Python 定期更新和渲染来自 Flask 的值
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Update and render a value from Flask periodically
提问by Depado
I want to display my CPU usage dynamically. I don't want to reload the page to see a new value. I know how to get the CPU usage in Python. Right now I render a template with the value. How can I continually update a page with a value from Flask?
我想动态显示我的 CPU 使用率。我不想重新加载页面以查看新值。我知道如何在 Python 中获取 CPU 使用率。现在我用这个值渲染一个模板。如何使用 Flask 中的值不断更新页面？
@app.route('/show_cpu')
def show_cpu():
cpu = getCpuLoad()
return render_template('show_cpu.html', cpu=cpu)
采纳答案by Depado
Using an Ajax request
使用 Ajax 请求
Python
Python
@app.route('/_stuff', methods= ['GET'])
def stuff():
cpu=round(getCpuLoad())
ram=round(getVmem())
disk=round(getDisk())
return jsonify(cpu=cpu, ram=ram, disk=disk)
Javascript
Javascript
function update_values() {
$SCRIPT_ROOT = {{ request.script_root|tojson|safe }};
$.getJSON($SCRIPT_ROOT+"/_stuff",
function(data) {
$("#cpuload").text(data.cpu+" %")
$("#ram").text(data.ram+" %")
$("#disk").text(data.disk+" %")
});
}
Using Websockets
使用 Websocket
project/app/views/request/websockets.py
project/app/views/request/websockets.py
# -*- coding: utf-8 -*-
# OS Imports
import json
# Local Imports
from app import sockets
from app.functions import get_cpu_load, get_disk_usage, get_vmem
@sockets.route('/_socket_system')
def socket_system(ws):
"""
Returns the system informations, JSON Format
CPU, RAM, and Disk Usage
"""
while True:
message = ws.receive()
if message == "update":
cpu = round(get_cpu_load())
ram = round(get_vmem())
disk = round(get_disk_usage())
ws.send(json.dumps(dict(received=message, cpu=cpu, ram=ram, disk=disk)))
else:
ws.send(json.dumps(dict(received=message)))
project/app/__init__.py
project/app/__init__.py
# -*- coding: utf-8 -*-
from flask import Flask
from flask_sockets import Sockets
app = Flask(__name__)
sockets = Sockets(app)
app.config.from_object('config')
from app import views
Using Flask-Websockets made my life a lot easier. Here is the launcher :
launchwithsockets.sh
使用 Flask-Websockets 让我的生活更轻松。这是启动器：
launchwithsockets.sh
#!/bin/sh
gunicorn -k flask_sockets.worker app:app
Finally, here is the client code :custom.js
The code is a bit too long, so here it is.
Note that I'm NOT using things like socket.io, that's why the code is long. This code also tries to reconnect to the server periodically, and can stop trying to reconnect on a user action. I use the Messenger lib to notify the user that something went wrong. Of course it's a bit more complicated than using socket.io but I really enjoyed coding the client side.
最后，这里是客户端代码：custom.js
代码有点长，所以在这里。
请注意，我没有使用 socket.io 之类的东西，这就是代码很长的原因。此代码还尝试定期重新连接到服务器，并且可以停止尝试重新连接用户操作。我使用 Messenger 库通知用户出现问题。当然，它比使用 socket.io 复杂一些，但我真的很喜欢在客户端编写代码。
