403 Forbidden connecting using websocket through Postman

[Pk13055]

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Example Code

from collections import deque
from typing import Any, Dict, Set

from fastapi import APIRouter, WebSocket, WebSocketDisconnect, FastAPI
from starlette.middleware.cors import CORSMiddleware


class EngineServer:
    """WebSocket server for the engine"""

    clients: Set[WebSocket] = set()
    _responses: deque = deque(maxlen=1000)
    port: int = 8080
    host: str = "0.0.0.0"

    @classmethod
    async def init(
        cls, host: str | None = None, port: int | None = None
    ) -> "EngineServer":
        if host: cls.host = host
        if port: cls.port = port
        return cls

    @classmethod
    async def connect(cls, websocket: WebSocket):
        await websocket.accept()
        cls.clients.add(websocket)

    @classmethod
    def disconnect(cls, websocket: WebSocket):
        cls.clients.remove(websocket)

    @classmethod
    async def send(cls, message: dict, websocket: WebSocket):
        await websocket.send_json(message)

    @classmethod
    async def _receive(cls, websocket: WebSocket) -> dict[str, Any]:
        response = await websocket.receive_json()
        cls._responses.append(response)
        return response


router = APIRouter(
    prefix="",
    tags=["engine"],
)


@router.websocket("/query/ws", name="query-websocket")
async def websocket_endpoint(websocket: WebSocket):
    """Query websocket route"""
    engine_client = await EngineServer.init()
    await engine_client.connect(websocket)
    try:
        while True:
            data = await engine_client._receive(websocket)
            print(data)
            await engine_client.send(data, websocket)
    except WebSocketDisconnect:
        engine_client.disconnect(websocket)


app = FastAPI()
app.add_middleware(
    CORSMiddleware,
    allow_origins=settings.ALLOWED_HOSTS,
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)
app.include_router(router)

Description

• Open Postman (new websocket request)
• Try to connect to ws://0.0.0.0:8000/engine/query/ws/
• Error:

Request URL: http://0.0.0.0:8000/engine/query/ws/
Request Method: GET
Status Code: 403 Forbidden
-----------------
Request Headers
Sec-WebSocket-Version: 13
Sec-WebSocket-Key: zFafMFebNPPOXUEFv9KZZw==
Connection: Upgrade
Upgrade: websocket
Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits
Host: 0.0.0.0:8000
-----------------
Response Headers
Server: nginx/1.23.4
Date: Sat, 13 May 2023 11:00:42 GMT
Content-Type: text/plain
Content-Length: 0
Connection: keep-alive

Operating System

macOS

Operating System Details

No response

FastAPI Version

0.95.1

Python Version

Python 3.11.3

Additional Context

This application is running inside docker as part of a compose stack. Additionally, I am using nginx as a reverse proxy. Following is my nginx local.conf

upstream engine_server {
    server engine:4200;
}

# now we declare our main server
server {

    listen 80;
    server_name localhost;
    client_max_body_size 10M;

    location /engine/query/ws/ {
        proxy_pass http://engine_server/engine/query/ws;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_set_header Host $host;
        proxy_redirect off;
    }

    location /engine/ {
        proxy_pass http://engine_server/;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_redirect off;
    } 
}

[wertyac]

I meet the same issue， FastAPI Websocket in docker。 meet 403 issue.

[fakeesp]

i have same issue, fastapi runs on vps locally behind nginx

also i tried to run example that i found in official docs(online chat) and got this:

[Kwojtanek]

Hey, for me it was url trailing slash issue.
So config looks like this:
NGINX:

location /websocket {
        proxy_pass http://localhost:8080;  
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "Upgrade";
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto https;
        proxy_set_header Origin "";
    
        # Optional WebSocket timeouts
        proxy_read_timeout 86400s;  
        proxy_send_timeout 86400s;
    
    }

websocket:

@app.websocket("/websocket")
async def websocket_endpoint(websocket: WebSocket):
    await websocket.accept()

URL INSIDE:
uri = "ws://localhost:8080/websocket"
URL IN JS:
"wss://www.investron.ai/websocket"

[YuriiMotov]

Trailing slash is important with websocket routes. You defined route path as /query/ws, but trying to connect to /query/ws/