How to export file polygon with date in PyQgis?

Question

I want to export my polygon with this file name : yyyymmdd_PVD.gpkg

from qgis import processing
import datetime
    
dir = 'C:/Users/CMCA/Downloads/'+ str(datetime.datetime.now())+'.gpkg'
processing.run("native:savefeatures", 
               {'INPUT':iface.activeLayer(),
               'OUTPUT':dir,
               'LAYER_NAME':'test',
               'DATASOURCE_OPTIONS':'',
               'LAYER_OPTIONS':''})

Error:

Traceback (most recent call last):
  File "C:\PROGRA~1\QGIS32~1.0\apps\Python39\lib\code.py", line 90, in runcode
    exec(code, self.locals)
  File "<input>", line 1, in <module>
  File "<string>", line 61, in <module>
  File "C:\PROGRA~1/QGIS32~1.0/apps/qgis/./python/plugins\processing\tools\general.py", line 108, in run
    return Processing.runAlgorithm(algOrName, parameters, onFinish, feedback, context)
  File "C:\PROGRA~1/QGIS32~1.0/apps/qgis/./python/plugins\processing\core\Processing.py", line 187, in runAlgorithm
    ret, results = execute(alg, parameters, context, feedback, catch_exceptions=False)
  File "C:\PROGRA~1/QGIS32~1.0/apps/qgis/./python/plugins\processing\gui\AlgorithmExecutor.py", line 72, in execute
    results, ok = alg.run(parameters, context, feedback, {}, False)
_core.QgsProcessingException: Could not create layer C:/Users/CMCA/Downloads/2023-03-21 17:19:46.771813.gpkg: Unable to load C:/Users/CMCA/Downloads/2023-03-21 17 provider

Answer 1

You are importing the datetime module with import datetime but then you try to use a now() method from a date object/module which does not exist.

You probably meant to use datetime.datetime.now().

Answer 2

You need to change the date special characters to meet prerequisites for creating folder structures in Windows.

You cannot create folders with characters like : or /

Another problem you may face, is that the word dir is reserved in Python, avoid using it as a variable name

Format the date without the character :

from qgis import processing
from datetime import datetime

date = datetime.strftime(datetime.now(), "%Y_%m_%d_%H_%M_%S") # or "%Y%m%d_%H%M%S"
    
archive= f'C:/Users/CMCA/Downloads/{date}.gpkg'
processing.run("native:savefeatures", 
               {'INPUT':iface.activeLayer(),
               'OUTPUT':archive,
               'LAYER_NAME':'test',
               'DATASOURCE_OPTIONS':'',
               'LAYER_OPTIONS':''})