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Using the Request Directly

Up to now, you have been declaring the parts of the request that you need with their types.

Taking data from:

  • The path as parameters.
  • Headers.
  • Cookies.
  • etc.

And by doing so, FastAPI is validating that data, converting it and generating documentation for your API automatically.

But there are situations where you might need to access the Request object directly.

Details about the Request object

As FastAPI is actually Starlette underneath, with a layer of several tools on top, you can use Starlette's Request object directly when you need to.

It would also mean that if you get data from the Request object directly (for example, read the body) it won't be validated, converted or annotated (with OpenAPI, for the automatic documentation) by FastAPI.

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

But there are specific cases where it's useful to get the Request object.

Use the Request object directly

Let's imagine you want to get the client's IP address/host inside of your path operation function.

For that you need to access the request directly.

Import the Request

First, import the Request class from Starlette:

from fastapi import FastAPI
from starlette.requests import Request

app = FastAPI()


@app.get("/items/{item_id}")
def read_root(item_id: str, request: Request):
    client_host = request.client.host
    return {"client_host": client_host, "item_id": item_id}

Declare the Request parameter

Then declare a path operation function parameter with the type being the Request class:

from fastapi import FastAPI
from starlette.requests import Request

app = FastAPI()


@app.get("/items/{item_id}")
def read_root(item_id: str, request: Request):
    client_host = request.client.host
    return {"client_host": client_host, "item_id": item_id}

Tip

Note that in this case, we are declaring a path parameter besides the request parameter.

So, the path parameter will be extracted, validated, converted to the specified type and annotated with OpenAPI.

The same way, you can declare any other parameter as normally, and additionally, get the Request too.

Request documentation

You can read more details about the Request object in the official Starlette documentation site.