FastAPI returns "405 Method Not Allowed" error when sending an HTTP request

Question

I have a simple FastAPI endpoint, where I want to receive a string value. In this case, I tried it with a JSON body, but basically it doesn't need to be JSON. I really need only a simple string to separate the requests from each other. Unfortunately, I can't access any of the request parameters with a GET method. I also tried POST method instead, but I get an error:

request:

url = "http://127.0.0.1:5000/ping/"

payload=json.dumps({"key":"test"})
headers = {
"Content-Type": "application/json"
            }
response = requests.request("POST", url, headers=headers, json=payload)

print(response.text)

api:

@app.get("/ping/{key}")
async def get_trigger(key: Request):

    key = key.json()
    test = json.loads(key)
    print(test)
    test2 = await key.json()
    print(key)
    print(test2)


    return 

I can't print anything with post or put:

@app.post("/ping/{key}")
async def get_trigger(key: Request):
...
   or

@app.put("/ping/{key}")
async def get_trigger(key: Request):

I get a 405 Method not allowed error.

How can I get this fixed?

Mackinnon

Answer 1

The 405 Method Not Allowed status code indicates that "the server knows the request method, but the target resource doesn't support this method". You get this error when you attempt, for instance, to send a POST request to a GET route (as shown in your first example).

This, however, is not the only issue with your code (on both client and server sides). Below is given an example on how to achieve what you described in the question using Path parameters. The same could be achieved using Query parameters, as well as Request Body. Please have a look at Python requests documentation on how to specify the parameters/body for each case. I would also highly suggest to take the FastAPI tutorial online—you'll find most of the answers you are looking for there.

app.py

from fastapi import FastAPI

app = FastAPI()

@app.get("/ping/{ping_id}")
async def get_trigger(ping_id: str):
    return {"ping_id": ping_id}

test.py

import requests

url = 'http://127.0.0.1:8000/ping/test1'
resp = requests.get(url=url) 
print(resp.json())

Related answers to 405 Method Not Allowed errors can be found here and here.

Falchion

I get a 404 not found with your solution – Mackinnon

Yes, I tried it in the browser. this is the fastapi terminal output: INFO: 127.0.0.1:64153 - "GET /ping/test1 HTTP/1.1" 404 Not Found. I'm on port 5000 btw – Mackinnon

I know that. If I would use the wrong port I'd not see fastapi printing the INFO. I copy/pasted your code, but by starting the server with uvicorn main:app --reloadas described in the doc's I get ERROR: Error loading ASGI app. Could not import module "main".. my file is named main.py – Mackinnon

Btw, I need to read / print ping_idon the backend side, not on the client side. The print statement in your solution is on the client side. – Mackinnon