I know that there are some caching classes introduced in the iphone sdk recently, and there is also a TTURLRequest from three20\'s library that allows you to cache a request
Take a look at: http://allseeing-i.com/ASIHTTPRequest/ASIWebPageRequest
If the page has AJAX already, why not store the JavaScript/HTML in the application bundle to start rather than downloading it on the first launch? Then load the page with the code Corey gave below and let the AJAX handle hitting the network for the updated parts of the page.
You can save an HTML in the documents directory and load the page directly from the documents directory on launch.
To save the webview content: Reading HTML content from a UIWebView
To load:
NSString* path = [[NSBundle mainBundle] pathForResource:@"about" ofType:@"html"];
NSURL* url = [NSURL fileURLWithPath:path];
NSURLRequest* request = [NSURLRequest requestWithURL:url];
[webView loadRequest:request];
There are a bunch of articles about the way the cache of the UIWebView works and the global feeling is that even if some mechanisms seems to work OK under MacOS X, the same approaches may have curious behavior under iPhone.
HOWEVER, I'm doing it by playing with the global cache that is accessed by any NSURLConnection
, UIWebView
included. And in my case, it works ;).
What you need to understand is the global flow:
loadRequest
on a UIWebView
NSURLCache
to ask "is there something cached for this request?":- (NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request
From that, here's what I do to handle the cache on the disk, on my side, to speed up the load of a UIWebView:
NSURLCache
and override the get control over the -(NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request
selectorNow the code :
@interface MyCache : NSURLCache {
}
@end
@implementation MyCache
-(NSCachedURLResponse *)cachedResponseForRequest:(NSURLRequest *)request {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSLog(@"CACHE REQUEST S%@", request);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSArray* tokens = [request.URL.relativePath componentsSeparatedByString:@"/"];
if (tokens==nil) {
NSLog(@"ignoring cache for %@", request);
return nil;
}
NSString* pathWithoutRessourceName=@"";
for (int i=0; i<[tokens count]-1; i++) {
pathWithoutRessourceName = [pathWithoutRessourceName stringByAppendingString:[NSString stringWithFormat:@"%@%@", [tokens objectAtIndex:i], @"/"]];
}
NSString* absolutePath = [NSString stringWithFormat:@"%@%@", documentsDirectory, pathWithoutRessourceName];
NSString* absolutePathWithRessourceName = [NSString stringWithFormat:@"%@%@", documentsDirectory, request.URL.relativePath];
NSString* ressourceName = [absolutePathWithRessourceName stringByReplacingOccurrencesOfString:absolutePath withString:@""];
NSCachedURLResponse* cacheResponse = nil;
//we're only caching .png, .js, .cgz, .jgz
if (
[ressourceName rangeOfString:@".png"].location!=NSNotFound ||
[ressourceName rangeOfString:@".js"].location!=NSNotFound ||
[ressourceName rangeOfString:@".cgz"].location!=NSNotFound ||
[ressourceName rangeOfString:@".jgz"].location!=NSNotFound) {
NSString* storagePath = [NSString stringWithFormat:@"%@/myCache%@", documentsDirectory, request.URL.relativePath];
//this ressource is candidate for cache.
NSData* content;
NSError* error = nil;
//is it already cached ?
if ([[NSFileManager defaultManager] fileExistsAtPath:storagePath]) {
//NSLog(@"CACHE FOUND for %@", request.URL.relativePath);
content = [[NSData dataWithContentsOfFile:storagePath] retain];
NSURLResponse* response = [[NSURLResponse alloc] initWithURL:request.URL MIMEType:@"" expectedContentLength:[content length] textEncodingName:nil];
cacheResponse = [[NSCachedURLResponse alloc] initWithResponse:response data:content];
} else {
//trick here : if no cache, populate it asynchronously and return nil
[NSThread detachNewThreadSelector:@selector(populateCacheFor:) toTarget:self withObject:request];
}
} else {
NSLog(@"ignoring cache for %@", request);
}
return cacheResponse;
}
-(void)populateCacheFor:(NSURLRequest*)request {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
//NSLog(@"PATH S%@", paths);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSArray* tokens = [request.URL.relativePath componentsSeparatedByString:@"/"];
NSString* pathWithoutRessourceName=@"";
for (int i=0; i<[tokens count]-1; i++) {
pathWithoutRessourceName = [pathWithoutRessourceName stringByAppendingString:[NSString stringWithFormat:@"%@%@", [tokens objectAtIndex:i], @"/"]];
}
NSString* absolutePath = [NSString stringWithFormat:@"%@/myCache%@", documentsDirectory, pathWithoutRessourceName];
//NSString* absolutePathWithRessourceName = [NSString stringWithFormat:@"%@%@", documentsDirectory, request.URL.relativePath];
//NSString* ressourceName = [absolutePathWithRessourceName stringByReplacingOccurrencesOfString:absolutePath withString:@""];
NSString* storagePath = [NSString stringWithFormat:@"%@/myCache%@", documentsDirectory, request.URL.relativePath];
NSData* content;
NSError* error = nil;
NSCachedURLResponse* cacheResponse = nil;
NSLog(@"NO CACHE FOUND for %@", request.URL);
//NSLog(@"retrieving content (timeout=%f) for %@ ...", [request timeoutInterval], request.URL);
content = [NSData dataWithContentsOfURL:request.URL options:1 error:&error];
//NSLog(@"content retrieved for %@ / error:%@", request.URL, error);
if (error!=nil) {
NSLog(@"ERROR %@ info:%@", error, error.userInfo);
NSLog(@"Cache not populated for %@", request.URL);
} else {
NSURLResponse* response = [[NSURLResponse alloc] initWithURL:request.URL MIMEType:@"" expectedContentLength:[content length] textEncodingName:nil];
cacheResponse = [[NSCachedURLResponse alloc] initWithResponse:response data:content];
//the store is invoked automatically.
[[NSFileManager defaultManager] createDirectoryAtPath:absolutePath withIntermediateDirectories:YES attributes:nil error:&error];
BOOL ok;// = [[NSFileManager defaultManager] createDirectoryAtPath:absolutePath withIntermediateDirectories:YES attributes:nil error:&error];
ok = [content writeToFile:storagePath atomically:YES];
NSLog(@"Caching %@ : %@", storagePath , ok?@"OK":@"KO");
}
[pool release];
}
@end
And the use of it in your application:
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString* documentsDirectory = [paths objectAtIndex:0];
NSString* diskCachePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory, @"myCache"];
NSError* error;
[[NSFileManager defaultManager] createDirectoryAtPath:diskCachePath withIntermediateDirectories:YES attributes:nil error:&error];
MyCache* cacheMngr = [[MyCache alloc] initWithMemoryCapacity:10000 diskCapacity:100000000 diskPath:diskCachePath];
[NSURLCache setSharedURLCache:cacheMngr];
This code deserves a lot of cleanup.. but the main things should be in there. I had a lot of trouble to get this working, hope this helps.
I recently found this project under github : http://github.com/rs/SDURLCache The approach is quite the same as my previous answer described here How to save the content in UIWebView for faster loading on next launch? , but the code looks more polished so maybe it makes sense to give it a try.