Imported from SVN by Bitbucket

Paste-1.7.5.1-py2.6.egg/paste/response.py

@@ -0,0 +1,240 @@
+# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
+# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
+"""Routines to generate WSGI responses"""
+
+############################################################
+## Headers
+############################################################
+import warnings
+
+class HeaderDict(dict):
+
+    """
+    This represents response headers.  It handles the headers as a
+    dictionary, with case-insensitive keys.
+
+    Also there is an ``.add(key, value)`` method, which sets the key,
+    or adds the value to the current value (turning it into a list if
+    necessary).
+
+    For passing to WSGI there is a ``.headeritems()`` method which is
+    like ``.items()`` but unpacks value that are lists.  It also
+    handles encoding -- all headers are encoded in ASCII (if they are
+    unicode).
+
+    @@: Should that encoding be ISO-8859-1 or UTF-8?  I'm not sure
+    what the spec says.
+    """
+
+    def __getitem__(self, key):
+        return dict.__getitem__(self, self.normalize(key))
+
+    def __setitem__(self, key, value):
+        dict.__setitem__(self, self.normalize(key), value)
+
+    def __delitem__(self, key):
+        dict.__delitem__(self, self.normalize(key))
+
+    def __contains__(self, key):
+        return dict.__contains__(self, self.normalize(key))
+
+    has_key = __contains__
+
+    def get(self, key, failobj=None):
+        return dict.get(self, self.normalize(key), failobj)
+
+    def setdefault(self, key, failobj=None):
+        return dict.setdefault(self, self.normalize(key), failobj)
+
+    def pop(self, key, *args):
+        return dict.pop(self, self.normalize(key), *args)
+
+    def update(self, other):
+        for key in other:
+            self[self.normalize(key)] = other[key]
+
+    def normalize(self, key):
+        return str(key).lower().strip()
+
+    def add(self, key, value):
+        key = self.normalize(key)
+        if key in self:
+            if isinstance(self[key], list):
+                self[key].append(value)
+            else:
+                self[key] = [self[key], value]
+        else:
+            self[key] = value
+
+    def headeritems(self):
+        result = []
+        for key, value in self.items():
+            if isinstance(value, list):
+                for v in value:
+                    result.append((key, str(v)))
+            else:
+                result.append((key, str(value)))
+        return result
+
+    #@classmethod
+    def fromlist(cls, seq):
+        self = cls()
+        for name, value in seq:
+            self.add(name, value)
+        return self
+
+    fromlist = classmethod(fromlist)
+
+def has_header(headers, name):
+    """
+    Is header named ``name`` present in headers?
+    """
+    name = name.lower()
+    for header, value in headers:
+        if header.lower() == name:
+            return True
+    return False
+
+def header_value(headers, name):
+    """
+    Returns the header's value, or None if no such header.  If a
+    header appears more than once, all the values of the headers
+    are joined with ','.   Note that this is consistent /w RFC 2616
+    section 4.2 which states:
+
+        It MUST be possible to combine the multiple header fields
+        into one "field-name: field-value" pair, without changing
+        the semantics of the message, by appending each subsequent
+        field-value to the first, each separated by a comma.
+
+    However, note that the original netscape usage of 'Set-Cookie',
+    especially in MSIE which contains an 'expires' date will is not
+    compatible with this particular concatination method.
+    """
+    name = name.lower()
+    result = [value for header, value in headers
+              if header.lower() == name]
+    if result:
+        return ','.join(result)
+    else:
+        return None
+
+def remove_header(headers, name):
+    """
+    Removes the named header from the list of headers.  Returns the
+    value of that header, or None if no header found.  If multiple
+    headers are found, only the last one is returned.
+    """
+    name = name.lower()
+    i = 0
+    result = None
+    while i < len(headers):
+        if headers[i][0].lower() == name:
+            result = headers[i][1]
+            del headers[i]
+            continue
+        i += 1
+    return result
+
+def replace_header(headers, name, value):
+    """
+    Updates the headers replacing the first occurance of the given name
+    with the value provided; asserting that no further occurances
+    happen. Note that this is _not_ the same as remove_header and then
+    append, as two distinct operations (del followed by an append) are
+    not atomic in a threaded environment. Returns the previous header
+    value for the provided name, if any.   Clearly one should not use
+    this function with ``set-cookie`` or other names that may have more
+    than one occurance in the headers.
+    """
+    name = name.lower()
+    i = 0
+    result = None
+    while i < len(headers):
+        if headers[i][0].lower() == name:
+            assert not result, "two values for the header '%s' found" % name
+            result = headers[i][1]
+            headers[i] = (name, value)
+        i += 1
+    if not result:
+        headers.append((name, value))
+    return result
+
+
+############################################################
+## Deprecated methods
+############################################################
+
+def error_body_response(error_code, message, __warn=True):
+    """
+    Returns a standard HTML response page for an HTTP error.
+    **Note:** Deprecated
+    """
+    if __warn:
+        warnings.warn(
+            'wsgilib.error_body_response is deprecated; use the '
+            'wsgi_application method on an HTTPException object '
+            'instead', DeprecationWarning, 2)
+    return '''\
+<html>
+  <head>
+    <title>%(error_code)s</title>
+  </head>
+  <body>
+  <h1>%(error_code)s</h1>
+  %(message)s
+  </body>
+</html>''' % {
+        'error_code': error_code,
+        'message': message,
+        }
+
+
+def error_response(environ, error_code, message,
+                   debug_message=None, __warn=True):
+    """
+    Returns the status, headers, and body of an error response.
+
+    Use like:
+
+    .. code-block:: python
+
+        status, headers, body = wsgilib.error_response(
+            '301 Moved Permanently', 'Moved to <a href="%s">%s</a>'
+            % (url, url))
+        start_response(status, headers)
+        return [body]
+
+    **Note:** Deprecated
+    """
+    if __warn:
+        warnings.warn(
+            'wsgilib.error_response is deprecated; use the '
+            'wsgi_application method on an HTTPException object '
+            'instead', DeprecationWarning, 2)
+    if debug_message and environ.get('paste.config', {}).get('debug'):
+        message += '\n\n<!-- %s -->' % debug_message
+    body = error_body_response(error_code, message, __warn=False)
+    headers = [('content-type', 'text/html'),
+               ('content-length', str(len(body)))]
+    return error_code, headers, body
+
+def error_response_app(error_code, message, debug_message=None,
+                       __warn=True):
+    """
+    An application that emits the given error response.
+
+    **Note:** Deprecated
+    """
+    if __warn:
+        warnings.warn(
+            'wsgilib.error_response_app is deprecated; use the '
+            'wsgi_application method on an HTTPException object '
+            'instead', DeprecationWarning, 2)
+    def application(environ, start_response):
+        status, headers, body = error_response(
+            environ, error_code, message,
+            debug_message=debug_message, __warn=False)
+        start_response(status, headers)
+        return [body]
+    return application