def _parseRemoteInterface(self, iname, attrs):
remote_attrs = {}
remote_name = attrs.get("__remote_name__", iname)
# and see if there is a __remote_name__ . We delete it because
# InterfaceClass doesn't like arbitrary attributes
if attrs.has_key("__remote_name__"):
del attrs["__remote_name__"]
# determine all remotely-callable methods
names = [
name
for name in attrs.keys()
if (
(type(attrs[name]) == types.FunctionType and not name.startswith("_"))
or IConstraint.providedBy(attrs[name])
)
]
# turn them into constraints. Tag each of them with their name and
# the RemoteInterface they came from.
for name in names:
m = attrs[name]
if not IConstraint.providedBy(m):
m = RemoteMethodSchema(method=m)
m.name = name
m.interface = self
remote_attrs[name] = m
# delete the methods, so zope's InterfaceClass doesn't see them.
# Particularly necessary for things defined with IConstraints.
del attrs[name]
return remote_name, remote_attrs
class SetConstraint(OpenerConstraint):
"""The object must be a Set of some sort, with a given maximum size. To
accept sets of any size, use maxLength=None. All member objects must obey
the given constraint. By default this will accept both mutable and
immutable sets, if you want to require a particular type, set mutable= to
either True or False.
"""
# TODO: if mutable!=None, we won't throw out the wrong set type soon
# enough. We need to override checkOpenType to accomplish this.
opentypes = [("set",), ("immutable-set",)]
name = "SetConstraint"
def __init__(self, constraint, maxLength=None, mutable=None):
self.constraint = IConstraint(constraint)
self.maxLength = maxLength
self.mutable = mutable
def checkObject(self, obj, inbound):
if not isinstance(obj, (set, frozenset)):
raise Violation("not a set")
if (self.mutable == True and
not isinstance(obj, set)):
raise Violation("obj is a set, but not a mutable one")
if (self.mutable == False and
not isinstance(obj, frozenset)):
raise Violation("obj is a set, but not an immutable one")
if self.maxLength is not None and len(obj) > self.maxLength:
raise Violation("set is too large")
if self.constraint:
for o in obj:
self.constraint.checkObject(o, inbound)
class DictConstraint(OpenerConstraint):
opentypes = [("dict",)]
name = "DictConstraint"
def __init__(self, keyConstraint, valueConstraint, maxKeys=None):
self.keyConstraint = IConstraint(keyConstraint)
self.valueConstraint = IConstraint(valueConstraint)
self.maxKeys = maxKeys
def checkObject(self, obj, inbound):
if not isinstance(obj, dict):
raise Violation, "'%s' (%s) is not a Dictionary" % (obj,
type(obj))
if self.maxKeys != None and len(obj) > self.maxKeys:
raise Violation, "Dict keys=%d > maxKeys=%d" % (len(obj),
self.maxKeys)
for key, value in obj.iteritems():
self.keyConstraint.checkObject(key, inbound)
self.valueConstraint.checkObject(value, inbound)
def adapt_obj_to_iconstraint(iface, t):
if iface is not IConstraint:
return None
assert not IConstraint.providedBy(t) # not sure about this
c = constraintMap.get(t, None)
if c:
return c
for (typ, constraintMaker) in constraintTypeMap:
if isinstance(t, typ):
c = constraintMaker(t)
if c:
return c
# RIFoo means accept either a Referenceable that implements RIFoo, or a
# RemoteReference that points to just such a Referenceable. This is
# hooked in by remoteinterface.py, when it calls addToConstraintTypeMap
# we are the only way to make constraints
raise UnknownSchemaType("can't make constraint from '%s' (%s)" %
(t, type(t)))
def __init__(self, *elemConstraints):
self.constraints = [IConstraint(e) for e in elemConstraints]
class RemoteReference(RemoteReferenceOnly):
def callRemote(self, _name, *args, **kwargs):
# Note: for consistency, *all* failures are reported asynchronously.
return defer.maybeDeferred(self._callRemote, _name, *args, **kwargs)
def callRemoteOnly(self, _name, *args, **kwargs):
# the remote end will not send us a response. The only error cases
# are arguments that don't match the schema, or broken invariants. In
# particular, DeadReferenceError will be silently consumed.
d = defer.maybeDeferred(self._callRemote, _name, _callOnly=True,
*args, **kwargs)
del d
return None
def _callRemote(self, _name, *args, **kwargs):
req = None
broker = self.tracker.broker
# remember that "none" is not a valid constraint, so we use it to
# mean "not set by the caller", which means we fall back to whatever
# the RemoteInterface says. Using None would mean an AnyConstraint,
# which is not the same thing.
methodConstraintOverride = kwargs.get("_methodConstraint", "none")
resultConstraint = kwargs.get("_resultConstraint", "none")
useSchema = kwargs.get("_useSchema", True)
callOnly = kwargs.get("_callOnly", False)
if "_methodConstraint" in kwargs:
del kwargs["_methodConstraint"]
if "_resultConstraint" in kwargs:
del kwargs["_resultConstraint"]
if "_useSchema" in kwargs:
del kwargs["_useSchema"]
if "_callOnly" in kwargs:
del kwargs["_callOnly"]
if callOnly:
if broker.disconnected:
# DeadReferenceError is silently consumed
return
reqID = 0
else:
# newRequestID() could fail with a DeadReferenceError
reqID = broker.newRequestID()
# in this section, we validate the outbound arguments against our
# notion of what the other end will accept (the RemoteInterface)
# first, figure out which method they want to invoke
(interfaceName,
methodName,
methodSchema) = self._getMethodInfo(_name)
req = call.PendingRequest(reqID, self, interfaceName, methodName)
# TODO: consider adding a stringified stack trace to that
# PendingRequest creation, so that DeadReferenceError can emit even
# more information about the call which failed
# for debugging: these are put into the messages emitted when
# logRemoteFailures is turned on
req.interfaceName = interfaceName
req.methodName = methodName
if methodConstraintOverride != "none":
methodSchema = methodConstraintOverride
if useSchema and methodSchema:
# check args against the arg constraint. This could fail if
# any arguments are of the wrong type
try:
methodSchema.checkAllArgs(args, kwargs, False)
except Violation, v:
v.setLocation("%s.%s(%s)" % (interfaceName, methodName,
v.getLocation()))
raise
# the Interface gets to constraint the return value too, so
# make a note of it to use later
req.setConstraint(methodSchema.getResponseConstraint())
# if the caller specified a _resultConstraint, that overrides
# the schema's one
if resultConstraint != "none":
# overrides schema
req.setConstraint(IConstraint(resultConstraint))
clid = self.tracker.clid
slicer = call.CallSlicer(reqID, clid, methodName, args, kwargs)
# up to this point, we are not committed to sending anything to the
# far end. The various phases of commitment are:
# 1: once we tell our broker about the PendingRequest, we must
# promise to retire it eventually. Specifically, if we encounter an
# error before we give responsibility to the connection, we must
# retire it ourselves.
# 2: once we start sending the CallSlicer to the other end (in
# particular, once they receive the reqID), they might send us a
# response, so we must be prepared to handle that. Giving the
# PendingRequest to the broker arranges for this to happen.
# So all failures which occur before these commitment events are
# entirely local: stale broker, bad method name, bad arguments. If
# anything raises an exception before this point, the PendingRequest
# is abandoned, and our maybeDeferred wrapper returns a failing
# Deferred.
# commitment point 1. We assume that if this call raises an
# exception, the broker will be sure to not track the dead
# PendingRequest
if not callOnly:
broker.addRequest(req)
# if callOnly, the PendingRequest will never know about the
# broker, and will therefore never ask to be removed from it
# TODO: there is a decidability problem here: if the reqID made
# it through, the other end will send us an answer (possibly an
# error if the remaining slices were aborted). If not, we will
# not get an answer. To decide whether we should remove our
# broker.waitingForAnswers[] entry, we need to know how far the
# slicing process made it.
try:
# commitment point 2
d = broker.send(slicer)
# d will fire when the last argument has been serialized. It will
# errback if the arguments (or any of their children) could not
# be serialized. We need to catch this case and errback the
# caller.
# if we got here, we have been able to start serializing the
# arguments. If serialization fails, the PendingRequest needs to
# be flunked (because we aren't guaranteed that the far end will
# do it).
d.addErrback(req.fail)
except:
req.fail(failure.Failure())
# the remote end could send back an error response for many reasons:
# bad method name
# bad argument types (violated their schema)
# exception during method execution
# method result violated the results schema
# something else could occur to cause an errback:
# connection lost before response completely received
# exception during deserialization of the response
# [but only if it occurs after the reqID is received]
# method result violated our results schema
# if none of those occurred, the callback will be run
return req.deferred
def __init__(self, keyConstraint, valueConstraint, maxKeys=None):
self.keyConstraint = IConstraint(keyConstraint)
self.valueConstraint = IConstraint(valueConstraint)
self.maxKeys = maxKeys
class RemoteMethodSchema(object):
"""
This is a constraint for a single remotely-invokable method. It gets to
require, deny, or impose further constraints upon a set of named
arguments.
This constraint is created by using keyword arguments with the same
names as the target method's arguments. Two special names are used:
__ignoreUnknown__: if True, unexpected argument names are silently
dropped. (note that this makes the schema unbounded)
__acceptUnknown__: if True, unexpected argument names are always
accepted without a constraint (which also makes this schema unbounded)
The remotely-accesible object's .getMethodSchema() method may return one
of these objects.
"""
taster = {} # this should not be used as a top-level constraint
opentypes = [] # overkill
ignoreUnknown = False
acceptUnknown = False
name = None # method name, set when the RemoteInterface is parsed
interface = None # points to the RemoteInterface which defines the method
# under development
def __init__(self, method=None, _response=None, __options=[], **kwargs):
if method:
self.initFromMethod(method)
return
self.argumentNames = []
self.argConstraints = {}
self.required = []
self.responseConstraint = None
# __response in the argslist gets treated specially, I think it is
# mangled into _RemoteMethodSchema__response or something. When I
# change it to use _response instead, it works.
if _response:
self.responseConstraint = IConstraint(_response)
self.options = {} # return, wait, reliable, etc
if "__ignoreUnknown__" in kwargs:
self.ignoreUnknown = kwargs["__ignoreUnknown__"]
del kwargs["__ignoreUnknown__"]
if "__acceptUnknown__" in kwargs:
self.acceptUnknown = kwargs["__acceptUnknown__"]
del kwargs["__acceptUnknown__"]
for argname, constraint in list(kwargs.items()):
self.argumentNames.append(argname)
constraint = IConstraint(constraint)
self.argConstraints[argname] = constraint
if not isinstance(constraint, Optional):
self.required.append(argname)
def initFromMethod(self, method):
# call this with the Interface's prototype method: the one that has
# argument constraints expressed as default arguments, and which
# does nothing but returns the appropriate return type
names, _, _, typeList = inspect.getargspec(method)
if names and names[0] == 'self':
why = "RemoteInterface methods should not have 'self' in their argument list"
raise InvalidRemoteInterface(why)
if not names:
typeList = []
# 'def foo(oops)' results in typeList==None
if typeList is None or len(names) != len(typeList):
# TODO: relax this, use schema=Any for the args that don't have
# default values. This would make:
# def foo(a, b=int): return None
# equivalent to:
# def foo(a=Any, b=int): return None
why = "RemoteInterface methods must have default values for all their arguments"
raise InvalidRemoteInterface(why)
self.argumentNames = names
self.argConstraints = {}
self.required = []
for i in range(len(names)):
argname = names[i]
constraint = typeList[i]
if not isinstance(constraint, Optional):
self.required.append(argname)
self.argConstraints[argname] = IConstraint(constraint)
# call the method, its 'return' value is the return constraint
self.responseConstraint = IConstraint(method())
self.options = {} # return, wait, reliable, etc
def getPositionalArgConstraint(self, argnum):
if argnum >= len(self.argumentNames):
raise Violation("too many positional arguments: %d >= %d" %
(argnum, len(self.argumentNames)))
argname = self.argumentNames[argnum]
c = self.argConstraints.get(argname)
assert c
if isinstance(c, Optional):
c = c.constraint
return (True, c)
def getKeywordArgConstraint(self,
argname,
num_posargs=0,
previous_kwargs=[]):
previous_args = self.argumentNames[:num_posargs]
for pkw in previous_kwargs:
assert pkw not in previous_args
previous_args.append(pkw)
if argname in previous_args:
raise Violation("got multiple values for keyword argument '%s'" %
(argname, ))
c = self.argConstraints.get(argname)
if c:
if isinstance(c, Optional):
c = c.constraint
return (True, c)
# what do we do with unknown arguments?
if self.ignoreUnknown:
return (False, None)
if self.acceptUnknown:
return (True, None)
raise Violation("unknown argument '%s'" % argname)
def getResponseConstraint(self):
return self.responseConstraint
def checkAllArgs(self, args, kwargs, inbound):
# first we map the positional arguments
allargs = {}
if len(args) > len(self.argumentNames):
raise Violation("method takes %d positional arguments (%d given)" %
(len(self.argumentNames), len(args)))
for i, argvalue in enumerate(args):
allargs[self.argumentNames[i]] = argvalue
for argname, argvalue in list(kwargs.items()):
if argname in allargs:
raise Violation(
"got multiple values for keyword argument '%s'" %
(argname, ))
allargs[argname] = argvalue
for argname, argvalue in list(allargs.items()):
accept, constraint = self.getKeywordArgConstraint(argname)
if not accept:
# this argument will be ignored by the far end. TODO: emit a
# warning
pass
try:
constraint.checkObject(argvalue, inbound)
except Violation as v:
v.setLocation("%s=" % argname)
raise
for argname in self.required:
if argname not in allargs:
raise Violation("missing required argument '%s'" % argname)
def checkResults(self, results, inbound):
if self.responseConstraint:
# this might raise a Violation. The caller will annotate its
# location appropriately: they have more information than we do.
self.responseConstraint.checkObject(results, inbound)
def __init__(self, constraint, maxLength=None, mutable=None):
self.constraint = IConstraint(constraint)
self.maxLength = maxLength
self.mutable = mutable
def __init__(self, *alternatives):
self.alternatives = [IConstraint(a) for a in alternatives]
self.alternatives = tuple(self.alternatives)
def __init__(self, keyConstraint, valueConstraint, maxKeys=None):
self.keyConstraint = IConstraint(keyConstraint)
self.valueConstraint = IConstraint(valueConstraint)
self.maxKeys = maxKeys
def __init__(self, constraint, maxLength=None, minLength=0):
self.constraint = IConstraint(constraint)
self.maxLength = maxLength
self.minLength = minLength
def __init__(self, constraint, maxLength=None, mutable=None):
self.constraint = IConstraint(constraint)
self.maxLength = maxLength
self.mutable = mutable
