feat(congodb): implement CongoDB MongoDB wire-protocol compatible in-memory server and APIs

ts/congodb/server/CommandRouter.ts

@@ -0,0 +1,180 @@
+import * as plugins from '../congodb.plugins.js';
+import type { IStorageAdapter } from '../storage/IStorageAdapter.js';
+import type { IParsedCommand } from './WireProtocol.js';
+import type { CongoServer } from './CongoServer.js';
+
+// Import handlers
+import { HelloHandler } from './handlers/HelloHandler.js';
+import { InsertHandler } from './handlers/InsertHandler.js';
+import { FindHandler } from './handlers/FindHandler.js';
+import { UpdateHandler } from './handlers/UpdateHandler.js';
+import { DeleteHandler } from './handlers/DeleteHandler.js';
+import { AggregateHandler } from './handlers/AggregateHandler.js';
+import { IndexHandler } from './handlers/IndexHandler.js';
+import { AdminHandler } from './handlers/AdminHandler.js';
+
+/**
+ * Handler context passed to command handlers
+ */
+export interface IHandlerContext {
+  storage: IStorageAdapter;
+  server: CongoServer;
+  database: string;
+  command: plugins.bson.Document;
+  documentSequences?: Map<string, plugins.bson.Document[]>;
+}
+
+/**
+ * Command handler interface
+ */
+export interface ICommandHandler {
+  handle(context: IHandlerContext): Promise<plugins.bson.Document>;
+}
+
+/**
+ * CommandRouter - Routes incoming commands to appropriate handlers
+ */
+export class CommandRouter {
+  private storage: IStorageAdapter;
+  private server: CongoServer;
+  private handlers: Map<string, ICommandHandler> = new Map();
+
+  // Cursor state for getMore operations
+  private cursors: Map<bigint, ICursorState> = new Map();
+  private cursorIdCounter: bigint = BigInt(1);
+
+  constructor(storage: IStorageAdapter, server: CongoServer) {
+    this.storage = storage;
+    this.server = server;
+    this.registerHandlers();
+  }
+
+  /**
+   * Register all command handlers
+   */
+  private registerHandlers(): void {
+    // Create handler instances with shared state
+    const helloHandler = new HelloHandler();
+    const findHandler = new FindHandler(this.cursors, () => this.cursorIdCounter++);
+    const insertHandler = new InsertHandler();
+    const updateHandler = new UpdateHandler();
+    const deleteHandler = new DeleteHandler();
+    const aggregateHandler = new AggregateHandler(this.cursors, () => this.cursorIdCounter++);
+    const indexHandler = new IndexHandler();
+    const adminHandler = new AdminHandler();
+
+    // Handshake commands
+    this.handlers.set('hello', helloHandler);
+    this.handlers.set('ismaster', helloHandler);
+    this.handlers.set('isMaster', helloHandler);
+
+    // CRUD commands
+    this.handlers.set('find', findHandler);
+    this.handlers.set('insert', insertHandler);
+    this.handlers.set('update', updateHandler);
+    this.handlers.set('delete', deleteHandler);
+    this.handlers.set('findAndModify', updateHandler);
+    this.handlers.set('getMore', findHandler);
+    this.handlers.set('killCursors', findHandler);
+
+    // Aggregation
+    this.handlers.set('aggregate', aggregateHandler);
+    this.handlers.set('count', findHandler);
+    this.handlers.set('distinct', findHandler);
+
+    // Index operations
+    this.handlers.set('createIndexes', indexHandler);
+    this.handlers.set('dropIndexes', indexHandler);
+    this.handlers.set('listIndexes', indexHandler);
+
+    // Admin/Database operations
+    this.handlers.set('ping', adminHandler);
+    this.handlers.set('listDatabases', adminHandler);
+    this.handlers.set('listCollections', adminHandler);
+    this.handlers.set('drop', adminHandler);
+    this.handlers.set('dropDatabase', adminHandler);
+    this.handlers.set('create', adminHandler);
+    this.handlers.set('serverStatus', adminHandler);
+    this.handlers.set('buildInfo', adminHandler);
+    this.handlers.set('whatsmyuri', adminHandler);
+    this.handlers.set('getLog', adminHandler);
+    this.handlers.set('hostInfo', adminHandler);
+    this.handlers.set('replSetGetStatus', adminHandler);
+    this.handlers.set('isMaster', helloHandler);
+    this.handlers.set('saslStart', adminHandler);
+    this.handlers.set('saslContinue', adminHandler);
+    this.handlers.set('endSessions', adminHandler);
+    this.handlers.set('abortTransaction', adminHandler);
+    this.handlers.set('commitTransaction', adminHandler);
+    this.handlers.set('collStats', adminHandler);
+    this.handlers.set('dbStats', adminHandler);
+    this.handlers.set('connectionStatus', adminHandler);
+    this.handlers.set('currentOp', adminHandler);
+    this.handlers.set('collMod', adminHandler);
+    this.handlers.set('renameCollection', adminHandler);
+  }
+
+  /**
+   * Route a command to its handler
+   */
+  async route(parsedCommand: IParsedCommand): Promise<plugins.bson.Document> {
+    const { commandName, command, database, documentSequences } = parsedCommand;
+
+    // Create handler context
+    const context: IHandlerContext = {
+      storage: this.storage,
+      server: this.server,
+      database,
+      command,
+      documentSequences,
+    };
+
+    // Find handler
+    const handler = this.handlers.get(commandName);
+
+    if (!handler) {
+      // Unknown command
+      return {
+        ok: 0,
+        errmsg: `no such command: '${commandName}'`,
+        code: 59,
+        codeName: 'CommandNotFound',
+      };
+    }
+
+    try {
+      return await handler.handle(context);
+    } catch (error: any) {
+      // Handle known error types
+      if (error.code) {
+        return {
+          ok: 0,
+          errmsg: error.message,
+          code: error.code,
+          codeName: error.codeName || 'UnknownError',
+        };
+      }
+
+      // Generic error
+      return {
+        ok: 0,
+        errmsg: error.message || 'Internal error',
+        code: 1,
+        codeName: 'InternalError',
+      };
+    }
+  }
+}
+
+/**
+ * Cursor state for multi-batch queries
+ */
+export interface ICursorState {
+  id: bigint;
+  database: string;
+  collection: string;
+  documents: plugins.bson.Document[];
+  position: number;
+  batchSize: number;
+  createdAt: Date;
+}