : @"NO"));

Can someone give me some code snippet on how to accomplish this?

Thanks!

-----------------------------------------------------------------------

NEW CODE REVISION:

NSURL *url = [NSURL URLWithString:imageURL];

ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request setDownloadCache:[ASIDownloadCache sharedCache]];
[request setCacheStoragePolicy:ASICachePermanentlyCacheStoragePolicy];
[request setCachePolicy:ASIOnlyLoadIfNotCachedCachePolicy];
[request setSecondsToCache:60*60*24*30]; // Cache for 30 days

[request startSynchronous];//startAsynchronous];

BOOL success = [request didUseCachedResponse];
NSLog(@"------------>>>>>>> Success is %@\n", (success ? @"YES" : @"NO"));

NSData *responseData = [request responseData];
UIImage *image = [[UIImage alloc] initWithData:responseData];

This only works with [request startSynchronous]; if I try Asynchronous method, it dosent call this function:

- (void)requestFinished:(ASIHTTPRequest *)request

Answer 1

You are missing something like this,

ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request setDownloadCache:[ASIDownloadCache sharedCache]];
[request setCacheStoragePolicy:ASICachePermanentlyCacheStoragePolicy];
[request setCachePolicy:ASIOnlyLoadIfNotCachedCachePolicy];
[request setSecondsToCache:60*60*24*30]; // Cache for 30 days
[request setDelegate:self]; // A delegate must be specified
[request setDidFinishSelector:@selector(requestFinished:)]; // And an appropriate selector specified

And you should also have

- (void)requestFinished:(ASIHTTPRequest *)request {
  BOOL success = [request didUseCachedResponse];
  NSLog(@"------------>>>>>>> Success is %@\n", (success ? @"YES" : @"NO"));

  NSData *responseData = [request responseData];
  UIImage *image = [[UIImage alloc] initWithData:responseData];

  ...
}

This should do the trick.

Answer 2

nytimes.com sets a lot of "don't cache me" type headers:

    $ HEAD http://www.nytimes.com/           
    200 OK
    Cache-Control: no-cache
    Date: Fri, 13 Aug 2010 07:14:46 GMT
    Pragma: no-cache
    Server: Sun-ONE-Web-Server/6.1
    Content-Length: 121266
    Content-Type: text/html
    Expires: Thu, 01 Dec 1994 16:00:00 GMT

So I would expect these are the problem.

You could try setting:

[[ASIDownloadCache sharedCache] shouldRespectCacheControlHeaders:NO];