## Proxy with a stripped path prefix

Having a proxy with a stripped path prefix, in this case, means that you could declare a path at `/app` in your code, but then, you add a layer on top (the proxy) that would put your **FastAPI** application under a path like `/api/v1`.

In this case, the original path `/app` would actually be served at `/api/v1/app`.

Even though all your code is written assuming there's just `/app`.

### Return a Response Directly

The most common case would be [returning a Response directly as explained later in the advanced docs](../advanced/response-directly.md){.internal-link target=_blank}.

```Python hl_lines="8  10-11"
{!> ../../../docs_src/response_model/tutorial003_02.py!}
```

#### "Schema"

A "schema" is a definition or description of something. Not the code that implements it, but just an abstract description.

#### API "schema"

In this case, <a href="https://github.com/OAI/OpenAPI-Specification" class="external-link" target="_blank">OpenAPI</a> is a specification that dictates how to define a schema of your API.

This way you will be able to have things ordered and grouped correctly for the client code:

<img src="/img/tutorial/generate-clients/image06.png">

In this case you have:

* `ItemsService`
* `UsersService`

### Client Method Names

Right now the generated method names like `createItemItemsPost` don't look very clean:

```TypeScript

from typing import Optional

from fastapi.exceptions import HTTPException
from fastapi.openapi.models import HTTPBase as HTTPBaseModel
from fastapi.openapi.models import HTTPBearer as HTTPBearerModel
from fastapi.security.base import SecurityBase
from fastapi.security.utils import get_authorization_scheme_param
from pydantic import BaseModel
from starlette.requests import Request
from starlette.status import HTTP_401_UNAUTHORIZED, HTTP_403_FORBIDDEN

Of course, there are some cases where there's no problem in running the previous steps multiple times, in that case, it's a lot easier to handle.

!!! tip
    Also, keep in mind that depending on your setup, in some cases you **might not even need any previous steps** before starting your application.

    In that case, you wouldn't have to worry about any of this. 🤷

### Examples of Previous Steps Strategies

```

Calling this program outputs:

```
John Doe
```

The function does the following:

* Takes a `first_name` and `last_name`.
* Converts the first letter of each one to upper case with `title()`.
* <abbr title="Puts them together, as one. With the contents of one after the other.">Concatenates</abbr> them with a space in the middle.

```Python hl_lines="2"
{!../../../docs_src/python_types/tutorial001.py!}

# Bigger Applications - Multiple Files

If you are building an application or a web API, it's rarely the case that you can put everything on a single file.

**FastAPI** provides a convenience tool to structure your application while keeping all the flexibility.

!!! info
    If you come from Flask, this would be the equivalent of Flask's Blueprints.

## An example file structure

Let's say you have a file structure like this:

```
.
├── app

## Password hashing

"Hashing" means converting some content (a password in this case) into a sequence of bytes (just a string) that looks like gibberish.

Whenever you pass exactly the same content (exactly the same password) you get exactly the same gibberish.

* `main`: il file `main.py` (il "modulo" Python).
* `app`: l'oggetto creato dentro `main.py` con la riga di codice `app = FastAPI()`.
* `--reload`: ricarica il server se vengono rilevati cambiamenti del codice. Usalo solo durante la fase di sviluppo.

</details>

### Testa l'API

Apri il browser all'indirizzo <a href="http://127.0.0.1:8000/items/5?q=somequery" class="external-link" target="_blank">http://127.0.0.1:8000/items/5?q=somequery</a>.