pythonweb和nodejs（Node与Python 双向通信的实现代码）

# 封装的 Python 包， 体积巨大
from mb import MB
# 从数据包中查询
mbe.get('1.0.1.0')

const { spawn } = require('child_process');
const ls = spawn('python3', ['index.py']);

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

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

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

import sys
import fcntl
import select
from mb import MB
import json

mbe = MB('./data')

# epoll 模型
fd = sys.stdin.fileno()
epoll = select.epoll()
epoll.register(fd, select.EPOLLIN)

try:
    while True:
        events = epoll.poll(10) # 同步非阻塞
        data = ''
        for fileno, event in events:
            data += sys.stdin.readline() # 通过标准输入获取数据
            if data == '' or data == '\n':
                continue
            items = xxx # 数处理过程
            for item in items:
                result = mbe.get(item)
                sys.stdout.write(json.dumps(result, ensure_ascii=False) +'\n') # 写入到标准输出
                sys.stdout.flush() # 缓冲区刷新
finally:
    epoll.unregister(fd)
    epoll.close()

const child_process = require('child_process');
const child = child_process.spawn('python3', ['./base.py']);

let callbacks =  [], 
    chunks=Buffer.alloc(0), 
    chunkArr = [], 
    data = '', 
    onwork = false; // buffer 无法动态扩容
    
child.stdout.on('data', (chunk) => {
    chunkArr.push(chunk)
    if (onwork) return;
    onwork = true;
    while(chunkArr.length) {
        chunks = Buffer.concat([chunks, chunkArr.pop()]);
        const length = chunks.length;
        let trunkAt = -1;
        for(const [k, d] of chunks.entries()) {
            if (d == '0x0a') { // 0a 结尾
                data += chunks.slice(trunkAt+1, trunkAt=k);
                const cb = callbacks.shift();
                cb(null, data === 'null' ? null : data )
                data = '';
            }
        }
        if (trunkAt < length) {
            chunks = chunks.slice(trunkAt+1)
        }
    }
    onwork = false;
})

setInterval(() => {
    if (callbacks.length) child.stdin.write(`\n`); // Nodejs端的标准输入输出没有flush方法，只能 hack， 写入后python无法及时获取到最新
}, 500)

exports.getMsg = function getMsg(ip, cb) {
    callbacks.push(cb)
    child.stdin.write(`${ip}\n`); // 把数据写入到子进程的标准输入
}