I'm trying to embed the Python interpreter and need to customize the way the Python standard library is loaded. Our library will be loaded from the same directory as the executable, not from prefix/lib/.
We have been successful in making this work by manually modifying sys.path after calling Py_Initialize(), however, this generates a warning because Py_Initialize is looking for site.py in ./lib/, and it's not present until after Py_Initialize has been called and we have updated sys.path.
The Python c-api docs hint that it's possible to override Py_GetPrefix() and Py_GetPath(), but give no indication of how. Does anyone know how I would go about overriding them?
You could set Py_NoSiteFlag = 1, call PyInitialize and import site.py yourself as needed.
Have you considered using putenv to adjust PYTHONPATH before calling Py_Initialize?
I see it was asked long ago, but I've just hit the same problem. Py_NoSiteFlag will help with the site module, but generally it's better to rewrite Modules/getpath.c; Python docs officially recommend this for “[a]n application that requires total control.” Python does import some modules during initialization (the one that hit me was encodings), so, unless you don't want them or have embedded them too, the module search path has to be ready before you call Py_Initialize().
From what I understand Py_GetPath merely returns module search path; Py_GetProgramFullPath is self-describing; and Py_GetPrefix and Py_GetExecPrefix are not used by anyone, except some mysterious “ILU”.
The following functions can be called before calling Py_Initialize():
Py_SetProgramName()
Py_SetPythonHome()
Py_SetPath()
All of these affect the way Python finds modules. I recommend reading the documentation on these functions and playing around with them.
Related
Currently I am calling an R script from C++ in the following way:
system("PATH C:\\Program Files\\R\\R-3.0.1\\bin\\x64");
system("RScript CommandTest.R");
Where CommandTest.R is my script.
This works, but is slow, since I need a particular package and this method makes the package load on every call.
Is there a way to load the package once and then keep that instance of Rscript open so that I can continue to make calls to it without having to reload the package every time?
PS: I know that the 'better' method is probably to go with Rcpp/Rinside, and I will go down that route if necessary, but I thought it'd be worth asking if there's an easy way to do what I need without it.
It seems like the Rserve package is what you seek. Basically it keeps open a "server" which can be asked to evaluate expressions.
It has options for Java, C++ and communication between one R session and another.
In the documentation, you might want to look at run.Rserve and self.ctrlEval
I'm not aware of a solution to keeping R permanently open, but you can speed up startup by calling R with the --vanilla option. (See Appendix B.1 of Intro to R for more options.)
You could also try accessing the functions using :: to save completely loading the package. (Try profiling to see if that really saves you much time. Is the package load actually the slow part of your analysis?)
I want to embed Python 3.x in our C++ application to allow scripting of maintenance and other tasks. It so far does everything we need including file manipulation.
The problem is that to meet some specifications (like PCI), we aren't allowed to arbitrarily run shell commands such as with subprocess.call or popen.
Is there a way to prevent and similar calls from working in embedded Python?
One option is to remove all the modules that allow running arbitrary shell commands, i.e.: subprocess.py*, os.py*... and include only the modules that the end users are allowed to have immediate access to.
Unless your application is really locked down I don't think you can prevent someone from loading their own python module from an arbitrary directory (with import) so I don't think you can prevent execution of arbitrary code as long as you have python embedded.
I am new to python and wxpython, I am making a automated tool using python and for user interface wxpython and i use shell script.shell script can be called from the python. but now I am facing problem with the spinctrl value. whenever that spinctrl value changes it have to send that value into one txt.exe file which is written in BASH .{ if we run txt.exe file in command line it will ask for number then it will accept that value whenever we press enter}. but i am not able to understand that how to send value from spinctrl to txt.exe whenever i press "ok" button in GUI. please share your thoughts and knowledge.
Thank you
To call an executable in Python, you need to look at Python's subprocess module: http://docs.python.org/2/library/subprocess.html
If your exe doesn't accept arguments, then it won't work. If you created the exe yourself using something like PyInstaller or py2Exe, then you need to make it so your app can accept arguments. The simplest way is using sys.argv, but there are also the optparse and argparse libraries in Python as well.
I do not get a good feeling about your concept. It is hard to say, but I suspect you would benefit from talking with someone experienced about what you are trying to achieve and how it could best be done.
However, to get you started down your current path, I think you should take a look at wxExecute ( http://docs.wxwidgets.org/2.8/wx_processfunctions.html#wxexecute ). This will allow you to run your txt.exe utility from inside your GUI.
wxExecute is a wxWidgets utility. If you are working in python then there will be a more direct way to do this using a python utility - some-one else will have to advise on that. I suggest you edit your question for clarity so a python expert can help you.
I know how I can bind C++ functions to AngelScript, but in my C++ code, how do I load an .as script file? How can I say in my C++ "Execute myscript.as now!" ?
In the AngelScript API I don't find any function like "LoadScript" or "ExecuteScript".
Or do I have to define a path somewhere from where AngelScript loads all scripts and I don't need to tell it the exact files?
Just found it out (in a small side sentence in the docs):
AngelScript doesn't provide a build in file loading. That's why there is no API function. So the manual loading is indeed the only way.
asIScriptModule::AddScriptSection will load a script string. asIScriptContext::Execute will execute a function from a script. The documentation was pretty clear about all of this; you might want to give it a look.
My problem is that I'm having trouble specifying paths for Lua to look in.
For example, in my script I have a require("someScript") line that works perfectly (it is able to use functions from someScript when the script is run standalone.
However, when I run my app, the script fails. I believe this is because Lua is looking in a location relative to the application rather than relative to the script.
Hardcoding the entire path down to the drive isn't an option since people can download the game wherever they like so the highest I can go is the root folder for the game.
We have XML files to load in information on objects. In them, when we specify the script the object uses, we only have to do something like Content/Core/Scripts/someScript.lua where Content is in the same directory as Debug and the app is located inside Debug. If I try putting that (the Content/Core...) in Lua's package.path I get errors when I try to run the script standalone.
I'm really stuck, and am not sure how to solve this. Any help is appreciated. Thanks.
P.S. When I print out the default package.path in the app I see syntax like ;.\?.lua
in a sequence like...
;.\?.lua;c:...(long file path)\Debug\?.lua; I assume the ; means the end of the path, but I have no idea what the .\?.lua means. Any Lua file in the directory?
You can customize the way require loads modules by putting your own loader into the package.loaders table. See here:
http://www.lua.org/manual/5.1/manual.html#pdf-package.loaders
If you want to be sure that things are nicely sandboxed, you'll probably want to remove all the default loaders and replace them with one that does exactly what you want and nothing more. (It will probably be somewhat similar to one of the existing ones, so you can use those as a guide.)