如何从pythonwin32com或comtypes使用COM访问IRTDServer？

2条回答

网友

1楼 · 编辑于 2024-06-28 20:21:57

似乎已经有了用于Excel 2002的服务器/客户端。
pyrtd

看看这个源代码，一旦您创建了一个分派对象，那么它似乎被强制转换到IRtdServer。
提取相关零件，如下所示。

from win32com import client, universal
from win32com.server.util import wrap

def __init__(self, classid):
    self._classid = classid
    self._rtd = None

def connect(self, event_driven=True):
    dispatch = client.Dispatch(self._classid)
    self._rtd = client.CastTo(dispatch, 'IRtdServer')
    if event_driven:
        self._rtd.ServerStart(wrap(self))
    else:
        self._rtd.ServerStart(None)

请参考客户端.py和例子/rtdtime.py以下来源。
pyrtd - default
pyrtd/电阻式温度检测器/客户端.py
pyrtd/示例/rtdtime.py

网友

2楼 · 编辑于 2024-06-28 20:21:57

我也遇到了同样的问题。在

我还试着用win32com让excel运行，说实话，这有点不稳定…我甚至连我的excel都摸不着。在

所以我花了一些时间来研究这个问题。问题出在卡斯托身上。认为您（和我）加载的COM对象没有包含足够的信息来进行强制转换（有些方法，如GetTypeInfo没有实现等等…）

因此，我创建了一个包装器，使那些COM对象的方法可调用…不明显。这似乎对我有用。在

客户机代码是从一个名为pyrtd的项目中修改的，该项目由于各种原因而不能工作（想想由于RTD模型的改变…RefreshData的返回现在完全不同了）。在

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()

环境

问题

使用win32com库的代码

使用comtypes库的代码

我尝试过的其他解决方案

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