Question

我正在尝试允许用户下载包含其操作定义的数据的CSV文件。该文件不存在，它是动态创建的。我怎么能在Flask中做到这一点？

Answer 1

使用csv.writer和stream the response生成数据。使用StringIO写入内存缓冲区而不是生成中间文件。

以下是如何执行此操作的简短示例。

import csv
from datetime import datetime
from cstringio import StringIO
from flask import Flask, stream_with_context
from werkzeug.datastructures import Headers
from werkzeug.wrappers import Response

app = Flask(__name__)

# example data, this could come from wherever you are storing logs
log = [
    ('login', datetime(2015, 1, 10, 5, 30)),
    ('deposit', datetime(2015, 1, 10, 5, 35)),
    ('order', datetime(2015, 1, 10, 5, 50)),
    ('withdraw', datetime(2015, 1, 10, 6, 10)),
    ('logout', datetime(2015, 1, 10, 6, 15))
]

@app.route('/')
def download_log():
    def generate():
        data = StringIO()
        w = csv.writer(data)

        # write header
        w.writerow(('action', 'timestamp'))
        yield data.getvalue()
        data.seek(0)
        data.truncate(0)

        # write each log item
        for item in log:
            w.writerow((
                item[0],
                item[1].isoformat()  # format datetime as string
            ))
            yield data.getvalue()
            data.seek(0)
            data.truncate(0)

    # add a filename
    headers = Headers()
    headers.set('Content-Disposition', 'attachment', filename='log.csv')

    # stream the response as the data is generated
    return Response(
        stream_with_context(generate()),
        mimetype='text/csv', headers=headers
    )

app.run()

Answer 2

Flask-Excel库使用PyExcel生成CSV或其他电子表格格式，并生成Flask响应。这些文档列出了如何产生其他格式以及可以使用哪些数据的完整API。

pip install flask-excel

import flask_excel as excel

@app/route('/download', methods=['GET'])
def download_data():
    sample_data=[0, 1, 2]
    excel.init_excel(app)
    extension_type = "csv"
    filename = "test123" + "." extension_type
    d = {'colName': sample_data}
    return excel.make_response_from_dict(d, file_type=extension_type, file_name=filename)

从Flask视图创建并下载CSV文件

2 个答案: