* the data from the client to be sent through the network
* the data sent by your program to be received by the client through the network
* the contents of a file in the disk to be read by the system and given to your program
* the contents your program gave to the system to be written to disk
* a remote API operation
* a database operation to finish
* a database query to return the results
* etc.

* You don't have to use `File()` in the default value of the parameter.
* It uses a "spooled" file:
    * A file stored in memory up to a maximum size limit, and after passing this limit it will be stored in disk.
* This means that it will work well for large files like images, videos, large binaries, etc. without consuming all the memory.
* You can get metadata from the uploaded file.

framework'den geliyorsanız ve küçük bir performans kazancı (yaklaşık 100 nanosaniye) için  "def" ile *path fonksiyonu* tanımlamaya alışkınsanız, **FastAPI**'de tam tersi olacağını unutmayın. Bu durumlarda, *path fonksiyonu* <abbr title="Input/Output: disk okuma veya yazma, ağ iletişimleri.">G/Ç</abbr> engelleyen durum oluşturmadıkça "async def" kullanmak daha iyidir.

Yine de, her iki durumda da, **FastAPI**'nin önceki frameworkden [hala daha hızlı](index.md#performans){.internal-link target=_blank}...

In that case, it could be better to have only 2 servers and use a higher percentage of their resources (CPU, memory, disk, network bandwidth, etc).

(aproximadamente 100 nanosegundos), ten en cuenta que en **FastAPI** el efecto sería bastante opuesto. En estos casos, es mejor usar `async def` a menos que tus *path operation functions* usen un código que realice el bloqueo <abbr title="Input/Output: disk reading or writing, network communications.">I/O</abbr>.

Aún así, en ambas situaciones, es probable que **FastAPI** sea [aún más rápido](index.md#rendimiento){.Internal-link target=_blank} que (o al menos comparable) a tu framework anterior....

The same models are shared among requests, so, it's not one model per request, or one per user or something similar.

Let's imagine that loading the model can **take quite some time**, because it has to read a lot of **data from disk**. So you don't want to do it for every request.

A container image is comparable to the **program** file and contents, e.g. `python` and some file `main.py`.

#!/bin/sh -e

if [ -d 'dist' ] ; then
    rm -r dist
fi
if [ -d 'site' ] ; then
    rm -r site

    response = client.get("/docs")
    assert response.status_code == 200, response.text
    assert (
        "https://unpkg.com/swagger-ui-dist@5.9.0/swagger-ui-bundle.js" in response.text
    )
    assert "https://unpkg.com/swagger-ui-dist@5.9.0/swagger-ui.css" in response.text


def test_swagger_ui_oauth2_redirect_html(client: TestClient):
    response = client.get("/docs/oauth2-redirect")

def test_swagger_ui():
    response = client.get("/docs")
    assert response.status_code == 200, response.text
    assert response.headers["content-type"] == "text/html; charset=utf-8"
    assert "swagger-ui-dist" in response.text
    print(client.base_url)
    assert "oauth2RedirectUrl" not in response.text


def test_swagger_ui_no_oauth2_redirect():
    response = client.get("/docs/oauth2-redirect")