feat: preserve Jupyter MIME output in Streamlit

src/ipython_webapp/jupyter/app.py

@@ -7,7 +7,7 @@ from fastapi import Body, FastAPI, HTTPException, Path, Response
 from fastapi.responses import StreamingResponse
 from pydantic import BaseModel
 
-from ipython_shell.jupyter import InputRequest, JupyterApp, KernelMessage
+from ipython_shell.jupyter import InputRequest, JupyterApp, ParsedJupyterMessage
 
 app = FastAPI(title="IPython Jupyter Web App", version="0.1.0")
 shell_app = JupyterApp()
@@ -19,7 +19,7 @@ class InputReply(BaseModel):
     value: str
 
 
-def serialize_event(event: KernelMessage | InputRequest) -> dict[str, object]:
+def serialize_event(event: ParsedJupyterMessage | InputRequest) -> dict[str, object]:
     """Turn a shell event into JSON-safe data for a web client."""
     if isinstance(event, InputRequest):
         return {
@@ -31,11 +31,15 @@ def serialize_event(event: KernelMessage | InputRequest) -> dict[str, object]:
 
     # Some Jupyter messages keep binary payloads in message buffers. Base64
     # makes those buffers safe to carry beside JSON MIME data in the stream.
+    content = event.content
+    if isinstance(content, BaseModel):
+        content = content.model_dump(mode="json")
+
     return {
         "type": "kernel_message",
         "msg_type": event.msg_type,
         "parent_id": event.parent_id,
-        "content": event.content,
+        "content": content,
         "buffers": [
             base64.b64encode(buffer).decode("ascii") for buffer in event.buffers
         ],