rune-langium / lsp-server/src / createConnectionAdapter

Function: createConnectionAdapter()

function createConnectionAdapter(server): any;

Defined in: packages/lsp-server/src/connection-adapter.ts:291

Create a vscode-languageserver-compatible Connection backed by an @lspeasy/server LSPServer.

Parameters

Parameter	Type	Description
server	LSPServer<ServerCapabilities<any>>	The @lspeasy/server LSPServer instance to adapt.

Returns

any

A duck-typed Connection object compatible with Langium's createDefaultSharedModule({ connection }).

Remarks

Langium's startLanguageServer() expects a Connection object from vscode-languageserver. This adapter bridges the gap: it translates Langium's typed handler registration methods (onHover, onCompletion, etc.) into @lspeasy/server request/notification registrations via a Proxy.

The initialize request receives special composite handling that replicates @lspeasy/server's internal state transitions (Created → Initializing → Initialized) AND forwards to Langium's handler. Without this, Langium's startLanguageServer would register its own handler that bypasses the state machine, causing all subsequent non-lifecycle requests to be rejected with ServerNotInitialized.

Use When

• Wiring a custom @lspeasy/server instance into Langium in tests or advanced embedding scenarios where createRuneLspServer() does not fit.

Avoid When

• Normal usage — prefer createRuneLspServer() which calls this internally.

Pitfalls

• The returned object is typed any — do not expose it to callers that expect vscode-languageserver.Connection; the shape matches but TypeScript cannot verify structural compatibility without the vscode-languageserver package installed.
• Sub-objects (console, window, workspace, languages) are stubs or delegates. Methods that require two-way communication (e.g., workspace.getConfiguration) may return empty results if the underlying transport is not yet connected.