将 Python 脚本连接到 Nodejs

Question

Complete new to Node.js. Recently I was provided with a task to web scrape a website with python and connect the python script to Node.js using python-shell package in Node.js. I'm done with the scraping part but not having any prior knowledge of Node.js. Can you please guide me on how to approach this problem?

Answer 1

Since you must use python-shell package and assuming that your source file is my_file.py , you can simply read the documentation of the npm package and in particular this example:

import {PythonShell} from 'python-shell';
let pyshell = new PythonShell('my_script.py'); // 1
 
pyshell.on('message', function (message) {
  // received a message sent from the Python script (a simple "print" statement)
  console.log(message); // here there will be logged your pyoutput
}); // 2
 
// end the input stream and allow the process to exit
pyshell.end(function (err,code,signal) {
  if (err) throw err;
  console.log('The exit code was: ' + code);
  console.log('The exit signal was: ' + signal);
  console.log('finished');
  console.log('finished');
}); // 3

What this script does:

1. launches the python script without arguments
2. gets every write on the stdoutput of your pyscript and logs it into nodejs stdout.
3. closes the python script reporting some optional info

If your scripts logs the webscrape into the stdout this should work fine.

Answer 2

import sys 
# Takes first name and last name via command 
# line arguments and then display them 
print("Output from Python") 
print("First name: " + sys.argv[1]) 
print("Last name: " + sys.argv[2]) 

# save the script as hello.py 

// import express JS module into app 
// and creates its variable. 
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'); 
} ) 

// Function callName() is executed whenever 
// url is of the form localhost:3000/name 
app.get('/name', callName); 

function callName(req, res) { 

    // 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=Mike&lastname=Will 
    // so, first name = Mike and last name = Will 
    var process = spawn('python',["./hello.py", 
                            req.query.firstname, 
                        req.query.lastname] ); 

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

// save code as start.js

After saving the Python script and server script code, run the code from its source folder by following command :

node start.js

Access the application through link :

localhost:3000/name?firstname="Enter first name"&lastname="Enter last name"

For e g. : localhost:3000/name?firstname=Ram&lastname=Sharma