feat(api): add streaming support to search route

src/app/api/search/route.ts

@@ -33,6 +33,7 @@ interface ChatRequestBody {
   embeddingModel?: embeddingModel;
   query: string;
   history: Array<[string, string]>;
+  stream?: boolean;
 }
 
 export const POST = async (req: Request) => {
@@ -48,6 +49,7 @@ export const POST = async (req: Request) => {
 
     body.history = body.history || [];
     body.optimizationMode = body.optimizationMode || 'balanced';
+    body.stream = body.stream || false;
 
     const history: BaseMessage[] = body.history.map((msg) => {
       return msg[0] === 'human'
@@ -125,6 +127,7 @@ export const POST = async (req: Request) => {
       [],
     );
 
+    if (!body.stream) {
       return new Promise(
         (
           resolve: (value: Response) => void,
@@ -133,7 +136,7 @@ export const POST = async (req: Request) => {
           let message = '';
           let sources: any[] = [];
 
-        emitter.on('data', (data) => {
+          emitter.on('data', (data: string) => {
             try {
               const parsedData = JSON.parse(data);
               if (parsedData.type === 'response') {
@@ -152,13 +155,98 @@ export const POST = async (req: Request) => {
             resolve(Response.json({ message, sources }, { status: 200 }));
           });
 
-        emitter.on('error', (error) => {
+          emitter.on('error', (error: any) => {
             reject(
               Response.json({ message: 'Search error', error }, { status: 500 }),
             );
           });
         },
       );
+    }
+
+    const encoder = new TextEncoder();
+    
+    // Create an AbortController to handle cancellation
+    const abortController = new AbortController();
+    const { signal } = abortController;
+    
+    const stream = new ReadableStream({
+      start(controller) {
+        let sources: any[] = [];
+
+        // Send an initial message to keep the connection alive
+        controller.enqueue(encoder.encode("data: " + JSON.stringify({
+          type: 'init',
+          data: 'Stream connected'
+        }) + "\n\n"));
+
+        // Set up cleanup function for when client disconnects
+        signal.addEventListener('abort', () => {
+          // Remove all listeners from emitter to prevent memory leaks
+          emitter.removeAllListeners();
+          
+          // Close the controller if it's still active
+          try {
+            controller.close();
+          } catch (error) {
+            // Controller might already be closed
+          }
+        });
+
+        emitter.on('data', (data: string) => {
+          // Check if request has been cancelled before processing
+          if (signal.aborted) return;
+          
+          try {
+            const parsedData = JSON.parse(data);
+            
+            if (parsedData.type === 'response') {
+              controller.enqueue(encoder.encode("data: " + JSON.stringify({
+                type: 'response',
+                data: parsedData.data
+              }) + "\n\n"));
+            } else if (parsedData.type === 'sources') {
+              sources = parsedData.data;
+              controller.enqueue(encoder.encode("data: " + JSON.stringify({
+                type: 'sources',
+                data: sources
+              }) + "\n\n"));
+            }
+          } catch (error) {
+            controller.error(error);
+          }
+        });
+
+        emitter.on('end', () => {
+          // Check if request has been cancelled before processing
+          if (signal.aborted) return;
+          
+          controller.enqueue(encoder.encode("data: " + JSON.stringify({
+            type: 'done'
+          }) + "\n\n"));
+          controller.close();
+        });
+
+        emitter.on('error', (error: any) => {
+          // Check if request has been cancelled before processing
+          if (signal.aborted) return;
+          
+          controller.error(error);
+        });
+      },
+      
+      cancel() {
+        abortController.abort();
+      }
+    });
+
+    return new Response(stream, {
+      headers: {
+        'Content-Type': 'text/event-stream',
+        'Cache-Control': 'no-cache, no-transform',
+        'Connection': 'keep-alive',
+      },
+    });
   } catch (err: any) {
     console.error(`Error in getting search results: ${err.message}`);
     return Response.json(