# Dependencies { #dependencies }

**FastAPI** has a very powerful but intuitive **<abbr title="also known as components, resources, providers, services, injectables">Dependency Injection</abbr>** system.

It is designed to be very simple to use, and to make it very easy for any developer to integrate other components with **FastAPI**.

## What is "Dependency Injection" { #what-is-dependency-injection }

That's what all the systems with "login with Facebook, Google, X (Twitter), GitHub" use underneath.

### OAuth 1 { #oauth-1 }

There was an OAuth 1, which is very different from OAuth2, and more complex, as it included direct specifications on how to encrypt the communication.

It is not very popular or used nowadays.

OAuth2 doesn't specify how to encrypt the communication, it expects you to have your application served with HTTPS.

/// tip

///

This is a very simple and short tutorial, if you want to learn about databases in general, about SQL, or more advanced features, go to the <a href="https://sqlmodel.tiangolo.com/" class="external-link" target="_blank">SQLModel docs</a>.

    }

    /**
     * Test very long URL handling
     */
    public void test_veryLongUrl() {
        String sessionId = "test-session-020";
        urlFilter.init(sessionId);

        // Create a very long URL
        StringBuilder longUrl = new StringBuilder("https://example.com/");
        for (int i = 0; i < 1000; i++) {
            longUrl.append("very/long/path/segment/");
        }

# GraphQL { #graphql }

As **FastAPI** is based on the **ASGI** standard, it's very easy to integrate any **GraphQL** library also compatible with ASGI.

You can combine normal FastAPI *path operations* with GraphQL on the same application.

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

# Security Policy

Security is very important for FastAPI and its community. 🔒

Learn more about it below. 👇

## Versions

The latest version of FastAPI is supported.

You are encouraged to [write tests](https://fastapi.tiangolo.com/tutorial/testing/) for your application and update your FastAPI version frequently after ensuring that your tests are passing. This way you will benefit from the latest features, bug fixes, and **security fixes**.

	KMSVersions := []string{
		kmsAPIVersionPrefix,
	}

	gz, err := gzhttp.NewWrapper(gzhttp.MinSize(1000), gzhttp.CompressionLevel(gzip.BestSpeed))
	if err != nil {
		// Static params, so this is very unlikely.
		logger.Fatal(err, "Unable to initialize server")
	}

	for _, version := range KMSVersions {
		// KMS Status APIs

<div class="screenshot">
<img src="/img/tutorial/request-form-models/image01.png">
</div>

## Forbid Extra Form Fields { #forbid-extra-form-fields }

In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.

/// note

This is supported since FastAPI version `0.114.0`. 🤓

///

* Implement and use well-known cryptographic tools, like Passlib and JWT tokens, etc.
* Add more granular permission controls with OAuth2 scopes where needed.
* ...etc.

Nevertheless, you might have a very specific use case where you really need to disable the API docs for some environment (e.g. for production) or depending on configurations from environment variables.

This is normally the best way to contribute to the project.

## External Contributions

External contributions are very welcome and appreciated, including answering questions, submitting PRs, etc. 🙇‍♂️