How to integrate a python library into a Ruby on Rails application - python

I want to know if there is a way to integrate a library written in Python into my Rails application. I have always used gems to implement outside libraries so I have no idea how to do this(yet).
Is it possible to use this Python library?

This is mostly what you want:
Calling Python from Ruby
I've looked into this question before and, excepting the Heroku deploy, the answer was "easily! check this out". (On a fun note, there's a gem to let you embed Perl code in a Ruby file)
However, while I can't seem to find it right now, I remember reading that deploying both to Heroku required a custom buildpac, since one won't normally include the binaries necessary for the other.

Related

How can I wrap Python processes in an OSGi deployment

I need to integrate a body of Python code into an existing OSGi (Apache Felix) deployment.
I assume, or at least hope, that packages exist to help with this effort.
If it helps, the Python code is still relatively new and small, so can probably re re-architected to meet whatever constraints are needed. However, it must remain in Python, because of dependencies on third-party libraries.
What are suggested best practices?
The trick is to make this an extender, see 1 and 2. You want your Python code to be separate from the code that handles the interaction with the interpreter. So what you do is wrap the Python code and any native libraries in a bundle. This is trivial since it is just a zip file.
You then develop a bundle that listens to starting bundle (see the BundleTracker) that have python code. A manifest is often used but you can also look in a directory in the JAR. If you detect this code, you extract any native libraries and run the code in the interpeter of your choice.
If can use JYthon then that would be highly recommended. You can then carry the interpreter as an OSGi bundle that runs on the VM. If you need to use a native compiler your life is less rosy. You can rely on the environment to provide you with an interpreter but then why use OSGi in the first place. You basically lose the write once run anywhere advantage. You could go the full monty by creating bundles that contain Python installers for all platforms you support. Can be done, not even that hard, but a maintenance nightmare. Believe me, native code suck, it only does it a bit faster than Java.

Python and Django Source Code Navigation in Emacs

I am wondering if there is a way to to navigate Python(Django) code in Emacs similar to how one can M-. for Common Lisp code when using SLIME.
I have installed ELPY and a mode called python-django. However, they do not seem to provide this functionality.
I am particularly interested in doing this why developing using Django. However, even navigation for standalone Python projects would be nice.
I will give dumb-jump a chance.
It is not as fancy as other go-to-definition methods, as it only searchs for some predefined regex in your project. But it simply works most of the time, and you can add your own regex if you need them.

Execution permissions in Python

I need to send code to remote clients to be executed in them but security is a concern for me right now. I don't want unsafe code to be executed there so I would like to control what a program is doing. I mean for example, know if is making connections, where is connecting to, if is reading local files, etc. Is this possible with Python?
EDIT: I'm thinking in something similar to Android permission system. I want to know what a code will do and if it does something different, stop it.
You could use a different Python runtime:
if you run your script using Jython; you can exploit Java's permission system
with Pypy's sandboxed version you can choose what is allowed to run in your controller script
There used to be a module in Python called bastian, but that was deprecated as it wasn't that secure. There's also I believe something called RPython, but I don't know too much about that.
I would in this case use Pyro and write the code on the target server. That way you know clients can only execute written and tested code.
edit - it's probably worth noting that Pyro also supports http://en.wikipedia.org/wiki/Privilege_separation - although I've not had to use it for that.
I think you are looking for a sandboxed python. There used to be an effort to implement this, but it has been abolished a couple of years ago.
Sandboxed python in the python wiki offers a nice overview of possible options for your usecase.
The most rigourous (but probably the slowest) way is to run Python on a bare OS in an emulator.
Depending on the OS you use, there are several ways of running programs with restrictions, but without the overhead of an emulator:
FreeBSD has a nice integrated solution in the form of jails.
These grew out of the chroot system call.
Linux-VServer aims to do more or less the same on Linux.

Would it be possible to integrate Python or Perl with Ruby?

Would it be possible to integrate Python (and/or Perl) and Ruby? I've looked at http://www.goto.info.waseda.ac.jp/~fukusima/ruby/python/doc/ and http://code.google.com/p/ruby-perl/ , but they both seem rather outdated.
Has someone generated a Ruby interface for Python's C API?
Edit: Python can be integrated with many other languages according to http://wiki.python.org/moin/IntegratingPythonWithOtherLanguages . However, that list doesn't include Ruby.
My school (Georgia Tech), along with Bryn Mawr and Microsoft Research, are doing a project right now called Pyjama. Basically, it uses the Microsoft DLR to allow you to freely mix Python and Ruby. I haven't tried it, but it sounds pretty cool.
Here's an example from the website. You enter the class in "Python mode". Then it gets compiled, and you run the command in "Ruby mode".
class PythonClass:
def hello(self, value):
print "Python says hello to", value
pc = python_class().new
pc.hello "Ruby"
Which produces "Python says hello to Ruby".
Integrating dynamic languages is one of the goals of the Parrot project. It's a virtual machine that dynamic language compilers target. Once compiled to the same virtual machine, you should be able to used the "object" form in any of the languages no matter the object's source.
The issue at the moment, however, is stabilizing the virtual machine and finishing off the mostly done compilers. However, that's been the state for a long time. :)
You can write extensions for Ruby in C.
So, if Python has a C API, you can write a C extension for Ruby which uses this API.
I know nothing about the Python API or how large of a piece you want to integrate with, but if it is not too big, this could (possibly) give you a way to run Python code from Ruby.
For a research project I wanted to use the fabulous matplotlib that's available for Python. I also found that library that you referred to. However, it doesn't look like something popular and well tested. So I decided to write the script that generated graphs using pure Python and called it from Ruby via popen. That worked very well for me.
It might by possible, but not very practical. It would be significantly easier to port whatever modules you need from one to the other than it would be to embed one of the interpreters within the other.
If you absolutely have to use both languages in a project, your best option would probably the combination of Jython and Jruby, or IronPython and IronRuby. I'm not sure if you could get them to talk to each other, but at the very least you could host them on the same virtual machine.
Another strategy, as used by Facebook, is to expose APIs via Thrift. You define lightweight service APIs and the RPCs are inter-process.

How can I run Python code on a windows system?

I am used to using PHP and it is easy to set up, I can just run an exe package like Xampp and have apache and PHP running in 5 minutes on my windows system. Is there something similar to Python?
Unlike PHP, Python's primary purpose is a general-purpose tool for running on the desktop/server, not necessarily as a web application. It has bindings to many powerful GUI toolkits (Qt and wx are two examples of free and popular toolkits that work great on Windows), and so on. Therefore you just download it (either from python.org or from activestate), install it, and run it. That's it.
That said, Python is actually great for web apps too. See the Django tutorial for running a simple web-app on your PC in just a few minutes. Python actually comes with a simple web-server built-in, and it supports SQLite out of the box as well, so you can have a fully functional DB-backed web-application running without actually installing anything else. Naturally, if you need to use tools like MySQL and Apache, these are easy to connect to Python on the desktop too. Just start with that Django tutorial and everything will be clear.
Yes, you can find python from http://python.org
and If you like to make executable files from .py source file you may use py2exe
You don't say in your question what you are going to use Python for, so most answers above are completely correct in pointing out that you install Python by downloading it from Python.org. But you seem to expect more. Is it correct to assume you are going to use it to do web development?
In that case, prepare for a shock, because Python doesn't do things like PHP does at all. You want to use a web framework. There are loads of them for Python. Which on to use depends both on what you are going to do, and your personal taste.
The only "Download as one file and install to run" web system I know of that's based on Python is Plone. And Plone is great, but it's not a webframework, it's a content management system. But hey, maybe that's what you want? :-)
The other frameworks are usually easy to install as well.
(In the long run: If you are going to do web development, you'll be happier with something Unix based. Just saying.)
Download python installer and run python.
Nope no easy way out for you yet, Python is obviously not popular enough in Web dev. You should install mod_python and django. There are some nice step here.
Here's my opinionated answer:
Download and install ActivePython
Open Command Prompt and type pypm install django
Follow the Django tutorial
Note that Django does not necessarily require a webserver like Apache, as it already includes one for development purposes. Nor do you necessarily have to install MySQL as Python already includes SQLite which is supported by Django.

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