# History, Design and Future { #history-design-and-future }

Some time ago, <a href="https://github.com/fastapi/fastapi/issues/3#issuecomment-454956920" class="external-link" target="_blank">a **FastAPI** user asked</a>:

> What’s the history of this project? It seems to have come from nowhere to awesome in a few weeks [...]

Here's a little bit of that history.

## Alternatives { #alternatives }

     * This is usually set by the Maven launcher script using the "maven.home" system property.
     *
     * @return the Maven installation directory path
     */
    @Nonnull
    Path installationDirectory();

    /**
     * Returns the user's home directory.
     * This is typically obtained from the "user.home" system property.
     *
     * @return the user's home directory path
     */
    @Nonnull
    Path userHomeDirectory();

**FastAPI** provides several tools to help you deal with **Security** easily, rapidly, in a standard way, without having to study and learn all the security specifications.

But first, let's check some small concepts.

## In a hurry? { #in-a-hurry }

If you don't care about any of these terms and you just need to add security with authentication based on username and password *right now*, skip to the next chapters.

# (And we run it after the main build so that that build has already downloaded Java 11 if necessary.)
./mvnw --projects '!guava-testlib,!guava-tests,!guava-bom,!guava-gwt' initialize -P print-java-11-home
export JAVA_HOME=$(<target/java_11_home)

# Gradle Wrapper overwrites some files when it runs.
# To avoid modifying the Git client, we copy everything we need to another directory.
# That provides general hygiene, including avoiding release errors:
#

issue if there is one) requesting the feature and describing specific use cases
for it.

If the feature has merit, it will go through a thorough process of API design
and review. Any code should come after this.

[APIs]: https://en.wikipedia.org/wiki/Application_programming_interface
[issue]: https://github.com/google/guava/issues

Pull requests
-------------

### `HTMLResponse` { #htmlresponse }

Takes some text or bytes and returns an HTML response, as you read above.

### `PlainTextResponse` { #plaintextresponse }

Takes some text or bytes and returns a plain text response.

{* ../../docs_src/custom_response/tutorial005.py hl[2,7,9] *}

### `JSONResponse` { #jsonresponse }

Takes some data and returns an `application/json` encoded response.

     */
    @Nullable
    Path cwd();

    /**
     * Returns the Maven home directory.
     * If not explicitly set, this value will be detected during parsing.
     *
     * @return the Maven home directory path, or null if not set
     */
    @Nullable
    Path mavenHome();

    /**
     * Returns the user's home directory.
     * If not explicitly set, this value will be detected during parsing.
     *

They are handled automatically by **FastAPI** and converted to JSON.

///

## Add custom headers { #add-custom-headers }

There are some situations in where it's useful to be able to add custom headers to the HTTP error. For example, for some types of security.

You probably won't need to use it directly in your code.

But in case you needed it for an advanced scenario, you can add custom headers:

Asynchronous code just means that the language 💬 has a way to tell the computer / program 🤖 that at some point in the code, it 🤖 will have to wait for *something else* to finish somewhere else. Let's say that *something else* is called "slow-file" 📝.

So, during that time, the computer can go and do some other work, while "slow-file" 📝 finishes.

**Spoiler alert**: il tutorial - Guida Utente include:

* Dichiarazione di **parameters** da altri posti diversi come: **headers**, **cookies**, **form fields** e **files**.
* Come stabilire **vincoli di validazione** come `maximum_length` o `regex`.