Lib/wsgiref/util.py

   1 """Miscellaneous WSGI-related Utilities"""
   2
   3 import posixpath
   4
   5 __all__ = [
   6     'FileWrapper', 'guess_scheme', 'application_uri', 'request_uri',
   7     'shift_path_info', 'setup_testing_defaults',
   8 ]
   9
  10
  11 class FileWrapper:
  12     """Wrapper to convert file-like objects to iterables"""
  13
  14     def __init__(self, filelike, blksize=8192):
  15         self.filelike = filelike
  16         self.blksize = blksize
  17         if hasattr(filelike,'close'):
  18             self.close = filelike.close
  19
  20     def __getitem__(self,key):
  21         data = self.filelike.read(self.blksize)
  22         if data:
  23             return data
  24         raise IndexError
  25
  26     def __iter__(self):
  27         return self
  28
  29     def next(self):
  30         data = self.filelike.read(self.blksize)
  31         if data:
  32             return data
  33         raise StopIteration
  34
  35
  36
  37
  38
  39
  40
  41
  42 def guess_scheme(environ):
  43     """Return a guess for whether 'wsgi.url_scheme' should be 'http' or 'https'
  44     """
  45     if environ.get("HTTPS") in ('yes','on','1'):
  46         return 'https'
  47     else:
  48         return 'http'
  49
  50 def application_uri(environ):
  51     """Return the application's base URI (no PATH_INFO or QUERY_STRING)"""
  52     url = environ['wsgi.url_scheme']+'://'
  53     from urllib import quote
  54
  55     if environ.get('HTTP_HOST'):
  56         url += environ['HTTP_HOST']
  57     else:
  58         url += environ['SERVER_NAME']
  59
  60         if environ['wsgi.url_scheme'] == 'https':
  61             if environ['SERVER_PORT'] != '443':
  62                 url += ':' + environ['SERVER_PORT']
  63         else:
  64             if environ['SERVER_PORT'] != '80':
  65                 url += ':' + environ['SERVER_PORT']
  66
  67     url += quote(environ.get('SCRIPT_NAME') or '/')
  68     return url
  69
  70 def request_uri(environ, include_query=1):
  71     """Return the full request URI, optionally including the query string"""
  72     url = application_uri(environ)
  73     from urllib import quote
  74     path_info = quote(environ.get('PATH_INFO',''))
  75     if not environ.get('SCRIPT_NAME'):
  76         url += path_info[1:]
  77     else:
  78         url += path_info
  79     if include_query and environ.get('QUERY_STRING'):
  80         url += '?' + environ['QUERY_STRING']
  81     return url
  82
  83 def shift_path_info(environ):
  84     """Shift a name from PATH_INFO to SCRIPT_NAME, returning it
  85
  86     If there are no remaining path segments in PATH_INFO, return None.
  87     Note: 'environ' is modified in-place; use a copy if you need to keep
  88     the original PATH_INFO or SCRIPT_NAME.
  89
  90     Note: when PATH_INFO is just a '/', this returns '' and appends a trailing
  91     '/' to SCRIPT_NAME, even though empty path segments are normally ignored,
  92     and SCRIPT_NAME doesn't normally end in a '/'.  This is intentional
  93     behavior, to ensure that an application can tell the difference between
  94     '/x' and '/x/' when traversing to objects.
  95     """
  96     path_info = environ.get('PATH_INFO','')
  97     if not path_info:
  98         return None
  99
 100     path_parts = path_info.split('/')
 101     path_parts[1:-1] = [p for p in path_parts[1:-1] if p and p != '.']
 102     name = path_parts[1]
 103     del path_parts[1]
 104
 105     script_name = environ.get('SCRIPT_NAME','')
 106     script_name = posixpath.normpath(script_name+'/'+name)
 107     if script_name.endswith('/'):
 108         script_name = script_name[:-1]
 109     if not name and not script_name.endswith('/'):
 110         script_name += '/'
 111
 112     environ['SCRIPT_NAME'] = script_name
 113     environ['PATH_INFO']   = '/'.join(path_parts)
 114
 115     # Special case: '/.' on PATH_INFO doesn't get stripped,
 116     # because we don't strip the last element of PATH_INFO
 117     # if there's only one path part left.  Instead of fixing this
 118     # above, we fix it here so that PATH_INFO gets normalized to
 119     # an empty string in the environ.
 120     if name=='.':
 121         name = None
 122     return name
 123
 124 def setup_testing_defaults(environ):
 125     """Update 'environ' with trivial defaults for testing purposes
 126
 127     This adds various parameters required for WSGI, including HTTP_HOST,
 128     SERVER_NAME, SERVER_PORT, REQUEST_METHOD, SCRIPT_NAME, PATH_INFO,
 129     and all of the wsgi.* variables.  It only supplies default values,
 130     and does not replace any existing settings for these variables.
 131
 132     This routine is intended to make it easier for unit tests of WSGI
 133     servers and applications to set up dummy environments.  It should *not*
 134     be used by actual WSGI servers or applications, since the data is fake!
 135     """
 136
 137     environ.setdefault('SERVER_NAME','127.0.0.1')
 138     environ.setdefault('SERVER_PROTOCOL','HTTP/1.0')
 139
 140     environ.setdefault('HTTP_HOST',environ['SERVER_NAME'])
 141     environ.setdefault('REQUEST_METHOD','GET')
 142
 143     if 'SCRIPT_NAME' not in environ and 'PATH_INFO' not in environ:
 144         environ.setdefault('SCRIPT_NAME','')
 145         environ.setdefault('PATH_INFO','/')
 146
 147     environ.setdefault('wsgi.version', (1,0))
 148     environ.setdefault('wsgi.run_once', 0)
 149     environ.setdefault('wsgi.multithread', 0)
 150     environ.setdefault('wsgi.multiprocess', 0)
 151
 152     from StringIO import StringIO
 153     environ.setdefault('wsgi.input', StringIO(""))
 154     environ.setdefault('wsgi.errors', StringIO())
 155     environ.setdefault('wsgi.url_scheme',guess_scheme(environ))
 156
 157     if environ['wsgi.url_scheme']=='http':
 158         environ.setdefault('SERVER_PORT', '80')
 159     elif environ['wsgi.url_scheme']=='https':
 160         environ.setdefault('SERVER_PORT', '443')
 161
 162
 163
 164
 165 _hoppish = {
 166     'connection':1, 'keep-alive':1, 'proxy-authenticate':1,
 167     'proxy-authorization':1, 'te':1, 'trailers':1, 'transfer-encoding':1,
 168     'upgrade':1
 169 }.__contains__
 170
 171 def is_hop_by_hop(header_name):
 172     """Return true if 'header_name' is an HTTP/1.1 "Hop-by-Hop" header"""
 173     return _hoppish(header_name.lower())
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 205 #