I use a couple of Python API functions to do this kind of thing. The first one downloads the map's source as a JSON file:
def download_data(gis: GIS, item_id: str, save_path: str):
"""
Opens the specified item's data and saves it to the specified path.
:param gis: The GIS connection.
:param item_id: The Item ID to open.
:param save_path: The location to save the item data.
:return: None.
"""
content_mgr = gis.content
item = content_mgr.get(item_id)
if item is None:
raise Exception(f"download_data: Could not open item.")
item_data = item.get_data()
with open(save_path, "w") as output_file:
json.dump(item_data, output_file)
The first thing I do is create a backup copy of this download in case I botch something. Next, I crack the JSON open in a text editor and do whatever I need to do; in your case this would probably be finding and replacing two layer properties:
Sometimes I'll do things like downloading multiple maps and copying symbology or pop-up settings from one and pasting it into another, or writing additional code to bulk update properties.
Then I use this function to push the definition back up:
def update_data(gis: GIS, item_id: str, file_path: str):
"""
Updates the specified item with the data in the specified file.
:param gis: The GIS connection.
:param item_id: The Item ID to update.
:param file_path: The file to update the item with.
:return: None.
"""
content_mgr = gis.content
item = content_mgr.get(item_id)
if item is None:
raise Exception(f"update_data: Could not open item.")
with open(file_path) as input_file:
input_file_data = input_file.read()
if not item.update(data=input_file_data):
raise Exception(f"update_data: update() returned failure code.")
I would definitely recommend trying this workflow out on a map you don't care about first!
