"""Support for dynamic COM client support.
Introduction
Dynamic COM client support is the ability to use a COM server without
prior knowledge of the server. This can be used to talk to almost all
COM servers, including much of MS Office.
In general, you should not use this module directly - see below.
Example
>>> import win32com.client
>>> xl = win32com.client.Dispatch("Excel.Application")
# The line above invokes the functionality of this class.
# xl is now an object we can use to talk to Excel.
>>> xl.Visible = 1 # The Excel window becomes visible.
"""
import traceback
from itertools import chain
from types import MethodType
import pythoncom # Needed as code we eval() references it.
import win32com.client
import winerror
from pywintypes import IIDType
from . import build
debugging = 0 # General debugging
debugging_attr = 0 # Debugging dynamic attribute lookups.
LCID = 0x0
# These errors generally mean the property or method exists,
# but can't be used in this context - eg, property instead of a method, etc.
# Used to determine if we have a real error or not.
ERRORS_BAD_CONTEXT = [
winerror.DISP_E_MEMBERNOTFOUND,
winerror.DISP_E_BADPARAMCOUNT,
winerror.DISP_E_PARAMNOTOPTIONAL,
winerror.DISP_E_TYPEMISMATCH,
winerror.E_INVALIDARG,
]
ALL_INVOKE_TYPES = [
pythoncom.INVOKE_PROPERTYGET,
pythoncom.INVOKE_PROPERTYPUT,
pythoncom.INVOKE_PROPERTYPUTREF,
pythoncom.INVOKE_FUNC,
]
def debug_print(*args):
if debugging:
for arg in args:
print(arg, end=" ")
print()
def debug_attr_print(*args):
if debugging_attr:
for arg in args:
print(arg, end=" ")
print()
# get the type objects for IDispatch and IUnknown
PyIDispatchType = pythoncom.TypeIIDs[pythoncom.IID_IDispatch]
PyIUnknownType = pythoncom.TypeIIDs[pythoncom.IID_IUnknown]
_GoodDispatchTypes = (str, IIDType)
def _GetGoodDispatch(IDispatch, clsctx=pythoncom.CLSCTX_SERVER):
# quick return for most common case
if isinstance(IDispatch, PyIDispatchType):
return IDispatch
if isinstance(IDispatch, _GoodDispatchTypes):
try:
IDispatch = pythoncom.connect(IDispatch)
except pythoncom.ole_error:
IDispatch = pythoncom.CoCreateInstance(
IDispatch, None, clsctx, pythoncom.IID_IDispatch
)
else:
# may already be a wrapped class.
IDispatch = getattr(IDispatch, "_oleobj_", IDispatch)
return IDispatch
def _GetGoodDispatchAndUserName(IDispatch, userName, clsctx):
# Get a dispatch object, and a 'user name' (ie, the name as
# displayed to the user in repr() etc.
if userName is None:
if isinstance(IDispatch, str):
userName = IDispatch
## ??? else userName remains None ???
else:
userName = str(userName)
return (_GetGoodDispatch(IDispatch, clsctx), userName)
def _GetDescInvokeType(entry, invoke_type):
# determine the wFlags argument passed as input to IDispatch::Invoke
# Only ever called by __getattr__ and __setattr__ from dynamic objects!
# * `entry` is a MapEntry with whatever typeinfo we have about the property we are getting/setting.
# * `invoke_type` is either INVOKE_PROPERTYGET | INVOKE_PROPERTYSET and really just
# means "called by __getattr__" or "called by __setattr__"
if not entry or not entry.desc:
return invoke_type
if entry.desc.desckind == pythoncom.DESCKIND_VARDESC:
return invoke_type
# So it's a FUNCDESC - just use what it specifies.
return entry.desc.invkind
def Dispatch(
IDispatch,
userName=None,
createClass=None,
typeinfo=None,
clsctx=pythoncom.CLSCTX_SERVER,
):
IDispatch, userName = _GetGoodDispatchAndUserName(IDispatch, userName, clsctx)
if createClass is None:
createClass = CDispatch
lazydata = None
try:
if typeinfo is None:
typeinfo = IDispatch.GetTypeInfo()
if typeinfo is not None:
try:
# try for a typecomp
typecomp = typeinfo.GetTypeComp()
lazydata = typeinfo, typecomp
except pythoncom.com_error:
pass
except pythoncom.com_error:
typeinfo = None
olerepr = MakeOleRepr(IDispatch, typeinfo, lazydata)
return createClass(IDispatch, olerepr, userName, lazydata=lazydata)
def MakeOleRepr(IDispatch, typeinfo, typecomp):
olerepr = None
if typeinfo is not None:
try:
attr = typeinfo.GetTypeAttr()
# If the type info is a special DUAL interface, magically turn it into
# a DISPATCH typeinfo.
if (
attr[5] == pythoncom.TKIND_INTERFACE
and attr[11] & pythoncom.TYPEFLAG_FDUAL
):
# Get corresponding Disp interface;
# -1 is a special value which does this for us.
href = typeinfo.GetRefTypeOfImplType(-1)
typeinfo = typeinfo.GetRefTypeInfo(href)
attr = typeinfo.GetTypeAttr()
if typecomp is None:
olerepr = build.DispatchItem(typeinfo, attr, None, 0)
else:
olerepr = build.LazyDispatchItem(attr, None)
except pythoncom.ole_error:
pass
if olerepr is None:
olerepr = build.DispatchItem()
return olerepr
def DumbDispatch(
IDispatch,
userName=None,
createClass=None,
clsctx=pythoncom.CLSCTX_SERVER,
):
"Dispatch with no type info"
IDispatch, userName = _GetGoodDispatchAndUserName(IDispatch, userName, clsctx)
if createClass is None:
createClass = CDispatch
return createClass(IDispatch, build.DispatchItem(), userName)
class CDispatch:
def __init__(self, IDispatch, olerepr, userName=None, lazydata=None):
if userName is None:
userName = "<unknown>"
self.__dict__["_oleobj_"] = IDispatch
self.__dict__["_username_"] = userName
self.__dict__["_olerepr_"] = olerepr
self.__dict__["_mapCachedItems_"] = {}
self.__dict__["_builtMethods_"] = {}
self.__dict__["_enum_"] = None
self.__dict__["_unicode_to_string_"] = None
self.__dict__["_lazydata_"] = lazydata
def __call__(self, *args):
"Provide 'default dispatch' COM functionality - allow instance to be called"
if self._olerepr_.defaultDispatchName:
invkind, dispid = self._find_dispatch_type_(
self._olerepr_.defaultDispatchName
)
else:
invkind, dispid = (
pythoncom.DISPATCH_METHOD | pythoncom.DISPATCH_PROPERTYGET,
pythoncom.DISPID_VALUE,
)
if invkind is not None:
allArgs = (dispid, LCID, invkind, 1) + args
return self._get_good_object_(
self._oleobj_.Invoke(*allArgs), self._olerepr_.defaultDispatchName, None
)
raise TypeError("This dispatch object does not define a default method")
def __bool__(self):
return True # ie "if object:" should always be "true" - without this, __len__ is tried.
# _Possibly_ want to defer to __len__ if available, but I'm not sure this is
# desirable???
def __repr__(self):
return "<COMObject %s>" % (self._username_)
def __str__(self):
# __str__ is used when the user does "print(object)", so we gracefully
# fall back to the __repr__ if the object has no default method.
try:
return str(self.__call__())
except pythoncom.com_error as details:
if details.hresult not in ERRORS_BAD_CONTEXT:
raise
return self.__repr__()
def __dir__(self):
attributes = chain(self.__dict__, dir(self.__class__), self._dir_ole_())
try:
attributes = chain(attributes, [p.Name for p in self.Properties_])
except AttributeError:
pass
return list(set(attributes))
def _dir_ole_(self):
items_dict = {}
for iTI in range(0, self._oleobj_.GetTypeInfoCount()):
typeInfo = self._oleobj_.GetTypeInfo(iTI)
self._UpdateWithITypeInfo_(items_dict, typeInfo)
return list(items_dict)
def _UpdateWithITypeInfo_(self, items_dict, typeInfo):
typeInfos = [typeInfo]
# suppress IDispatch and IUnknown methods
inspectedIIDs = {pythoncom.IID_IDispatch: None}
while len(typeInfos) > 0:
typeInfo = typeInfos.pop()
typeAttr = typeInfo.GetTypeAttr()
if typeAttr.iid not in inspectedIIDs:
inspectedIIDs[typeAttr.iid] = None
for iFun in range(0, typeAttr.cFuncs):
funDesc = typeInfo.GetFuncDesc(iFun)
funName = typeInfo.GetNames(funDesc.memid)[0]
if funName not in items_dict:
items_dict[funName] = None
# Inspect the type info of all implemented types
# E.g. IShellDispatch5 implements IShellDispatch4 which implements IShellDispatch3 ...
for iImplType in range(0, typeAttr.cImplTypes):
iRefType = typeInfo.GetRefTypeOfImplType(iImplType)
refTypeInfo = typeInfo.GetRefTypeInfo(iRefType)
typeInfos.append(refTypeInfo)
# Delegate comparison to the oleobjs, as they know how to do identity.
def __eq__(self, other):
other = getattr(other, "_oleobj_", other)
return self._oleobj_ == other
def __ne__(self, other):
other = getattr(other, "_oleobj_", other)
return self._oleobj_ != other
def __int__(self):
return int(self.__call__())
def __len__(self):
invkind, dispid = self._find_dispatch_type_("Count")
if invkind:
return self._oleobj_.Invoke(dispid, LCID, invkind, 1)
raise TypeError("This dispatch object does not define a Count method")
def _NewEnum(self):
try:
invkind = pythoncom.DISPATCH_METHOD | pythoncom.DISPATCH_PROPERTYGET
enum = self._oleobj_.InvokeTypes(
pythoncom.DISPID_NEWENUM, LCID, invkind, (13, 10), ()
)
except pythoncom.com_error:
return None # no enumerator for this object.
from . import util
return util.WrapEnum(enum, None)
def __getitem__(self, index): # syver modified
# Improved __getitem__ courtesy Syver Enstad
# Must check _NewEnum before Item, to ensure b/w compat.
if isinstance(index, int):
if self.__dict__["_enum_"] is None:
self.__dict__["_enum_"] = self._NewEnum()
if self.__dict__["_enum_"] is not None:
return self._get_good_object_(self._enum_.__getitem__(index))
# See if we have an "Item" method/property we can use (goes hand in hand with Count() above!)
invkind, dispid = self._find_dispatch_type_("Item")
if invkind is not None:
return self._get_good_object_(
self._oleobj_.Invoke(dispid, LCID, invkind, 1, index)
)
raise TypeError("This object does not support enumeration")
def __setitem__(self, index, *args):
# XXX - todo - We should support calling Item() here too!
# print("__setitem__ with", index, args)
if self._olerepr_.defaultDispatchName:
invkind, dispid = self._find_dispatch_type_(
self._olerepr_.defaultDispatchName
)
else:
invkind, dispid = (
pythoncom.DISPATCH_PROPERTYPUT | pythoncom.DISPATCH_PROPERTYPUTREF,
pythoncom.DISPID_VALUE,
)
if invkind is not None:
allArgs = (dispid, LCID, invkind, 0, index) + args
return self._get_good_object_(
self._oleobj_.Invoke(*allArgs), self._olerepr_.defaultDispatchName, None
)
raise TypeError("This dispatch object does not define a default method")
def _find_dispatch_type_(self, methodName):
if methodName in self._olerepr_.mapFuncs:
item = self._olerepr_.mapFuncs[methodName]
return item.desc[4], item.dispid
if methodName in self._olerepr_.propMapGet:
item = self._olerepr_.propMapGet[methodName]
return item.desc[4], item.dispid
try:
dispid = self._oleobj_.GetIDsOfNames(0, methodName)
except: ### what error?
return None, None
return pythoncom.DISPATCH_METHOD | pythoncom.DISPATCH_PROPERTYGET, dispid
def _ApplyTypes_(self, dispid, wFlags, retType, argTypes, user, resultCLSID, *args):
result = self._oleobj_.InvokeTypes(
*(dispid, LCID, wFlags, retType, argTypes) + args
)
return self._get_good_object_(result, user, resultCLSID)
def _wrap_dispatch_(
self,
ob,
userName=None,
returnCLSID=None,
):
# Given a dispatch object, wrap it in a class
return Dispatch(ob, userName)
def _get_good_single_object_(self, ob, userName=None, ReturnCLSID=None):
if isinstance(ob, PyIDispatchType):
# make a new instance of (probably this) class.
return self._wrap_dispatch_(ob, userName, ReturnCLSID)
if isinstance(ob, PyIUnknownType):
try:
ob = ob.QueryInterface(pythoncom.IID_IDispatch)
except pythoncom.com_error:
# It is an IUnknown, but not an IDispatch, so just let it through.
return ob
return self._wrap_dispatch_(ob, userName, ReturnCLSID)
return ob
def _get_good_object_(self, ob, userName=None, ReturnCLSID=None):
"""Given an object (usually the retval from a method), make it a good object to return.
Basically checks if it is a COM object, and wraps it up.
Also handles the fact that a retval may be a tuple of retvals"""
if ob is None: # Quick exit!
return None
elif isinstance(ob, tuple):
return tuple(
map(
lambda o,
s=self,
oun=userName,
rc=ReturnCLSID: s._get_good_single_object_(o, oun, rc),
ob,
)
)
else:
return self._get_good_single_object_(ob)
def _make_method_(self, name):
"Make a method object - Assumes in olerepr funcmap"
methodName = build.MakePublicAttributeName(name) # translate keywords etc.
methodCodeList = self._olerepr_.MakeFuncMethod(
self._olerepr_.mapFuncs[name], methodName, 0
)
methodCode = "\n".join(methodCodeList)
try:
# print(f"Method code for {self._username_} is:\n", methodCode)
# self._print_details_()
codeObject = compile(methodCode, "<COMObject %s>" % self._username_, "exec")
# Exec the code object
tempNameSpace = {}
# "Dispatch" in the exec'd code is win32com.client.Dispatch, not ours.
globNameSpace = globals().copy()
globNameSpace["Dispatch"] = win32com.client.Dispatch
exec(
codeObject, globNameSpace, tempNameSpace
) # self.__dict__, self.__dict__
name = methodName
# Save the function in map.
fn = self._builtMethods_[name] = tempNameSpace[name]
return MethodType(fn, self)
except:
debug_print("Error building OLE definition for code ", methodCode)
traceback.print_exc()
return None
def _Release_(self):
"""Cleanup object - like a close - to force cleanup when you don't
want to rely on Python's reference counting."""
for childCont in self._mapCachedItems_.values():
childCont._Release_()
self._mapCachedItems_ = {}
if self._oleobj_:
self._oleobj_.Release()
self.__dict__["_oleobj_"] = None
if self._olerepr_:
self.__dict__["_olerepr_"] = None
self._enum_ = None
def _proc_(self, name, *args):
"""Call the named method as a procedure, rather than function.
Mainly used by Word.Basic, which whinges about such things."""
try:
item = self._olerepr_.mapFuncs[name]
dispId = item.dispid
return self._get_good_object_(
self._oleobj_.Invoke(*(dispId, LCID, item.desc[4], 0) + (args))
)
except KeyError:
raise AttributeError(name)
def _print_details_(self):
"Debug routine - dumps what it knows about an object."
print("AxDispatch container", self._username_)
try:
print("Methods:")
for method in self._olerepr_.mapFuncs:
print("\t", method)
print("Props:")
for prop, entry in self._olerepr_.propMap.items():
print(f"\t{prop} = 0x{entry.dispid:x} - {entry!r}")
print("Get Props:")
for prop, entry in self._olerepr_.propMapGet.items():
print(f"\t{prop} = 0x{entry.dispid:x} - {entry!r}")
print("Put Props:")
for prop, entry in self._olerepr_.propMapPut.items():
print(f"\t{prop} = 0x{entry.dispid:x} - {entry!r}")
except:
traceback.print_exc()
def __LazyMap__(self, attr):
try:
if self._LazyAddAttr_(attr):
debug_attr_print(
f"{self._username_}.__LazyMap__({attr}) added something"
)
return 1
except AttributeError:
return 0
# Using the typecomp, lazily create a new attribute definition.
def _LazyAddAttr_(self, attr):
if self._lazydata_ is None:
return 0
res = 0
typeinfo, typecomp = self._lazydata_
olerepr = self._olerepr_
# We need to explicitly check each invoke type individually - simply
# specifying '0' will bind to "any member", which may not be the one
# we are actually after (ie, we may be after prop_get, but returned
# the info for the prop_put.)
for i in ALL_INVOKE_TYPES:
try:
x, t = typecomp.Bind(attr, i)
# Support 'Get' and 'Set' properties - see
# bug 1587023
if x == 0 and attr[:3] in ("Set", "Get"):
x, t = typecomp.Bind(attr[3:], i)
if x == pythoncom.DESCKIND_FUNCDESC: # it's a FUNCDESC
r = olerepr._AddFunc_(typeinfo, t, 0)
elif x == pythoncom.DESCKIND_VARDESC: # it's a VARDESC
r = olerepr._AddVar_(typeinfo, t, 0)
else: # not found or TYPEDESC/IMPLICITAPP
r = None
if not r is None:
key, map = r[0], r[1]
item = map[key]
if map == olerepr.propMapPut:
olerepr._propMapPutCheck_(key, item)
elif map == olerepr.propMapGet:
olerepr._propMapGetCheck_(key, item)
res = 1
except:
pass
return res
def _FlagAsMethod(self, *methodNames):
"""Flag these attribute names as being methods.
Some objects do not correctly differentiate methods and
properties, leading to problems when calling these methods.
Specifically, trying to say: ob.SomeFunc()
may yield an exception "None object is not callable"
In this case, an attempt to fetch the *property* has worked
and returned None, rather than indicating it is really a method.
Calling: ob._FlagAsMethod("SomeFunc")
should then allow this to work.
"""
for name in methodNames:
details = build.MapEntry(self.__AttrToID__(name), (name,))
self._olerepr_.mapFuncs[name] = details
def __AttrToID__(self, attr):
debug_attr_print(
"Calling GetIDsOfNames for property {} in Dispatch container {}".format(
attr, self._username_
)
)
return self._oleobj_.GetIDsOfNames(0, attr)
def __getattr__(self, attr):
if attr == "__iter__":
# We can't handle this as a normal method, as if the attribute
# exists, then it must return an iterable object.
try:
invkind = pythoncom.DISPATCH_METHOD | pythoncom.DISPATCH_PROPERTYGET
enum = self._oleobj_.InvokeTypes(
pythoncom.DISPID_NEWENUM, LCID, invkind, (13, 10), ()
)
except pythoncom.com_error:
raise AttributeError("This object can not function as an iterator")
# We must return a callable object.
class Factory:
def __init__(self, ob):
self.ob = ob
def __call__(self):
import win32com.client.util
return win32com.client.util.Iterator(self.ob)
return Factory(enum)
if attr.startswith("_") and attr.endswith("_"): # Fast-track.
raise AttributeError(attr)
# If a known method, create new instance and return.
try:
return MethodType(self._builtMethods_[attr], self)
except KeyError:
pass
# XXX - Note that we current are case sensitive in the method.
# debug_attr_print("GetAttr called for %s on DispatchContainer %s" % (attr,self._username_))
# First check if it is in the method map. Note that an actual method
# must not yet exist, (otherwise we would not be here). This
# means we create the actual method object - which also means
# this code will never be asked for that method name again.
if attr in self._olerepr_.mapFuncs:
return self._make_method_(attr)
# Delegate to property maps/cached items
retEntry = None
if self._olerepr_ and self._oleobj_:
# first check general property map, then specific "put" map.
retEntry = self._olerepr_.propMap.get(attr)
if retEntry is None:
retEntry = self._olerepr_.propMapGet.get(attr)
# Not found so far - See what COM says.
if retEntry is None:
try:
if self.__LazyMap__(attr):
if attr in self._olerepr_.mapFuncs:
return self._make_method_(attr)
retEntry = self._olerepr_.propMap.get(attr)
if retEntry is None:
retEntry = self._olerepr_.propMapGet.get(attr)
if retEntry is None:
retEntry = build.MapEntry(self.__AttrToID__(attr), (attr,))
except pythoncom.ole_error:
pass # No prop by that name - retEntry remains None.
if retEntry is not None: # see if in my cache
try:
ret = self._mapCachedItems_[retEntry.dispid]
debug_attr_print("Cached items has attribute!", ret)
return ret
except (KeyError, AttributeError):
debug_attr_print("Attribute %s not in cache" % attr)
# If we are still here, and have a retEntry, get the OLE item
if retEntry is not None:
invoke_type = _GetDescInvokeType(retEntry, pythoncom.INVOKE_PROPERTYGET)
debug_attr_print(
"Getting property Id 0x%x from OLE object" % retEntry.dispid
)
try:
ret = self._oleobj_.Invoke(retEntry.dispid, 0, invoke_type, 1)
except pythoncom.com_error as details:
if details.hresult in ERRORS_BAD_CONTEXT:
# May be a method.
self._olerepr_.mapFuncs[attr] = retEntry
return self._make_method_(attr)
raise
debug_attr_print("OLE returned ", ret)
return self._get_good_object_(ret)
# no where else to look.
raise AttributeError(f"{self._username_}.{attr}")
def __setattr__(self, attr, value):
if (
attr in self.__dict__
): # Fast-track - if already in our dict, just make the assignment.
# XXX - should maybe check method map - if someone assigns to a method,
# it could mean something special (not sure what, tho!)
self.__dict__[attr] = value
return
# Allow property assignment.
debug_attr_print(
f"SetAttr called for {self._username_}.{attr}={value!r} on DispatchContainer"
)
if self._olerepr_:
# Check the "general" property map.
if attr in self._olerepr_.propMap:
entry = self._olerepr_.propMap[attr]
invoke_type = _GetDescInvokeType(entry, pythoncom.INVOKE_PROPERTYPUT)
self._oleobj_.Invoke(entry.dispid, 0, invoke_type, 0, value)
return
# Check the specific "put" map.
if attr in self._olerepr_.propMapPut:
entry = self._olerepr_.propMapPut[attr]
invoke_type = _GetDescInvokeType(entry, pythoncom.INVOKE_PROPERTYPUT)
self._oleobj_.Invoke(entry.dispid, 0, invoke_type, 0, value)
return
# Try the OLE Object
if self._oleobj_:
if self.__LazyMap__(attr):
# Check the "general" property map.
if attr in self._olerepr_.propMap:
entry = self._olerepr_.propMap[attr]
invoke_type = _GetDescInvokeType(
entry, pythoncom.INVOKE_PROPERTYPUT
)
self._oleobj_.Invoke(entry.dispid, 0, invoke_type, 0, value)
return
# Check the specific "put" map.
if attr in self._olerepr_.propMapPut:
entry = self._olerepr_.propMapPut[attr]
invoke_type = _GetDescInvokeType(
entry, pythoncom.INVOKE_PROPERTYPUT
)
self._oleobj_.Invoke(entry.dispid, 0, invoke_type, 0, value)
return
try:
entry = build.MapEntry(self.__AttrToID__(attr), (attr,))
except pythoncom.com_error:
# No attribute of that name
entry = None
if entry is not None:
try:
invoke_type = _GetDescInvokeType(
entry, pythoncom.INVOKE_PROPERTYPUT
)
self._oleobj_.Invoke(entry.dispid, 0, invoke_type, 0, value)
self._olerepr_.propMap[attr] = entry
debug_attr_print(
"__setattr__ property {} (id=0x{:x}) in Dispatch container {}".format(
attr, entry.dispid, self._username_
)
)
return
except pythoncom.com_error:
pass
raise AttributeError(f"Property '{self._username_}.{attr}' can not be set.")
结合这个文件
本文详细解析了do_QueryInterface函数的工作原理及其内部实现机制。通过构造nsQueryInterface对象并利用nsCOMPtr进行接口查询，最终完成对象赋值过程。
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