def get_header(self, name, required=False, default=None, _name_cache={}):
"""Retrieve the raw string value for the given header.
Args:
name (str): Header name, case-insensitive (e.g., 'Content-Type')
Keyword Args:
required (bool): Set to ``True`` to raise
``HTTPBadRequest`` instead of returning gracefully when the
header is not found (default ``False``).
default (any): Value to return if the header
is not found (default ``None``).
Returns:
str: The value of the specified header if it exists, or
the default value if the header is not found and is not
required.
Raises:
HTTPBadRequest: The header was not found in the request, but
it was required.
"""
try:
asgi_name = _name_cache[name]
except KeyError:
asgi_name = name.lower().encode('latin1')
if len(_name_cache
) < 64: # Somewhat arbitrary ceiling to mitigate abuse
_name_cache[name] = asgi_name
# Use try..except to optimize for the header existing in most cases
try:
# Don't take the time to cache beforehand, using HTTP naming.
# This will be faster, assuming that most headers are looked
# up only once, and not all headers will be requested.
return self._asgi_headers[asgi_name].decode('latin1')
except KeyError:
if not required:
return default
raise errors.HTTPMissingHeader(name)
def get_header(self, name, required=False):
"""Retrieve the raw string value for the given header.
Args:
name (str): Header name, case-insensitive (e.g., 'Content-Type')
required (bool, optional): Set to ``True`` to raise
``HTTPBadRequest`` instead of returning gracefully when the
header is not found (default ``False``).
Returns:
str: The value of the specified header if it exists, or ``None`` if
the header is not found and is not required.
Raises:
HTTPBadRequest: The header was not found in the request, but
it was required.
"""
wsgi_name = name.upper().replace('-', '_')
# Use try..except to optimize for the header existing in most cases
try:
# Don't take the time to cache beforehand, using HTTP naming.
# This will be faster, assuming that most headers are looked
# up only once, and not all headers will be requested.
return self.env['HTTP_' + wsgi_name]
except KeyError:
# NOTE(kgriffs): There are a couple headers that do not
# use the HTTP prefix in the env, so try those. We expect
# people to usually just use the relevant helper properties
# to access these instead of .get_header.
if wsgi_name in WSGI_CONTENT_HEADERS:
try:
return self.env[wsgi_name]
except KeyError:
pass
if not required:
return None
raise errors.HTTPMissingHeader(name)
