在Flask响应头中设置Unicode文件名

Question

我正在尝试设置Content-Disposition标头以将文件发送到客户端.文件名是Unicode.当我尝试设置标题时,它失败了UnicodeEncodeError.我试过的各种组合encode和decode,但不能让它开始工作.如何发送带有Unicode文件名的文件？

destination_file = '??????_report.html'
response.headers['Content-Disposition'] = 'attachment; filename=' + destination_file

  File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/http/server.py", line 495, in send_header
    ("%s: %s\r\n" % (keyword, value)).encode('latin-1', 'strict'))
UnicodeEncodeError: 'latin-1' codec can't encode characters in position 41-42: ordinal not in range(256)

Answer 1

RFC 2231第4节描述了如何指定要使用的编码而不是Latin-1作为标头值.使用标头选项filename*=UTF-8''...,其中...是url编码的名称.您还可以包含filename提供Latin-1后备的选项.

直到最近,浏览器才一直支持这一点.此页面包含一些有关浏览器支持的指标.值得注意的是,IE8将忽略UTF-8选项,如果UTF-8选项出现在Latin-1选项之前,它将完全失败.

Flask 1.0 支持send_file使用Unicode文件名进行调用.如果使用Flask 1.0,则可以使用send_filewith as_attachment=True和Unicode文件名.

from flask import send_file

@app.route('/send-python-report')
def send_python_report():
    return send_file('??????_report.html', as_attachment=True)

在此之前,您可以使用Flask将使用的相同过程手动构建标题.

import unicodedata

from flask import send_file
from werkzeug.urls import url_quote

@app.route('/send-python-report')
def send_python_report():
    filename = '??????_report.html'
    rv = send_file(filename)

    try:
        filename = filename.encode('latin-1')
    except UnicodeEncodeError:
        filenames = {
            'filename': unicodedata.normalize('NFKD', filename).encode('latin-1', 'ignore'),
            'filename*': "UTF-8''{}".format(url_quote(filename)),
        }
    else:
        filenames = {'filename': filename}

    rv.headers.set('Content-Disposition', 'attachment', **filenames)
    return rv

为了安全起见,send_from_directory如果文件名由用户输入提供,则应使用.该过程与上述相同,取代了该功能.

WSGI不确保头选项的顺序,因此如果要支持IE8,则必须使用dump_options_headerwith 完全手动构造头值OrderedDict.否则,filename*可能会出现之前filename,如上所述,在IE8中不起作用.

from collections import OrderedDict
import unicodedata

from flask import send_file
from werkzeug.http import dump_options_header
from werkzeug.urls import url_quote

@app.route('/send-python-report')
def send_python_report():
    filename = '??????_report.html'
    rv = send_file(filename)
    filenames = OrderedDict()

    try:
        filename = filename.encode('latin-1')
    except UnicodeEncodeError:
        filenames['filename'] = unicodedata.normalize('NFKD', filename).encode('latin-1', 'ignore')
        filenames['filename*']: "UTF-8''{}".format(url_quote(filename))
    else:
        filenames['filename'] = filename

    rv.headers.set('Content-Disposition', dump_options_header('attachment', filenames))
    return rv