在包含unicode_literals的Flask应用程序中添加标题 [英] Add headers in a Flask app with unicode_literals
问题描述
添加启用了unicode_literals的头文件似乎与Nginx,uWSGI和一个简单的Flask应用程序失败:
# - * - coding :utf-8 - * -
from __future__ import unicode_literals $ b $ from flask flask烧瓶,make_response
app =烧瓶('test')
@ app.route('/')
def index():
response = make_response()
response.status_code = 401
response.headers = {'WWW-Authenticate': 'Basic realm ='test''}#失败
#response.headers = {b'WWW-Authenticate':b'Basic realm =test'}#成功
返回响应
if __name__ =='__main__':
app.run(debug = True)
该应用程序可直接用于调试目的,也可以通过Nginx - > uWSGI - > Flask运行。
WWW-Authenticate
标头是正确的。
<李>同样的请求通过Nginx返回一个头 Transfert-Encoding:chunked
和
丢弃 WWW-Authenticate
头。
强制字符串( b'...')格式添加标题使应用程序按预期工作在这两种情况下。
编码声明。
文件以UTF-8编码,Python解释器有一个
我们使用Python 2.7.3,Nginx 1.4.2和uWSGI 1.3。
Nginx或uWSGI,Flask和unicode_literals之间是否存在任何已知的不兼容性?
Thanks!
编辑:
问题似乎来自uWSGI(
https://github.com/unbit/uwsgi/blob/master/plugins/python/wsgi_headers.c# L116 ),因为它只检查PyString而不检查Python2的PyUnicode,如果我理解这个代码正确。
编辑:
Armin Ronacher has修复了类似的错误( https://github.com/mitsuhiko/flask/issues/758)5个月前,但我没有在werkzeug git log中找到提交。我不知道该修补程序的作用域是 redirect()
函数还是更广泛地处理标题。我使用的是Werkzeug 0.9.4和Flask 0.10.1。
这个问题确实是由于 WERKZEUG 即可。正如您注意到的,自2013年6月4日起,现已更正(参见相关的提交在Github上)。您可以使用 0.9.5 而不是 0.9.4 的版本获得Werkzeug的免费版本。
<此外,为了解决您的问题,我在Flask应用程序的初始化之后添加了 app.debug = True
。这允许我在uWSGI日志中得到以下错误:
$ b $ pre $ code Traceback最近一次调用最后一次
文件 /home/afigura/.virtualenvs/stack-python2/lib/python2.7/site-packages/flask/app.py,第1836行,在__call__
中返回self.wsgi_app(environ,start_response)
文件/home/afigura/.virtualenvs/stack-python2/lib/python2.7/site-packages/flask/app.py,行1821,在wsgi_app
返回响应(environ,start_response)
文件/home/afigura/.virtualenvs/stack-python2/lib/python2.7/site-packages/werkzeug/wrappers.py,行1201,在__call__
start_response(status,headers)
TypeError:http头键必须是字符串
这对应于您在Github上找到的bug
因此,您可以使用以下解决方法获取 Flask / Werkzeug 与 或者: 但是我建议只要更新你的Werkzeug版本到> = 0.9.5就可以了。 另外请注意,虽然<$ c Flask / Werkzeug响应的$ c> headers unicode_literals $ c
属性的行为类似于字典,实际上它是一个
$ $ p $ response.headers = {b'WWW-Authenticate':'Basic realm =test'}
response.headers = {str('WWW-Authenticate'):'Basic realm =test'}
Headers
对象(请参阅 Werkzeug源代码)。因此,我建议你如下使用它:
response.headers ['WWW-Authenticate'] ='Basic realm = test'
你可以在 Flask文档 make_response
p>
Adding headers with unicode_literals enabled seems to fail with Nginx, uWSGI and a simple Flask app:
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from flask import Flask, make_response
app = Flask('test')
@app.route('/')
def index():
response = make_response()
response.status_code = 401
response.headers = {'WWW-Authenticate': 'Basic realm="test"'} # Fail
# response.headers = {b'WWW-Authenticate': b'Basic realm="test"'} # Succeed
return response
if __name__ == '__main__':
app.run(debug=True)
The app is available directly for debug purpose or through Nginx -> uWSGI -> Flask and works well.
- When I use a browser to connect directly to the app, I've got a login dialog and the
WWW-Authenticate
header is correct. - The same request going through Nginx returns a header
Transfert-Encoding: chunked
and discard theWWW-Authenticate
header.
Forcing bytestring (b'...') format to add the header make the app works as expected in both cases.
The file is encoded in UTF-8 and there's a
coding` declaration for the Python interpreter.
We're using Python 2.7.3, Nginx 1.4.2 and uWSGI 1.3.
Is there any known incompatibility between Nginx or uWSGI, Flask and unicode_literals? Thanks!
edit: The problem seems to come from uWSGI ( https://github.com/unbit/uwsgi/blob/master/plugins/python/wsgi_headers.c#L116), since it only checks for PyString and not PyUnicode for Python2, if I understand this code correctly.
edit:
Armin Ronacher has fixed a similar bug (https://github.com/mitsuhiko/flask/issues/758) 5 months ago, but I didn't find the commit in werkzeug git log yet. I don't know if the fix is scoped to the redirect()
function or more broadly on headers handling. I'm using Werkzeug 0.9.4 and Flask 0.10.1.
This problem is indeed due to a bug in Werkzeug. As you noticed, this is now corrected since Jun 4, 2013 (cf. the related commit on Github). You can have a bug free version of Werkzeug by using the version 0.9.5 instead of the 0.9.4.
Moreover, to troubleshoot your problem, I added app.debug = True
just after the initialization of your Flask application. This allows me to got the following error in uWSGI logs:
Traceback (most recent call last):
File "/home/afigura/.virtualenvs/stack-python2/lib/python2.7/site-packages/flask/app.py", line 1836, in __call__
return self.wsgi_app(environ, start_response)
File "/home/afigura/.virtualenvs/stack-python2/lib/python2.7/site-packages/flask/app.py", line 1821, in wsgi_app
return response(environ, start_response)
File "/home/afigura/.virtualenvs/stack-python2/lib/python2.7/site-packages/werkzeug/wrappers.py", line 1201, in __call__
start_response(status, headers)
TypeError: http header key must be a string
This corresponds to the error mentioned in the bug you found on Github.
So, you can use the following workaround to get Flask/Werkzeug working with unicode_literals
:
response.headers = {b'WWW-Authenticate': 'Basic realm="test"'}
Or:
response.headers = {str('WWW-Authenticate'): 'Basic realm="test"'}
But I recommend to simply update your Werkzeug version to >=0.9.5 if you can.
Also, please note that although the headers
attribute of a Flask/Werkzeug response behaves like a dictionary, it is in fact a Headers
object (see Werkzeug source code). Hence, I advise you to use it as follows:
response.headers['WWW-Authenticate'] = 'Basic realm="test"'
You can see some examples about this on the Flask documentation of the function make_response
.
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