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# Calling Python Scripts from Basic

Calling Python scripts from LibreOffice Basic macros is possible, and valuable features can be obtained such as:

- ComputerName identification or OSName detection are possible,

- Basic FileLen() function and com.sun.star.ucb.SimpleFileAccess.getSize() API function exhibit a 2 Gigabytes file size upper limit that Python helps to overcome,

- com.sun.star.util.PathSettings can be normalized,

- and many more.

A reasonable exposure to LibreOffice Basic and to Application Programming Interface (API) features is recommended prior to perform inter-language calls from Basic to Python, to JavaScript or any other script engine.

## Retrieving Python Scripts

Python scripts can be personal, shared, or embedded in documents. In order to execute them, LibreOffice Basic needs to be provided with Python script locations. Locating com.sun.star.script.provider.XScript interface compliant UNO objects allows the execution of Python scripts:

             Option Explicit

             Public Function GetPythonScript(macro As String, _
                     Optional location As String) As com.sun.star.script.provider.Xscript
                 ''' Grab Python script object before execution
                 ' Arguments:
                 '    macro   : as "library/module.py$macro" or "module.py$macro"
                 '    location: as "document", "share", "user" or ENUM(eration)
                 ' Result:
                 '    located com.sun.star.script.provider.XScript UNO service'''
                 If IsMissing(location) Then location = "user"
                 Dim mspf As Object ' com.sun.star.script.provider.MasterScriptProviderFactory
                 Dim sp As Object ' com.sun.star.script.provider.XScriptProvider compatible
                 Dim uri As String
                 If location="document" Then
                     sp = ThisComponent.getScriptProvider()
                 Else
                     mspf = CreateUnoService("com.sun.star.script.provider.MasterScriptProviderFactory")
                     sp = mspf.createScriptProvider("")
                 End If
                 uri = "vnd.sun.star.script:"& macro &"?language=Python&location="& location
                 GetPythonScript = sp.getScript(uri)
             End Function ' GetPythonScript

## Executing Python Scripts

The LibreOffice Application Programming Interface (API) Scripting Framework supports inter-language script execution between Python and Basic, or other supported programming languages for that matter. Arguments can be passed back and forth across calls, provided that they represent primitive data types that both languages recognize, and assuming that the Scripting Framework converts them appropriately.

### Syntax

workstation_name = script.invoke(Array(), Array(), Array())

opSysName = script.invoke(Array(), in_outs, Array()) ' in_out is an Array

file_len = script.invoke(Array(systemFilePath), Array(), Array())

normalizedPath = script.invoke(Array(systemFilePath), Array(), Array())

### Embedded Scripts Examples

Below ComputerName, and GetFilelen routines are calling their Python counterparts, using aforementioned GetPythonScript function. Exception handling is not detailed.

             Option Explicit
             Option Compatible ' Properties are supported

             Private scr As Object ' com.sun.star.script.provider.XScript

             Private Property Get ComputerName As String
                 '''Workstation name'''
                 scr = GetPythonScript("Platform.py$computer_name", "document")
                 ComputerName = scr.invoke(Array(), Array(), Array())
             End Property ' ComputerName

             Private Function GetFilelen(systemFilePath As String) As Currency
                 '''File size in bytes'''
                 scr = GetPythonScript("Os/Path.py$get_size", Script.ISEMBEDDED)
                 GetFilelen = scr.invoke(Array(systemFilePath), Array(), Array(),)
             End Function ' GetFilelen

             Private Type _SCRIPT_LOCATION
                 ISEMBEDDED As String ' document script
                 ISPERSONAL As String ' user script
                 ISSHARED As String ' LibreOffice macro
             End Type ' _SCRIPT_LOCATION

             Public Function Script() As Object ' Text enumeration
                 Static enums As _SCRIPT_LOCATION : With enums
                 If .ISEMBEDDED = "" Then
                     .ISEMBEDDED = "document" ' document script
                     .ISPERSONAL = "user" ' user scripts
                     .ISSHARED = "share" ' LibreOffice macro
                 End If : End With ' enums
                 Script = enums
             End Function ' Script

Two different Python modules are called. They can either be embedded in the current document, either be stored on the file system. Argument type checking is skipped for clarity:

- Platform.py

             # -*- coding: utf-8 -*-
             from __future__ import unicode_literals

             import platform

             def computer_name() -> str:
                 return platform.node()

             def OSname() -> str:
                 return platform.system()

- Os/Path.py

             # -*- coding: utf-8 -*-
             from __future__ import unicode_literals

             import os.path

             def get_size(systemFilePath: str) -> str:
                 return str(os.path.getsize(systemFilePath))

             def normalyze(systemPath: str) -> str:
                 return os.path.normpath(systemPath)

### Personal or Shared Scripts Examples

The calling mechanism for personal or shared Python scripts is identical to that of embedded scripts. Library names are mapped to folders. Computing LibreOffice user profile and shared modules system file paths can be performed as detailed in Getting session information. Below OSName, HelloWorld and NormalizePath routines are calling their Python counterparts, using aforementioned GetPythonScript function. Exception handling is not detailed.

             Option Explicit
             Option Compatible ' Properties are supported

             Private scr As Object ' com.sun.star.script.provider.XScript

             Private Property Get OSName As String
                 '''Platform name as "Linux", "Darwin" or "Windows"'''
                 scr = GetPythonScript("Platform.py$OSname", Script.ISPERSONAL)
                 OSName = scr.invoke(Array(), Array(), Array())
             End Property ' OSName

             Private Sub HelloWorld()
                 '''LibreOffice Python shared sample'''
                 scr = GetPythonScript("HelloWorld.py$HelloWorldPython", Script.ISSHARED)
                 scr.invoke(Array(), Array(), Array(),)
             End Sub ' HelloWorld

             Public Function NormalizePath(systemFilePath As String) As String
                 '''Strip superfluous '\..' in path'''
                 scr = GetPythonScript("Os/Path.py$normalyze", "user")
                 NormalizePath = scr.invoke(Array(systemFilePath), Array(), Array())
             End Function ' NormalizePath

## Python standard modules

LibreOffice embedded Python contains many standard libraries to benefit from. They bear a rich feature set, such as but not limited to:

- argparse Parser for command-line options, arguments and sub-commands

- cmath Mathematical functions for complex numbers

- csv CSV files reading and writing

- datetime Genuine date and time types

- json JSON encoder and decoder

- math Mathematical functions

- re Regular expression operations

- socket Low-level networking interface

- sys System-specific parameters and functions

- unittest and trace Unit testing framework and Track Python execution

- xml.etree.ElementTree ElementTree XML API

Поврзани теми

Calling Basic Macros from Python

LibreOffice Basic Help

LibreOffice Python Scripts Help