iOS SDK - Link static library with static library - ios

I have the following issue: I am writing an app that consists of a main project for the GUI and similar and two static libraries: One for authentication to a service and a second one for using a part of that service. The problem is, that I need to use parts of the auth library in the service library for instance the auth library offers an API http client that I want to use in the service library.
I managed to get it running when building the whole app with GUI an everything but I didn't manage it to get in running if the service lib should be build stand-alone (for continues integration tests etc.) My deployment target is 5.0, my SDK is 6.1.
Is there a way to do this rightâ„¢?
Thanks for any help.
Philip
EDIT: Of course I could just put the auth lib into the service lib as a sub project but if I need to use more then one service libs in a future app that would be quite messy, wouldn't it?

The fundamental issue you are missing is:
Static libraries are not linked.
They are simply an archive of object files, with Mach-O extending this concept to support multiple architectures in the same file (see lipo).
The only way multiple static libraries are linked together is in the final binary (app or dylib).

Related

Using dynamic library in static framework or using static library in dynamic framework

Static framework become part of the executable, and are statically linked to client apps. What happens if I use a dynamic library when building a static framework? I think it's reasonable that the become executables.
As for dynamic framework, libraries are not part of the executable file. What happens if I use a static framework when building a dynamic framework?
The behaviour will depend on the configuration of the intended host.
If you built an app/framework using a dynamically library say ssl. Then you are assuming the intended host already has this ssl library, and the correct version, installed and available to the app. If it is not the app will not run.
If you use a statically linked library in your app/framework then the app will run regardless of the library being previously installed or not.

Framework using cocoapods inside other framework using cocoapods inside app project

I have a app which historically has grown a lot and to be a bit cleaner and to have the option to give out code to third party developers in the future, I was thinking about splitting my project into multiple projects which I then could export as a framework.
Currently everything is in one big project. I have:
4 App targets
Shared view controllers
Shared web services
Shared model classes
Shared utility classes
Shared extensions
Shared protocols
The thing is that not every web service is used in every app. Not every protocoll is used in every app. Not every extension is used in every app and so on.
Now correct me if I'm wrong but can't I put, for example, the web services in their own framework and then use the framework in the project where I have my app targets?
Can I do the same for a "core" which contains all utilities, extension, protocolls and models?
Can I then use the "core" in the webs service framework as well as in the app targets?
What would such a structure look like? I already tried creating two framework projects and then use one framework inside the other but I cant build it. Is it because I would need to use Cocoapods inside each of the framework projects? Is that possible?
The web services for example would need "RxSwift" and "Moya" but the "Core" would also need "RxSwift".
Do I have a wrong thinking here? Shall I only use one Core framework and put everything in there which is shared? I'm confused and probably lack the deeper understanding of how the frameworks work.
I'm using CocoaPods and have separate from main app web service and core frameworks. This way it looks in the project:
Lets start with core because even web service depends on it. I call it Common instead of core and it is available on GitHub. It contains multiple subfolders which represent frameworks they extend. And there are two podspecs.
CommonExtended contains functions that are not available in app extensions (for example in Today Extension) and depends on Common. So, splitting core into two separate frameworks provide a way to use it in both main app and app extensions. Although Common is available on GitHub, I download and use it locally (but it can be downloaded from remote whenever you update your pods, you just need to specify remote address)
web service is a local folder which is called Api and its podspec looks this way:
As you can see, it has such dependencies as RxSwift, Moya and Common (the desired behavior from your question - framework contains framework).
So, whenever I need to use any of the frameworks in an app or its extensions - I just specify what kind of framework is required as dependency:
Then just import your frameworks and use them:
import Api
import Common
import CommonExtended
P.S. This is just an experiment, I'm not a CocoaPods professional. But it works for me.
Edit. Local pods are easy to update. You just make changes and see them in your project (as I remember Cmd+B on main project makes the changes to be visible). But this only works with files in local pod which already exist. If you need to add new file to a local pod - run pod install to make this file visible.
All the local pods are 100% local and they live in the same repository as main project. But Common is a remote repository which is downloaded locally. Why? Because it is used in different projects. So, on each machine you have to write its own path to Common in podfile. This link provides a way to define a path to Common on each machine and never change podfile again. Don't forget to commit Common changes to the remote. Other local pods will be committed with the project automatically.

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

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...

Static Library added as sub-project vs static library added as target

First of all I'd like to say that I'm pretty new to this topic so I'm a bit confused on some general aspects of how it works.
Basically I'm working on an iOS project which has two targets, one is the app itself which I'm developing and it is a front-end iOS client, one is a static library which the former developer used to define classes belonging to a back-end framework.
Both the files of the app itself (the client I'm working on) and the static library (the back-end framework) are in the same xcode project bundle.
Even If I've never done the "setup procedure" of the static library anything seems to be working just fine on compilation.
Now the question is: I'm setting up unit tests because I'd like to start developing new features adopting a Test Driven Development approach, so one of the things I was struggling on was if I had to generate or not two separate test targets, one for the iOS app and one for the static library (since they're two separate targets), ore use one single test target for both the static library and the iOS App.
So, reading on the internet to find a solution I discovered that, as even Apple suggests here , a common approach is to add the static library as a "sub-project" of the app project.
I'm just asking myself why and what is the difference with my current situation (one project, to targets, one of it is the static library). Are there any drawbacks? Should I reorganize the whole project?
My experience agrees with Apple and the common approach. I'd suggest making the framework a subproject. (I've had some issues finding headers, but that's my lack of mastery over Xcode, not a flaw in the process.)
Set up unit tests on each project, independently. This way, your tests are true to your objective with a framework: You've successfully decoupled the framework from the parent project entirely.
If you write the all of the unit tests in the parent project, what happens when the framework is needed in another project? You've got two choices. You can not test the framework, or string along the original parent. Do the right thing and split up your tests.
I've got an open source framework that I built, called SpiffyKit, that has a parent project called SpiffyTester. (I admittedly didn't unit test much, because it's all UI and no logic.) It may serve as a good example of a starting point.
Depending on your needs you can use Pods, static or adding it to the project. If you add a library as a "subproject" is useful when you are working on the 2 projects at once. For example if you add something new to the library you just compile the library and voila you have access to the new library in your project. However if you just link the static library you will have to open the project for the library then build then replace it in the library and add the new headers witch is a lot of setup work.

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