Generic Serial Device

This page was written by Pluto and imported with their permission when LinuxMCE branched off in February, 2007. In general any information should apply to LinuxMCE. However, this page should be edited to reflect changes to LinuxMCE and remove old references to Pluto.

Generic_Serial_Device (also knowk as GSD) is a Pluto device that allows enduser to do simple programming for RS232, serial USB or network connected devices.

Note : The information is not quite complete because I'm not the original author.

Short description

It's a standard DCE device, it only can execute commands and send events (no event handler yet, but Aaron wants it badly).

The main idea is instead of programming a device in C++, compile, link whith proper libraries you can edit (in a webpage) few lines of code in ruby which will be executed when device receives that command. It exports several objects into ruby so you'll have access to devicedata, device hierarchy, established connection and so on.

The ruby code for each device template is storred somewhere in InfraredGroup_Command table. To edit infrared code, on pluto-admin website go to Wizard> Devices > Generic_Serial_Devices. You have to add a device from a device template in order to see anything in that page.

Select the device, and click "RubyCodes" button to be able to edit code that will be executed. You should be able to see commands that are specified in device template (like ON/OFF/WhateverElse) and a group of Internal commands which are used to perform certain actions ar to add helper functions.

If the command you are trying to add doesn't show on first page, go to Add/Remove commands and add more commands for your device.

There are 2 forms of ruby code you can write :

• standard ruby code (check [1] and [2] for syntax, referencies and programming guides)
• short form for conn_.Send

<$"PWON\r"$>

which simply will send the string "PWON\r" to device.

Implementation notes

On initialisation GSD retrieves Ruby codes from Infrared_Plugin. With this code it creates following ruby source:

  0:require 'Ruby_Generic_Serial_Device'
  1:class Command < Ruby_Generic_Serial_Device::RubyCommandWrapper
  2:end
  3:class Device_47 < Ruby_Generic_Serial_Device::RubySerialWrapper
  4:#### 84 ####################################################################
  5:def cmd_84(data, format, disable_aspect_lock, streamid, width, height)
  6:@returnParamArray.clear
  7:conn_.Reconnect()
  8:auth_s=device_.devdata_[114]+":"+device_.devdata_[115]
  9:auth_a=Array.new;
 10:auth_s.each{|c| auth_a.push(c)}
 11:
 12:fix_path=device_.devdata_[2];
 13:fix_path='/'+fix_path if(fix_path[0]!='/'[0]);
 14:
 15:s = "GET "+fix_path+" HTTP/1.0\r\n"
 16:s+= "Accept: */*\r\n"
 17:s+= "Authorization: Basic "+auth_a.pack("m").chop+"\r\n"
 18:s+= "\r\n"
 19:
 20:conn_.Send(s)
 21:recv=""
 22:while(true)
 23:  buff=conn_.Recv(16384, 5000)
 24:  if(buff.length() == 0)
 25:     break
 26:   end
 27:   recv = recv +  buff
 28:end
 29:if (recv=~ /^HTTP[^\r\n]+200\sOK.+?\r\n\r\n(.+)$/m)
 30:  fileName="/tmp/ip_camera_img"+device_.devid_.to_s
 31:  data_set($1)
 32:  format_set('jpg')
 33:end
 34:return @returnParamArray
 35:end
...
194:#### START SETTERS ####################################################################
195:def initialize()
196:super
197:@returnParamArray=Array.new
198:end
199:def data_set(value)
200:@returnParamArray[19]=value
201:end
202:def format_set(value)
203:@returnParamArray[20]=value
204:end
205:####  END  SETTERS ####################################################################
206:end

Examples

For more details check GSD_Ruby_Interface