feat: enhance streaming response handling with ping mechanism

Author: caozhiyuan

README.md

@@ -184,11 +184,12 @@ The server exposes several endpoints to interact with the Copilot API. It provid
 
 These endpoints mimic the OpenAI API structure.
 
-| Endpoint                    | Method | Description                                               |
-| --------------------------- | ------ | --------------------------------------------------------- |
-| `POST /v1/chat/completions` | `POST` | Creates a model response for the given chat conversation. |
-| `GET /v1/models`            | `GET`  | Lists the currently available models.                     |
-| `POST /v1/embeddings`       | `POST` | Creates an embedding vector representing the input text.  |
+| Endpoint                    | Method | Description                                                      |
+| --------------------------- | ------ | ---------------------------------------------------------------- |
+| `POST /v1/responses`        | `POST` | Most advanced interface for generating model responses.          |
+| `POST /v1/chat/completions` | `POST` | Creates a model response for the given chat conversation.        |
+| `GET /v1/models`            | `GET`  | Lists the currently available models.                            |
+| `POST /v1/embeddings`       | `POST` | Creates an embedding vector representing the input text.         |
 
 ### Anthropic Compatible Endpoints
 

src/routes/responses/handler.ts

@@ -52,13 +52,29 @@ export const handleResponses = async (c: Context) => {
   if (isStreamingRequested(payload) && isAsyncIterable(response)) {
     consola.debug("Forwarding native Responses stream")
     return streamSSE(c, async (stream) => {
-      for await (const chunk of response) {
-        consola.debug("Responses stream chunk:", JSON.stringify(chunk))
-        await stream.writeSSE({
-          id: (chunk as { id?: string }).id,
-          event: (chunk as { event?: string }).event,
-          data: (chunk as { data?: string }).data ?? "",
-        })
+      const pingInterval = setInterval(async () => {
+        try {
+          await stream.writeSSE({
+            event: "ping",
+            data: JSON.stringify({ timestamp: Date.now() }),
+          })
+        } catch (error) {
+          consola.warn("Failed to send ping:", error)
+          clearInterval(pingInterval)
+        }
+      }, 3000)
+
+      try {
+        for await (const chunk of response) {
+          consola.debug("Responses stream chunk:", JSON.stringify(chunk))
+          await stream.writeSSE({
+            id: (chunk as { id?: string }).id,
+            event: (chunk as { event?: string }).event,
+            data: (chunk as { data?: string }).data ?? "",
+          })
+        }
+      } finally {
+        clearInterval(pingInterval)
       }
     })
   }