Flask socketio不倾听事件

Question

我正在利用flask socketio构建一个flask应用程序。我在Ubuntu 20.04上本地运行它，在localhost:8000上运行gunicorn和eventlet。

我的服务器端测试代码如下所示：

$(document).ready(function() {
    // const socketGame = io(window.location.hostname + "/coin")
    var socket = io.connect('http://127.0.0.1:8000');

    socket.on('connect', function() {
        console.log("ok");
        socket.send('User has connected!');
    });

    socket.on('message', function(msg) {
        console.log('Received message');
    });

});

在我的服务器中，我有以下侦听器：

import re

from flask import render_template, request, redirect, url_for, jsonify, current_app
from flask_mail import Mail, Message
from flask_socketio import emit, join_room, leave_room, rooms
from flask_login import LoginManager, UserMixin, login_user, login_required, current_user, logout_user
from werkzeug.security import generate_password_hash, check_password_hash

from .. import socketio
from . import games_blueprint
from app.models import *
from app.utilities import sanitizeHtml

#socketio chat server
#need to create event for admin broadcasting messages
@socketio.on('message', namespace='/')
def handleMessage(msg):
    print('Message: ' + msg)
    send(msg, broadcast=True)

它只需在终端中打印来自客户端的消息并广播回消息。但是，从gunicorn日志来看，服务器似乎正在从客户端接收事件，而不是将其传递给侦听器：

(vegazbetenv) jveiga@LAPTOP-C6PJKMM6:~/vegazbet$ gunicorn --worker-class eventlet -w 1 wsgi:application
[2021-11-24 21:00:59 -0300] [134633] [INFO] Starting gunicorn 20.1.0
[2021-11-24 21:00:59 -0300] [134633] [INFO] Listening at: http://127.0.0.1:8000 (134633)
[2021-11-24 21:00:59 -0300] [134633] [INFO] Using worker: eventlet
[2021-11-24 21:00:59 -0300] [134635] [INFO] Booting worker with pid: 134635
Server initialized for eventlet.
Server initialized for eventlet.
Server initialized for eventlet.
HYYx0QNgrNr7YodDAAAA: Sending packet OPEN data {'sid': 'HYYx0QNgrNr7YodDAAAA', 'upgrades': ['websocket'], 'pingTimeout': 20000, 'pingInterval': 25000}
HYYx0QNgrNr7YodDAAAA: Received packet MESSAGE data 0
HYYx0QNgrNr7YodDAAAA: Sending packet MESSAGE data 0{"sid":"q1NjSbTlPRYmT_TYAAAB"}
HYYx0QNgrNr7YodDAAAA: Received request to upgrade to websocket
HYYx0QNgrNr7YodDAAAA: Received packet MESSAGE data 2["message","User has connected!"]
received event "message" from q1NjSbTlPRYmT_TYAAAB [/]
HYYx0QNgrNr7YodDAAAA: Upgrade to websocket successful
HYYx0QNgrNr7YodDAAAA: Sending packet PING data None
HYYx0QNgrNr7YodDAAAA: Received packet PONG data 

从日志中可以看出，websocket连接已成功升级，并且ocock-io服务器接收到来自客户端的消息，它只是没有将其传递给应该侦听事件的函数。

为了澄清一下，我正在使用应用程序工厂模式运行flask，侦听器代码在蓝图视图中。py文件，遵循我的app factory代码和蓝图：

app/__init__.py

import os

from flask import Flask, jsonify, render_template, request, redirect, url_for
from flask_login import LoginManager, UserMixin, login_user, login_required, current_user, logout_user
from flask_mail import Mail
from flask_socketio import SocketIO
from flask_mongoengine import MongoEngine
from flask_wtf.csrf import CSRFProtect
from celery import Celery


from config import Config
from app.models import *
from config import *


### Flask extension objects instantiation ###
mail = Mail()
csrf = CSRFProtect()
login_manager = LoginManager()
# socketio = SocketIO(engineio_logger=True, logger=True, message_queue=os.getenv('CELERY_BROKER_URL'), cors_allowed_origins="*")
socketio = SocketIO(engineio_logger=True, logger=True, cors_allowed_origins="*")

### Celery instantiation ###
celery = Celery(__name__, broker=Config.CELERY_BROKER_URL, result_backend=Config.RESULT_BACKEND)


### Application Factory ###
def create_app():

    app = Flask(__name__)

    # Configure the flask app instance
    CONFIG_TYPE = os.getenv('CONFIG_TYPE', default='config.DevelopmentConfig')
    app.config.from_object(CONFIG_TYPE)

    #Configure celery
    celery.conf.update(app.config)

    # Initialize flask extension objects
    initialize_extensions(app)

    # Register blueprints
    register_blueprints(app)

    #setup db integration
    configure_db(app)

    # Configure logging
    configure_logging(app)

    # Register error handlers
    register_error_handlers(app)

    #setup db for flask-login
    @login_manager.user_loader
    def load_user(user_id):
        user = User.objects(id=user_id)[0]
        return user

    return app


### Helper Functions ###
def register_blueprints(app):
    from app.auth import auth_blueprint
    from app.main import main_blueprint
    from app.games import games_blueprint
    from app.admin import admin_blueprint

    app.register_blueprint(auth_blueprint, url_prefix='/users')
    app.register_blueprint(main_blueprint)
    app.register_blueprint(games_blueprint, url_prefix='/games')
    app.register_blueprint(admin_blueprint, url_prefix='/admin')

def initialize_extensions(app):
    mail.init_app(app)
    login_manager.init_app(app)
    csrf.init_app(app)
    socketio.init_app(app)

def register_error_handlers(app):

    # 400 - Bad Request
    @app.errorhandler(400)
    def bad_request(e):
        return render_template('400.html'), 400

    # 401 - Unauthorized
    @app.errorhandler(401)
    def bad_request(e):
        return render_template('401.html'), 401

    # 403 - Forbidden
    @app.errorhandler(403)
    def forbidden(e):
        return render_template('403.html'), 403

    # 404 - Page Not Found
    @app.errorhandler(404)
    def page_not_found(e):
        return render_template('404.html'), 404

    # 405 - Method Not Allowed
    @app.errorhandler(405)
    def method_not_allowed(e):
        return render_template('405.html'), 405

    # 500 - Internal Server Error
    @app.errorhandler(500)
    def server_error(e):
        return render_template('500.html'), 500

def configure_logging(app):
    import logging
    from flask.logging import default_handler
    from logging.handlers import RotatingFileHandler

    # Deactivate the default flask logger so that log messages don't get duplicated
    app.logger.removeHandler(default_handler)

    # Create a file handler object
    file_handler = RotatingFileHandler('flaskapp.log', maxBytes=16384, backupCount=20)

    # Set the logging level of the file handler object so that it logs INFO and up
    file_handler.setLevel(logging.INFO)

    # Create a file formatter object
    file_formatter = logging.Formatter('%(asctime)s %(levelname)s: %(message)s [in %(filename)s: %(lineno)d]')

    # Apply the file formatter object to the file handler object
    file_handler.setFormatter(file_formatter)

    # Add file handler object to the logger
    app.logger.addHandler(file_handler)

def configure_db(app):
    db = MongoEngine(app)

app/games/__init__.py

#This bluepint will deal with all site functionality

from flask import Blueprint

games_blueprint = Blueprint('games', __name__, template_folder='templates')

from . import views

有没有想过为什么会发生这种情况以及如何解决？

Answer 1

不太确定这里的细节，但以下更改使服务器正常工作。

在最初的应用程序工厂函数中，我调用了socketio。在注册蓝图之前初始化app（app）。我刚刚将其移动到应用程序工厂中的最后一个操作：

def create_app():

    app = Flask(__name__)

    # Configure the flask app instance
    CONFIG_TYPE = os.getenv('CONFIG_TYPE', default='config.DevelopmentConfig')
    app.config.from_object(CONFIG_TYPE)

    #Configure celery
    celery.conf.update(app.config)

    # Register blueprints
    register_blueprints(app)

    #setup db integration
    configure_db(app)

    # Configure logging
    configure_logging(app)

    # Register error handlers
    register_error_handlers(app)
    
    ##########################################
    # HERE
    # Initialize flask extension objects
    initialize_extensions(app)
    ##########################################

    #setup db for flask-login
    @login_manager.user_loader
    def load_user(user_id):
        user = User.objects(id=user_id)[0]
        return user

    return app

我猜想操作顺序在某种程度上阻止了socketio实际注册事件处理程序。如果任何对flask socketio更有经验的人能够深入了解这个问题，我们将不胜感激。

Answer 2

您的客户正在寻找套接字。在（'message'，incoming_message_as_a_string）上，但您的服务器正在发送套接字。send（'just the string without an event'）

尝试：

socket.on('connect', function() {
    socket.send('message', 'User has connected!');
});

但是我会养成在客户端和服务器上始终使用emit的习惯：

socket.on('connect', function() {
    console.log("ok");
    socket.emit('message', 'User has connected!');
});

原因是发射可以同时发送对象或字符串，而发送只能发送字符串。

再看看你的问题，我认为你的双方并不匹配。当发送套接字消息时，第一个参数是“事件名称”-基本上是一个触发器，它为另一端提供了一些需要注意的内容（以便套接字侦听器可以区分不同类型的消息）。

服务器只侦听消息事件，然后发送自己的消息，这意味着客户端必须先发送一些东西。通常，这是一条“连接”消息——当客户端连接时，它确实会发送其中一条消息，但服务器端没有侦听该事件。它只监听“消息”事件，客户端只在第一次从服务器收到消息事件后发送消息事件。

在服务器端，尝试更改以下内容：

@socketio.on('message', namespace='/')
def handleMessage(msg):
    print('Message: ' + msg)
    send(msg, broadcast=True)

为此：

@socketio.on('connect')
def handleConnect():
    print('Someone connected')
    send('message', 'A user has joined', broadcast=True)

@socketio.on('message')
def handleMessage(msg):
    print('Message: ' + msg)
    send(msg, broadcast=True)

PS-我删除了名称空间的东西，因为我在没有它的情况下工作，我不确定它会如何影响结果。一旦你做得更进一步，你可以把它加回去。