This is a variant of the old "dyld: Library not loaded: #rpath/libswiftCore.dylib" problem. I'm pretty sure I know what the issue is, but I don't have any ideas on how to fix it.
I'll reference the project I'm working on, so I don't clutter the question with huge blocks of code.
The project generates a dylib that can be thrown into another project, and abstract a huge block of coding for developers (a communication layer of a client/server system).
I want the framework to be as simple as possible to to use; even if that means making it a big fat pig. I just want people to be able to toss it into their project (Swift or ObjC), and not have to worry about playing around with different variants for things like simulators and devices.
I use a variant of the old Wenderlich script to lipo the executables for x86 and ARM together.
Note the commented-out section. There be draggones.
Works great. In Swift.
Objective-C, not so great. That's because of the various Swift frameworks that need to be carried into the Objective-C program.
I switched on the embed frameworks setting, and the target dutifully gives me all my frameworks.
The problem is that each architecture has frameworks for ONLY that architecture. They aren't "fat" frameworks, so my hand-built "fat" framework really is kinda skinny, because it will only work on certain architectures.
My question is whether or not there's a way to ensure that the Swift frameworks I embed can be made "fat," or if I just have to give up, and package different variants of the framework for Objective-C programmers.
Any ideas?
I'm giving up on this sucker.
You cain't git thar f'm here.
This library will be Swift-only.
Related
My goal is to build a swift iOS framework which uses two other frameworks (included as separate projects) and which shouldn't reveal the source code after built.
Is there some text/guide/documentation which would explain and navigate me through the process of building such a framework properly and correctly?
I built framework with aggregate target adding and linking frameworks on which my custom framework is dependent using run script as indicated here. I was able to add built of my custom framework to my custom app, together with other two dependencies (again as a separate projects), and run it on the device. However, I am not convinced by the correctness of my custom framework built.
Moreover, I was not able to upload the archive to the Appstore due to the various errors of "Unsupported architectures...", "CFBundleIdentifier Collision...", "Invalid Bundle...", "Invalid Binary" and so on. After sorting these errors out according to the various stackoverflow answers and installing the app from the TestFlight, the app crashed after launch and wasn't working at all.
I was checking various blog posts, stackoverflow questions/answers and Apple Framework Programming Guide but nothing gave me comprehensive understanding on building custom framework under conditions described above.
Everything I did was just following step-by-step tutorials without explanation of the purpose of the steps. I am sure I am missing the basics. Could you please help me and give me some guides?
I can understand you frustration. I, a while ago too searched probably for many documents on how to write a framework correctly but like you I also didn't find anything really that satisfying. From my own experiences I can give a couple of advices.
NO External Libraries
In my opinion DO NOT use external libraries in your own framework. I don't really know what your frameworks purpose is but most of the stuff you want to do can be done without using external libraries. Depending on other libraries is not a good idea especially if its a framework you are working on. Anytime these libraries get updated or even worse if they don't you will have to wait for them to be updated or find another library.So rather than this happening later on I think its better if you do it from the start. So loose the external libraries.
Universal Framework Binary
Second one is pretty easy. Generating a universal framework. I suggest you don't use a script. Most of the scripts I found were either outdated or they didn't work at all. Later on I found out that actually it was pretty easy to generate one on your own. You can do this by building your project once for a real device and one for the simulator.Then you can generate a universal binary by using the command lipo -create "Your simulator executable path" "your iOS device executable path" -output "your framework name". What this does is that it combines your two executable files and generates a universal one. Then you can just go and copy your simulator documents from the modules file and paste them in you iphoneos modules file. I am going to share a link were you can go through the walkthrough yourself. https://medium.com/wireless-registry-engineering/create-a-universal-fat-swift-framework-b7409bbfa18f
Use Objective-C(If you can)
This one is bit of a tricky one unless you know objective-c. What I would recommend is that you implement your framework using Objective-C and writing a swift wrapper around it. I would not have said this if you were creating an iOS app but in case of a framework I still think you should go for objective-c. This is because Objective-c has been around for over 30 years and most of the very old apps are in objective-c. If you want your framework to easily be used by older apps coded in objective-c I recommend you go with it. I have read tons of posts on how people have problems trying to use frameworks written in swift in their objective-c apps. Swift will be the first and probably only choice in the near future but not just yet. On the plus side if you still haven't you will have learnt Objective-C which will give definitely give you a better understanding on how things work. It will be challenging but I promise you it will be worth your while .I have a good read on this which you can checkout yourself. https://academy.realm.io/posts/altconf-conrad-kramer-writing-iOS-sdk/
Naming Conventions
This is a pretty straight forward one. I suggest you stick to apples naming conventions. This is because you will be sharing your code this time and people will look for familiarity when trying to integrate your framework. This will make your code easier to understand. You can check out these two links for more info.https://github.com/raywenderlich/objective-c-style-guide (obj-c) https://github.com/raywenderlich/swift-style-guide (swift)
Access Control
This in my opinion is an important one. When working on you framework think before you implement a class or a function. Consider if you would like someone else to be able to use that part of your code. You may want to limit the user while they use your framework and correct access control is the way to do it. You can easily guide the users so the users do exactly what you want them to do with your framework.
Document Your Code
This is a must if you want your framework be a professional one. You should be documenting every function and variable the user will use. Documenting and explaining what your code does makes a lot of peoples lives easy. You don't one anyone trying to understand what your code does for half an hour while you could have easily written a small explanation for what the parameters do and one that function or variable should be used for.
Test Your Code
Last but not least do write tests for your code. This does take some time but it assures you that your code works the way it should.
Look at other good frameworks
You should definitely checkout other open source libraries and look at what they have done. Usually there is no point in reinventing the wheel unless you are doing something absolutely different but even then there are very familiar ways to do things. I can suggest you check out the mantle sdk(https://github.com/Mantle/Mantle). Another one is the very popular Alamofire sdk(https://github.com/Alamofire/Alamofire) and also the Realm sdk(https://github.com/realm/realm-cocoa). These are good examples of frameworks. Take a look at them. Look how they have done things. It will give you an insight on how your framework should look like.
I know all of these points may also be valid if you were writing an app but what makes these a must is the fact that you will be sharing your code with others. You may manage by not doing some of these while implementing an app but for a framework things do change a little bit. It is always a pleasure to work with easy to use frameworks which make coding a pleasure. These types of small things will make your framework preferable. Happy coding.
I think I just must be stupid.
I'm having a lot trouble understanding very basic things concerning frameworks in Xcode/iOs/Swift. While I've certainly gotten some things to work, I've gotten more and more confused about what I'm actually doing. And the documentation on the web just confuses me more.
When I see discussions about how to import particular frameworks (e.g. https://github.com/danielgindi/Charts is the library I'm playing with, but I've seen this pattern repeated in other libraries) they seem to always tell me include the Xcode project file as a child project of my project, in addition to linking things as an embedded binary. This confuses me. Is it not possible to link an already compiled framework to my project without including all the source code of the project?
That is, can't I just take a library.framework file, and add it to my embedded libraries list and be done with it?
In the frameworks I've played with (again https://github.com/danielgindi/Charts is my primary example, but this is true in many others I've played with) I can't seem to use the framework without Carthage or CocoaPods. For me at this stage, that is just confusing... I accept that they are useful tools to automate a difficult process, but I'd really like to understand what that process actually is before I let a tool automate it for me. As I search the web I just seem to always be led back to these tools as being the correct way to do things.
So here are my questions.
If I find a framework library on the web... do I need its source code or can I somehow just link to a compiled version of the framework?
In my reading, it seems that libraries made with Swift are somehow second-class citizens because Swift is a newer thing. Is that still the case? (The articles I read about this seems to date from 2014-2015).
Is there are good place to understand how Apple expects me to add a framework to a project, without using CocoaPods or Carthage?
No need to add source code. Just add the framework to Target ->
General -> Linked Framework and Libraries -> Tap on + and select
your framework.
In my opinion, many new libraries are being written is Swift. So you won't be left behind for using swift.
Apple has documentation about adding frameworks to XCode. But I would suggest to use Cocoapods , as its easy to manage libraries.
Cheers :)
I need to use a framework for and old obj-c project. The problem is, before I used to compile again and again code in a binary and then lipo it. Now with the swift architecture, it generate some Apple specific files, and of course, it is too hard for (or unintuitive to) Xcode to generate the framework for the architecture I want.
I googled how to do it, but to my surprise, I just found old post who talk about the old way with the standard binary output.
My question is how to simply generate a swift framework for the wanted arch. For the moment the only solution to my problem is to compile a framework for the simulator and another one for the phone. But I have no idea how to fat it. Or if it is the right approach.
I can't believe there is no way to ask Xcode to build it. But since we are talking about Xcode...
Using iOS 8, Xcode 6.
Let's say I have 2 dynamic frameworks, frameworkA and frameworkB and they are both dependent on libC. In addition, I have an app that uses both frameworkA and frameworkB. My original thought was to make frameworkA and frameworkB umbrella frameworks and libC a subframework. However, Apple advises against umbrella framework and this post describes why umbrella framework is a bad idea due to potential linker conflict issue.
My second option is to use cocoapods (still new to this so a bit fuzzy on details) to use libC as a pod which then gets compiled into frameworkA and frameworkB. However, it occurred to me that both frameworks still has its own copy of the libC. Since the app uses both frameworks, will this result in a linker conflict issue as well? Is there a better way to solve this problem?
UPDATE
#Rob The projects I work on do require complex dependency management but I kept the problem domain simple in the question to try to better understand how and if using cocoapods can help solve the linker conflict issue with umbrella frameworks. I work with a team of developers who write libraries and can depend on each other's base libraries that provide versioned common APIs. We are required to package and deliver as few libraries as possible to a different organization that is building an app with our libraries and one of their key requirement is that we deliver a dynamic framework.
The best way to solve most problems is to put all the code in a project and compile it. When you have specialized problems that make that problematic, then you should look at other solutions, such as static libraries, and finally frameworks.
Static libraries can make sense if you have a code base that has pieces which require different build requirements. If all the pieces have the same build settings, then just "add files" them into your project from a "common" directory and build your project. Static libraries can be attractive if your build times are very significant and some pieces never change and you want to be able to "clean" without rebuilding those parts. But wait until you start having that problem before you go making complicated multi-package projects.
If you sell closed-source libraries, then frameworks are very attractive. You should strongly avoid adding third-party dependencies for the reasons you note. If you must, the best way is to help your customers package all the pieces as frameworks and have them link everything at the end. But that adds a lot of annoyance; so make sure you really need that third-party piece.
You might also consider frameworks if you have a very large piece of reusable code that has its own lifecycle separate from the main products. But again, keep it simple. Avoid third party stuff inside of it, and if you must have third party stuff, then have the consumers link it at the end.
(This isn't a new solution, BTW. When you use curl, if you want SSL, you need to also download and build OpenSSL and link them together yourself. Curl doesn't come with OpenSSL built in.)
But in the vast majority of cases, this is all overkill. Don't jump to frameworks. Don't jump to libraries. Just put all the code in the project and compile it. 90% of your problems will evaporate. iOS projects in particular just aren't that big usually. What problem is a framework solving?
If you have a lot of code that your organization uses repeatedly in lots of products, then I have heard many teams have good luck using internal CocoaPods to manage that. But that's just to simplify checking the code out. It still all goes into a project and you compile it together into one binary; no frameworks needed. Dynamic frameworks are a nice feature in for certain kinds of problems that were really painful before. But, for most situations, they're just complexity looking for a problem.
(If you have one of those specialized problems, edit your question and I'm happy to discuss further how you might approach it.)
EDIT: (You fall into that "specialized problem," so let's talk about it. I did, too, for many years inside of a large multi-team Mac and iOS dev environment. And we tried just about every different solution, including Frameworks. They're only new on iOS.)
Within an org like you describe, I would strongly recommend packaging each dependency as its own framework (AFNetworking, JSONKit, etc) and each of your pieces as a framework, and then have the app devs link all of them together at the end. In this way, it is identical to other dynamic libraries (libcurl, openssl, etc.) which require the app dev to link everything together.
In no case should dynamic frameworks include other frameworks that could otherwise be required (i.e. frameworks should never package "third party" stuff). That will explode. You cannot make that not explode. You'll either have bloat, build conflicts, or runtime conflicts. It's like merge conflicts. There's a point at which a developer has to make a choice. App-level linking is making that choice.
Making components over-dependent on other components is the source of decades of trouble, from Windows DLL Hell to iOS apps with competing crash handlers. All the best component systems look like Legos, where the end user assembles small pieces that have minimal dependencies. As much as possible, make your internal frameworks rely on nothing but Cocoa. This has some tangible design influences:
Avoid directly requiring logging or analytic engines. Provide a delegate interface that can be adapted to the engines of the caller.
Avoid trivial categories (methods that save just a few lines of code). Just write the code directly.
Avoid adding framework dependencies that aren't buying you a lot. Don't add AFNetworking just to save a few lines of code over NSURLConnection. Of course if you're heavily relying on the features of another framework, that's different. But as a framework developer your threshold should be quite high before requiring another framework.
Strongly avoid being clever in the build or version control. I've seen too many cases where people want to make everything "automatic" for the app-level developer, and so make the system really complicated. Just say "you need to link this and import this and put this in your app delegate startup." Don't create complicated build and version control systems to save 2 minutes on the first build or two lines of initialization logic. These things blow up and waste hours to work around. Don't get clever with +load magic. Just make it clear and consistent.
And of course, good luck. Supporting other devs is always an interesting challenge.
The first thing I tried is to create a static library but later I found out that it's not supported yet. Apple Xcode Beta 4 Release Notes:
Xcode does not support building static libraries that include Swift
code. (17181019)
I was hoping that Apple will be able to add this in the next Beta release or the GA version but I read the following on their blog:
While your app’s runtime
compatibility is ensured, the Swift language itself will continue to
evolve, and the binary interface will also change. To be safe, all
components of your app should be built with the same version of Xcode
and the Swift compiler to ensure that they work together.
This means that frameworks need to be managed carefully. For instance,
if your project uses frameworks to share code with an embedded
extension, you will want to build the frameworks, app, and extensions
together. It would be dangerous to rely upon binary frameworks that
use Swift — especially from third parties. As Swift changes, those
frameworks will be incompatible with the rest of your app. When the
binary interface stabilizes in a year or two, the Swift runtime will
become part of the host OS and this limitation will no longer exist.
The news is really alarming for me a person who writes components for other developers to use and include in their apps. Is this means that I have to distribute the source code or wait for two years?. Is there any other way to distribute the library without exposing the code (company policy)?
Update:
Is Swift code obfuscation an option at this point ?
Swift is beta now, and even for 1.0 Apple has been pretty clear they're after a restricted feature set -- better to do a small number of things well than to try to do everything.
So for now, there's no way to distribute binary static libraries. Presumably that'll change sometime after Swift 1.0. For now, you can:
Distribute source
Ship a binary framework (instead of a library) if you're okay with the ABI being fragile
Use ObjC for library code
You can always combine approaches, too: e.g., implement the critical (secret) details of your library in ObjC, and ship Swift source that wraps it in a nice Swift API.
Obfuscating code written in a language that's very much subject to change sounds like a recipe for a maintenance nightmare.
I believe the whole approach is wrong. You cannot do something that is not (yet) doable by the technology you are trying to use.
Rationale: Swift is a new language, currently in Beta, and therefore changing. As I see it, this fact means not only that you are not able to ship static libraries, but that (real) developers will not be actually use third-party static libraries. What's the actual use of a library that may not work in the next release of the compiler? The issue gets bigger if you whant to use more than one library, because they might not be compatible! Therefore, even if you would be able to ship static libraries, they wouldn't be actually useful for production environment. So, what's the point?
Suggestion: write your static libraries in Objective-C (or C or whatever "non-beta"). Developers who need third-party libraries (e.g. yours) shouldn't expect them to be written in Swift until Swift is stable. You don't use experimental materials to build real bridges, right? You use well-tested, predictable ones.
From Xcode 9 beta 4, Xcode supports static library with Swift sources.