def hydrate(cls, db, limit):
"""
Given a limit dict, as generated by dehydrate(), generate an
appropriate instance of Limit (or a subclass). If the
required limit class cannot be found, returns None.
"""
# Extract the limit name from the keyword arguments
cls_name = limit.pop('limit_class')
# Is it in the registry yet?
if cls_name not in cls._registry:
try:
utils.import_class(cls_name)
except ImportError:
# If we failed to import, ignore...
pass
# Look it up in the registry
cls = cls._registry.get(cls_name)
# Instantiate the thing
return cls(db, **limit) if cls else None
def turnstile_filter(global_conf, **local_conf):
"""
Factory function for turnstile.
Returns a function which, when passed the application, returns an
instance of the TurnstileMiddleware.
"""
# Select the appropriate middleware class to return
klass = TurnstileMiddleware
if 'turnstile' in local_conf:
klass = utils.import_class(local_conf['turnstile'])
def wrapper(app):
return klass(app, local_conf)
return wrapper
def __init__(self, app, local_conf):
"""
Initialize the turnstile middleware. Saves the configuration
and sets up the list of preprocessors, connects to the
database, and initiates the control daemon thread.
"""
# Save the application
self.app = app
self.limits = []
self.mapper = None
# Split up the configuration into groups of related variables
self.config = {
None: {
'status': '413 Request Entity Too Large',
},
}
for key, value in local_conf.items():
outer, _sep, inner = key.partition('.')
# Deal with prefix-less keys
if not inner:
outer, inner = None, outer
# Make sure we have a place to put them
self.config.setdefault(outer, {})
self.config[outer][inner] = value
# Set up request preprocessors
self.preprocessors = []
for preproc in self.config[None].get('preprocess', '').split():
# Allow ImportError to bubble up
self.preprocessors.append(utils.import_class(preproc))
# Next, let's configure redis
redis_args = self.config.get('redis', {})
self.db = database.initialize(redis_args)
# And start up the control daemon
control_args = self.config.get('control', {})
self.control_daemon = database.ControlDaemon(self.db, self,
control_args)
def parse_limit_node(db, idx, limit):
"""
Given an XML node describing a limit, return a Limit object.
:param db: Handle for the Redis database.
:param idx: The index of the limit in the XML file; used for error
reporting.
:param limit: The XML node describing the limit.
"""
# First, try to import the class; this will raise ImportError if
# we can't import it
klass = utils.import_class(limit.get('class'))
# Build the list of required attributes
required = set(k for k, v in klass.attrs.items()
if 'default' not in v)
# Now, use introspection on the class to interpret the attributes
attrs = {}
for child in limit:
# Basic validation of child elements
if child.tag != 'attr':
warnings.warn("Unrecognized element %r while parsing limit at "
"index %d; ignoring..." % (child.tag, idx))
continue
# Get the attribute name
attr = child.get('name')
# Be liberal in what we accept--ignore unrecognized attributes
# (with a warning)
if attr not in klass.attrs:
warnings.warn("Limit at index %d does not accept an attribute "
"%r; ignoring..." % (idx, attr))
continue
# OK, get the attribute descriptor
desc = klass.attrs[attr]
# Grab the attribute type
attr_type = desc.get('type', str)
if attr_type == list:
# Lists are expressed as child elements; we ignore the
# child element names
subtype = desc.get('subtype', str)
value = []
for grandchild in child:
if grandchild.tag != 'value':
warnings.warn("Unrecognized element %r while parsing "
"%r attribute of limit at index %d; "
"ignoring..." %
(grandchild.tag, attr, idx))
continue
value.append(subtype(grandchild.text))
elif attr_type == dict:
# Dicts are expressed as child elements, with the tags
# identifying the attribute name
subtype = desc.get('subtype', str)
value = {}
for grandchild in child:
if grandchild.tag != 'value':
warnings.warn("Unrecognized element %r while parsing "
"%r attribute of limit at index %d; "
"ignoring..." %
(grandchild.tag, attr, idx))
continue
elif 'key' not in grandchild.attrib:
warnings.warn("Missing 'key' attribute of 'value' "
"element while parsing %r attribute of "
"limit at index %d; ignoring..." %
(attr, idx))
continue
value[grandchild.get('key')] = subtype(grandchild.text)
else:
# Simple type conversion
value = attr_type(child.text)
# Save the attribute
attrs[attr] = value
# Remove from the required set
required.discard(attr)
# Did we get all required attributes?
if required:
raise TypeError("Missing required attributes %s" %
(', '.join(repr(a) for a in sorted(required))))
# OK, instantiate and return the class
return klass(db, **attrs)
def initialize(config):
"""
Initialize a connection to the Redis database.
"""
# Extract relevant connection information from the configuration
kwargs = {}
for cfg_var, type_ in [('host', str), ('port', int), ('db', int),
('password', str), ('socket_timeout', int),
('unix_socket_path', str)]:
if cfg_var in config:
kwargs[cfg_var] = type_(config[cfg_var])
# Make sure we have at a minimum the hostname
if 'host' not in kwargs and 'unix_socket_path' not in kwargs:
raise redis.ConnectionError("No host specified for redis database")
# Look up the connection pool configuration
cpool_class = None
cpool = {}
for key, value in config.items():
if key.startswith('connection_pool.'):
_dummy, _sep, varname = key.partition('.')
if varname == 'connection_class':
cpool[varname] = utils.import_class(value)
elif varname == 'max_connections':
cpool[varname] = int(value)
elif varname == 'parser_class':
cpool[varname] = utils.import_class(value)
else:
cpool[varname] = value
if cpool:
cpool_class = redis.ConnectionPool
# Use custom connection pool class if requested...
if 'connection_pool' in config:
cpool_class = utils.import_class(config['connection_pool'])
# If we're using a connection pool, we'll need to pass the keyword
# arguments to that instead of to redis
if cpool_class:
cpool.update(kwargs)
# Use a custom connection class?
if 'connection_class' not in cpool:
if 'unix_socket_path' in cpool:
if 'host' in cpool:
del cpool['host']
if 'port' in cpool:
del cpool['port']
cpool['path'] = cpool['unix_socket_path']
del cpool['unix_socket_path']
cpool['connection_class'] = redis.UnixDomainSocketConnection
else:
cpool['connection_class'] = redis.Connection
# Build the connection pool to use and set up to pass it into
# the redis constructor...
kwargs = dict(connection_pool=cpool_class(**cpool))
# Build and return the database
return TurnstileRedis(**kwargs)
