DefCon

This is a Defold developer console. The console allows you to interact with a running game (locally or on device) through a browser.

Requirements

DefCon relies on the Javascript Fetch API and the ReadableStream API. Please refer to the ReadableStream browser compatibility chart for supported browser versions and any configuration options that need to be enabled in order to use DefCon.

Installation

You can use DefCon in your own project by adding this project as a Defold library dependency. Open your game.project file and in the dependencies field under project add:

https://github.com/britzl/defcon/archive/master.zip

Or point to the ZIP file of a specific DefCon release.

You also need to add a dependency to DefNet and a compatible dependency for LuaSocket:

https://github.com/britzl/defnet/archive/6.3.0.zip

Once you have added the dependencies to your project all you need to do is to add the defcon/console.go or defcon/console.script to a collection in your project. The next time you launch your game the console will be running and you should be able to point your browser to localhost:8098 or ip_of_your_device:8098 to access the console.

Under the hood

The console is served using the web server from DefNet (a simple web server created on top of LuaSocket). The web server accepts incoming connections, reads the entire HTTP request, looks at the HTTP request line, tries to match the request to a known route and invokes the function bound to that route and finally returns a response. When a request is sent to the web root (localhost:8098/) the web server is configured to return a web page with the simple console that is used to send commands to the console. The console consists of a text area to show command results and a text input where commands are entered. When a command is entered it is sent to the http server (localhost:8098/console) using the Fetch API.

Commands

The console comes with a few basic commands:

• inspect [name] - Inspect a table with the given name and pretty print it's contents. The command will search the global scope, loaded modules and added modules.
• commands - Show all commands
• modules - Show all added modules (read more about this below)
• toggle_profiler - Toggle the on-screen profiler
• toggle_physics_debug - Toggle physics debug
• start_record [filename] - Start recording video to a file with the given name
• stop_record - Stop recording video
• log - [start|stop] Start/stop capturing print commands

Running arbitrary Lua code

If the command given to the console doesn't match any known command the entered string will be run as arbitrary Lua code instead.

Extend

You can extend the console with commands of your own.

Commands from module functions

You can register whole modules and have all functions mapped as commands:

local foobar_module = require("foobar_module")
local console = require("defcon.console")
console.register_module(foobar_module)

Custom commands

You can also add custom commands:

local console = require("defcon.console")
console.register_command("mycommand", function(args, stream)
	-- execute command here
	return "Return this back to console"
end)

The stream argument is a function that allows the client to stream data instead of returning everything in one go. Call the function with the data to send to the client. Start by sending a header indicating a chunked transfer encoding.

Set global environment

By default, Lua commands will run with the global table as the environment. If you need to expand or confine this environment, you can provide a custom table:

local console = require("defcon.console")
local my_env = { foo = "bar" }
setmetatable(my_env, { __index = _G })
console.set_environment(my_env) -- foo will now be available to Lua commands and inspect

Download files

The web server also allows you to download files available to your game. If you make an HTTP GET or open your browser to the following URL the specified file will be returned:

localhost:8098/download/path/to/myfile

Custom web server routes

It's possible to add custom web server routes to serve specific content over HTTP:

local console = require("defcon.console")
console.server.router.get("^/greet/(.*)$", function(matches)
	local path = matches[1]
	return console.server.html("Hello " .. path .. "!")
end)

For a more complex async response example plase refer to the code samples: https://github.com/britzl/defcon/blob/master/example/example.gui_script#L21-L37

Credits

• URL encode/decode from CGILua
• String split from Lua wiki