bug: wrong content-type in POST payload and FastAPI

[alexanderdann]

Provide environment information

System Information:
System: Darwin
Release: 24.1.0
Machine: arm64
Processor: arm
Python: 3.12.7 (main, Oct 1 2024, 02:05:46) [Clang 16.0.0 (clang-1600.0.26.3)]
encord-agents version: v0.1.2

Describe the bug

I am working on integrating a custom editor agent and started with a minimal example along the lines of your documentation. However it is not working as expected. I get "POST / HTTP/1.1" 422 Unprocessable Entity. It seems as if the payload is not in the expected format.

Chrome tells me that the content-type is:

content-type: text/plain

However for pydantic it needs to be json.

import json
from typing import Annotated

from encord.objects.ontology_labels_impl import LabelRowV2
from encord_agents import FrameData
from encord_agents.fastapi import dep_label_row
from fastapi import Depends, FastAPI, Form, Request
from fastapi.middleware.cors import CORSMiddleware

app = FastAPI()
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*", "https://app.encord.com"],
    allow_methods=["POST"],  # I had to add this line
)


# This does not work, from: https://agents-docs.encord.com/editor_agents/fastapi/
@app.post("/")
def my_agent(
    frame_data: Annotated[FrameData, Form()],
    label_row: Annotated[LabelRowV2, Depends(dep_label_row)],
):
    # ... Do your edits to the labels
    label_row.save()


# This works, mind to uncomment the previous function to see this function at work
@app.post("/")
async def my_agent(
    request: Request,
):
    # ... Do your edits to the labels
    body = await request.body()
    data = json.loads(body)
    frame_data = FrameData(**data)

    return frame_data

To reproduce

pip install encord==0.1.152 "fastapi[standard]==0.115.6" encord-agents==0.1.2 && fastapi dev main.py

Additional information

No response

[frederik-encord]

You are right. Will be fixed with next release.
Could you confirm if this enough? I believe it should be.

@app.post("/")
async def my_agent(
   frame_data: FrameData,
):
    return frame_data

[frederik-encord]

FYI #36 includes a fix for this issue. Will be included in the next release.

In fact, it'll become even easier to set up a FastAPI server with the right CORS middleware:

No need to set the allow_methods param and the allowed origins. That's all predefined in the EncordCORSMiddleware:

from encord_agents import FrameData
from encord_agents.fastapi.cors import EncordCORSMiddleware

# Initialize FastAPI app
app = FastAPI()
app.add_middleware(EncordCORSMiddleware)

@app.post("/your-endpoint")
def your_endpoint(frame_data: FrameData) -> None:
    ...

Caution

If you find it not working after updating to encord-agents >= 0.1.4 plus using the above template, please check the network tab in your browser to see if triggering your agent sends data with the text/plain content type. If that's the case, it is because we (at Encord) registered that you were using editor agents prior to making the change to application/json content type. As a consequence, we have done our best to keep your existing agents from breaking. Please reach out and we'll upgrade your organisation to application/json.

[alexanderdann]

Unfortunately I still get the same error. Testing via curl works, i.e.,

curl localhost:8000 -H "Content-type: application/json" -d '{
    "projectHash": "<project_hash>",
    "dataHash": "<data_hash>",
    "frame": 0
}'

This indicates that the message sent from Encord itself is malformed.