writeToFile以原子方式返回NO

Question

I have the following code:

NSString *errorStr = nil;
NSData *plistData = [NSPropertyListSerialization dataFromPropertyList:dict
                                                               format:NSPropertyListBinaryFormat_v1_0
                                                     errorDescription:&errorStr];
if (errorStr) {
    // Darn.
    NSLog(@"saving dictionary error %@", errorStr);
} else {
    // [plistData writeToFile:file atomically:YES];
    // (ankit): Changing this to NO for speed.
    success = [plistData writeToFile:file atomically:NO];
}

however this returns NO, for the following dictionary:

  {
    entries = (
                {
            author = "Jada Wong";
            cellIdentifier = default;
            date = "2012-10-15 02:22:41 +0000";
            domain = Readability;
            feedUrl = "readability://feed";
            imagesAreOnPulsesubscriber = 0;
            order = 0;
            summary = "";
            templateUrl = "default_template.html";
            title = "We\U2019re Going To Try Out Dolce & Gabbana\U2019s Beauty Look This Weekend";
            url = "http://www.styleite.com/media/styledish-10122012/";
        }
    );
}

but it works for the following dict:

{
    entries =     (
                {
            author = "Colleen Taylor";
            cellIdentifier = default;
            date = "2012-10-15 01:00:05 +0000";
            domain = TechCrunch;
            domainUrl = "http://techcrunch.com";
            feedUrl = "http:/asdasdm/TechCrunch";
            images =             (
                "http://asdshot-2012-10-14-at-5-20-43-pm.png"
            );
            imagesAreOnPulsesubscriber = 1;
            lastUpdated = 1350263095;
            order = 0;
            shortLink = "http://bete.me/s/ej2Tg";
            summary = "Bonobos, the men's clothing company, has gained lots of ground since it was founded in 2007 for its presence on the web as a mostly pure e-commerce p...";
            templateUrl = "default_template.html";
            title = "Inside Bonobos\U2019 New Palo Alto Digs, Where The Startup Known For E-Commerce Is Investing In Bricks & Mortar";
            url = "http://techcrunch.com/2012/10/14/bonobos-palo-alto-mike-hart/";
        }
    );
}

Any idea why? It worked for different dictionary The file path I am writing to is:

/var/mobile/Applications/4B60A704-BE00-4160-BFB4-AD89187FADD1/Library/Caches/StoryCache/readability:  feed

The error I got is:

"The operation couldn\u2019t be completed. (Cocoa error 512.)" UserInfo=0xb41580 {NSFilePath=/var/mobile/Applications/4B60A704-BE00-4160-BFB4-AD89187FADD1/Library/Caches/StoryCache/readability:  feed, NSUnderlyingError=0xbb8930 "The operation couldn\u2019t be completed. Is a directory"}

Answer 1

Use writeToFile:options:error: instead of writeToFile:atomically: so you can log the error code.

NSError *error;
success = [plistData writeToFile:file options:0 error:&error];
if (!success) {
    NSLog(@"writeToFile failed with error %@", error);
}

UPDATE

Based on the error you pasted into your question, I guess you already have a directory named /var/mobile/Applications/4B60A704-BE00-4160-BFB4-AD89187FADD1/Library/Caches/StoryCache/readability: feed . You cannot overwrite a directory with a file. You need to rename or delete the directory first. You can use -[NSFileManager removeItemAtPath:error:] to delete a directory and all of its contents recursively.

Answer 2

I accidentally wrote NSURL.absoluteString as the argument to writeToFile:. Make sure you do NSURL.path not NSURL.asboluteString!!!!!

Answer 3

The reason is "" and NSNull value of Dictionary is not allowed to save to file. In your case :"summary = "";" so, writetofail return NO.