如何从python win32com或comtypes使用COM来访问IRTDServer? [英] How to use COM from python win32com or comtypes to access an IRTDServer?
问题描述
Windows 10 + python 3.6.3 64位(也尝试使用32位).我是一名Python开发人员，尝试(几乎)第一次使用COM并击中这个巨大的阻止程序.
Windows 10 + python 3.6.3 64 bit (also tried 32 bit). I am a python developer trying to use COM for (nearly) the first time and hit this huge blocker.
当尝试通过 win32com 或 comtypes 使用在dll(不是我写的)中实现的IRTDServer时，遇到了各种错误.事实证明，使用 win32com 更加困难.我在下面提供了两个库的单元测试示例.
I have had various errors when trying to use an IRTDServer implemented in a dll (not written by me), via either win32com or comtypes. Using win32com turned out to be more difficult. I have an included an example unittest for both libraries below.
从Excel 2016访问服务器的工作符合预期；这将返回预期值:
Accessing the server from Excel 2016 works as expected; this returns the expected value:
=RTD("foo.bar", , "STAT1", "METRIC1")
使用win32com库的代码
这是一个简单的测试用例，应连接到服务器，但不能连接到服务器.(这只是一个版本，因为我多次尝试调试此问题，因此对其进行了更改.)
Code using win32com library
Here is a simple test case which should connect to the server but doesn't. (This is just one version, as I have changed it many times trying to debug the problem.)
from unittest import TestCase
class COMtest(TestCase):
def test_win32com(self):
import win32com.client
from win32com.server.util import wrap
class RTDclient:
# are these only required when implementing the server?
_com_interfaces_ = ["IRTDUpdateEvent"]
_public_methods_ = ["Disconnect", "UpdateNotify"]
_public_attrs_ = ["HeartbeatInterval"]
def __init__(self, *args, **kwargs):
self._comObj = win32com.client.Dispatch(*args, **kwargs)
def connect(self):
self._rtd = win32com.client.CastTo(self._comObj, 'IRtdServer')
result = self._rtd.ServerStart(wrap(self))
assert result > 0
def UpdateNotify(self):
print("UpdateNotify() callback")
def Disconnect(self):
print("Disconnect() called")
HeartbeatInterval = -1
_rtd = RTDclient("foo.bar")
_rtd.connect()
结果:
Traceback (most recent call last):
File "env\lib\site-packages\win32com\client\gencache.py", line 532, in EnsureDispatch
ti = disp._oleobj_.GetTypeInfo()
pywintypes.com_error: (-2147467263, 'Not implemented', None, None)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "test\test.py", line 23, in test_win32com
_rtd.connect()
File "test\test.py", line 16, in connect
self._rtd = win32com.client.CastTo(dispatch, 'IRtdServer')
File "env\lib\site-packages\win32com\client\__init__.py", line 134, in CastTo
ob = gencache.EnsureDispatch(ob)
File "env\lib\site-packages\win32com\client\gencache.py", line 543, in EnsureDispatch
raise TypeError("This COM object can not automate the makepy process - please run makepy manually for this object")
TypeError: This COM object can not automate the makepy process - please run makepy manually for this object
按照这些指示，我成功运行了 makepy 脚本:
Following those directions, I ran the makepy script successfully:
> env\Scripts\python.exe env\lib\site-packages\win32com\client\makepy.py "foo.bar"
Generating to C:\Users\user1\AppData\Local\Temp\gen_py\3.5\longuuid1x0x1x0.py
Building definitions from type library...
Generating...
Importing module
(出于隐私目的，我在stackoverflow上替换了UUID.此UUID与"foo.bar"的typelib UUID相同.)
生成的文件包含 IRtdServer 和 IRTDUpdateEvent 的各种功能和类型定义.但是在此文件中，两个接口都是 win32com.client.DispatchBaseClass 的子类，而根据OleViewDotNet，它们应该是 IUnknown 的子类?
The generated file contains various the function and type definitions of both IRtdServer and IRTDUpdateEvent. But in this file, both interfaces are subclasses of win32com.client.DispatchBaseClass, while according to OleViewDotNet, they should be subclasses of IUnknown?
但是，当我尝试再次运行单元测试时，收到了与以前完全相同的错误.好像查找机制没有找到生成的模块?
However, when I attempted to run the unittest again, I received the exact same error as before. It is as if the lookup mechanism is not finding the generated module?
此外，返回未实现的 GetTypeInfo 使我感到震惊.据我了解，win32com使用该方法(IDispatch COM接口的一部分)来确定参数和其他接口(包括IRtdServer )中所有其他函数的返回类型.如果未实现，将无法正确确定类型.但是，生成的文件似乎包含此信息，这也令人困惑.
Also, GetTypeInfo returning Not implemented is alarming me. From my understanding, win32com uses that method (part of IDispatch COM interface) to determine the argument and return types for all other functions in other interfaces, including IRtdServer. If it's not implemented, it would be unable to determine the types correctly. Yet, the generated file seems to include this information, which is also perplexing.
from unittest import TestCase
class COMtest(TestCase):
def test_comtypes(self):
import comtypes.client
class RTDclient:
# are these for win32com only?
_com_interfaces_ = ["IRTDUpdateEvent"]
_public_methods_ = ["Disconnect", "UpdateNotify"]
_public_attrs_ = ["HeartbeatInterval"]
def __init__(self, clsid):
self._comObj = comtypes.client.CreateObject(clsid)
def connect(self):
self._rtd = self._comObj.IRtdServer()
result = self._rtd.ServerStart(self)
assert result > 0
def UpdateNotify(self):
print("UpdateNotify() callback")
def Disconnect(self):
print("Disconnect() called")
HeartbeatInterval = -1
_rtd = RTDclient("foo.bar")
_rtd.connect()
结果:
File "test\test.py", line 27, in test_comtypes
_rtd.connect()
File "test\test.py", line 16, in connect
self._rtd = self._comObj.IRTDServer()
File "env\lib\site-packages\comtypes\client\dynamic.py", line 110, in __getattr__
dispid = self._comobj.GetIDsOfNames(name)[0]
File "env\lib\site-packages\comtypes\automation.py", line 708, in GetIDsOfNames
self.__com_GetIDsOfNames(riid_null, arr, len(names), lcid, ids)
_ctypes.COMError: (-2147352570, 'Unknown name.', (None, None, None, 0, None))
我尝试过的其他解决方案
(基于谷歌搜索和下面评论中的答案)
Some other solutions I've tried
(Based on googling and answers in the comments below)
- (重新)注册DLL
- 注册了DLL的32位版本，并尝试使用python 32位版本
- 将
python.exe的兼容模式设置为Windows XP SP3 -
尝试不实例化IRtdServer，即替换以下两行:
- (Re-)Registered the DLL
- Registered the 32 bit version of the DLL and tried python 32 bit
- Set compatibility mode of
python.exeto Windows XP SP3 Tried not instantiating IRtdServer, that is, replacing these two lines:
self._rtd = self._comObj.IRtdServer()
result = self._rtd.ServerStart(self)
具有:
result = self._comObj.ServerStart(self)
这次错误是:
TypeError: 'NoneType' object is not callable
这似乎表明 ServerStart 函数存在，但是未定义?(似乎真的很奇怪.这个谜必须有更多.)
That would seem to indicate that the ServerStart function exists, but is undefined? (Seems really weird. There must be more to this mystery.)
尝试将 interface ="IRtdServer" 参数传递给 CreateObject :
def __init__(self, clsid):
self._comObj = comtypes.client.CreateObject(clsid, interface="IRtdServer")
def connect(self):
result = self._comObj.ServerStart(self)
...
收到的错误是:
File "test\test.py", line 13, in __init__
self._comObj = comtypes.client.CreateObject(clsid, interface="IRtdServer")
File "env\lib\site-packages\comtypes\client\__init__.py", line 238, in CreateObject
obj = comtypes.CoCreateInstance(clsid, clsctx=clsctx, interface=interface)
File "env\lib\site-packages\comtypes\__init__.py", line 1223, in CoCreateInstance
p = POINTER(interface)()
TypeError: Cannot create instance: has no _type_
comtypes 库中的跟踪代码，这似乎表明interface参数需要接口类，而不是字符串.我在 comtypes 库中定义了各种接口: IDispatch ， IPersist ， IServiceProvider .它们都是 IUnknown 的子类.根据OleViewDotNet， IRtdServer 也是 IUnknown 的子类.这使我相信，为了使用该接口，我需要类似地在python中编写一个IRtdServer类，但是我不知道该怎么做.
Tracing code in the comtypes library, that would seem to indicate that the interface parameter wants an interface class, not a string. I found various interfaces defined in the comtypes library: IDispatch, IPersist, IServiceProvider. All are subclasses of IUnknown. According to OleViewDotNet, IRtdServer is also a subclass of IUnknown. This leads me to believe that I need to similarly write an IRtdServer class in python in order to use the interface, but I don't know how to do that.
我注意到 CreateObject 的 dynamic 参数.该代码表明这与 interface 参数是互斥的，因此我尝试了以下操作:
I noticed the dynamic parameter of CreateObject. The code indicates this is mutually exclusive to the interface parameter, so I tried that:
def __init__(self, clsid):
self._comObj = comtypes.client.CreateObject(clsid, dynamic=True)
def connect(self):
self._rtd = self._comObj.IRtdServer()
result = self._rtd.ServerStart(self)
但是错误与我的原始错误相同: IRtdServer 具有 _ctypes.COMError:(-2147352570，'Unknown name.',,(None，None，None，0，None))
But the error is the same as my original error: IRtdServer has _ctypes.COMError: (-2147352570, 'Unknown name.', (None, None, None, 0, None))
任何帮助或线索将不胜感激.预先谢谢你.
Any help or clues would be greatly be appreciated. Thank you in advance.
(不知道我在做什么)，我尝试使用OleViewDotNet来查看DLL:
(Not really knowing what I'm doing,) I tried to use OleViewDotNet to look at the DLL:
推荐答案
我遇到了同样的问题.
我还尝试使用win32com来为我运行excel，说实话，这有点不稳定...我什至不能触摸我的Excel.
I also tried using win32com to get excel run that for me, that's a bit unstable to be honest...I cannot even touch my Excel.
因此，我花了一些时间对此进行研究.问题出在CastTo.认为您(和我)加载的COM对象没有包含足够的信息以进行强制转换(某些方法如GetTypeInfo尚未实现，等等)
Therefore I spent some time looking into this. The problem lies with CastTo. Think that COM object you (and I) loaded just does not contain enough information to be casted (some methods like GetTypeInfo are not implemented etc...)
因此，我创建了一个包装程序，使那些COM对象的方法可调用...不明显.这似乎对我有用.
Therefore I created a wrapper that makes methods of those COM objects callable...not obvious. And this seems working for me.
客户端代码是从名为pyrtd的项目中修改的，该项目由于各种原因而无法正常工作(认为是由于RTD模型的更改而已... RefreshData的返回现在完全不同了.)
Client code is modified from a project called pyrtd, which didn't work for various reasons (think due to change of RTD model...return of RefreshData is just completely different now).
import functools
import pythoncom
import win32com.client
from win32com import universal
from win32com.client import gencache
from win32com.server.util import wrap
EXCEL_TLB_GUID = '{00020813-0000-0000-C000-000000000046}'
EXCEL_TLB_LCID = 0
EXCEL_TLB_MAJOR = 1
EXCEL_TLB_MINOR = 4
gencache.EnsureModule(EXCEL_TLB_GUID, EXCEL_TLB_LCID, EXCEL_TLB_MAJOR, EXCEL_TLB_MINOR)
universal.RegisterInterfaces(EXCEL_TLB_GUID,
EXCEL_TLB_LCID, EXCEL_TLB_MAJOR, EXCEL_TLB_MINOR,
['IRtdServer', 'IRTDUpdateEvent'])
# noinspection PyProtectedMember
class ObjectWrapperCOM:
"""
This object can act as a wrapper for an object dispatched using win32com.client.Dispatch
Sometimes the object written by 3rd party is not well constructed that win32com will not be able to obtain
type information etc in order to cast the object to a certain interface. win32com.client.CastTo will fail.
This wrapper class will enable the object to call its methods in this case, even if we do not know what exactly
the wrapped object is.
"""
LCID = 0x0
def __init__(self, obj):
self._impl = obj # type: win32com.client.CDispatch
def __getattr__(self, item):
flags, dispid = self._impl._find_dispatch_type_(item)
if dispid is None:
raise AttributeError("{} is not a valid property or method for this object.".format(item))
return functools.partial(self._impl._oleobj_.Invoke, dispid, self.LCID, flags, True)
# noinspection PyPep8Naming
class RTDUpdateEvent:
"""
Implements interface IRTDUpdateEvent from COM imports
"""
_com_interfaces_ = ['IRTDUpdateEvent']
_public_methods_ = ['Disconnect', 'UpdateNotify']
_public_attrs_ = ['HeartbeatInterval']
# Implementation of IRTDUpdateEvent.
HeartbeatInterval = -1
def __init__(self, event_driven=True):
self.ready = False
self._event_driven = event_driven
def UpdateNotify(self):
if self._event_driven:
self.ready = True
def Disconnect(self):
pass
class RTDClient:
"""
Implements a Real-Time-Data (RTD) client for accessing COM data sources that provide an IRtdServer interface.
"""
MAX_REGISTERED_TOPICS = 1024
def __init__(self, class_id):
"""
:param classid: can either be class ID or program ID
"""
self._class_id = class_id
self._rtd = None
self._update_event = None
self._topic_to_id = {}
self._id_to_topic = {}
self._topic_values = {}
self._last_topic_id = 0
def connect(self, event_driven=True):
"""
Connects to the RTD server.
Set event_driven to false if you to disable update notifications.
In this case you'll need to call refresh_data manually.
"""
dispatch = win32com.client.Dispatch(self._class_id)
self._update_event = RTDUpdateEvent(event_driven)
try:
self._rtd = win32com.client.CastTo(dispatch, 'IRtdServer')
except TypeError:
# Automated makepy failed...no detailed construction available for the class
self._rtd = ObjectWrapperCOM(dispatch)
self._rtd.ServerStart(wrap(self._update_event))
def update(self):
"""
Check if there is data waiting and call RefreshData if necessary. Returns True if new data has been received.
Note that you should call this following a call to pythoncom.PumpWaitingMessages(). If you neglect to
pump the message loop you'll never receive UpdateNotify callbacks.
"""
# noinspection PyUnresolvedReferences
pythoncom.PumpWaitingMessages()
if self._update_event.ready:
self._update_event.ready = False
self.refresh_data()
return True
else:
return False
def refresh_data(self):
"""
Grabs new data from the RTD server.
"""
(ids, values) = self._rtd.RefreshData(self.MAX_REGISTERED_TOPICS)
for id_, value in zip(ids, values):
if id_ is None and value is None:
# This is probably the end of message
continue
assert id_ in self._id_to_topic, "Topic ID {} is not registered.".format(id_)
topic = self._id_to_topic[id_]
self._topic_values[topic] = value
def get(self, topic: tuple):
"""
Gets the value of a registered topic. Returns None if no value is available. Throws an exception if
the topic isn't registered.
"""
assert topic in self._topic_to_id, 'Topic %s not registered.' % (topic,)
return self._topic_values.get(topic)
def register_topic(self, topic: tuple):
"""
Registers a topic with the RTD server. The topic's value will be updated in subsequent data refreshes.
"""
if topic not in self._topic_to_id:
id_ = self._last_topic_id
self._last_topic_id += 1
self._topic_to_id[topic] = id_
self._id_to_topic[id_] = topic
self._rtd.ConnectData(id_, topic, True)
def unregister_topic(self, topic: tuple):
"""
Un-register topic so that it will not get updated.
:param topic:
:return:
"""
assert topic in self._topic_to_id, 'Topic %s not registered.' % (topic,)
self._rtd.DisconnectData(self._topic_to_id[topic])
def disconnect(self):
"""
Closes RTD server connection.
:return:
"""
self._rtd.ServerTerminate()
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