Flask、Windows、IIS、Plotly-Dash。读取WSGI处理程序时出错

Question

我希望你能帮助我解决Flask在Windows服务器上部署plotly-dash时遇到的错误。

除了我的网站在wwwroot文件夹中的位置之外，我已经使用以下指南逐字地设置了Flask：Flask on IIS

当我使用最基本的应用程序时，它工作得很好，例如下面的代码：

from flask import Flask
app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello from FastCGI via IIS!"

if __name__ == "__main__":
    app.run()

但是如果我尝试一些稍微复杂一些的东西，比如basic Dash演示：

import dash
import dash_core_components as dcc
import dash_html_components as html

app = dash.Dash()

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

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

    dcc.Graph(
        id='example-graph',
        figure={
            'data': [
                {'x': [1, 2, 3], 'y': [4, 1, 2], 'type': 'bar', 'name': 'SF'},
                {'x': [1, 2, 3], 'y': [2, 4, 5], 'type': 'bar', 'name': u'Montréal'},
            ],
            'layout': {
                'title': 'Dash Data Visualization'
            }
        }
    )
])

if __name__ == '__main__':
    app.run_server(debug=True)

我得到一个错误，如下所示(为了便于解释，我已经尝试对其进行了整理)：

Error occurred while reading WSGI handler: 
Traceback (most recent call last): 
    File "C:\inetpub\wwwroot\wfastcgi.py", line 791, in main env, handler = read_wsgi_handler(response.physical_path) 
    File "C:\inetpub\wwwroot\wfastcgi.py", line 633, in read_wsgi_handler handler = get_wsgi_handler(os.getenv("WSGI_HANDLER")) 
    File "C:\inetpub\wwwroot\wfastcgi.py", line 600, in get_wsgi_handler handler = __import__(module_name, fromlist=[name_list[0][0]]) 
    File ".\app.py", line 1, in import dash 
    File "C:\Python36\lib\site-packages\dash\__init__.py", line 1, in from .dash import Dash # noqa: F401 
    File "C:\Python36\lib\site-packages\dash\dash.py", line 12, in import plotly 
    File "C:\Python36\lib\site-packages\plotly\__init__.py", line 31, in from plotly import (plotly, dashboard_objs, graph_objs, grid_objs, tools, 
    File "C:\Python36\lib\site-packages\plotly\plotly\__init__.py", line 10, in from . plotly import ( 
    File "C:\Python36\lib\site-packages\plotly\plotly\plotly.py", line 30, in from plotly import exceptions, files, session, tools, utils 
    File "C:\Python36\lib\site-packages\plotly\tools.py", line 59, in ipython_core_display = optional_imports.get_module('IPython.core.display') 
    File "C:\Python36\lib\site-packages\plotly\optional_imports.py", line 23, in get_module return import_module(name) 
    File "C:\Python36\lib\importlib\__init__.py", line 126, in import_module return _bootstrap._gcd_import(name[level:], package, level) 
    File "C:\Python36\lib\site-packages\IPython\__init__.py", line 55, in from .terminal.embed import embed 
    File "C:\Python36\lib\site-packages\IPython\terminal\embed.py", line 15, in from IPython.core.interactiveshell import DummyMod, InteractiveShell 
    File "C:\Python36\lib\site-packages\IPython\core\interactiveshell.py", line 61, in from IPython.utils import io 
    File "C:\Python36\lib\site-packages\IPython\utils\io.py", line 95, in stdin = IOStream(sys.stdin, fallback=devnull) 
    File "C:\Python36\lib\site-packages\IPython\utils\io.py", line 39, in __init__ for meth in filter(clone, dir(stream)): 
    File "C:\Python36\lib\site-packages\IPython\utils\io.py", line 38, in clone return not hasattr(self, meth) and not meth.startswith('_') 
    File "C:\Python36\lib\site-packages\IPython\utils\io.py", line 82, in closed return self.stream.closed 
    ValueError: underlying buffer has been detached StdOut: StdErr:

我已经做了大量的谷歌搜索，并尽力解码这个错误，但我遇到了障碍。有谁有什么想法吗？

根据@susodapop的建议，我删除了IPython，现在得到以下错误：

Error occurred: Traceback (most recent call last): File "C:\inetpub\wwwroot\wfastcgi.py", line 847, in main result = handler(record.params, response.start) 
TypeError: 'Dash' object is not callable StdOut: StdErr: C:\Python34\lib\site-packages\plotly\tools.py:103: UserWarning: Looks like you don't have 'read-write' permission to your 'home' ('~') directory or to our '~/.plotly' directory. 
That means plotly's python api can't setup local configuration files. No problem though! You'll just have to sign-in using 'plotly.plotly.sign_in()'. For help with that: 'help(plotly.plotly.sign_in)'. Questions? Visit https://support.plot.ly 

Answer 1

尝试使用wfastcgi.py的Microsoft's blessed version及其附带的配置说明。旧版本的wfastcgi.py在尝试将二进制输出写入非二进制对象时存在问题，这与您在这里看到的情况类似。

直到最近，在线提供的使用IIS配置Flask的说明都有点令人困惑。除非你使用Azure，否则微软自己的解决方案是最容易配置的。

Answer 2

我也遇到过类似的问题。以下是我为使其工作而运行的步骤：

1)确保"Add Module Mapping“可执行文件中的python.exe、pipe和wfastcgi.py文件之间没有空格。有关说明，请参阅此link。这为我抛出了一个500错误。

2)确保您使用的是flask应用实例，而不是dash应用实例。请参见Dash Deployment User Guide这是通过在WSGI_HANDLER环境变量中使用app.server而不是app.app来实现的。来自% 1的链接中的屏幕快照。

3)最后，如果您从原始问题中得到错误，请按照注释中的指示卸载IPython。

在这三个问题之后。我要在IIS上部署我的dash应用程序。