有Python背景，想要在Node.js应用程序中集成机器学习模型的人:

它使用了child_process核心模块:

const express = require('express')
const app = express()

app.get('/', (req, res) => {

    const { spawn } = require('child_process');
    const pyProg = spawn('python', ['./../pypy.py']);

    pyProg.stdout.on('data', function(data) {

        console.log(data.toString());
        res.write(data);
        res.end('end');
    });
})

app.listen(4000, () => console.log('Application listening on port 4000!'))

它不需要Python脚本中的sys模块。

下面是使用Promise执行任务的更模块化的方式:

const express = require('express')
const app = express()

let runPy = new Promise(function(success, nosuccess) {

    const { spawn } = require('child_process');
    const pyprog = spawn('python', ['./../pypy.py']);

    pyprog.stdout.on('data', function(data) {

        success(data);
    });

    pyprog.stderr.on('data', (data) => {

        nosuccess(data);
    });
});

app.get('/', (req, res) => {

    res.write('welcome\n');

    runPy.then(function(fromRunpy) {
        console.log(fromRunpy.toString());
        res.end(fromRunpy);
    });
})

app.listen(4000, () => console.log('Application listening on port 4000!'))

之前的大多数答案都将承诺的成功称为on(“数据”)，这不是正确的方法，因为如果你收到很多数据，你只会得到第一部分。相反，你必须在end事件上做。

const { spawn } = require('child_process');
const pythonDir = (__dirname + "/../pythonCode/"); // Path of python script folder
const python = pythonDir + "pythonEnv/bin/python"; // Path of the Python interpreter

/** remove warning that you don't care about */
function cleanWarning(error) {
    return error.replace(/Detector is not able to detect the language reliably.\n/g,"");
}

function callPython(scriptName, args) {
    return new Promise(function(success, reject) {
        const script = pythonDir + scriptName;
        const pyArgs = [script, JSON.stringify(args) ]
        const pyprog = spawn(python, pyArgs );
        let result = "";
        let resultError = "";
        pyprog.stdout.on('data', function(data) {
            result += data.toString();
        });

        pyprog.stderr.on('data', (data) => {
            resultError += cleanWarning(data.toString());
        });

        pyprog.stdout.on("end", function(){
            if(resultError == "") {
                success(JSON.parse(result));
            }else{
                console.error(`Python error, you can reproduce the error with: \n${python} ${script} ${pyArgs.join(" ")}`);
                const error = new Error(resultError);
                console.error(error);
                reject(resultError);
            }
        })
   });
}
module.exports.callPython = callPython;

电话:

const pythonCaller = require("../core/pythonCaller");
const result = await pythonCaller.callPython("preprocessorSentiment.py", {"thekeyYouwant": value});

python:

try:
    argu = json.loads(sys.argv[1])
except:
    raise Exception("error while loading argument")

通过extrabacon, Python -shell模块是一种从Node.js运行Python脚本的简单方法，具有基本但有效的进程间通信和更好的错误处理。

安装:

npm: NPM安装python-shell。

或者用纱线: 纱线加蟒壳

运行一个简单的Python脚本:

const PythonShell = require('python-shell').PythonShell;

PythonShell.run('my_script.py', null, function (err) {
  if (err) throw err;
  console.log('finished');
});

运行带有参数和选项的Python脚本:

const PythonShell = require('python-shell').PythonShell;

var options = {
  mode: 'text',
  pythonPath: 'path/to/python',
  pythonOptions: ['-u'],
  scriptPath: 'path/to/my/scripts',
  args: ['value1', 'value2', 'value3']
};

PythonShell.run('my_script.py', options, function (err, results) {
  if (err) 
    throw err;
  // Results is an array consisting of messages collected during execution
  console.log('results: %j', results);
});

要获得完整的文档和源代码，请访问https://github.com/extrabacon/python-shell

/*eslint-env es6*/
/*global require*/
/*global console*/
var express = require('express'); 
var app = express();

// Creates a server which runs on port 3000 and  
// can be accessed through localhost:3000
app.listen(3000, function() { 
    console.log('server running on port 3000'); 
} ) 

app.get('/name', function(req, res) {

    console.log('Running');

    // Use child_process.spawn method from  
    // child_process module and assign it 
    // to variable spawn 
    var spawn = require("child_process").spawn;   
    // Parameters passed in spawn - 
    // 1. type_of_script 
    // 2. list containing Path of the script 
    //    and arguments for the script  

    // E.g : http://localhost:3000/name?firstname=Levente
    var process = spawn('python',['apiTest.py', 
                        req.query.firstname]);

    // Takes stdout data from script which executed 
    // with arguments and send this data to res object
    var output = '';
    process.stdout.on('data', function(data) {

        console.log("Sending Info")
        res.end(data.toString('utf8'));
    });

    console.log(output);
}); 

这对我很管用。必须将python.exe添加到此代码段的路径变量中。另外，确保你的python脚本在你的项目文件夹中。

许多例子都是过时的，并且涉及复杂的设置。您可以尝试JSPyBridge/pythonia(完全披露:我是作者)。它是一种普通的JS，可以让你操作外部Python对象，就好像它们存在于JS中一样。事实上，它实现了互操作性，因此Python代码可以通过回调和传递函数返回调用JS。

numpy + matplotlib的例子，用ES6导入系统:

import { py, python } from 'pythonia'
const np = await python('numpy')
const plot = await python('matplotlib.pyplot')

// Fixing random state for reproducibility
await np.random.seed(19680801)
const [mu, sigma] = [100, 15]
// Inline expression evaluation for operator overloading
const x = await py`${mu} + ${sigma} * ${np.random.randn(10000)}`

// the histogram of the data
const [n, bins, patches] = await plot.hist$(x, 50, { density: true, facecolor: 'g', alpha: 0.75 })
console.log('Distribution', await n) // Always await for all Python access
await plot.show()
python.exit()

通过CommonJS(没有顶级await):

const { py, python } = require('pythonia')
async function main() {
  const np = await python('numpy')
  const plot = await python('matplotlib.pyplot')
  ...
  // the rest of the code
}
main().then(() => python.exit()) // If you don't call this, the process won't quit by itself.

我在节点10和子进程1.0.2上。来自python的数据是一个字节数组，必须进行转换。这是另一个用python发出http请求的快速示例。

node

const process = spawn("python", ["services/request.py", "https://www.google.com"])

return new Promise((resolve, reject) =>{
    process.stdout.on("data", data =>{
        resolve(data.toString()); // <------------ by default converts to utf-8
    })
    process.stderr.on("data", reject)
})

request.py

import urllib.request
import sys

def karl_morrison_is_a_pedant():   
    response = urllib.request.urlopen(sys.argv[1])
    html = response.read()
    print(html)
    sys.stdout.flush()

karl_morrison_is_a_pedant()

p.s.不是一个人为的例子，因为节点的http模块不加载我需要做的一些请求