使用Flask服务器和xlsxwriter导出Excel

Question

所以我过去一直在使用XLSXWriter导出一个excel文件，其中包含一个填充了两个pandas数据帧的选项卡。在过去，我只是将文件导出到用户计算机上的本地路径，但我正在转换到Web界面。

我想要的输出是拥有与下面代码相同的excel文件，但是在内存中创建并发送给用户以供他/她通过Web界面下载。我一直在看很多Django和StringIO，但我正在寻找可以与Flask一起工作的东西，我找不到任何实际工作的东西。

有人熟悉这个问题吗？

提前致谢！

xlsx_path = "C:\test.xlsx"
writer = pd.ExcelWriter(xlsx_path, engine='xlsxwriter')

df_1.to_excel(writer,startrow = 0, merge_cells = False, sheet_name = "Sheet_1")
df_2.to_excel(writer,startrow = len(df_1) + 4, merge_cells = False , sheet_name = "Sheet_1")                             

workbook = writer.book
worksheet = writer.sheets["Sheet_1"]
format = workbook.add_format()
format.set_bg_color('#eeeeee')
worksheet.set_column(0,9,28)

writer.close()

Answer 1

以下代码段适用于Win3，Python 3.4 64位。

Pandas ExcelWriter写入BytesIO流，然后通过Flask和send_file将其发送回用户。

import numpy as np
import pandas as pd
from io import BytesIO
from flask import Flask, send_file

app = Flask(__name__)
@app.route('/')

def index():

    #create a random Pandas dataframe
    df_1 = pd.DataFrame(np.random.randint(0,10,size=(10, 4)), columns=list('ABCD'))

    #create an output stream
    output = BytesIO()
    writer = pd.ExcelWriter(output, engine='xlsxwriter')

    #taken from the original question
    df_1.to_excel(writer, startrow = 0, merge_cells = False, sheet_name = "Sheet_1")
    workbook = writer.book
    worksheet = writer.sheets["Sheet_1"]
    format = workbook.add_format()
    format.set_bg_color('#eeeeee')
    worksheet.set_column(0,9,28)

    #the writer has done its job
    writer.close()

    #go back to the beginning of the stream
    output.seek(0)

    #finally return the file
    return send_file(output, attachment_filename="testing.xlsx", as_attachment=True)

app.run(debug=True)

参考文献：

• http://pandas.pydata.org/pandas-docs/stable/io.html
• http://flask.pocoo.org/snippets/32/

Answer 2

你可以使用类似于this的东西：

from flask import Flask, send_file
import io

myio = io.StringIO()

with open(xlsx_path, 'rb') as f:
    data = f.read()

myio.write(data)
myio.seek(0)

app = Flask(__name__)

@app.route('/')
def index():
    send_file(myio,
              attachment_filename="test.xlsx",
              as_attachment=True)

app.run(debug=True)

您可能还想使用tempfile编写excel文件

Answer 3

如果你想要xlsx文件作为响应而不将其存储在服务器端。您可以使用以下代码段。

from flask import Flask

app = Flask(__name__)

data = [[1, 2], [3, 4]]


@app.route('/')
def get_xslx_for_data():
    try:
        response = Response()
        response.status_code = 200
        output = StringIO.StringIO()
        workbook = xlsxwriter.Workbook(output, {'in_memory': True})
        worksheet = workbook.add_worksheet('hello')
        for i, d in enumerate(data):
            for j, res in enumerate(d):
                worksheet.write(i, j, res)
        workbook.close()
        output.seek(0)
        response.data = output.read()
        file_name = 'my_file_{}.xlsx'.format(
            datetime.now().strftime('%d/%m/%Y'))
        mimetype_tuple = mimetypes.guess_type(file_name)
        response_headers = Headers({
            'Pragma': "public",  # required,
            'Expires': '0',
            'Cache-Control': 'must-revalidate, post-check=0, pre-check=0',
            'Cache-Control': 'private',  # required for certain browsers,
            'Content-Type': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
            'Content-Disposition': 'attachment; filename=\"%s\";' % file_name,
            'Content-Transfer-Encoding': 'binary',
            'Content-Length': len(response.data)
        })

        if not mimetype_tuple[1] is None:
            response.update({
                'Content-Encoding': mimetype_tuple[1]
            })
        response.headers = response_headers
        response.set_cookie('fileDownload', 'true', path='/')
        return response
    except Exception as e:
        print(e)


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