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@piersstorey
Last active March 30, 2019 13:23
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Flask xlsx writer
from flask import Response
import StringIO, mimetypes
import xlsxwriter
from datetime import datetime
from werkzeug.datastructures import Headers
def xlsx_export():
try:
# Flask response
response = Response()
response.status_code = 200
# Create an in-memory output file for the new workbook.
output = StringIO.StringIO()
# Craete workbook
workbook = xlsxwriter.Workbook(output, {'in_memory': True})
worksheet = workbook.add_worksheet('hello')
# Write some test data.
worksheet.write(0, 0, 'Hello, world!')
# Close the workbook before streaming the data.
workbook.close()
# Rewind the buffer.
output.seek(0)
# Add output to response
response.data = output.read()
# Set filname and mimetype
file_name = 'export_{}_{}.xlsx'.format('this_awesome', datetime.now())
mimetype_tuple = mimetypes.guess_type(file_name)
# HTTP headers for forcing file download
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]
})
# Add headers
response.headers = response_headers
#jquery.fileDownload.js requirements
response.set_cookie('fileDownload', 'true', path='/')
# Return the response
return response
except Exception as e:
print(e)
@DylanRussell
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i don't think mimetype is needed here when we know what the content-type should be, and the file isn't encoded.

also the Cache-Control header is overwritten here (it's used as a key twice in the dictionary), also according to this post:
https://stackoverflow.com/questions/34663916/are-cache-control-pre-check-and-post-check-headers-still-supported-by-ie
pre-check / post-check headers don't need to be used

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