# 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.

# WebSockets

When defining WebSockets, you normally declare a parameter of type `WebSocket` and with it you can read data from the client and send data to it.

It is provided directly by Starlette, but you can import it from `fastapi`:

```python
from fastapi import WebSocket
```

!!! tip

	host, err := canonicalHost(u.Host)
	if err != nil {
		return
	}
	key := jarKey(host, j.psList)
	defPath := defaultPath(u.Path)

	j.mu.Lock()
	defer j.mu.Unlock()

	submap := j.entries[key]

	modified := false
	for _, cookie := range cookies {
		e, remove, err := j.newEntry(cookie, now, defPath, host)
		if err != nil {
			continue
		}
		id := e.id()
		if remove {
			if submap != nil {

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Declare como um parâmetro

Para adicionar o corpo na *função de operação de rota*, declare-o da mesma maneira que você declarou parâmetros de rota e consulta:

```Python hl_lines="18"
{!../../../docs_src/body/tutorial001.py!}
```

...E declare o tipo como o modelo que você criou, `Item`.

## Resultados

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.gradle.internal;

/**
 * Equivalent to {@code Transformer}, but does not declare nullability due to Java 6 restrictions.
 *
 * <p>A {@code Transformer} transforms objects of type.</p>
 *
 * <p>Implementations are free to return new objects or mutate the incoming value.</p>
 *

# you may need to define a router file `conf/my.application.routes`.
# Default to Routes in the root package (and conf/routes)
# application.router=my.application.Routes

# Database configuration
# ~~~~~
# You can declare as many datasources as you want.
# By convention, the default datasource is named `default`
#
# db.default.driver=org.h2.Driver
# db.default.url="jdbc:h2:mem:play"
# db.default.user=sa
# db.default.password=""

public abstract class KotlinForwardDeclarationProviderFactory : KotlinOptionalPlatformComponent {
    /**
     * Create a Kotlin/Native declaration provider for [ktModule].
     *
     * Generally, only Kotlin/Native KLIB libraries can declare forward declarations.
     * For other types of [KtModule]s the provider normally shouldn't be created.
     *
     * @return a declaration provider for [ktModule] or `null` if the module cannot contain forward declarations

## 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".

And then, that system (in this case **FastAPI**) will take care of doing whatever is needed to provide your code with those needed dependencies ("inject" the dependencies).

2. Annotate the property with `@Internal` or `@ServiceReference` (since 8.0).
3. Assign a shared build service provider to the property (optional, when using `@ServiceReference(<serviceName>)`).
4. Declare the association between the task and the service so Gradle can properly honor the build service lifecycle and its usage constraints (also optional when using `@ServiceReference`).

These functions can be declared with `async def` or normal `def`.

### `startup` event

To add a function that should be run before the application starts, declare it with the event `"startup"`:

```Python hl_lines="8"
{!../../../docs_src/events/tutorial001.py!}
```