I use CMake to build Qt project with internatiolization support. Using qt5_create_translation I can create *.ts files into the source directory and *.qm files into the build directory.
I want to reduce the number of files I should to distribute. Storing translation files :/translations/*.qm into the Qt resources is straitforward solution.
But during build process names of the resources are generated automatically and there is no native way to emplace them into the *.qrc file automatically.
How to achieve desired using, say, add_custom_command or something else?
Qt's qrc file is just xml files. Thus you can an external tool to add it.
A pure cmake solution could be:
Create a dummy resource file named #TRANS_FILE#
Add this file to your qrc file
Fetch the name of the translation file into a variable. Don't know how.
Use cmake's configure_file to replace the dummy resource name
Example:
set(TRANS_FILE ${NameOfTranslationFile})
configure_file(infile.qrc outfile.qrc #ONLY)
I'm a little bit confused about the qtquickcompiler, the JIT qml caching and what is available (and what is not) in the open source version of qt 5.8 (respectively 5.9).
Basically, I want to protect my .qml and .js files from being readable in my release build. I started a new example QtQuick project without editing any code. I followed these instructions and added the CONFIG += qtquickcompiler in the .pro file, but it has no effect.
My .qml files are built into the .exe (on Windows), but if look in the executable, e.g. with notepad++, I can still see the source code of the .qml files.
On the other hand, if I don't use the QRC for my .qml files, .qmlc files are created for every of my .qml at runtime. These files are not (easily?) readable. But I don't find a way to use only the .qmlc files without shipping the .qml files in my build (and I don't think it was meant to be like that).
Coming to my question: Is there a way to protect my .qml and .js files with the open source version of qt? And what is the difference between the qtquickcompiler and the new JIT .qmlc?
Updated answer:
Since Qt 5.11, the qt quick compiler is also available in the open source version:
CONFIG += qtquickcompiler
See https://wiki.qt.io/New_Features_in_Qt_5.11
No, it was going to be, but then they gave up on those plans for the time being and replaced it with the caching thing.
I don't think you will be able to reuse .qmlc files on another computer, as IIRC they are not architecture portable.
In the future, it should be possible to pre-compile .qml to .qmlc ahead of time and bundle those into the application binary.
If your files are on the file system, then there is no way to protect them, from being read, reverse engineered, or tampered with.
With the compiler, the QML code is translated to C++ code, which is then compiled to a native binary. Also, last time I checked, if you go for the compiler, it is an "either / or" situation, if you use compiled qml you can only use compiled qml, so no mixing with regular qml files. It is also ahead of time, and requires a commercial license.
The qml caching in contrast is just-in-time (possibly ahead of time in the future), doesn't require a commercial license and doesn't come with the limitation that prevents you from using regular qml files. I am not aware of the implementation details, but it certainly is not qml code translated to C++ and then compiled, as it happens on the client side and doesn't require having Qt or even a C++ compiler installed. It doesn't really sound like bytecode either, as IIRC it is not binary compatible between platforms, it is more like caching the qml file processing result to avoid on doing it every time.
As outlined in this answer, with some extra work it might be possible to implement a decent amount of protection, for example encrypted QML files or binary resources, but I still haven't dug into it.
Lastly, if you set compression for the qrc file with a low threshold, it will somewhat obfuscate the QML code in the executable binary, but even so, it is regular zip compression, so if your code is really worth stealing, it will not really prevent that, just make it a tad less trivial.
Is there a way to protect my .qml and .js files with the open source version of qt?
Not yet. Up to (and including) 5.8 you'll need to buy a license in order to use the QML compiler.
And what is the difference between the qtquickcompiler and the new JIT .qmlc?
That the compiler will turn QML into C++, which gets then compiled into your application. The .qmlc files are a cache generated by the engine to avoid parsing / optimizing / etc. the same files all over again. Yet, they're a cache -- you'll need to original source around in case they don't get used. At the Qt Contributors' Summit 2016 there have been some discussions about how to streamline and integrate the compiler with the cache, but so far nothing exists.
Coming to my question: Is there a way to protect my .qml and .js files
with the open source version of qt?
Yes, of course,
look at my answer:
https://stackoverflow.com/a/40861056
You can use an encripted resource file, an decrypt it in execution time...
I do that in all my projects ...
Is not a trivial job, but works fine.
I want to get a path to the project directory in Qt and reference the other files of my project relative to it. I know this issue have been already discussed here
Get current working directory in a Qt application
and here
How to get current working directory path of a Qt application?
but the answer is still unknown. In case it's impossible to get such a path then what is the approach of navigation among files of the Qt project.
Based on your comment, you are trying to:
Access some images which are being used in my program. I could of course put them into build target directory, but it becomes uncomfortable to pass my code to others.
The approach to store resource files in the project source directory and rely on such structure at runtime is not a greatest idea. I can't imagine the situation when mixing the concepts of initially decoupled source and build directories could be useful, correct me if I'm wrong.
So, according to your needs:
The most simple and plain way is to use the Qt resource system. The resource files are simply embedded into the executable, so there will be no need to access the file system.
Another way is the automatic deployment of the needed files. This answer describes the way to copy your files to the target directory using qmake.
I want to translate a program; but its language files (.qm) are in a .rcc file.
The program is not mine, so I haven't got any .qrc file.
Before asking this question, I have searched this site about this issue; but I don't attain anything.
Is there any way to extract/decompile it?
You can take my tool RccExtended - it based on the official Qt resource compiler with additional function to decompile binary resources.
Usage example:
cd \Path\To\MyQtResources\
rcc --reverse
Decompiler will unpack all .rcc files in the current directory, generate .qrc files and make.bat file to compile resources back to the binary format.
There isn't a supported way to decompile it as far as I'm aware, but it's a binary file format that can be read and handled. There's a nodejs example of how to read the file and extract PNGs on github: https://github.com/gcochard/png-extractor. It may be possible to extend that method out for the .qm files.
However there's other issues with attempting to add more translations to a Qt application without having the code, depending on the language you're attempting to add, how the developer has exposed the other languages etc.
Is there a way to add specific phrases from Qt frameworks's internal .ts files to my application's translation files? I only need to translate several phrases for QMessageBox and friends.
EDIT:
I also want to:
Bundle the phrases inside my application's .ts file
Prevent them from going obsolete after a routine lupdate
There's always an alternative to subclass QMessageBox, but I'd like to try a perfectionist solution first.
EDIT #2:
I've solved the problem the ugly way by shipping a .qm file with my application from the Qt distribution. I'll keep this question open in case somebody comes up with a more elegant solution.
EDITED:
For custom translation of internal Qt phrases you only need to do some steps:
Modify appropriate qt_lang.ts in translation folder inside Qt SDK directory. I strongly recommend you to use Qt linguist for this purpose.
Use lrelease utility on qt_lang.ts to produce .qm file.
Modify your code. You need to install generated translation file in your app by using QTranslator class.
Distribute your app with generated .qm. All .qm files must be arranged in special dir relative to your app binary. By default it is translations folder, but you can change this dir by using custom qt.conf.
So when you change app language you'll get needed (translated by you) phrases.
For example, if you want to achieve custom translation for russian friends you need to open qt_ru.ts in Qt Linguist, locate there QMessageBox context and translate all needed phrases. Then follow described above instruction.
In Qt you can load various ts files for your application, i would try not to extract the needed phrases but load the qt ts files along with your own translation