how to remove html5 local storage of an iOS app using UIWebview

Question

I have an app that uses UIWebview which is used to browser different sites/urls. I am in need of an option "clear client data" similar to iOS mobile safari "Remove All website Data" that removes cookies/local storage. I know how to do the cookies but i am unable to figure out how to remove/clear the later (local storage)

How to remove HTML5 persistant databases in UIWebView? discussed this but i didn't see how that works for my above case. localStorage.clear() javascript needs to be run in UIWebview stringByEvaluatingJavaScriptFromString() method but this didn't seem to have worked in my testing. The other concern with the above approach is that, localStorage is url/site specific - but i want to clear all the contents inside localStorage.

Tried removing/copying Appln/Library/WebKit/LocalStorage folder - but this didnt work out with access restriction errors.

Any suggestions/directions please ?

Answer 1

You should be able to do it cleaning the content of the Caches directory of your app:

EDIT: Update code as suggested by @RaphaelSchweikert because of wrong error management.

// first, remove the cookies. 
NSHTTPCookie *cookie;
NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage];
for (cookie in [storage cookies]) {
    [storage deleteCookie:cookie];
}

NSString *path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
NSArray *array = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:path error:nil];
for (NSString *string in array) {
    NSLog(@"Removing %@", [path stringByAppendingPathComponent:string]);
if ([[string pathExtension] isEqualToString:@"localstorage"])
    [[NSFileManager defaultManager] removeItemAtPath:[path stringByAppendingPathComponent:string] error:nil];
}

Inside that folder on my simulator I see many .localstorage files ;-) Try and let me know

Answer 2

Note, that, if you’re using PhoneGap, you’ll also have to clear their internal backup of the localstorage cache:

//Remove the localstorage db
NSString *path = [[[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"Backups"] stringByAppendingPathComponent:@"localstorage.appdata.db"];
[[NSFileManager defaultManager] removeItemAtPath:path error:nil];

//Also remove the cached versions
path = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
for (NSString *string in [[NSFileManager defaultManager] contentsOfDirectoryAtPath:path error:nil]) {
    if ([[string pathExtension] isEqualToString:@"localstorage"]) {
        [[NSFileManager defaultManager] removeItemAtPath:path error:nil];
    }
}