momcom is a command-line tool for Mac OS X that takes an uncompiled Core Data model created with Xcode and compiles it to produce a compiled .mom or .momd suitable for use at run time.
Please note that momcom is experimental. Although it is intended to be at least as as functional as compiling a data model using Xcode's built-in model compiler, it is not mature enough to recommend as a replacement. It was written mostly as an experiement to see if it could be done.
momcom requires the modern data model file format available with Xcode 4 and higher. The older model file format is not supported and likely never will be. If your project was created with Xcode 4 or higher, it most likely already uses this format. If your project is older than Xcode 4 then it probably uses the older format. You can choose the format in Xcode's data model editor.
Models compiled with momcom should be functionally equivalent to those compiled with Xcode's model compiler. If you have a data model that does not compile correctly with momcom, please let me know.
In addition, momcom does not suffer from the following bugs in Xcode's model compiler:
- Min/max limits on decimal attributes are truncated to integer values. This bug is described more fully at rdar://problem/13677527 and http://openradar.appspot.com/radar?id=2948402.
- Fetch request templates in a data model lose most of their configuration when compiled by Xcode. The fetch request name and target entity are maintained but all other attributes are lost and have default values at run time. rdar://problem/13863607 and http://www.openradar.me/radar?id=3009404.
momcom (Foo.xcdatamodel|Foo.xcdatamodeld) [output directory]
The first argument is the full path to a .xcdatamodel or .xcdatamodeld, and the second is the location where results should be written. If the second argument is omitted, the current working directory is used. Output files are automatically named based on the input.
If the first argument is a .xcdatamodel, that it, a single uncompiled managed object model, momcom produces a '.mom'. If the first argument is a .xcdatamodeld (which potentially contains multiple managed object model versions), momcom produces a .momd containing compiled versions of each model version. In this case it also produces a VersionInfo.plist indicating the current version and entity hashes for each version.
momcom Foo.xcdatamodel /private/tmp/
Compiles Foo.xcdatamodel to /private/tmp/Foo.mom.
momcom `Foo.xcdatamodeld`
Compiles Foo.xcdatamodeld to Foo.momd. This bundle includes all versions present in the uncompiled model as well as VersionInfo.plist.
This project contains a number of categories on Core Data classes that could be useful in other projects. The main entry point would be NSManagedObjectModel+momcom.h, which includes the following methods:
+ (NSManagedObjectModel *)compileFromDocument:(NSXMLDocument *)sourceModelDocument error:(NSError **)error;
Returns an NSManagedObjectModel compiled from the XML document contained in sourceModelDocument.
+ (NSString *)compileModelAtPath:(NSString *)modelPath inDirectory:(NSString *)resultDirectoryPath error:(NSError **)error;
Compiles the xcdatamodel or xcdatamodeld found at modelPath into the result directory.
Other categories are intended to be used by these methods.
Developed with Mac OS X 10.8.3 and Xcode 4.6.2. May work with older versions of both, but this has not been tested.
Uncompiled models must be saved in the modern model file format available with Xcode 4 and higher.
MIT-style license, see LICENSE for details.
By Tom Harrington, @atomicbird on most social networks.