Initial import

src/client/index.ts

@@ -0,0 +1,82 @@
+import { Protocol } from "../shared/protocol.js";
+import { Transport } from "../shared/transport.js";
+import {
+  ClientNotification,
+  ClientRequest,
+  ClientResult,
+  Implementation,
+  InitializeResult,
+  PROTOCOL_VERSION,
+  ServerCapabilities,
+  ServerNotification,
+  ServerRequest,
+  ServerResult,
+} from "../types/index.js";
+
+/**
+ * An MCP client on top of a pluggable transport.
+ *
+ * The client will automatically begin the initialization flow with the server when connect() is called.
+ */
+export class Client extends Protocol<
+  ServerRequest,
+  ServerNotification,
+  ServerResult,
+  ClientRequest,
+  ClientNotification,
+  ClientResult
+> {
+  private _serverCapabilities?: ServerCapabilities;
+  private _serverVersion?: Implementation;
+
+  /**
+   * Initializes this client with the given name and version information.
+   */
+  constructor(private _clientInfo: Implementation) {
+    super();
+  }
+
+  override async connect(transport: Transport): Promise<void> {
+    await super.connect(transport);
+
+    const result = (await this.request({
+      method: "initialize",
+      params: {
+        protocolVersion: 1,
+        capabilities: {},
+        clientInfo: this._clientInfo,
+      },
+    })) as InitializeResult;
+
+    if (result === undefined) {
+      throw new Error(`Server sent invalid initialize result: ${result}`);
+    }
+
+    if (result.protocolVersion !== PROTOCOL_VERSION) {
+      throw new Error(
+        `Server's protocol version is not supported: ${result.protocolVersion}`,
+      );
+    }
+
+    this._serverCapabilities = result.capabilities;
+    this._serverVersion = result.serverInfo;
+
+    await this.notification({
+      method: "notifications/initialized",
+    });
+  }
+
+  /**
+   * After initialization has completed, this will be populated with the server's reported capabilities.
+   */
+  getServerCapabilities(): ServerCapabilities | undefined {
+    return this._serverCapabilities;
+  }
+
+  /**
+   * After initialization has completed, this will be populated with information about the server's name and version.
+   */
+  getServerVersion(): Implementation | undefined {
+    return this._serverVersion;
+  }
+}