Monitoring Document Events

Next to assigning macros to events, one can monitor events raised by LibreOffice documents. Application Programming Interface (API) broadcasters are responsible for calling event scripts. Unlike listeners that require to define all supported methods, even if unused, document monitors require only two methods next to hooked event scripts.

Listening to Document Events

Monitoring is illustrated herewith for Basic and Python languages using object-oriented programming. Assigning OnLoad script, to the Open Document event, suffices to initiate and terminate document event monitoring. Tools – Customise... menu Events tab is used to assign either scripts.

Intercepting events helps setting scripts pre- and post-conditions such as loading and unloading libraries or track script processing in the background. Access2Base Trace module usage is illustrating that second context.

With Python

Events monitoring starts from object instantiation and ultimately stops when Python releases the object. Raised events are reported using Access2Base console.

note

OnLoad and OnUnload events can be used to respectively set and unset Python programs path. They are described as Open document and Document closed.



         # -*- coding: utf-8 -*-
         from __future__ import unicode_literals
             
         import os.path, uno, unohelper
         from com.sun.star.document import DocumentEvent, \
             XDocumentEventListener as AdapterPattern
         from com.sun.star.lang import EventObject
             
         class UiDocument(unohelper.Base, AdapterPattern):
             """ Monitor document events """
             '''
             adapted from 'Python script to monitor OnSave event' at
             https://forum.openoffice.org/en/forum/viewtopic.php?t=68887
             '''
             def __init__(self):
                 """ Document events monitor """
                 ''' report using Access2Base.Trace console OR
                 report in 1st sheet, 1st column for Calc docs '''
                 ctx = uno.getComponentContext()
                 smgr = ctx.getServiceManager()
                 desktop = smgr.createInstanceWithContext(
                 'com.sun.star.frame.Desktop' , ctx)
                 self.doc = desktop.CurrentComponent
                 #self.row = 0  # uncomment for Calc documents only
                 Console.setLevel("DEBUG")
                 self.listen()  # Start monitoring doc. events
             
             @property
             def Filename(self) -> str:
                 sys_filename = uno.fileUrlToSystemPath(self.doc.URL)
                 return os.path.basename(sys_filename)
             
             def setCell(self, calcDoc, txt: str):
                 """ Output doc. events on 1st column of a Calc spreadsheet """
                 sheet = calcDoc.getSheets().getByIndex(0)
                 sheet.getCellByPosition(0,self.row).setString(txt)
                 self.row = self.row + 1
             
             def listen(self, *args):  # OnLoad/OnNew at the earliest
                 """ Start doc. events monitoring """
                 self.doc.addDocumentEventListener(self)
                 Console.log("INFO", "Document events are being logged", True)
             
             def sleep(self, *args):  # OnUnload at the latest (optional)
                 """ Stop doc. events monitoring """
                 self.doc.removeDocumentEventListener(self)
                 Console.log("INFO", "Document events have been logged", True)
             
             def documentEventOccured(self, event: DocumentEvent):
                 """ Intercepts all doc. events """
                 #self.setCell(event.Source, event.EventName) # only for Calc docs
                 Console.log("DEBUG",
                     event.EventName+" in "+self.Filename,
                     False)
             
             def disposing(self, event: EventObject):
                 """ Release all activities """
                 self.sleep()
                 Console.show()
             
         def OnLoad(*args):  # 'Open Document' event
             listener = UiDocument()  # Initiates listening
             
         def OnUnload(*args):  # 'Document has been closed' event
             pass  # (optional) performed when disposed
             
         g_exportedScripts = (OnLoad,)
             
         from com.sun.star.script.provider import XScript
         class Console():
             """
             (Back/Fore)ground console to report/log program execution.
             """
             @staticmethod
             def trace(*args,**kwargs):
                 """ Print free item list to console """
                 scr = Console._a2bScript(script='DebugPrint', module='Compatible')
                 scr.invoke((args),(),())
             @staticmethod
             def log(level: str, text: str, msgBox=False):
                 """ Append log message to console, optional user prompt """
                 scr = Console._a2bScript(script='TraceLog')
                 scr.invoke((level,text,msgBox),(),())
             @staticmethod
             def setLevel(logLevel: str):
                 """ Set log messages lower limit """
                 scr = Console._a2bScript(script='TraceLevel')
                 scr.invoke((logLevel,),(),())
             @staticmethod
             def show():
                 """ Display console content/dialog """
                 scr = Console._a2bScript(script='TraceConsole')
                 scr.invoke((),(),())
             @staticmethod
             def _a2bScript(script: str, library='Access2Base',
                 module='Trace') -> XScript:
                 ''' Grab application-based Basic script '''
                 sm = uno.getComponentContext().ServiceManager
                 mspf = sm.createInstanceWithContext(
                     "com.sun.star.script.provider.MasterScriptProviderFactory",
                     uno.getComponentContext())
                 scriptPro = mspf.createScriptProvider("")
                 scriptName = "vnd.sun.star.script:"+library+"."+module+"."+script+"?language=Basic&location=application"
                 xScript = scriptPro.getScript(scriptName)
                 return xScript
      
warning

Mind the misspelled documentEventOccured method that inherits a typo from LibreOffice Application Programming Interface (API).


পরামর্শ আইকন

Start application and Close application events can respectively be used to set and to unset Python path for user scripts or LibreOffice scripts. In a similar fashion, document based Python libraries or modules can be loaded and released using Open document and Document closed events. Refer to Importing Python Modules for more information.


With LibreOffice Basic

The Onload script is assigned to Open document event using Tools – Customise... menu Events tab. Events monitoring starts from the moment a ConsoleLogger object is instantiated and ultimately stops when Basic engine releases it. OnLoad event loads necessary Basic libraries, while caught events are reported using Access2Base.Trace module.


          REM controller.Events module
          Option Explicit
          Private _obj As Object ' controller.ConsoleLogger instance
              
          Sub OnLoad(evt As com.sun.star.document.DocumentEvent) ' >> Open Document <<
              _obj = New ConsoleLogger : _obj.Start(evt)
          End Sub ' controller.OnLoad
          ' ----
          REM controller.ConsoleLogger class module
          Option Explicit
          Option Compatible
          Option ClassModule
              
          ' ADAPTER design pattern object to be instantiated in « Open Document » event
          Private Const UI_PROMPT = True
          Private Const UI_NOPROMPT = False ' Set it to True to visualise documents events
              
          ' CONSTRUCTOR/DESTRUCTOR
          Private Sub Class_Initialize()
          End Sub ' controller.ConsoleLogger.Initialize
          Private Sub Class_Terminate()
          End Sub ' controller.ConsoleLogger.Terminate
              
          ' MEMBERS
          Private _evtAdapter As Object ' com.sun.star.document.XDocumentEventBroadcaster
              
          ' PROPERTIES
          Private Property Get FileName As String
              ''' System-dependent filename '''
              Const _LIBRARY = "Tools" : With GlobalScope.BasicLibraries
                  If Not .IsLibraryLoaded(_LIBRARY) Then .LoadLibrary(_LIBRARY)
              End With
              Filename = Tools.Strings.FilenameOutofPath(ThisComponent.URL)
          End Property ' controller.ConsoleLogger.Filename
              
          ' METHODS
          Private Sub _documentEventOccured(evt As com.sun.star.document.DocumentEvent)
              ''' Monitor document events '''
              Access2Base.Trace.TraceLog("DEBUG", _
                  evt.EventName &" in "& Filename(evt.Source.URL), _
                  UI_NOPROMPT)
              Select Case evt.EventName
                  Case "OnUnload" : _Stop(evt)
              End Select
          End Sub ' controller.ConsoleLogger._documentEventOccured
              
          Private Sub _disposing(evt As com.sun.star.lang.EventObject)
          End Sub ' controller.ConsoleLogger.disposing
              
          Public Sub Start(Optional evt As com.sun.star.document.DocumentEvent)
              ''' Initialize document events logging '''
              Const _LIBRARY = "Access2Base" : With GlobalScope.BasicLibraries
                  If Not .IsLibraryLoaded(_LIBRARY) Then .LoadLibrary(_LIBRARY)
              End With : Access2Base.Trace.TraceLevel("DEBUG")
              Access2Base.Trace.TraceLog("INFO", _
                  IIf(IsMissing(evt),"",evt.EventName & "-") & "Document events are being logged", _
                  UI_PROMPT)
              
              _evtAdapter = CreateUnoListener( "_", "com.sun.star.document.XDocumentEventListener" )
              ThisComponent.addDocumentEventListener( _evtAdapter )
          End Sub ' controller.ConsoleLogger.Start
              
          Private Sub _Stop(Optional evt As com.sun.star.document.DocumentEvent)
              ''' Terminate document events logging '''
              ThisComponent.removeDocumentEventListener( _evtAdapter )
              Access2Base.Trace.TraceLog("INFO", _
                  IIf(IsMissing(evt),"",evt.EventName & "-") & "Document events have been logged", _
                  UI_PROMPT)
              Access2Base.Trace.TraceConsole() ' Captured events dialog
          End Sub ' controller.ConsoleLogger._Stop
              
          ' EVENTS
          ' Your code for handled events goes here
      
warning

Mind the misspelled _documentEventOccured method that inherits a typo from LibreOffice Application Programming Interface (API).


Discovering Documents Events

The broadcaster API object provides the list of events it is responsible for:

With Python


         # -*- coding: utf-8 -*-
         from __future__ import unicode_literals
             
         import uno, apso_utils as ui
             
         def displayAvailableEvents():
             """ Display document events """
             '''
             adapted from DisplayAvailableEvents() by A. Pitonyak
             https://forum.openoffice.org/en/forum/viewtopic.php?&t=43689
             '''
             ctx = XSCRIPTCONTEXT.getComponentContext()
             smgr = ctx.ServiceManager
             geb = smgr.createInstanceWithContext(
                 "com.sun.star.frame.GlobalEventBroadcaster", ctx)
             events = geb.Events.getElementNames()
             ui.msgbox('; '.join(events))
             
         g_exportedScripts = (displayAvailableEvents,)
      
note

The Alternative Python Script Organizer (APSO) extension is used to render events information on screen.


With LibreOffice Basic


         Sub DisplayAvailableEvents
             ''' Display document events '''
             Dim geb As Object ' com.sun.star.frame.GlobalEventBroadcaster
             Dim events() As String
             geb = CreateUnoService("com.sun.star.frame.GlobalEventBroadcaster")
             events = geb.Events.ElementNames()
             MsgBox Join(events, "; ")
         End Sub
      

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