如何从NodeJs调用python脚本 [英] How to call python script from NodeJs

问题描述

我需要在NodeJs中调用这个python脚本。

I need to call this python script in NodeJs.

Read.py

#!/usr/bin/env python
# -*- coding: utf8 -*-

import RPi.GPIO as GPIO
import MFRC522
import signal

continue_reading = True

# Capture SIGINT for cleanup when the script is aborted
def end_read(signal,frame):
    global continue_reading
    print "Ctrl+C captured, ending read."
    continue_reading = False
    GPIO.cleanup()

# Hook the SIGINT
signal.signal(signal.SIGINT, end_read)

# Create an object of the class MFRC522
MIFAREReader = MFRC522.MFRC522()

# Welcome message
print "Welcome to the MFRC522 data read example"
print "Press Ctrl-C to stop."

# This loop keeps checking for chips. If one is near it will get the UID and authenticate
while continue_reading:

    # Scan for cards    
    (status,TagType) = MIFAREReader.MFRC522_Request(MIFAREReader.PICC_REQIDL)

    # If a card is found
    if status == MIFAREReader.MI_OK:
    # Get the UID of the card
    (status,uid) = MIFAREReader.MFRC522_Anticoll()

    # If we have the UID, continue
    if status == MIFAREReader.MI_OK:

        # Print UID
        print "Card read UID: "+str(uid[0])+","+str(uid[1])+","+str(uid[2])+","+str(uid[3])

        # This is the default key for authentication
        key = [0xFF,0xFF,0xFF,0xFF,0xFF,0xFF]

        # Select the scanned tag
        MIFAREReader.MFRC522_SelectTag(uid)

        # Authenticate
        status = MIFAREReader.MFRC522_Auth(MIFAREReader.PICC_AUTHENT1A, 8, key, uid)

        # Check if authenticated
        if status == MIFAREReader.MI_OK:
            MIFAREReader.MFRC522_Read(8)
            MIFAREReader.MFRC522_StopCrypto1()
        else:
            print "Authentication error"

我使用了python-shell，这里是NodeJs的代码

I used python-shell, here is the NodeJs code for that

Test.js

var PythonShell = require('python-shell');

var options = {
scriptPath: '/home/pi/gpio-admin/MFRC522-python/'
};
var pyshell = new PythonShell('Read.py',options);


pyshell.on('message', function (message) {

    console.log(message);
});

但是当我运行此代码时，我在Node端没有看到任何内容。我认为当python脚本达到这个级别时会出现问题。

But when I ran this code I didn't see anything in Node side. I think problem occurs when python script comes to this level.

   (status,TagType) = MIFAREReader.MFRC522_Request(MIFAREReader.PICC_REQIDL)

因为我刚用while循环运行，只有print语句然后才有效。之后我尝试了另一种方法来实现这一目标。但是我遇到了与上面相同的问题。这是另一种方法

Because I just ran with while loop which has only print statement then it works. After that I tried another way to achieve this. But I got same problem which I have with above.Here is another method

AltTest.js

var python = require('child_process').spawn(
 'python',
 // second argument is array of parameters, e.g.:
 ["/home/pi/gpio-admin/MFRC522-python/Read.py"]
 );
 var output = "";
 python.stdout.on('data', function(){ 

    output += data ;
    console.log(data);
});
 python.on('close', function(code){ 

   console.log("Here you are there...");
 });

任何帮助将不胜感激

推荐答案

有多种方法可以做到这一点。

There are multiple ways of doing this.

• 第一种方法是做 npm install python-shell

• first way is by doing npm install python-shell

这里是代码

var PythonShell = require('python-shell');
//you can use error handling to see if there are any errors
PythonShell.run('my_script.py', options, function (err, results) { 
//your code

你可以使用
pyshell.send向python shell发送消息（'你好'）;

你可以在这里找到API参考 -
https://github.com/extrabacon/python-shell

you can find the API reference here- https://github.com/extrabacon/python-shell

• 第二种方式 - 你可以参考的另一个包是node python，你必须要做 npm install node-python

第三种方式 - 你可以参考这个问题，在那里你可以找到一个使用子进程的例子 -
如何从node.js调用外部脚本/程序

third way - you can refer to this question where you can find an example of using a child process- How to invoke external scripts/programs from node.js

更多参考文献 -
https://www.npmjs.com/package/python

a few more references - https://www.npmjs.com/package/python

如果你想使用面向服务的架构 -
http://ianhinsdale.com/ code / 2013/12/08 / nodes-between-nodejs-and-python /

if you want to use service-oriented architecture - http://ianhinsdale.com/code/2013/12/08/communicating-between-nodejs-and-python/

这篇关于如何从NodeJs调用python脚本的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！