无法连接到dash应用程序的服务器错误，我要在其中上载文件

Question

我正在尝试构建一个dash应用程序，允许用户上传wav文件，我尝试-

import base64
import os
from urllib.parse import quote as urlquote

from flask import Flask, send_from_directory
import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output


UPLOAD_DIRECTORY = "/project/app_uploaded_files"

if not os.path.exists(UPLOAD_DIRECTORY):
    os.makedirs(UPLOAD_DIRECTORY)


# Normally, Dash creates its own Flask server internally. By creating our own,
# we can create a route for downloading files directly:
server = Flask(__name__)
app = dash.Dash(server=server)


@server.route("/download/<path:path>")
def download(path):
    """Serve a file from the upload directory."""
    return send_from_directory(UPLOAD_DIRECTORY, path, as_attachment=True)


app.layout = html.Div(
    [
        html.H1("File Browser"),
        html.H2("Upload"),
        dcc.Upload(
            id="upload-data",
            children=html.Div(
                ["Drag and drop or click to select a file to upload."]
            ),
            style={
                "width": "100%",
                "height": "60px",
                "lineHeight": "60px",
                "borderWidth": "1px",
                "borderStyle": "dashed",
                "borderRadius": "5px",
                "textAlign": "center",
                "margin": "10px",
            },
            multiple=True,
        ),
        html.H2("File List"),
        html.Ul(id="file-list"),
    ],
    style={"max-width": "500px"},
)


def save_file(name, content):
    """Decode and store a file uploaded with Plotly Dash."""
    data = content.encode("utf8").split(b";base64,")[1]
    with open(os.path.join(UPLOAD_DIRECTORY, name), "wb") as fp:
        fp.write(base64.decodebytes(data))


def uploaded_files():
    """List the files in the upload directory."""
    files = []
    for filename in os.listdir(UPLOAD_DIRECTORY):
        path = os.path.join(UPLOAD_DIRECTORY, filename)
        if os.path.isfile(path):
            files.append(filename)
    return files


def file_download_link(filename):
    """Create a Plotly Dash 'A' element that downloads a file from the app."""
    location = "/download/{}".format(urlquote(filename))
    return html.A(filename, href=location)


@app.callback(
    Output("file-list", "children"),
    [Input("upload-data", "filename"), Input("upload-data", "contents")],
)
def update_output(uploaded_filenames, uploaded_file_contents):
    """Save uploaded files and regenerate the file list."""

    if uploaded_filenames is not None and uploaded_file_contents is not None:
        for name, data in zip(uploaded_filenames, uploaded_file_contents):
            save_file(name, data)

    files = uploaded_files()
    if len(files) == 0:
        return [html.Li("No files yet!")]
    else:
        return [html.Li(file_download_link(filename)) for filename in files]


if __name__ == "__main__":
    app.run_server(debug=False, port=8888)

但是，我收到一个错误，说当我转到http://127.0.0.1:888/时无法访问站点

为什么会发生这种情况？我的动机是建立一个网页，可以承载一个应用程序，最终用户可以按run，上传的文件可以被处理

Answer 1

您的URL中似乎有错误的端口，它应该是http://127.0.0.1:8888/（而不是http://127.0.0.1:888/）