如何在运行的python代码和nodejs之间进行通信 [英] How can I communicate between running python code and nodejs

问题描述

我想运行一些python代码并与nodejs express服务器通信.到目前为止，我可以使我的nodejs服务器通过两种机制之一调用python函数，以生成python任务或使其与zerorpc python服务器通信.

I'd like to have some python code running and communicating with a nodejs express server. So far, I can get my nodejs server to call python functions via one of two mechanisms, either to spawn a python task or to have it talk to a zerorpc python server.

首先， http://www .sohamkamani.com/blog/2015/08/21/python-nodejs-comm/，这有效:

var express = require( "express" );
var http = require( "http" );
var app = express();
var server = http.createServer( app ).listen( 3000 );
var io = require( "socket.io" )( server );

app.use( express.static( "./public" ) );

io.on( "connection", function( socket ) {

    // Repeat interval is in milliseconds
    setInterval( function() {

        var spawn = require( 'child_process' ).spawn,
        py    = spawn( 'python', [ 'mytime.py' ] ),
        message = '';

        py.stdout.on( 'data', function( data ) {
            message += data.toString();
        });

        py.stdout.on( 'end', function() {
            socket.emit( "message", message );
        });

    }, 50 );
});

mytime.py在哪里

Where mytime.py is

from datetime import datetime
import sys

def main():
    now = datetime.now()
    sys.stdout.write( now.strftime( "%-d %b %Y %H:%M:%S.%f" ) )

并使用zerorpc http://www.zerorpc.io/，如果此python代码正在运行:

And with zerorpc http://www.zerorpc.io/, if this python code is running:

from datetime import datetime
import sys
import zerorpc

class MyTime( object ):
    def gettime( self ):
        now = datetime.now()
        return now.strftime( "%-d %b %Y %H:%M:%S.%f" )

s = zerorpc.Server( MyTime() )
s.bind( "tcp://0.0.0.0:4242" )
s.run()

此nodejs代码有效:

This nodejs code works:

var express = require( "express" );
var http = require( "http" );
var app = express();
var server = http.createServer( app ).listen( 3000 );
var io = require( "socket.io" )( server );
var zerorpc = require( "zerorpc" );
var client = new zerorpc.Client();
client.connect( "tcp://127.0.0.1:4242" );

app.use( express.static( "./public" ) );

io.on( "connection", function( socket ) {

    // Repeat interval is in milliseconds
    setInterval( function() {

        client.invoke( "gettime", function( error, res, more ) {
            socket.emit( "message", res.toString( 'utf8' ) );
        } );

    }, 50 );
});

但是我想做的是，不仅仅是调用python函数，我还想运行一个单独的python进程，并将消息发送到nodejs服务器，该服务器监听并处理它们.我已经尝试过使用中间件socketio-wildcard，但是如果我尝试在与nodejs express服务器相同的端口上设置带有Zerorpc的python服务器，则会给出 zmq.error.ZMQError:地址已在使用错误.

But what I'd like to be able to do is instead of just having python functions called, I'd like a separate python process running and sending messages to the nodejs server which listens for them and then handles them. I've experimented with middleware socketio-wildcard, but if I try to set up a python server with zerorpc on the same port as the nodejs express server, it gives a zmq.error.ZMQError: Address already in use error.

我知道我没有考虑这个权利-我知道由于我的天赋，我在进程间通信方面缺少一些逻辑-所以如果有更好的方法来从python进程发送消息在nodejs服务器监听的情况下，我无所适从.

I know that I'm not thinking about this right--I know that I'm missing some logic around interprocess communication due to my naïveté here--so if there is a better way to do message sending from a python process with a nodejs server listening, I'm all ears.

有什么想法吗?

非常感谢！

推荐答案

对于那些试图弄清楚这一点的人，这里是

For those trying to figure this out, here's a solution thanks to Zeke Alexandre Nierenberg

对于node.js服务器代码:

For the node.js server code:

var express = require( "express" );
var app = express();
var http = require( "http" );
app.use( express.static( "./public" ) ); // where the web page code goes
var http_server = http.createServer( app ).listen( 3000 );
var http_io = require( "socket.io" )( http_server );

http_io.on( "connection", function( httpsocket ) {
    httpsocket.on( 'python-message', function( fromPython ) {
        httpsocket.broadcast.emit( 'message', fromPython );
    });
});

以及向其发送消息的python代码:

and the python code that sends it messages:

from datetime import datetime
from socketIO_client import SocketIO, LoggingNamespace
import sys

while True:
    with SocketIO( 'localhost', 3000, LoggingNamespace ) as socketIO:
        now = datetime.now()
        socketIO.emit( 'python-message', now.strftime( "%-d %b %Y %H:%M:%S.%f" ) )
        socketIO.wait( seconds=1 )

Voilà！

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