OSSL Script Library/ModSendCommand

Revision as of 14:21, 16 July 2010

You can pass data back and forth between region modules and scripts using a script function called modSendCommand() which was introduced in OpenSim 0.6.9. This is an alternative to manually patching in new script functions. Here's an example of how to do this.

Enabling modSendCommand()

The first thing is to enable modSendCommand() in OpenSim.ini. Make sure the line

AllowMODFunctions = true

is set to true and uncommented.

The Region Module

Secondly, we need a region module to listen for the data sent by modSendCommand() and send a reply.

using System;
using Nini.Config;
using OpenMetaverse;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;

namespace ModSendCommandExample
{
  public class MyRegionModule : IRegionModule
  {
    Scene m_scene;
    IScriptModuleComms m_commsMod;        

    public string Name { get { return "MyRegionModule"; } }
    public bool IsSharedModule { get { return false; } }
    public void Close() {}

    public void Initialise(Scene scene, IConfigSource source)
    {
       m_scene = scene;
    }

    public void PostInitialise()
    {
      m_commsMod
        = m_scene.RequestModuleInterface<IScriptModuleComms>();
      m_commsMod.OnScriptCommand += ProcessScriptCommand;
    }

    void ProcessScriptCommand(
      UUID scriptId,
      string reqId, string module, string input, string k)
    {
      if ("MYMOD" != module)
        return;

      string[] tokens
          = input.Split(
              new char[] { '|' }, StringSplitOptions.None);

      string command = tokens[0];
      switch (command)
      {
        case "Greet":
          string name = tokens[1];
          m_commsMod.DispatchReply(scriptId, 1, "Hello " + name, "");
          break;
      }
    }
  }
}

The module subscribes to the OnScriptCommand IScriptModuleComms event in PostInitialise(). When a script command event occurs, it checks that the module identifier is correct (MYMOD) and then splits the command into components delimited by a bar (|). This isn’t essential - it’s just one way of invoking arbitrary commands.

In this case, the command name is the first component. If it’s “Greet”, then a reply is sent back using the supplied name argument which is the second component.

The In-world Script

Here’s the in-world script that makes the call and receives the reply.

default
{
  touch_start(integer total_number)
  {
    modSendCommand("MYMOD", "Greet|World", "");
  }

  link_message(integer sender_num, integer num, string message, key id)
  {
    if (sender_num == -1)
    {
      llSay(0, message);
    }
  }
}

As you can see, a touch triggers the command to the module. The script receives back the link_message event and says the data in-world.

You can download compilable region module source and script code for this example from here.

References

At the moment, this page is a rather simplified version of this blog post.