## FastAPI Experts

These are the users that have been [helping others the most with questions in GitHub](help-fastapi.md#help-others-with-questions-in-github). 🙇

They have proven to be **FastAPI Experts** by helping many others. ✨

/// tip

        assertEquals("others", fileTypeHelper.get("non/existent"));
    }

    @Test
    public void test_get_withNullMimetype() {
        assertEquals("others", fileTypeHelper.get(null));
    }

    @Test
    public void test_get_withEmptyMimetype() {
        assertEquals("others", fileTypeHelper.get(""));
        assertEquals("others", fileTypeHelper.get(" "));
    }

    @Test

/// note | Technical Details

Actually, `Query`, `Path` and others you'll see next create objects of subclasses of a common `Param` class, which is itself a subclass of Pydantic's `FieldInfo` class.

And Pydantic's `Field` returns an instance of `FieldInfo` as well.

`Body` also returns objects of a subclass of `FieldInfo` directly. And there are others you will see later that are subclasses of the `Body` class.

* [Vote for **FastAPI** in AlternativeTo](https://alternativeto.net/software/fastapi/about/).
* [Say you use **FastAPI** on StackShare](https://stackshare.io/pypi-fastapi).

## Help others with questions in GitHub { #help-others-with-questions-in-github }

You can try and help others with their questions in:

* [GitHub Discussions](https://github.com/fastapi/fastapi/discussions/categories/questions?discussions_q=category%3AQuestions+is%3Aunanswered)

# Including WSGI - Flask, Django, others { #including-wsgi-flask-django-others }

You can mount WSGI applications as you saw with [Sub Applications - Mounts](sub-applications.md), [Behind a Proxy](behind-a-proxy.md).

For that, you can use the `WSGIMiddleware` and use it to wrap your WSGI application, for example, Flask, Django, etc.

## Using `WSGIMiddleware` { #using-wsgimiddleware }

/// info

* `le`: `l`ess than or `e`qual

/// info

`Query`, `Path`, and other classes you will see later are subclasses of a common `Param` class.

All of them share the same parameters for additional validation and metadata you have seen.

///

/// note | Technical Details

When you import `Query`, `Path` and others from `fastapi`, they are actually functions.

# Custom Response Classes - File, HTML, Redirect, Streaming, etc.

There are several custom response classes you can use to create an instance and return them directly from your *path operations*.

Read more about it in the [FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/).

You can import them directly from `fastapi.responses`:

```python
from fastapi.responses import (
    FileResponse,

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,

And all of them will use the same WebSocket connection.

## Using `Depends` and others { #using-depends-and-others }

In WebSocket endpoints you can import from `fastapi` and use:

* `Depends`
* `Security`
* `Cookie`
* `Header`
* `Path`
* `Query`

They work the same way as for other FastAPI endpoints/*path operations*:

{* ../../docs_src/websockets_/tutorial002_an_py310.py hl[68:69,82] *}

/*
 * Copyright 2012-2025 CodeLibs Project and the Others.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,