使用 child_process 将函数和参数从节点传递到 python

Question

我是 child_process 的新手，我想试验一下它的功能。

有什么方法可以使用 spawn 将函数和参数传递给 python 文件（或者 exec 或 execFile 是 spawn 无法做到的）？

我想做一些类似（伪代码）的事情

spawnORexecORexefile (python path/to/python/file function [argument1, argument2] ) 

或许

spawnORexecORexefile (python path/to/python/file function(argument1, argument2) ) 

请解释一下，也许可以举个例子，因为我是新手

我现在怎么样了？

在节点中

 var process = spawn('python', [path/to/pythonFile.py, 50, 60] );  

在pythonFile.py

import sys 
import awesomeFile

hoodie = int(sys.argv[1])
shoe = int(sys.argv[2])

awesomeFile.doYourMagic().anotherThing(hoodie, shoe)

如你所见，我从节点发送数据到pythonFile，然后到awesomeFile，发送到特定函数

我想“切断中间人”并删除pythonFile并将数据从节点直接发送到awesomeFile文件，发送到特定函数。这就是我问的原因

谢谢

Answer 1

您可以使用python -c 'import foo; print foo.hello()'（来自https://stackoverflow.com/a/3987113/5666087）的形式从命令行运行特定的Python函数。

将以下两个文件放在同一目录中，并使用node index.js 运行。您应该会看到以下输出：

Hoodie: 10
Shoe: 15

awesomeFile.py

def myfunc(hoodie, shoe):
    hoodie = int(hoodie)
    shoe = int(shoe)
    print("Hoodie:", hoodie)
    print("Shoe:", shoe)

index.js

const { spawn } = require('child_process');
let hoodie = 10,
    shoe = 15;
const result = spawn("python",
    ["-c", `import awesomeFile; awesomeFile.myfunc(${hoodie}, ${shoe})`])
result.stdout.pipe(process.stdout)

Answer 2

您可以将要调用的所有相关函数分组到类中，并从映射到类函数的类中创建一个字典。您可以直接调用awesome.py 而无需中间的index.py。你可以用你的方法扩展类AwesomeFile

以下程序将接受用户输入 -

1. 运行哪个 python 文件
2. 运行哪个方法
3. 方法参数
4. 参数数量不匹配
5. 如果给出未知方法怎么办

awesomeFile.py

import sys

class AwesomeFile:

    def __init__(self):
        pass

    def doYourMagic(self):
        return self
    
    def anotherThing(self, hoodie, shoe):
        print(int(hoodie))
        print(int(shoe))

awesomeFile = AwesomeFile()
methods = {m:getattr(awesomeFile, m) for m in dir(AwesomeFile) if not m.startswith('__')}

def run():
    method_name = sys.argv[1]
    if method_name not in methods:
        print(f"Unknown Method {method_name}")
        return
    methodArgCount = methods[method_name].__code__.co_argcount
    if methodArgCount - 1 != len(sys.argv[2:]):
        print(f"Method {method_name} takes {methodArgCount - 1} arguments but you have given {len(sys.argv[2:])}")
        return
    
    methods[method_name](*sys.argv[2:])

if __name__ == "__main__":
    run()

index.js

注意** - 您将安装 prompt - npm i prompt

'use strict';
var prompt = require('prompt');
const { spawn } = require( 'child_process' );

var prompt_attributes = [
    {        
        name: 'pythonFilePath'
    },
    {   
        name: 'cmdLineArgs'
    }
];

prompt.start();

prompt.get(prompt_attributes, function (err, result) {
    if (err) {
        console.log(err);
        return 1;
    }else {
        console.log('Command-line received data:');
        var filePath = result.pythonFilePath;
        var cmdLineArgs = result.cmdLineArgs;
        var args = cmdLineArgs.split(" ");
        args.unshift(filePath);
        
        const pythonProgram = spawn( 'python' , args);

        pythonProgram.stdout.on( 'data', data => {
            console.log( `stdout:\n\n ${data}` );
        } );

        pythonProgram.stderr.on( 'data', data => {
            console.log( `stderr: ${data.data}` );
        } );

        pythonProgram.on( 'close', code => {
            console.log( `child process exited with code ${code}` );
        } );
    
    }
});

运行程序 -

I/O:

参数不匹配 -

prompt: Python File Path. Give absolute or relative path: ../python_files/awesomeFile.py # python file can be any location in the system
prompt: Command Line Arguments. Format = func_name arguments_list (Ex addFunc 1 2):  anotherThing 1
Command-line received data:
stdout:

 Method anotherThing takes 2 arguments but you have given 1

child process exited with code 0

未找到函数

prompt: Python File Path. Give absolute or relative path:  ../python_files/awesomeFile.py
prompt: Command Line Arguments. Format = func_name arguments_list (Ex addFunc 1 2):  helloworld 1 2
Command-line received data:
stdout:

 Unknown Method helloworld

child process exited with code 0

成功案例：

prompt: Python File Path. Give absolute or relative path:  ../python_files/awesomeFile.py
prompt: Command Line Arguments. Format = func_name arguments_list (Ex addFunc 1 2):  anotherThing 50 60
Command-line received data:
stdout:

 50
60

child process exited with code 0