chore: introduce response type (#738)

src/response.ts

@@ -0,0 +1,101 @@
+/**
+ * Copyright (c) Microsoft Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import type { ImageContent, TextContent } from '@modelcontextprotocol/sdk/types.js';
+import type { Context } from './context.js';
+
+export class Response {
+  private _result: string[] = [];
+  private _code: string[] = [];
+  private _images: { contentType: string, data: Buffer }[] = [];
+  private _context: Context;
+  private _includeSnapshot = false;
+  private _snapshot: string | undefined;
+  private _includeTabs = false;
+
+  constructor(context: Context) {
+    this._context = context;
+  }
+
+  addResult(result: string) {
+    this._result.push(result);
+  }
+
+  addCode(code: string) {
+    this._code.push(code);
+  }
+
+  addImage(image: { contentType: string, data: Buffer }) {
+    this._images.push(image);
+  }
+
+  setIncludeSnapshot() {
+    this._includeSnapshot = true;
+  }
+
+  setIncludeTabs() {
+    this._includeTabs = true;
+  }
+
+  includeSnapshot() {
+    return this._includeSnapshot;
+  }
+
+  addSnapshot(snapshot: string) {
+    this._snapshot = snapshot;
+  }
+
+  async serialize(): Promise<{ content: (TextContent | ImageContent)[] }> {
+    const response: string[] = [];
+
+    // Start with command result.
+    if (this._result.length) {
+      response.push('### Result');
+      response.push(this._result.join('\n'));
+      response.push('');
+    }
+
+    // Add code if it exists.
+    if (this._code.length) {
+      response.push(`### Ran Playwright code
+\`\`\`js
+${this._code.join('\n')}
+\`\`\``);
+      response.push('');
+    }
+
+    // List browser tabs.
+    if (this._includeSnapshot || this._includeTabs)
+      response.push(...(await this._context.listTabsMarkdown(this._includeTabs)));
+
+    // Add snapshot if provided.
+    if (this._snapshot)
+      response.push(this._snapshot, '');
+
+    // Main response part
+    const content: (TextContent | ImageContent)[] = [
+      { type: 'text', text: response.join('\n') },
+    ];
+
+    // Image attachments.
+    if (this._context.config.imageResponses !== 'omit') {
+      for (const image of this._images)
+        content.push({ type: 'image', data: image.data.toString('base64'), mimeType: image.contentType });
+    }
+
+    return { content };
+  }
+}