带离线绘图图表的cefpython3

Question

我正在寻找一个在cefpython3中嵌入离线绘图图表的示例。据我所知，cefpython3就是为这样的项目而构建的。然而，我还没有成功地识别一个使用plotly的示例-这对我是python的新手很有帮助。无论如何，我将提供我尝试过的内容：

我的以下代码演示了如何将来自https://dash.plotly.com/layout的示例绘图图表与来自cefpython的hello_world.py示例相结合，可在以下位置找到：https://github.com/cztomczak/cefpython/blob/master/examples/hello_world.py

dashtest.py

from cefpython3 import cefpython as cef
import platform
import sys
#dash (plotly)---------------------
import dash
from dash import dcc
from dash import html
import plotly.express as px
import pandas as pd
#---------------------------------

def main():
    check_versions()
    sys.excepthook = cef.ExceptHook  # To shutdown all CEF processes on error
    cef.Initialize()
    cef.CreateBrowserSync(url="http://127.0.0.1:8050/",
                          window_title="Test")
    DashApp()
    cef.MessageLoop()
    cef.Shutdown()

def check_versions():
    ver = cef.GetVersion()
    print("[dashtest.py] CEF Python {ver}".format(ver=ver["version"]))
    print("[dashtest.py] Chromium {ver}".format(ver=ver["chrome_version"]))
    print("[dashtest.py] CEF {ver}".format(ver=ver["cef_version"]))
    print("[dashtest.py] Python {ver} {arch}".format(
           ver=platform.python_version(),
           arch=platform.architecture()[0]))
    assert cef.__version__ >= "57.0", "CEF Python v57.0+ required to run this"


def DashApp():
    app = dash.Dash()

    # assume you have a "long-form" data frame
    # see https://plotly.com/python/px-arguments/ for more options
    df = pd.DataFrame({
        "Fruit": ["Apples", "Oranges", "Bananas", "Apples", "Oranges", "Bananas"],
        "Amount": [4, 1, 2, 2, 4, 5],
        "City": ["SF", "SF", "SF", "Montreal", "Montreal", "Montreal"]
    })

    fig = px.bar(df, x="Fruit", y="Amount", color="City", barmode="group")

    app.layout = html.Div(children=[
        html.H1(children='Hello Dash'),

        html.Div(children='''
            Dash: A web application framework for your data.
        '''),

        dcc.Graph(
            id='example-graph',
            figure=fig
        )
    ])

    app.run_server(debug=False)

if __name__ == '__main__':
    main()

以下是我的命令提示符调试输出：

[dashtest.py] CEF Python 66.1
[dashtest.py] Chromium 66.0.3359.181
[dashtest.py] CEF 3.3359.1774.gd49d25f
[dashtest.py] Python 3.9.6 64bit

DevTools listening on ws://127.0.0.1:55905/devtools/browser/3e64411d-3a5b-4493-be7b-c12e8498e125
Dash is running on http://127.0.0.1:8050/

 * Serving Flask app 'dashtest' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
 * Running on http://127.0.0.1:8050/ (Press CTRL+C to quit)

通过调试工作，我发现如果我首先在单独的CMD窗口中运行plotly脚本，就可以让cefpython3加载plotly的本地主机页面。但是使用这种设置，它只能运行其中的一个-但不能在一个脚本中同时运行这两个脚本。

如何启动plotly服务器；并将cefpython作为单个应用程序运行？因为最终，我将拥有正在读取、写入和刷新图表的数据。

最重要的是--我可能用完全错误的方式来做这件事。希望我只是忽略了这里的一个基本步骤。谢谢你的关注。

Answer 1

您需要在线程中运行CEF窗口：

import threading

def cef_in_parallel():
    cef.Initialize()
    cef.CreateBrowserSync(url="http://127.0.0.1:8050/",
                          window_title="Test")
    cef.MessageLoop()


def main():
    cef_thread = theading.Thread(target=cef_in_parallel)
    cef_thread.start()
    DashApp()
    cef.Shutdown()

这似乎对我很有效。