# Security Tools

When you need to declare dependencies with OAuth2 scopes you use `Security()`.

But you still need to define what is the dependable, the callable that you pass as a parameter to `Depends()` or `Security()`.

There are multiple tools that you can use to create those dependables, and they get integrated into OpenAPI so they are shown in the automatic docs UI, they can be used by automatically generated clients and SDKs, etc.

    private const val FILE_HEADER_SIZE = 32L

    /**
     * Creates a new relay that reads a live stream from [upstream], using [file] to share that data
     * with other sources.
     *
     * **Warning:** callers to this method must immediately call [newSource] to create a source and
     * close that when they're done. Otherwise a handle to [file] will be leaked.
     */
    @Throws(IOException::class)

## What is "Dependency Injection"

**"Dependency Injection"** means, in programming, that there is a way for your code (in this case, your *path operation functions*) to declare things that it requires to work and use: "dependencies".

  // scope specifies the scope of this rule.
  // Valid values are "Cluster", "Namespaced", and "*"
  // "Cluster" means that only cluster-scoped resources will match this rule.
  // Namespace API objects are cluster-scoped.
  // "Namespaced" means that only namespaced resources will match this rule.
  // "*" means that there are no scope restrictions.
  // Subresources match the scope of their parent resource.
  // Default is "*".
  //

# OpenAPI Webhooks

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

## Webhooks steps

This method returns a function. And that function is what will receive a request and return a response.

Here we use it to create a `GzipRequest` from the original request.

```Python hl_lines="18-26"
{!../../../docs_src/custom_request_and_route/tutorial001.py!}
```

!!! note "Technical Details"
    A `Request` has a `request.scope` attribute, that's just a Python `dict` containing the metadata related to the request.

  // ResourceRules describes what operations on what resources/subresources the ValidatingAdmissionPolicy matches.
  // The policy cares about an operation if it matches _any_ Rule.
  // +listType=atomic
  // +optional
  repeated NamedRuleWithOperations resourceRules = 3;

  // ExcludeResourceRules describes what operations on what resources/subresources the ValidatingAdmissionPolicy should not care about.

/**
 * A set of worker threads that are shared among a set of task queues.
 *
 * Use [INSTANCE] for a task runner that uses daemon threads. There is not currently a shared
 * instance for non-daemon threads.
 *
 * The task runner is also responsible for releasing held threads when the library is unloaded.
 * This is for the benefit of container environments that implement code unloading.
 *

  }

  /**
   * Returns the {@link Method} instance for {@link #testAddAll_unsupportedNonePresent()} so that
   * tests can suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()} while we
   * figure out what to do with <a href="http://goo.gl/qJBruX">{@code ConcurrentHashMap} support for
   * {@code entrySet().add()}</a>.
   */
  @J2ktIncompatible

 * iterator} method only once, and should be tested using this class. Exceptions to this rule should
 * be clearly documented.
 *
 * <p>Note that although your APIs should be liberal in what they accept, your methods which
 * <i>return</i> iterables should make every attempt to return ones of the robust variety.
 *
 * <p>This testing utility is not thread-safe.
 *
 * @author Kevin Bourrillion