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2026-06-22T10:13:10Z

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= OpenSimulator Internals/Reading the Code =

== Overview ==

OpenSim is a .NET application. When reading the source, many calls are .NET runtime built-ins, not OpenSim code. Do not chase these into the framework -- they do what they say.

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== What to Skip ==

These namespaces are .NET runtime or third-party libraries. Treat them as black boxes.

{| class="wikitable"
! Namespace / Library !! Notes
|-
| System.Reflection (Assembly, MethodBase) || Runtime introspection -- finding the current executable, loading plugins dynamically
|-
| System.IO (Path, File, FileInfo, StreamReader) || File and path operations
|-
| System.Net (ServicePointManager, HttpWebRequest) || HTTP connection management
|-
| System.Security.Cryptography.X509Certificates || SSL certificate handling
|-
| System.Threading (Thread, Monitor) || Threading primitives
|-
| System.Environment || Process exit, environment variables
|-
| System.Console || Console output before the OpenSim console is initialised
|-
| log4net || Apache logging framework -- not Microsoft, not OpenSim
|-
| Nini || .ini file parser, third-party library
|}

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== What to Follow ==

These namespaces are OpenSim code.

{| class="wikitable"
! Namespace !! Notes
|-
| OpenSim.Framework || Core data structures and interfaces
|-
| OpenSim.Framework.Console || OpenSim console infrastructure
|-
| OpenSim.Framework.Monitoring || Stats and monitoring
|-
| OpenSim.Framework.Servers || Server base classes
|-
| OpenSim.Framework.Servers.HttpServer || HTTP server and handler infrastructure
|-
| OpenSim.Server.Base || ServerUtils, plugin loading
|-
| OpenSim.Server.Handlers || ROBUST HTTP endpoint handlers
|-
| OpenSim.Services || Service implementations
|-
| OpenSim.Region.CoreModules || Simulator-side modules and connectors
|}

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== ROBUST Startup Map ==

Execution entry point for ROBUST.exe:

OpenSimServer.cs
-- entry point
-- reads command line, loads connectors, starts HTTP server loop
|
HttpServerBase.cs
-- HTTP server setup
-- reads [Network] config (port, SSL)
-- starts HttpServer listener
|
ServicesServerBase.cs
-- config loading (.ini file chain)
-- loads connector plugins from [ServiceList]
-- main run loop
-- clean shutdown handling

Key points:

* Config is loaded as a chain: defaults → Robust.ini → any included files. Later files override earlier ones.
* Connectors are loaded from [ServiceList] in Robust.ini. Each connector registers its HTTP handlers on startup.
* The HTTP server is started before connectors are loaded -- handlers are registered into a running server.
* SuppressConsoleCommands = true in [GridService] prevents duplicate console command registration when GridService is loaded both by ROBUST and by a simulator in the same process (standalone mode).

== OpenSim.exe Startup Map ==

Execution entry point for OpenSim.exe (simulator):

OpenSim.cs
-- entry point
-- loads region modules, initialises scene
|
OpenSimBase.cs
-- reads OpenSim.ini
-- loads estate, region, and physics configuration
-- starts HTTP server for simulator port (default 9000)
|
Scene.cs
-- per-region object: avatars, objects, physics, scripting
-- holds references to all service connectors via Scene.AssetService, Scene.GridService, etc.

Key points:

* Each region runs as a Scene instance. A single OpenSim.exe can host multiple regions.
* Service connectors are loaded as region modules -- they attach to the scene and provide the service interface.
* In standalone mode, service implementations run in-process inside OpenSim.exe. In grid mode, connectors make HTTP calls to ROBUST.

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== See Also ==

* [[OpenSimulator Internals/Connector Architecture]]
* [[OpenSimulator Internals/ROBUST Services]]

OpenSimulator Internals/Reading the Code - Revision history

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