使用 WSGI（无框架）将用户重定向到 url

Question

我正在尝试使用 python 的 WSGI 开发一个小型 Web 应用程序。例如，如果用户选择 Google，他们将被重定向到 google.com，如果他们选择 Facebook，他们将被重定向到 facebook.com，等等

from wsgiref.simple_server import make_server
from cgi import parse_qs, escape

main_html = """
<html>
<head><title> Welcome to redirection test page </title> </head>
<body>
    <form method="get" action='/visit'>
        <input type=radio name='site' value=google> Google
        <input type=radio name='site' value=facebook> Facebook
        <input type=submit value=submit>
    </form>
</body>
</html>
"""


def main(environ, start_response):

    response_body = main_html
    print type(response_body)   
    status = '200 OK'

    response_headers = [
                        ('Content-Type','text/html'),
                        ('Content-Length', str(len(response_body)))
                       ]


    start_response(status, response_headers)
    return [response_body]


def visit(environ, start_response):
    qs = parse_qs(environ['QUERY_STRING'])
    dest = qs.ge('site')[0]
    if dest == 'google':
        start_response('301 Moved Permanently', [('Location','http://google.com')])
    else:
        start_response('301 Moved Permanently', [('Location','http://facebook.com')])

    return [1]


def app(environ, start_response):
    if environ['PATH_INFO'] == '/':
        return main(environ, start_response)
    elif environ['PATH_INFO'] == '/visit':
        return visit(environ, start_response)

httpd =  make_server('192.168.48.128',8052, app)
print 'Serving on port 8052'
httpd.serve_forever()

但是，当我运行这段代码时，出现以下错误：

Traceback (most recent call last):
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 86, in run
    self.finish_response()
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 131, in finish_response
    self.close()
  File "/usr/lib/python2.7/wsgiref/simple_server.py", line 33, in close
    self.status.split(' ',1)[0], self.bytes_sent
AttributeError: 'NoneType' object has no attribute 'split'

Answer 1

你有两个问题，都在 visit() 之内。第一个是打字错误，第二个是没有遵守 WSGI specification

def visit(environ, start_response):
    qs = parse_qs(environ['QUERY_STRING'])
    dest = qs.ge('site')[0]
    if dest == 'google':
        start_response('301 Moved Permanently', [('Location','http://google.com')])
    else:
        start_response('301 Moved Permanently', [('Location','http://facebook.com')])

    return [1]

查看第 dest = qs.ge('site')[0] 行。 qs 只是一个字典，没有方法 ge，只有 get。此外， cgi.parse_qs is deprecated - use urlparse.parse_qs() 代替。解决这个问题会给我们带来新的错误（我的地址是 127.0.0.1 因为我只是运行它脱离了本地主机）：

127.0.0.1 - - [05/Feb/2015 16:45:17] "GET /visit?site=facebook HTTP/1.1" 302 0 
Traceback (most recent call last):
  File "C:\Python27\lib\wsgiref\handlers.py", line 86, in run
    self.finish_response()
  File "C:\Python27\lib\wsgiref\handlers.py", line 128, in finish_response
    self.write(data)
  File "C:\Python27\lib\wsgiref\handlers.py", line 204, in write
    assert type(data) is StringType, "write() argument must be string"
AssertionError: write() argument must be string

这告诉我们某些东西应该是字符串，但实际上不是。再次查看 visit()，在 return 行，揭示了问题。您 returning [1] 而不是 ['1']。修复该错误会使一切正常。您会发现 PEP 333

中记录了此行为

The start_response callable must return a write(body_data) callable that takes one positional parameter: a string to be written as part of the HTTP response body.

最后，根据 this answer，您可能应该使用 '302 Found' 状态而不是 '301 Moved Permanently' 进行重定向，但无论哪种方式都有效。

用这个替换函数应该可以解决您的问题：

def visit(environ, start_response):
    qs = parse_qs(environ['QUERY_STRING'])
    dest = qs.get('site')[0]
    if dest == 'google':
        start_response('302 Found', [('Location','http://google.com')])
    else:
        start_response('302 Found', [('Location','http://facebook.com')])

    return ['1']

使用 WSGI（无框架）将用户重定向到 url

Redirect a user to url with WSGI (no framework)

python

python-2.7

redirect

wsgi

wsgiref