///

/// tip

If you need to do any type of validation that requires communicating with any **external component**, like a database or another API, you should instead use **FastAPI Dependencies**, you will learn about them later.

These custom validators are for things that can be checked with **only** the **same data** provided in the request.

///

### Understand that Code { #understand-that-code }

[guava.dev/api](https://guava.dev/api). You can also jump right to a specific
class by appending the class name to guava.dev. For example,
[guava.dev/ImmutableList](https://guava.dev/ImmutableList)!

## Learn about Guava

-   Our users' guide, [Guava Explained]
-   [A nice collection](https://www.tfnico.com/presentations/google-guava) of
    other helpful links

## Links

</blockquote>

## Investigation { #investigation }

By using all the previous alternatives I had the chance to learn from all of them, take ideas, and combine them in the best way I could find for myself and the teams of developers I have worked with.

For example, it was clear that ideally it should be based on standard Python type hints.

The `scope` `dict` and `receive` function are both part of the ASGI specification.

And those two things, `scope` and `receive`, are what is needed to create a new `Request` instance.

To learn more about the `Request` check <a href="https://www.starlette.dev/requests/" class="external-link" target="_blank">Starlette's docs about Requests</a>.

///

* The **database model** would probably need to have a hashed password.

/// danger

Never store user's plaintext passwords. Always store a "secure hash" that you can then verify.

If you don't know, you will learn what a "password hash" is in the [security chapters](security/simple-oauth2.md#password-hashing){.internal-link target=_blank}.

///

## Multiple models { #multiple-models }

That means that **any value** read in Python from an environment variable **will be a `str`**, and any conversion to a different type or any validation has to be done in code.

You will learn more about using environment variables for handling **application settings** in the [Advanced User Guide - Settings and Environment Variables](./advanced/settings.md){.internal-link target=_blank}.

///

## More info { #more-info }

To learn more about the options, check Starlette's documentation for:

* <a href="https://www.starlette.dev/websockets/" class="external-link" target="_blank">The `WebSocket` class</a>.

[build-system]
requires = ["pdm-backend"]
build-backend = "pdm.backend"

[project]
name = "fastapi"
dynamic = ["version"]
description = "FastAPI framework, high performance, easy to learn, fast to code, ready for production"
readme = "README.md"
license = "MIT"
license-files = ["LICENSE"]
requires-python = ">=3.9"
authors = [
    { name = "Sebastián Ramírez", email = "******@****.***" },
]
classifiers = [

  /**
   * <a
   * href="https://learn.microsoft.com/en-us/archive/blogs/vsofficedeveloper/office-2007-file-format-mime-types-for-http-content-streaming-2">Microsoft
   * Powerpoint</a> presentations.
   */
  public static final MediaType MICROSOFT_POWERPOINT =
      createConstant(APPLICATION_TYPE, "vnd.ms-powerpoint");

  /**
   * <a

       * UncheckedExecutionException, which has the stack trace from this thread and which has its
       * cause set to the underlying exception (which may be from another thread). If we someday
       * learn that some other exception besides IllegalArgumentException is common, then we could
       * add another special case to throw an instance of it, too.
       */
      throw e;
    }
  }