Cato: manage Xcode project dependencies with Rake

Cato makes it easy to manage your Xcode project's dependencies using Rake (a Make-like dependency management tool implemented in Ruby).

Cato unobtrusively downloads, builds, and copies static libraries and frameworks into the places where Xcode expects to find them.

Cato began as a set of Ruby scripts designed to manage dependencies in the LogCheck mobile app. Primarily for the sake of tidiness, I decided to factor it out into this gem. Maybe someone else will find it useful for their project. Who knows?

How to add Cato to your Xcode project

In a nutshell:

1. Create a Rakefile that includes require 'cato/tasks' and describes your dependencies.

2. In Xcode, add an "External Build System" target that runs rake cato:install --trace.

3. Add dependencies to your Xcode project (see below).

The above will work only if you install the cato gem ahead of time; if you want to make life easier on the developers using the project, you can write a shell script that will install the gem if needed.

How to add a new framework or static library dependency using Cato

1. Add a PackageTask to your Rakefile that describes where to download it from. Add one or more xcodebuild declarations if building from source, and add one or more static_library and/or framework declarations.

2. In Xcode, change the active scheme destination to "Generic iOS Device" (instead of a simulator). This shouldn't matter, but it does.

3. Build the project in Xcode, which will run rake cato:install. Rake will put the needed files into Xcode's BUILT_PRODUCTS_DIR. It's OK if the build fails, as long as the rake execution succeeded.

4. Navigate to the target's "Build Phases" tab and the "Link Binary With Libraries" section. IMPORTANT: When adding a static library or framework, navigate through the Cato/XcodeProducts folder link and select the item from there.

5. Within the "Build Phases" tab, ctrl-click the new library or framework and select "Reveal in Project Navigator"; from there, ctrl-click again and select "Show File Inspector".

6. In the File Inspector, change the Location to "Relative to Build Products". If everything is correct, the filename below the pop-up menu will appear without any leading path information. (For example, you should see libFooBar.a and not ../Debug-iphonesimulator/libFooBar.a.)

7. Build again and everything should be working!

TODO

• It would be helpful to pick some public projects using Carthage or CocoaPods and "Cato-ize" them, to test how well this thing works apart from the LogCheck app.

• I probably need to explain how Cato compares to CocoaPods and Carthage, in a polite way. :-)