cpython v0.10.1

node-cpython

Native bindings to run python in its native interpreter.

This Library is in rc status. Do only use if you know what you do

TL;DR

Sometimes you want to use Python scripts or even whole libraries, but you don't want to rely on child_process.exec() or child_process.spawn(). This module initializes the standard Python interpreter and passes Py code to it.

Implementation Status

Introduction

The following shall give background information and explain why you want to use this.

Motivation

In order to compile C code with Emscripten you'd have to run the Python script, which utilizes LLVM. However working with child_process.exec() or chold_process.spawn() seems odd, since it neither safe nor does it handle errors nor is it platform independent. So in order to run scripts programmatically it seemed a good idea to use the the perfect legit Python.h C-header in the standard implementation of Python.

Overview

Technical Overview

Rquirements:

• Node 4.0.0+

Platform

This module is currently tested on:

Roadmap

Please see list of the implemented methods for now.

API

Ncpy

Kind: global class

• Ncpy
  • new Ncpy()
  • .init(options) ⇒ Object
  • .repl()
  • .run(glob, Argv, [cb])
  • .runSync(glob, Argv, [cb])
  • .runString(string)
  • .simpleString(str, [flags], [cb])
  • .ffi(file, functionname) ⇒ Callback
  • .eval()
  • .initialize()
  • .isInitialized() ⇒ Boolean
  • .finalize(callback)
  • .isFinalized() ⇒ Boolean
  • .setProgramName(Program)
  • .setArgv(string)

new Ncpy()

Implements the Ncpy Python interpreter

ncpy.init(options) ⇒ Object

intitialze this module from init function rather than over constructor

Kind: instance method of Ncpy
Returns: Object - returns itself is chainable

Example

const ncpy = require('node-cpython')

let options = {
	\/\* Options go in here \*\/
}

ncpy.init(options)
\/\/ available options [here](https://github.com/eljefedelrodeodeljefe/node-cpython#options)

ncpy.repl()

Starts a Python contexts, runs a newline delimited string of python from Node's stdin, listens for SIGINT and finalizes the Python context.

Kind: instance method of Ncpy

ncpy.run(glob, Argv, cb)

Executes any number of Python source code files. This is JS userland API and automates and abstracts many choices of the below C-API. If you want to have more control, please use the below methods.

Kind: instance method of Ncpy

Example

'use strict'
const ncpy = require('node-cpython')

ncpy.on('error', function(err) {console.log(err)})

ncpy.run('[example/**\/*.py',[2, 10, 'someOtherArg'], function(err) {
	console.log(err)
})

ncpy.runSync(glob, Argv, cb)

Kind: instance method of Ncpy

ncpy.runString(string)

Exuute a line of Python script

Kind: instance method of Ncpy

ncpy.simpleString(str, flags, cb)

Executes the Python source code from command. See also Python docs for Reference

Kind: instance method of Ncpy

Example

'use strict'
const ncpy = require('node-cpython')

cpython.on('error', function(err) {console.log(err)})

cpython.simpleString('from time import time,ctime\nprint 'Today is',ctime(time())\n')

ncpy.ffi(file, functionname) ⇒ Callback

The ffi method serves as entry point for generally executing Python functions from .py-files. Important to note is, that is branching in two modes, depending how many arguments get passed. If there are arguments it makes a singular call to the script, you open and close a whole Python memory contexts for it.

Second, when called in a chain with the stream API (see below). The context get's created and only closed on stream end.

Use it accourdingly:

Kind: instance method of Ncpy
Returns: Callback - Tailcall with err and res

Example

const ncpy = require('node-cpython')

ncpy.ffi('multiplication.py', 'multiply', [ 20, 5], function (err, res) {
  console.log('ncpy -> easy call to multiply, here');
  console.log('ncpy -> ' + res + '\n');
})
	var Readable = require('stream').Readable;
var SomeStream = new Readable({ "objectMode": true })

SomeStream.push([1,2])
SomeStream.push([20,3])
SomeStream.push([3,40])
SomeStream.push([4,50])
SomeStream.push([55,66])
SomeStream.push(null)
ncpy.ffi
  // load the python script and intitialize the python interpreter
  .require('multiplication.py', { path: './examples' })
  // this expects a stream (in { objectMode: true })
  .init(SomeStream)
  // Tell `ncpy` what function to excute.
  .run('multiply')
  // add your own transform or any other stream here
  .pipe()
  .on('end', function() {
    console.log('ncpy -> Ending python context here.');
  })

ncpy.eval()

Kind: instance method of Ncpy

ncpy.initialize()

initialize python context, reserve memory.

Kind: instance method of Ncpy

ncpy.isInitialized() ⇒ Boolean

is-check for the interpreter not running

Kind: instance method of Ncpy
Returns: Boolean - returns true if Py_isInitialized is ecplictely not 0

ncpy.finalize(callback)

Finalize python context, clear memory.

Kind: instance method of Ncpy

ncpy.isFinalized() ⇒ Boolean

is-check for the interpreter not running

Kind: instance method of Ncpy
Returns: Boolean - return true if Py_isInitialized explictely is 0

ncpy.setProgramName(Program)

set low level python program name (optional)

Kind: instance method of Ncpy

ncpy.setArgv(string)

set low level python argv

Kind: instance method of Ncpy

License

MIT