Defold Persist

WhiteBoxDev · January 25, 2024, 7:53pm

Hi all,

Defold Persist provides a simple interface for saving and loading data in a Defold game engine project.

Please note that there are other wonderful modules out there that aim to solve the persistency problem, so feel free to have a look at those as well. Persist mainly focuses on simplicity and ease-of-use. I used this module in Cx6 and will continue to use it in the future.

Happy Defolding!

WhiteBoxDev · February 20, 2024, 3:53pm

In the documentation for Persist, I have the following table:

Here are all of the platforms that Defold supports at the moment:

If you have access to any of the platforms that aren’t listed in the documentation (most of them!) then please consider calling persist.save() or simply just:

-- File doesn't have to actually exist.
-- Simply returns the standardized save location as a string.
print(sys.get_save_file("Test App", "settings"))

Then either submitting a pull request or commenting on this thread with the output. I’d like to provide support for all platforms, but I don’t have access to many of them. Thanks!

GooseSwanson · February 20, 2024, 5:42pm

Using the dev app on Android gives me: /data/user/0/com.example.myapp/files/settings

From StackOverflow, the pattern is /data/user[_de]/<user_id>/<pkg>/files, with _de and user_id explained like this:

/data/user_de is the Device Encrypted storage on FBE devices which lets certain apps run on boot without asking for user credentials.
For multiple users/profiles, <user_id> is different, the device owner is always 0. /data/user/0 is a symlink to /data/data for historical reasons.

Potota · February 20, 2024, 6:56pm

On Linux, sys.get_save_file() defaults to ~/.{app_name}/{file_name}, e.g. /home/potota/.MyGame/save0. This is not great since it clutters up the user’s home folder. DefSave modifies the app name you give it so that files save to ~/.config/{app_name}/{file_name} instead, like other engines do:

github.com

subsoap/defsave/blob/6198f0187a060ce317fbe6b10616f89477bd234f/defsave/defsave.lua#L89

    
      
          
          
function M.get_file_path(file)
          	if M.appname == "defsave" then
          		print("DefSave: You need to set a non-default appname to defsave.appname")
          	end
          	if file == nil then
          		print("DefSave: Warning attempting to get a path for a nil file")
          		return nil
          	end
          	if M.sysinfo.system_name == "Linux" then
          		-- For Linux we must modify the default path to make Linux users happy
          		local appname = "config/" .. tostring(M.appname)
          		return sys.get_save_file(appname, file)
          	end
          	if html5 then
          		-- For HTML5 there's no need to get the full path
          		return M.appname .. "_" .. file
          	end
          	return sys.get_save_file(M.appname, file)
          end

Technically, it should be {config}/{app_name}/{file_name} where config is the environment variable XDG_CONFIG_HOME - defaulting to ~/.config if that’s not set. This is what Unity does, according to their docs.

WhiteBoxDev · February 21, 2024, 8:30pm

Thank you, I pushed this feature for Linux!

WhiteBoxDev · February 26, 2024, 3:44am

I added automatic JSON support for files that have the .json extension. This means that you can persist.save() and persist.load() data directly to and from JSON files. Please let me know if you run into any problems.