fix: update sessionIdGenerator (#320)

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##### Checklist
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- [ ] `npm test` passes
- [ ] tests and/or benchmarks are included
- [ ] documentation is changed or added
- [ ] commit message follows commit guidelines

##### Affected core subsystem(s)
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##### Description of change
<!-- Provide a description of the change below this comment. -->

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- any feature?
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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Refactor**
- Improved flexibility of session ID generation by allowing the
generator to accept the current request context.
- Enhanced session handling to support context-aware session ID
generation.
- **New Features**
- Added support for custom session IDs via request headers, enabling
consistent session identification across requests.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: akitaSummer

plugin/controller/lib/impl/mcp/MCPConfig.ts

@@ -1,3 +1,4 @@
+import type { Context } from 'egg';
 import { randomUUID } from 'node:crypto';
 import { EventStore } from '@modelcontextprotocol/sdk/server/streamableHttp.js';
 import { InMemoryEventStore } from '@modelcontextprotocol/sdk/examples/shared/inMemoryEventStore.js';
@@ -7,7 +8,7 @@ export interface MCPConfigOptions {
   sseMessagePath: string;
   streamPath: string;
   statelessStreamPath: string;
-  sessionIdGenerator?: () => string;
+  sessionIdGenerator?: (ctx: Context) => string;
   eventStore?: EventStore;
   sseHeartTime?: number;
 }
@@ -17,12 +18,12 @@ export class MCPConfig {
   private _sseMessagePath: string;
   private _streamPath: string;
   private _statelessStreamPath: string;
-  private _sessionIdGenerator: () => string;
+  private _sessionIdGenerator: (ctx: Context) => string;
   private _eventStore: EventStore;
   private _sseHeartTime: number;
 
   constructor(options: MCPConfigOptions) {
-    this._sessionIdGenerator = options.sessionIdGenerator ?? randomUUID;
+    this._sessionIdGenerator = options.sessionIdGenerator ?? (() => randomUUID());
     this._sseInitPath = options.sseInitPath;
     this._sseMessagePath = options.sseMessagePath;
     this._streamPath = options.streamPath;

plugin/controller/lib/impl/mcp/MCPControllerRegister.ts

@@ -250,7 +250,7 @@ export class MCPControllerRegister implements ControllerRegister {
           const eventStore = this.mcpConfig.eventStore;
           const self = this;
           const transport = new StreamableHTTPServerTransport({
-            sessionIdGenerator: () => this.mcpConfig.sessionIdGenerator(),
+            sessionIdGenerator: () => this.mcpConfig.sessionIdGenerator(ctx),
             eventStore,
             onsessioninitialized: async () => {
               if (MCPControllerRegister.hooks.length > 0) {

plugin/controller/test/fixtures/apps/mcp-app/config/config.default.js

@@ -1,4 +1,6 @@
 'use strict';
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { randomUUID } = require('node:crypto');
 
 module.exports = function() {
   const config = {
@@ -8,6 +10,11 @@ module.exports = function() {
         enable: false,
       },
     },
+    mcp: {
+      sessionIdGenerator: ctx => {
+        return ctx.request.headers['custom-session-id'] || randomUUID();
+      },
+    },
   };
   return config;
 };

plugin/controller/test/mcp/mcp.test.ts

@@ -181,14 +181,15 @@ describe('plugin/controller/test/mcp/mcp.test.ts', () => {
       });
       const baseUrl = await app.httpRequest()
         .post('/mcp/stream').url;
-      const streamableTransport = new StreamableHTTPClientTransport(new URL(baseUrl));
+      const streamableTransport = new StreamableHTTPClientTransport(new URL(baseUrl), { requestInit: { headers: { 'custom-session-id': 'custom-session-id' } } });
       const streamableNotifications: { level: string, data: string }[] = [];
       streamableClient.setNotificationHandler(LoggingMessageNotificationSchema, notification => {
         streamableNotifications.push({ level: notification.params.level, data: notification.params.data as string });
       });
       await streamableClient.connect(streamableTransport);
       // tool
       const tools = await listTools(streamableClient);
+      assert.deepEqual(streamableTransport.sessionId, 'custom-session-id');
       assert.deepEqual(tools, [
         {
           name: 'start-notification-stream',

plugin/controller/test/mcp/mcpCluster.test.ts

@@ -191,14 +191,15 @@ describe('plugin/controller/test/mcp/mcpCluster.test.ts', () => {
       });
       const baseUrl = await app.httpRequest()
         .post('/mcp/stream').url;
-      const streamableTransport = new StreamableHTTPClientTransport(new URL(baseUrl));
+      const streamableTransport = new StreamableHTTPClientTransport(new URL(baseUrl), { requestInit: { headers: { 'custom-session-id': 'custom-session-id' } } });
       const streamableNotifications: { level: string, data: string }[] = [];
       streamableClient.setNotificationHandler(LoggingMessageNotificationSchema, notification => {
         streamableNotifications.push({ level: notification.params.level, data: notification.params.data as string });
       });
       await streamableClient.connect(streamableTransport);
       // tool
       const tools = await listTools(streamableClient);
+      assert.deepEqual(streamableTransport.sessionId, 'custom-session-id');
       assert.deepEqual(tools, [
         {
           name: 'start-notification-stream',