Scripting Live Update

local function remove_old_mounts()
	local mounts = liveupdate.get_mounts() -- table with mounts

    -- Each mount has: mount.uri, mount.priority, mount.name
	for _,mount in ipairs(mounts) do

        -- This requires the file name to be unique, so that we don't get a file from a different archive
        -- This data is created by the developer as a way to specify meta data for the archive
		local version_data = sys.load_resource("/version_" .. mount.name .. ".json")

		if version_data then
			version_data = json.decode(version_data)
		else
			version_data = {version = 0} -- if it has no version file, it's likely an old/invalid archive
		end

        -- verify the archive version against the version supported by the game
        if version_data.version < sys.get_config_int("game.minimum_lu_version") then
            -- it was invalid, so we'll unmount it!
            liveupdate.remove_mount(mount.name)
        end
	end
end

{
    "a1b2c3...",
    "d4e5f6...",
    "7890ab...",
    ...
}

-- You'll need to track which archive contains which content
-- In this example, we only use a single liveupdate archive, containing all missing resource.
-- If you are using multiple archive, you need to structure the downloads accordingly
local lu_infos = {
    liveupdate = {
        name = "liveupdate",
        priority = 10,
    }
}

local function get_lu_info_for_level(level_name)
    if level_name == "level1" then
        return lu_infos['liveupdate']
    end
end

local function mount_zip(self, name, priority, path, callback)
	liveupdate.add_mount(name, "zip:" .. path, priority, function(_uri, _path, _status) -- <1>
		callback(_uri, _path, _status)
	end)
end

local function has_mount(name)
    for _, mount in ipairs(liveupdate.get_mounts()) do
        if mount.name == name then
            return true
        end
    end
    return false
end

function init(self)
    self.http_url = sys.get_config_string("game.http_url", nil) -- <2>

    local level_name = "level1"

    local info = get_lu_info_for_level(level_name) -- <3>

    msg.post("#", "load_level", {level = "level1", info = info }) -- <4>
end

function on_message(self, message_id, message, sender)
    if message_id == hash("load_level") then
        local proxy_resources = collectionproxy.get_resources("#" .. message.level) -- <5>

        -- With Strip Live Update Entries from Main Manifest enabled, this table is
        -- empty until the relevant archive is mounted. After mounting, it contains
        -- the resource hashes belonging to the proxy.
        if message.info and #proxy_resources == 0 and not has_mount(message.info.name) then
            msg.post("#", "download_archive", message) -- <6>
        else
            msg.post("#" .. message.level, "load")
        end

    elseif message_id == hash("download_archive") then
		local zip_filename = message.info.name .. ".zip"
		local download_path = sys.get_save_file("mygame", zip_filename)
        local url = self.http_url .. "/" .. zip_filename

        -- Make the request. You can use credentials
        http.request(url, "GET", function(self, id, response) -- <7>
			if response.status == 200 or response.status == 304 then
				mount_zip(self, message.info.name, message.info.priority, download_path, function(uri, path, status) -- <8>
					msg.post("#", "load_level", message) -- try to load the level again
				end)

			else
				print("Failed to download archive ", download_path, "from", url, ":", response.status)
			end
		end, nil, nil, {path=download_path})

    elseif message_id == hash("proxy_loaded") then -- the level is loaded, and we can enable it
        msg.post(sender, "init")
        msg.post(sender, "enable")
    end
end