My Delphi program uses Python4Delphi, and the Python script uses some standard libs. When deploying my program I don't want an entire Python installation, and it must work with python27.dll. What are the minimal set of necessary files? The document in Python4Delphi is dated and it's not clear to me...
Thanks for your help.
When I did this, I made the list myself, of what I needed for my embedded python application to work.
I remember this worked with python15.dll:
PythonXX.dll should work, without any other external files other than the Visual C++ Runtime DLLs, which require a side-by-side manifest (see the p4d wiki page) to work.
If you want to IMPORT something, then you need to ship it and anything it depends on. That means, either you pick part of the python standard libraries you want, or you pick all of it. There is no way you need all of Python's standard libraries. But I wouldn't want to live without OS and a a few other key ones. BUt the decision is yours.
Related
I have written a small program in python and QT5. I want it on raspberry PI as a single application. I have checked out buildroot and yocto but can't seems to find a single tutorial which can explain the steps from compiling the python code and make it part of buildroot/yocto. Can anyone please guide me or point me to a tutorial.
Regards,
In Buildroot, there are two ways that you can add your own Python code to the build.
Using a root filesystem overlay to add you python files in the appropriate place in the root filesystem. This has a lot of limitations though: it doesn't get byte-compiled, you have to make sure yourself that it gets installed in some location in PYTHONPATH, and generally it's a bit more difficult to maintain. However, it's a very simple approach for a first try.
Creating a custom python package. It's also not really complicated to do that, but you really do have to read the documentation.
I have written a python code which takes an input data file, performs some processing on the data and writes another data file as output.
I should distribute my code now but the users should not see the source code but be able to just giving the input and getting the output!
I have never done this before.
I would appreciate any advice on how to achieve this in the easiest way.
Thanks a lot in advance
As Python is an interpreted language by design; and as it compiles code to a bytecode (- which doesn't help the fact you're trying to conceal it, as bytecodes are easier to reverse -) there's no real secure way to hide your source code whereby it is not recoverable, as is true for any programming language, really.
Initially, if you'd wanted to work with a language that can't be so easily reversed- you should've gone for a more native language which compiles directly to the underlying architecture's machine code which is significantly harder to reproduce in the original language let alone read due to neat compiler optimizations, the overhead given by CISC et cetera.
However, some libraries that do convert your source code into an executable format (by packing the Python interpreter and the bytecode alongside it) can be used such as:
cx_Freeze - for freezing any code >=Python 2.7 for any platform, allegedly.
PyInstaller - for freezing general purpose code, it does state additionally that it works with third-party libraries.
py2exe -for freezing code into Windows-only executable format.
Or you might consider a substitute for this, which is code obfuscation which still allows the user to read the source code however make it near-to-impossible to read.
However, an issue brought up with this is that, it'd be harder for code addition as bad code obfuscation techniques could make the code static. Also, on the latter case, the code could have overhead brought by redundant code meant to fool or trick the user into thinking the code is doing something which it is not.
Also in general it negates the standard practice of open-source which is what Python loves to do and support.
So to really conclude, if you don't want to read everything above; the first thing you did wrong was choose Python for this, a language that supports open source and is open source as well. Thus to mitigate the issue you should either reconsider the language, or follow the references above to links to modules which might help aide basic source code concealment.
Firstly, as Python is an interpreted language, I think you cannot completely protect your Python code, .pyc files can be uncompiled to get back .py files (using uncompyle6 for example).
So the only thing you can do is make it very hard to read.
I recommend to have a look at code obfuscation, which consists in making your code unreadable by changing variables/function names, removing comments and docstrings, removing useless spaces, etc. Pyminifier does that kind of things.
You can also write your own obfuscation script.
Then you can also turn your program into a single executable (using pyinstaller for example). I am pretty sure there is a way to get .py files back from the executable, but it just makes it harder. Also beware of cross-platform compatibility when making an executable.
Going through above responses, my understanding is that some of the strategies mentioned may not work if your client wants to execute your protected script along with other unprotected scripts.
One other option is to encrypt your script and then use an interpreter that can decrypt and execute it. It too has some limitations.
ipepycrypter is a suite that helps protect python scripts. This is accomplished by hiding script implementation through encryption. The encrypted script is executed by modifed python interpreter. ipepycrypter consists of encryption tool ipepycrypt and python interpreter ipepython.
More information is available at https://ipencrypter.com/user-guides/ipepycrypter/
One other option, of course, is to expose the functionality over the web, so that the user can interact through the browser without ever having access to the actual code.
There are several tools which compile Python code into either (a) compiled modules usable with CPython, or (b) a self-contained executable.
https://cython.org/ is the best known, and probably? oldest, and it only takes a very small amount of effort to prepare a traditional Python package so that it can be compiled with Cython.
http://numba.pydata.org/ and https://pythran.readthedocs.io/ can also be used in this way, to produce Python compiled modules such that the source doesnt need to be distributed, and it will be very difficult to decompile the distributable back into usable source code.
https://mypyc.readthedocs.io is newer player, an offshoot of the mypy toolkit.
Nuitka is the most advanced at creating a self-contained executable. https://github.com/Nuitka/Nuitka/issues/392#issuecomment-833396517 shows that it is very hard to de-compile code once it has passed through Nuitka.
https://github.com/indygreg/PyOxidizer is another tool worth considering, as it creates a self-contained executable of all the needed packages. By default, only basic IP protection is provided, in that the packages inside it are not trivial to inspect. However for someone with a bit of knowledge of the tool, it is trivial to see the packages enclosed within the binary. However it is possible to add custom module loaders, so that the "modules" in the binary can be stored in unintelligible formats.
Finally, there are many Python to C/go/rust/etc transpilers, however these will very likely not be usable except for small subsets of the language (e.g. will 3/0 throw the appropriate exception in the target language?), and likely will only support a very limited subset of the standard library, and are unlikely to support any imports of packages beyond the standard library. One example is https://github.com/py2many/py2many , but a search for "Python transpiler" will give you many to consider.
Consider that I have a package called "A" consisting of several modules and also nested packages. Now, I want to distribute this package to user and I do not want user to see my code at all. I heard that ".pyc" can be de-compiled. So, I am just wondering what could be the other alternatives for this problem.
It would be great if someone gives some ideas in this regard.
You actually have few options. First, you can compile your code into pyc files. However, this can be circumvented with the disassembler library dis, but this requires a lot of technical know-how. You can also use py2exe to package it as an exe file; this converts the pyc file into an exe file. This can still be disassembled but adds an extra layer. You also have a few encryption solutions; for example you can use pyconcrete to encrypt your imports until they are loaded into memory. You can also just encryption the entire application, then ship the decrypter and launcher with it as a C/C++ application (or any other compiled language). Lastly, if you are comfortable with getting python to run custom C/C++ code, you can also put your private code into a DLL or SO and call it directly for the script.
Python is an interpreted language. That means that if you want to distribute pyc files you'll have to have them run on the same OS/architecture as yours or you'll run into subtle problems. That, and the fact that most code can be decompiled to some degree, would urge me to rethink your use case.
Can you rethink your package as a service instead?
I've read the Python documentation chapter explaining how to embed the Python interpreter in a C/C++ application. Also, I've read that you can install Python modules either in a system-wide fashion, or locally to a given user.
But let's suppose my C/C++ application will use some Python modules such as SymPy, Matplotlib, and other related modules. And let's suppose end users of my application won't have any kind of Python installation in their machines.
This means that my application needs to ship with "pseudo-installed" modules, inside its data directories (just like the application has a folder for icons and other resources, it will need to have a directory for Python modules).
Another requirement is that the absolute path of my application installation isn't fixed: the user can "drag" the application bundle to another directory and it will run fine there (it already works this way but that's prior to embedding Python in it, and I wish it continues being this way after embedding Python).
I guess my question could be expressed more concisely as "how can I use Python without installing Python, neither system-wide, nor user-wide?"
There are various ways you could attempt to do this, but none of them are general solutions. From the (docs):
5.5. Embedding Python in C++
It is also possible to embed Python in a C++ program; precisely how this is done will depend on the details of the C++ system used; in general you will need to write the main program in C++, and use the C++ compiler to compile and link your program. There is no need to recompile Python itself using C++.
This is the shortest section in the document, and is roughly equivalent to: 'left as an exercise for the reader`. I do not believe you will find any straight forward solutions.
Use pyinstaller to gather the pieces:
This means that my application needs to ship with "pseudo-installed" modules, inside its data directories (just like the application has a folder for icons and other resources, it will need to have a directory for Python modules).
If I needed to tackle this problem, I would use pyinstaller as a base. (Disclosure: I am an occasional contributer). One of the major functions of pyinstaller is to gather up all of the needed resources for a python program. In onedir mode, all of the things needed to let the program run are gathered into one directory.
You could include this tool into your make system, and have it place all of the needed pieces into your python data directory in your build tree.
Is it possible to deploy python applications such that you don't release the source code and you don't have to be sure the customer has python installed?
I'm thinking maybe there is some installation process that can run a python app from just the .pyc files and a shared library containing the interpreter or something like that?
Basically I'm keen to get the development benefits of a language like Python - high productivity etc. but can't quite see how you could deploy it professionally to a customer where you don't know how there machine is set up and you definitely can't deliver the source.
How do professional software houses developing in python do it (or maybe the answer is that they don't) ?
You protect your source code legally, not technologically. Distributing py files really isn't a big deal. The only technological solution here is not to ship your program (which is really becoming more popular these days, as software is provided over the internet rather than fully installed locally more often.)
If you don't want the user to have to have Python installed but want to run Python programs, you'll have to bundle Python. Your resistance to doing so seems quite odd to me. Java programs have to either bundle or anticipate the JVM's presence. C programs have to either bundle or anticipate libc's presence (usually the latter), etc. There's nothing hacky about using what you need.
Professional Python desktop software bundles Python, either through something like py2exe/cx_Freeze/some in-house thing that does the same thing or through embedding Python (in which case Python comes along as a library rather than an executable). The former approach is usually a lot more powerful and robust.
Yes, it is possible to make installation packages. Look for py2exe, cx_freeze and others.
No, it is not possible to keep the source code completely safe. There are always ways to decompile.
Original source code can trivially be obtained from .pyc files if someone wants to do it. Code obfuscation would make it more difficult to do something with the code.
I am surprised no one mentioned this before now, but Cython seems like a viable solution to this problem. It will take your Python code and transpile it into CPython compatible C code. You also get a small speed boost (~25% last I checked) since it will be compiled to native machine code instead of just Python byte code. You still need to be sure the user has Python installed (either by making it a pre-requisite pushed off onto the user to deal with, or bundling it as part of the installer process). Also, you do need to have at least one small part of your application in pure Python: the hook into the main function.
So you would need something basic like this:
import cython_compiled_module
if __name__ == '__main__':
cython_compiled_module.main()
But this effectively leaks no implementation details. I think using Cython should meet the criteria in the question, but it also introduces the added complexity of compiling in C, which loses some of Python's easy cross-platform nature. Whether that is worth it or not is up to you.
As others stated, even the resulting compiled C code could be decompiled with a little effort, but it is likely much more close to the type of obfuscation you were initially hoping for.
Well, it depends what you want to do. If by "not releasing the source code" you mean "the customer should not be able to access the source code in any way", well, you're fighting a losing battle. Even programs written in C can be reverse engineered, after all. If you're afraid someone will steal from you, make them sign a contract and sue them if there's trouble.
But if you mean "the customer should not care about python files, and not be able to casually access them", you can use a solution like cx_Freeze to turn your Python application into an executable.
Build a web application in python. Then the world can use it via a browser with zero install.