FRCoreDataExportOperation

Core Data is possibly one of the most useful frameworks in iOS. People have different feelings towards it, but i'm a solid fan. One issue that i'm sure everyone has had with core data at one point or another is getting data in and out of Core Data. This ultimately led to creation of the FRCoreDataOperation project.

A few months ago I started using FRCoreDataOperation to serialize Core Data objects to disk. Sure you could do this with plists, but thats a little too restrictive especially if you want the serialized data to be compatible with other applications and platforms. Usually my format of choice is CSV, as you can import it into excel/ google docs easily, also python has a great module for loading CSV data.

For another project I found myself needing to do the same thing again, the classic sign that it was time to do make something reusable and adaptable. So FRCoreDataExportOperation was born. FRCoreDataExportOperation is a concrete subclass of FRCoreDataOperation and can be used without subclassing. Below is an example of how you use the class.

	FRCoreDataExportOperation *op = [[FRCoreDataExportOperation alloc] initWithEntityName:@"Destination" managedObjectContext:<MAIN CONTEXT>];
	//[Optional] Set the name of the output file
	[op setFileName:@"output.txt"];
	//Set the entity formatter
	[op setEntityFormatter:[[FRCSVEntityFormatter alloc] init]];
	[<YOUR OPERATION QUEUE> addOperation:op];
	//[Optional] Set a completion block to know when the file is complete
	[op setCompletionBlock:^{
	//Refresh the UI or send a notification
	}];

view raw gistfile1.m hosted with ❤ by GitHub

There are a series of initializers that you can use in tandem with the class, but the one you'll probably most interested in is below.

	- (id)initWithEntityName:(NSString *)aName
	predicate:(NSPredicate *)aPredicate
	sortDescriptors:(NSArray *)sortDescriptors
	managedObjectContext:(NSManagedObjectContext *)aMOC

view raw gistfile1.m hosted with ❤ by GitHub

As you can see by using a predicate and sort descriptors along with the entity name you can select the objects you want to export. The export operation also supports relationships, it's not completely recursive, and will only explore entities that have a direct relationship with the entity you specified.

The next step is to select a formatter, the actual serialization format is completely abstracted from the class and is performed by the object assigned to FRCoreDataExportOperation's entityFormatter property. Thus far i've only created the FRCoreDataEntityFormatter, FRCSVEntityFormatter, but you can create your own by implementing the FRCoreDataEntityFormatter protocol.

The FRCSVEntityFormatter is somewhat customizable, and allows you to specify a NSArray with the  keypaths that you want to be serialized to disk. The columns will be written in the order they appear in the array. If you choose to use the formatter without a whitelist, all of the properties will be written in the alphabetical order of the property name.

Best of all you can get this for yourself via Cocoapods, pod is aptly called FRCoreDataOperation

Happy exporting

Stars!

During a chat with some of my colleagues I remembered one of my favourite games, Stars!

The concept was simple, you start with a single planet, and then expand across the universe, encountering new technologies and races as the years pass. In many ways it's a fantastically engineered game. It's UI works just as effectively at 640x480 as it does at 2560x1600, It never crashes, it uses a small amount of memory and turns are quick, even with a 33Mhz CPU.

Despite it's basic appearance, it's extremely addictive. If you want to play it yourself you can find serial numbers and download links here.

Building Git on OSX

Getting this error message when running make with a fresh clone of the git source code?

GIT_VERSION = 1.8.2.rc1.19.g443d803
    * new build flags
    CC credential-store.o
In file included from credential-store.c:1:
In file included from ./cache.h:8:
./gettext.h:17:11: fatal error: 'libintl.h' file not found
#       include <libintl.h>
                ^
1 error generated.
make: *** [credential-store.o] Error 1


The solution is to disable this the component, which can be done by creating a config.mak file in the same directory with the following contents:

NO_GETTEXT = 1;

Your  welcome