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2026-06-28T10:13:37Z

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= OpenSimulator Internals/Code Map/Shared =

== Overview ==

Both ROBUST and OpenSim.exe are built from the same source tree and share the same DLL output. The code listed here is used by both processes -- not just one side calling the other.

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=== Core Data Structures ===

OpenSim/Framework/

Contains the fundamental data types that flow between all parts of the system. Neither ROBUST nor the simulator can function without these.

Key types:

{| class="wikitable"
! Type !! Notes
|-
| AssetBase || Asset metadata and binary data -- passed between asset service and callers
|-
| GridRegion || Region descriptor -- returned by GridService queries, used by simulator and ROBUST
|-
| InventoryItemBase || Inventory item -- passed between inventory service and callers
|-
| InventoryFolderBase || Inventory folder
|-
| RegionInfo || Region configuration -- loaded from Regions.ini, used by simulator startup
|-
| UserAccount || User account data -- passed between UserAccountService and callers
|-
| UUID || OpenMetaverse UUID wrapper -- used everywhere as primary identifier
|}

Also contains utility classes used by both processes:

{| class="wikitable"
! Class !! Notes
|-
| Util || General utilities: coordinate conversion, string helpers, Unix timestamps, UUID parsing
|-
| Constants || Grid constants: RegionSize, MaximumRegionSize, region coordinate limits
|-
| RegionFlags || Enum of region flag bitmask values -- used by GridService and simulators
|-
| AssetType || Enum of asset type numbers
|-
| AssetFlags || Enum of asset flag bitmask values
|}

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=== Service Interfaces ===

OpenSim/Services/Interfaces/

All service contracts are defined here as C# interfaces. Both ROBUST (which implements them) and the simulator (which calls them) depend on these interfaces. Neither side depends on the other's implementation.

Key interfaces:

{| class="wikitable"
! Interface !! Notes
|-
| IAssetService || Get, Store, Delete, AssetsExist, GetData, GetMetadata
|-
| IGridService || RegisterRegion, DeregisterRegion, GetRegionByUUID, GetNeighbours, etc.
|-
| IInventoryService || GetRootFolder, GetFolderItems, AddItem, DeleteItems, etc.
|-
| IUserAccountService || GetUserAccount, CreateUser, SetUserAccount
|-
| IPresenceService || LoginAgent, LogoutAgent, GetAgents
|-
| IAuthenticationService || Authenticate, Verify, SetPassword
|-
| IAvatarService || GetAvatar, SetAvatar
|-
| IFriendsService || GetFriends, StoreFriend, Delete
|-
| IGridUserService || LoggedIn, LoggedOut, SetHome, GetGridUserInfo
|}

In standalone mode, the simulator holds a direct reference to the service implementation. In grid mode, it holds a reference to a remote connector that calls ROBUST over HTTP. The interface is identical either way.

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=== HTTP Server Infrastructure ===

OpenSim/Framework/Servers/HttpServer/BaseHttpServer.cs
OpenSim/Framework/Servers/MainServer.cs

Both ROBUST and OpenSim.exe run HTTP servers. Both use the same base classes.

{| class="wikitable"
! Class !! Notes
|-
| BaseHttpServer || HTTP listener -- both processes instantiate this. Also contains IndexPHPHandler (line 2276) -- handles GET /index.php requests on the login port. Dispatches on ?method= parameter. Registered by both ROBUST (ServerMain.cs) and the simulator (OpenSim/Region/Application/OpenSim.cs) -- in standalone mode the simulator is its own login server.
|-
| MainServer || Singleton registry of all running HTTP servers. GetHttpServer(port) creates a server on demand for a given port. MainServer.Instance is the primary server.
|-
| BaseStreamHandler || Base class for all HTTP handlers that read/write streams
|-
| BaseRequestHandler || Base class for simpler request handlers
|-
| IOSHttpRequest / IOSHttpResponse || Request/response abstractions passed to all handlers
|}

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=== Plugin Loading and Serialization ===

OpenSim/Server/Base/ServerUtils.cs

Used by both processes to load plugins and serialize HTTP responses.

Key methods:

{| class="wikitable"
! Method !! Notes
|-
| LoadPlugin<T>() || Loads a class from a DLL by name using .NET reflection -- used by both ROBUST and simulator module loading
|-
| BuildXmlResponse() || Serializes a Dictionary<string,object> to XML -- used by all ROBUST service handlers
|-
| SerializeResult() || Serializes an object via XmlSerializer -- used by asset and grid handlers
|-
| ParseQueryString() || Parses POST body key-value pairs -- used by all ROBUST handlers that accept POST
|}

----

=== Database Abstraction Layer ===

OpenSim/Data/
OpenSim/Data/MySQL/

Both processes use the same database abstraction layer, but against different tables:

{| class="wikitable"
! Interface !! Used by !! Tables
|-
| IRegionData || ROBUST (GridService) || regions
|-
| IAssetDataPlugin || ROBUST (AssetService) || assets
|-
| IInventoryDataPlugin || ROBUST (InventoryService) || inventoryfolders, inventoryitems
|-
| IUserAccountData || ROBUST (UserAccountService) || UserAccounts
|-
| IPresenceData || ROBUST (PresenceService) || Presence
|-
| ISimulationDataStore || OpenSim.exe (Scene) || prims, primshapes, terrain, land, estate_*
|}

The MySQL implementations live in OpenSim/Data/MySQL/ and are loaded as plugins at runtime. Both processes use the same plugin loading mechanism -- only the interface and connection string differ.

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== See Also ==

* [[OpenSimulator Internals/Code Map]]
* [[OpenSimulator Internals/Code Map/ROBUST]]
* [[OpenSimulator Internals/Code Map/OpenSim]]
* [[OpenSimulator Internals/Connector Architecture]]
* [[OpenSimulator Internals/Databases]]

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