Creating framework that requires (depends on) another framework - ios

I'd like to create a framework using Cocoa Touch Framework Project in Swift. However, I'm building this framework on top of another framework called RNCryptor, which is Objective-C based. I've seen various tutorials on how to create a framework in Xcode but none has covered a framework with its own dependency.
I tried to create a framework project and then using CocoaPods to manage its dependencies. However, there are errors appeared: 'Check Dependencies' Unable to run command...'
So the question is: is it possible to create a framework on top of another framework in Xcode. And if so, how?

Frameworks should never embed other frameworks directly. This leads to collisions if the importing project or any other framework also includes that framework. Instead, you need to tell your consumer that they also need to include your dependency. CocoaPods will do this for you automatically, so you should let it. (If you're having trouble with CocoaPods dependencies, you should ask a question about that and get it cleared up. The whole point of CocoaPods is to manage these kinds of things.)
Note that I will be releasing the Swift version of RNCryptor into beta today (or tomorrow, but I really hope today). This version bridges to ObjC and will be the preferred version going forward. (The ObjC version will continue to be available of course for projects that cannot or don't want to include Swift.)

Related

xcode how to develop with frameworks

Thanks for spending time reading my question.
I've been working as an iOS developer for more than 2 years and today I still feel shame because I don't know how to deal with frameworks. I've build some projects using my own frameworks, but I've never understood exactly what's the best practice doing this.
Lets see the following example:
Project -> FrameworkA -> AFNetworking - Charts - FMDB - more
So, I have a big FrameworkA with mostly all the app behavior and then a small project referencing this FrameworkA and customizing just icons, texts and images. I use to manage dependencies with CocoaPods and I would like to use it with FrameworkA. By this I could reference external libraries easily, but it seems it doesn't work for frameworks, only for projects. So, my questions is: how can I add AFNetworking, Charts, FMDB, etc to my FrameworkA and then reference the framework form my project?
I appreciate if you can give me some idea using CocoaPods or any other dependency manager. I don't like the old way by doing this manually.
I hope my case is clear.
Thanks!
It sounds like you are asking how to embed external frameworks such as AFNetworking into a framework you are developing, and then use that framework in your app.
This is what's known as embedded frameworks where one framework is stored within another. Generally speaking it's not a great idea and should be avoided because it can cause version clash issues.
The way I'd recommend doing this is to use CocoaPods or Carthage to link the external frameworks (AFNetworking, etc) into your framework project. But do to try to embedded them.
Then in your app project, again use CocoaPods or Carthage to link in your framework (you won't need to link the external ones unless you are directly using them in the app code). Then add the necessary build steps to copy both your framework file and all the external framework files to the finished app's framework directory.

How to add iOS framework in iOS project effectively

Recently started work on an iOS project, written in swift and objective-c. As of now, we have a monolithic repo. Now we are focusing on creating few frameworks so that we can reuse same framework across multiple apps. I would like to know your opinion on below points.
If I add framework.xcodeproj in my client app project, I'm able to access the framework's public entities after writing the import statement. My concern is every time I build by client app project, this framework.xcodeproj is also compiling though its has not changed since last build nor it is dependent on any other framework.
If I add framework by adding it as framework.framework and make its entry into embed framework, I can access the public entities of the framework. What's alarming in this case is that whenever I change the code of framework I need to update the framework in the client app project too.
Is there any way to include framework in client app project where I can access the public entities and it does not get build every time I build client app project ?
It's absolutely fine if framework get's build when its code is updated.
I have used Visual studio in past which let me build my client project without building dependent projects if there is not code change in dependent projects.
If the framework is build every time you build your app, depends on the type of the framework:
There are Cocoa Touch Static Libraries and Cocoa Touch Frameworks.
Cocoa Touch Frameworks
They are always open-source and will be built just like your app. (So Xcode will sometimes compile it, when you run your app and always after you cleaned the project.) Frameworks only support iOS 8 and newer, but you can use Swift and Objective-C in the framework.
Cocoa Touch Static Libraries
As the name says, they are static. So they are already compiled, when you import them to your project. You can share them with others without showing them your code. Note that Static Libraries currently don't support Swift. You will have to use Objective-C within the library. The app itself can still be written in Swift.
Conclusion
If you don't mind using Objective-C, Static Libraries seem to fit your requirement, that the framework should only be built once.
But since I love Swift, I would personally recommend you to use frameworks (if you don't mind that others that use the framework can see your code). My experience showed, that it's not a big problem, that the framework is built sometimes.
AddThis wrote a good blog post about deciding whether to use Static Libraries or Frameworks.
Cocoa Touch Static Library vs. Cocoa Touch Framework

How to build an iOS Framework with a dependency on another without creating an Umbrella Framework

I am trying to streamline my development by creating some re-usable Frameworks which incorporate features I commonly re-use in multiple projects.
However, having setup one of my Frameworks I have encountered a problem, the classes have a dependency on the Firebase framework. Having read the Apple docs it's not recommended to create an Umbrella Framework (one which embeds another) especially if you do not have ownership of the embedded Framework (which I do not).
So the question is:
How can I create a Framework project which allows me to build the Framework without including the dependencies which would create an Umbrella Framework. I presume this is what people like Firebase do because when you add their Framework there are others you have to add to your project as well. I can't quite see how you would configure a project to allow you to build the Framework without errors but not include the dependencies.
For reference I am using the latest Xcode and need to support iOS 8 and above.
Thanks in advance for any thoughts / suggestions on this
For the benefit of anyone who is struggling with the same issue, the answer is much simpler than I had anticipated.
The Frameworks are linked dynamically and simply adding a Framework to the project for your own framework will not cause it to be embedded in the output file and therefore not generate an Umbrella Framework. You don't actually need to do anything. Any Frameworks that are required by your own Framework can be included in your project so that you can compile your own Framework, and will also need to be included in any projects that utilise your Framework.

Embedding frameworks inside closed-source Swift framework

Our company wants to distribute a closed-source SDK for iOS to our clients. I've been using Cocoapods to build the framework and built an example app making use of it. Previously the app worked fine on the simulator as well as when deployed on the device. However, I was also embedding the Pods.framework file in the app itself. One other piece of information that may be of interest is that the framework is written in Swift, the included cocoapods dependencies are both Swift and Objective-C.
I wanted to make the pods requirements easier to manage so the user doesn't need to be concerned with them and tried to embed the Pods.framework file inside of the SDK we're building - so I removed the steps to Embed Pods Frameworks and Copy Pods Resources from the example app, leaving them only in the framework, I also removed Pods.framework as a dependency of the example app, leaving it only in the SDK. This seemed to work in the simulator, but the app now crashes on mobile device with dyld: Library not loaded error.
Upon researching it, I stumbled into a few related discussions:
https://github.com/CocoaPods/CocoaPods/issues/344 https://objectpartners.com/2014/06/25/developing-private-in-house-libraries-with-cocoapods/
However, the suggested solution of using private pods does not look like it would work for us, it's my understanding that the source code in the private pod would still be open, and we can't share it with our clients.
Could someone advise on a solution that would work in this case?
OK, I finally have a more durable solution. It's a modified, cleaner version of my old one now that I understand how Xcode links in my Swift sub-frameworks better
Problem that makes distribution/compilation a bit ugly:
Since Swift standard libraries aren't bundled on the device like Obj-C, nor are they guaranteed to be stable between versions yet (stable binary interface promised in Swift 3: https://github.com/apple/swift-evolution#development-major-version--swift-30) we have to make sure the entire project is compiled against the same version of Swift. That means the guy using your closed-source framework has to be using the same version of Swift in their Xcode for their project as you did for compiling the library, even if he's not using Swift in his code because ultimately it's his version of Swift that gets bundled into the app and your SDK runs against. This is only an issue for closed-source frameworks because open-source ones will always be compiled against the same version as final project. Possible workaround is to restrict clients to same version you use or distribute multiple compilations (i.e. Swift 2.1 and Swift 2.0). To remedy this, you could provide users with copies of binaries compiled against multiple versions of Swift.
Aside from that, here is what I had to do during compilation/distribution to make a binary framework that works in Swift:
When building the framework:
In project target, make sure to add Pods.framework to Linked Frameworks and Libraries (make sure this is a pre-compiled RED version of Pods.framework, I had a black compiled Pods.framework in the same directory which built fine but then resulted in a framework that would cause the project to complain about missing armv7 architecture during linker phase in later project)
In Build Settings, under User-Defined section, add a field called BITCODE_GENERATION_MODE and set it to bitcode
DO NOT #import any frameworks in your bridging header, all instructions telling you to do that are leftover from Swift 1.0-1.2 days, you don't need it anymore and it does more harm than good (the later project will complain that it can't find these headers that aren't even exposed to it)
Change build target to Generic iOS Device, Archive and Export the framework
When building the project using the framework:
Drag and drop the framework into the project, in General tab add it to Embedded Binaries and Linked Frameworks and Libraries (you only need to add the framework itself, not the sub-frameworks or the pods file)
In Build Settings tab, add a new path to Framework Search Paths: $(PROJECT_DIR)/MyFramework.framework/Frameworks
Build the project

iOS Framework build: what is the best practice to link with third-party libraries?

I'm build a Framework for iOS and my framework has AFNetworking as dependency.
So what is the best practice to include AFNetworing? Reading other posts (specially this question here) i came up with three options:
Copy all the .h.m files from AFNetworing in to my project and compile my framework with it. But according to this, it will possible cause a situation where some third part developer using my Framework are already using AFNetworking and will get a compile-time error that some class is declared twice.
Use CocoaPods and link AFNetworking to my Framework. This is causing this error: -lPods is not an object file (not allowed in a library).
Build something like the Aeris SDK where the third part developer using my Framework will be responsibly to add AFNetworking to their project.
I think that option 3 is the best but i don't know how to do that. How can i dev my framework calling AFNetworking classes/methods but do not include on the final framework product?
Thanks!
That's a very bad practice to use third party library in you library.
Ideally you should avoid doing that.
But if you really need it, you can define and add prefixes to class names.
Refer this article Avoiding dependency collisions in iOS static library managed by CocoaPods
Ok. I decided to go with the option 3.
A just added all the header files from any third-party lib to the my framework project (you can also add the .m files but not include them on the static library target).
And a i also documented everything, so developers using my framework will know what are the dependencies and how to include/install them on their own projects (including third-party lib versions, CocoaPods support, etc).
I decided not to go with option 1 because that will cause some situations where a project will have two copies of the same lib compiled on the final app. Even if a change the namespace for the libs on my framework code (to prevent "duplicated symbols" errors) that will still cause some other possible problems like an APP with larger size, possible bugs related to two or more instances of the same lib running together, etc...

Resources