Lua Socket: Difference between revisions

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→config: 98.0 - allow tcp connections by luasocket as default (udp is still restricted)
 
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LuaSocket is a development branch of spring:
LuaSockets allow a widget to use tcp/udp sockets. With luasockets you can create a client or a server connecting to a server and transfering some data.


see https://github.com/spring/spring/tree/luasocket
There are many possibilties what could be done with luasockets in spring, some ideas:


* webserver that shows all files in VFS
* telnet console, that allows control of spring
* statistics webpage
* ingame widget updater
* ingame news pages
* ...
==config==
All LuaSocket related config is readonly for LuaWidgets. They can be only changed through unitsync.
As default, socket access is restricted, as default no connections are allowed. To allow a connection / sending a packet, the destination has to the corresponding allow rule. For example, if a lua widget wants to connect to springrts.com at port 80,
<code><pre>TCPAllowConnect springrts.com:80</pre></code>
has to be set.
Since spring 97.0 lobby.springrts.com:8200 is allowed as default.
Since Spring 98.0 all tcp connections are allowed by default (udp is still restricted).
Creating a server socket needs no config value to be set.
===possible config values===
{|
|-
|LuaSocketEnabled = 1
|Default is 1 means, all Socket functions are enabled, 0 disables access to sockets.
|-
|TCPAllowConnect
|allow TCP-connections to the listed hosts, for example: "springrts.com:80 springfiles.com:80" which allows luasockets to connect to springrts.com at port 80 and springfiles.com at port 80.
|-
|UDPAllowConnect
|see TCPAllowConnect
|-
|}


==example code==
==example code==


see https://github.com/spring/spring/blob/luasocket/cont/examples/Widgets/luasocket.lua
* [https://github.com/spring/spring/blob/develop/cont/examples/Widgets/luasocket.lua luasocket.lua]
* [https://github.com/spring/spring/blob/develop/cont/examples/Widgets/luasocket_console.lua luasocket_console.lua]


==Notes / known issues / TODO ==
==Notes / known issues / TODO ==


*dns resolving is blocking
* only ipv4 is supported (could be solved by using unstable luasocket2: http://code.matthewwild.co.uk/luasocket2-hg/) or https://github.com/diegonehab/luasocket (seems to be the more official)
*allow rules have exactly match the host:port in script. currently its not possible to use host:port in a lua widget and use the resolved hostname for connecting (and vice versa) (simple workaround, add both as rule)
* dns resolving is blocking, solutions: worker thread or some lib:
*socket=require("socket") is needed
** adns http://www.chiark.greenend.org.uk/~ian/adns/
*most lua scripts from luasocket won't work as they are blocking! rewriting them non-blocking is required! (should be in most cases few work, as parsing stuff can be reused)
** dns.c http://25thandclement.com/~william/projects/dns.c.html
*udp sendto isn't checked, only binding the udp-socket
** tadns http://adns.sourceforge.net/
** or a lua implementation? biggest problem would be to [http://stackoverflow.com/questions/2916675/programmatically-obtain-dns-servers-of-host find the local dns-server]
* most lua scripts from luasocket won't work as they are blocking! rewriting them non-blocking is required! (should be in most cases few work, as parsing stuff can be reused)
* config file should be better protected, see https://github.com/spring/spring/blob/develop/rts/System/Config/ConfigHandler.cpp#L289 + https://github.com/spring/spring/commit/948d6fb9d1c95b99b5cc7929cf3e0de0f9d6d93e maybe just locking the file is best?! see also http://springrts.com/mantis/view.php?id=2891 (private report)
* access to autohost interface / game host is denied
* If you get this error:
<code><pre>
Error in Initialize(): [string "LuaUI/Widgets/luasocket.lua"]:65:
attempt to index upvalue 'socket' (a nil value)</pre></code>
you maybe need to add to system.lua: socket = socket,


==documentation==
==documentation==
Line 21: Line 67:
*http://w3.impa.br/~diego/software/luasocket/tcp.html
*http://w3.impa.br/~diego/software/luasocket/tcp.html
*http://w3.impa.br/~diego/software/luasocket/udp.html
*http://w3.impa.br/~diego/software/luasocket/udp.html
==links==
{{forumlink|topic=27526|title=lua sockets in spring}} - original thread
{{forumlink|topic=28071|title=Lua Lobby / Socket}} - some code pieces for connecting to spring lobby server & protocol
[[Category: Lua]]

Latest revision as of 17:50, 11 October 2014

LuaSockets allow a widget to use tcp/udp sockets. With luasockets you can create a client or a server connecting to a server and transfering some data.

There are many possibilties what could be done with luasockets in spring, some ideas:

  • webserver that shows all files in VFS
  • telnet console, that allows control of spring
  • statistics webpage
  • ingame widget updater
  • ingame news pages
  • ...

config

All LuaSocket related config is readonly for LuaWidgets. They can be only changed through unitsync.

As default, socket access is restricted, as default no connections are allowed. To allow a connection / sending a packet, the destination has to the corresponding allow rule. For example, if a lua widget wants to connect to springrts.com at port 80, 

TCPAllowConnect springrts.com:80

has to be set.

Since spring 97.0 lobby.springrts.com:8200 is allowed as default.

Since Spring 98.0 all tcp connections are allowed by default (udp is still restricted).

Creating a server socket needs no config value to be set.


possible config values

LuaSocketEnabled = 1 Default is 1 means, all Socket functions are enabled, 0 disables access to sockets.
TCPAllowConnect allow TCP-connections to the listed hosts, for example: "springrts.com:80 springfiles.com:80" which allows luasockets to connect to springrts.com at port 80 and springfiles.com at port 80.
UDPAllowConnect see TCPAllowConnect

example code

Notes / known issues / TODO

Error in Initialize(): [string "LuaUI/Widgets/luasocket.lua"]:65:
attempt to index upvalue 'socket' (a nil value)

you maybe need to add to system.lua: socket = socket,

documentation

links

lua sockets in spring - original thread Lua Lobby / Socket - some code pieces for connecting to spring lobby server & protocol

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