<img src="/img/tutorial/bigger-applications/image01.png">

## Include the same router multiple times with different `prefix` { #include-the-same-router-multiple-times-with-different-prefix }

You can also use `.include_router()` multiple times with the *same* router using different prefixes.

This could be useful, for example, to expose the same API under different prefixes, e.g. `/api/v1` and `/api/latest`.

///

## Password hashing { #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.

But you cannot convert from the gibberish back to the password.

///

And we are using this model to declare our input and the same model to declare our output:

{* ../../docs_src/response_model/tutorial002_py310.py hl[16] *}

Now, whenever a browser is creating a user with a password, the API will return the same password in the response.

In this case, it might not be a problem, because it's the same user sending the password.

	encodedQuery := query.Encode()

	// Verify if date query is same.
	if req.Form.Get(xhttp.AmzDate) != query.Get(xhttp.AmzDate) {
		return ErrSignatureDoesNotMatch
	}
	// Verify if expires query is same.
	if req.Form.Get(xhttp.AmzExpires) != query.Get(xhttp.AmzExpires) {
		return ErrSignatureDoesNotMatch
	}
	// Verify if signed headers query is same.

For example, if you have a function:

```Python
@lru_cache
def say_hi(name: str, salutation: str = "Ms."):
    return f"Hello {salutation} {name}"
```

your program could execute like this:

```mermaid
sequenceDiagram

participant code as Code

/// tip

And these same full-stack generators were the base of the [**FastAPI** Project Generators](project-generation.md){.internal-link target=_blank}.

/// info

Flask-apispec was created by the same Marshmallow developers.

///

/// check | Inspired **FastAPI** to

Generate the OpenAPI schema automatically, from the same code that defines serialization and validation.

///

{* ../../docs_src/dependencies/tutorial008_an_py39.py hl[18:19,26:27] *}

The same way, you could have some dependencies with `yield` and some other dependencies with `return`, and have some of those depend on some of the others.

And you could have a single dependency that requires several other dependencies with `yield`, etc.

						return nil, setupType,
							config.ErrInvalidErasureEndpoints(nil).Msg(fmt.Sprintf("same path '%s' can not be served by different port on same address", endpoint.Path))
					}
					pathIPMap[endpoint.Path] = IPSet.Union(hostIPSet)
				} else {
					pathIPMap[endpoint.Path] = hostIPSet
				}
			}
		}

		// Check whether same path is used for more than 1 local endpoints.
		{

Here's an example of how an HTTPS API could look like, step by step, paying attention mainly to the ideas important for developers.

### Domain Name { #domain-name }

It would probably all start by you **acquiring** some **domain name**. Then, you would configure it in a DNS server (possibly your same cloud provider).