Saver

Saver - is a library for saving and loading save data in Defold projects. It provides a simple API for saving and loading save data, as well as support for migrations and simple key-value storage. The library supports saving and loading data in JSON, Lua or binary format, and can save and load files to and from the file system.

Features

• Save and Load Game State: Save and load Lua tables with a simple API.
• File Management: Save and load data from filesystem or application data folder.
• Auto-Save: Automatically save state at regular intervals.
• Storage: Store key-value pairs in the game state.
• Format support: Save and load Lua tables in "json", "lua" or "serialized" format.
• Binary Data: Save and load the raw binary data (like images) with dedicated functions.
• Migrations: Apply migrations to game state when the migration version changed.

Setup

Dependency

Open your game.project file and add the following line to the dependencies field under the project section:

Saver

https://github.com/Insality/defold-saver/archive/refs/tags/5.zip

After that, select Project ▸ Fetch Libraries to update library dependencies. This happens automatically whenever you open a project so you will only need to do this if the dependencies change without re-opening the project.

Library Size

Note: The library size is calculated based on the build report per platform

Platform	Library Size
HTML5	5.23 KB
Desktop / Mobile	8.68 KB

Configuration [optional]

You can configure the module in the game.project file:

[saver]
save_name = game
save_folder = Defold Saver
autosave_timer = 3
saver_key = saver
lua_require_as_string = 0

All of these settings you can also set in the saver.init function.

saver.init({
	save_name = "game",
	save_folder = "Defold Saver",
	autosave_timer = 3,
	saver_key = "saver",
	lua_require_as_string = 0,
})

This configuration section for game.project defines various settings:

• save_name: The name of the save file. Default is game. The file will be stored in the save_folder folder. Can have an extension like .json, .lua (but will not keep the userdata types like vmath.vector3, hash etc).
• save_folder: The folder name where the save file will be stored. Default is your project.title name (with only alphanumeric, underscores or spaces characters).
• autosave_timer: The time interval in seconds between auto-saves. Default is 3.
• saver_key: The key in the save data table that contains the Saver state. Default is saver.
• lua_require_as_string: If set to 1, the require() function will load Lua files as strings instead of Lua tables. This is useful for loading external files and processing their paths. The default value is 0. This setting only affects the Lua format and works for load function. Very special case!

Core Concepts

Defold Saver uses the following core concepts:

• Auto-Save: Automatically save data at regular intervals. It used as a default save method. This allows you to specify the data you want to keep in the save file and the library will handle the rest.
• Save State: A Save state contains a set of table references in the save file. You can bind multiple save states. Bindings is done by the saver.bind_save_state(id, table_reference) function. When you bind the table to save state and previous data was saved, the save data will override values in your reference table. So usually you should bind the default table from module or your game data on game loader step.
• Migration: Migrations are used to update the save data if required. Migration is a just list of functions that will be applied to the save data if the migration version in save is less than the migrations count. You can set migrations by saver.set_migrations function before saver.init and apply them by saver.apply_migrations function after.
• Storage: Storage is a simple key-value storage that can be utilized in many ways and you don't want to make a separate save state for it. You can set and get values by saver.set_value and saver.get_value functions.
• Saving Userdata: Take a note, if your data contains Defold userdata, like vmath.vector3, hash etc, you should don't use the json file format, due the userdata will be lost. Use lua or serialized format instead. Read more in Use Cases section.
• Binary Data Handling: The library provides dedicated functions for handling binary data (like images or other non-Lua tables). Use saver.save_binary_by_name/saver.load_binary_by_name and saver.save_binary_by_path/saver.load_binary_by_path for raw binary data.
• HTML5 Support: The library supports HTML5 platform and uses sys.serialize with base64 encoding for saving all data instead all other formats.

Basic Usage

Bind your lua table to make it persistent:

local saver = require("saver.saver")

local game_data = {
	score = 0,
	level = 1,
}

function init(self)
	saver.init()
	saver.bind_save_state("game", game_data)

	-- Now we can change game_data content and it will be saved automatically via autosave
	game_data.score = game_data.score + 1

	-- Or you can save it manually by saver.save_game_state() if you want to save it immediately
	saver.save_game_state()
end

Using the simple storage API:

local saver = require("saver.saver")

function init(self)
	local run_count = saver.get_value("run_count", 0)
	run_count = run_count + 1
	saver.set_value("run_count", run_count)
end

API Reference

Quick API Reference

local saver = require("saver.saver")

-- Main functions
saver.init()
saver.bind_save_state(table_key_id, table_reference)
saver.save_game_state([save_name])
saver.load_game_state([save_name])
saver.set_game_state(game_state)
saver.get_game_state()
saver.delete_game_state([save_name])

-- File Handling by absolute path
saver.save_file_by_path(data, absolute_file_path, [format])
saver.load_file_by_path(absolute_file_path, [format])
saver.save_binary_by_path(data, absolute_file_path)
saver.load_binary_by_path(absolute_file_path)
saver.delete_file_by_path(absolute_file_path)
saver.is_file_exists_by_path(absolute_file_path)

-- File Handling by relative path in application data folder (from sys.get_save_path())
-- Subfolders are supported
saver.save_file_by_name(data, file_name, [format])
saver.load_file_by_name(file_name, [format])
saver.save_binary_by_name(data, file_name)
saver.load_binary_by_name(file_name)
saver.delete_file_by_name(file_name)
saver.is_file_exists_by_name(file_name)

-- File format constants
saver.FORMAT.SERIALIZED -- "serialized", save and load as Lua serialized table. Default format.
saver.FORMAT.JSON -- "json", save and load as JSON. Autoselect if path ends with .json
saver.FORMAT.LUA -- "lua", save and load as Lua. Autoselect if path ends with .lua

-- Storage
saver.set_value(key_id, value)
saver.get_value(key_id, [default_value])
saver.is_value_exists(key_id)

-- Migrations
saver.set_migrations(migration_list)
saver.apply_migrations()

-- Other
saver.set_autosave_timer(seconds)
saver.get_save_path(file_name)
saver.get_save_version()
saver.set_logger(logger)
saver.get_current_game_project_folder()
saver.before_save_callback = function() "Called before saver saves data" end

---@deprecated Use `saver.set_value` and `saver.get_value` instead
local storage = require("saver.storage")
storage.set(id, value)
storage.get(id, [default_value])
storage.get_number(id, [default_value])
storage.get_string(id, [default_value])
storage.get_boolean(id, [default_value])

API Reference

• Saver API: saver_api.md
• Storage API: storage_api.md (deprecated, use saver.set_value and saver.get_value instead)

Use Cases

Read the Use Cases file to see several examples of how to use the this module in your Defold game development projects.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Issues and Suggestions

For any issues, questions, or suggestions, please create an issue.

👏 Contributors

Changelog

V1

• Initial release

V2

• Update docs, missing API for saver.delete_* functions
• Fix error with get_current_game_project_folder while using in HTML5 builds
• Add saver.before_save_callback callback for custom save logic. Can be used to prepare/update data before saving, like transfing from real-time data to save data

V3

• BREAKING: HTML5 data now using sys.serialize instead json.encode due the issue with json.encode (sparse arrays, number keys)

  • I'm not expecting any game in production to use this feature, but if you are using it, please implement migration for your save data

• BREAKING: Change the way to get the project file name. Now it's removing the spaces and special characters from the project title.

  • To get the previous behavior, you should set the save_folder in the game.project file.

• Add saver.save_folder configuration option to README.md.

• Fix saver.delete_file_by_path for HTML5.

V4

• Add binary data handling with explicit API for different file formats
  • Previously, this library was designed to save and load a Lua table to persistent storage. But sometimes you want to operate with binary data, like images, audio, etc. Now you can use saver.save_binary_by_name/saver.load_binary_by_name and saver.save_binary_by_path/saver.load_binary_by_path for raw binary data.
• Better file format detection and improved internal implementation
• More consistent API for saving and loading files
• Deprecated saver.storage module
  • Now you should use saver.set_value and saver.get_value for key-value storage

V5

• #10 Add Configuration options via api to saver.init(config) to cover all game.project settings

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