HTTP 204s do not conform to HTTP spec #3013
Description
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Description
Hello! I have noticed that fastAPI's HTTP 204's No Content response does not appear to conform to the HTTP spec by default. Per the HTTP spec: https://tools.ietf.org/html/rfc2616#section-10.2.5:
The 204 response MUST NOT include a message-body, and thus is always
terminated by the first empty line after the header fields.
It appears that fastapi is attempting to serialize as a JSON, and thus adding data to the message body. Here is an example that you can use to reproduce:
from fastapi import FastAPI, HTTPException
app = FastAPI()
@app.get("/")
def read_root():
raise HTTPException(status_code=204)Curling this will result in:
curl -v localhost:8000/
* Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 8000 (#0)
> GET / HTTP/1.1
> Host: 127.0.0.1:8000
> User-Agent: curl/7.64.1
> Accept: */*
>
< HTTP/1.1 204 No Content
< date: Mon, 29 Mar 2021 20:28:47 GMT
< server: uvicorn
< content-length: 23
< content-type: application/json
<
* Excess found in a non pipelined read: excess = 23 url = / (zero-length body)
* Connection #0 to host 127.0.0.1 left intact
* Closing connection 0
This line indicates the issue:
* Excess found in a non pipelined read: excess = 23 url = / (zero-length body)
It looks as though it's adding the following to the body:
{"detail":"No Content"}
Expected Behavior
The expected behavior is to not return anything in the body. This behavior should be the default when handling HTTPException of a status code of 204.
The current behavior can cause issues if you have your service being fronted with a proxy that strongly enforces the HTTP spec.
I don't have time today to attempt to fix, but would be happy to.
Environment
- OS: [e.g. Linux / Windows / macOS]: macOS
- FastAPI Version [e.g. 0.3.0]: 0.63.0
- Python version: 3.8.5