You can declare a parameter in a *path operation function* or dependency to be of type `Response` and then you can set data for the response like headers or cookies.

You can also use it directly to create an instance of it and return it from your *path operations*.

You can import it directly from `fastapi`:

```python
from fastapi import Response
```

## `Depends()`

Dependencies are handled mainly with the special function `Depends()` that takes a callable.

Here is the reference for it and its parameters.

You can import it directly from `fastapi`:

```python
from fastapi import Depends
```

::: fastapi.Depends

## `Security()`

name: Privileged
description: You are @tiangolo or he asked you directly to create an issue here. If not, check the other options. 👇
body:
  - type: markdown
    attributes:
      value: |
        Thanks for your interest in FastAPI! 🚀

        If you are not @tiangolo or he didn't ask you directly to create an issue here, please start the conversation in a [Question in GitHub Discussions](https://github.com/fastapi/fastapi/discussions/categories/questions) instead.

///

## Run your code with your debugger

Because you are running the Uvicorn server directly from your code, you can call your Python program (your FastAPI application) directly from the debugger.

---

For example, in Visual Studio Code, you can:

* Go to the "Debug" panel.
* "Add configuration...".
* Select "Python"

go 1.21

require (
	github.com/olekukonko/tablewriter v0.0.5
	github.com/pkg/xattr v0.4.9
)

require (
	github.com/mattn/go-runewidth v0.0.15 // indirect
	github.com/rivo/uniseg v0.4.4 // indirect
	golang.org/x/sys v0.15.0 // indirect

# and also repacks libtensorflow-src.jar into a standardized format.

# Helper function to copy a srcjar after moving any source files
# directly under the root to the "maven-style" src/main/java layout
#
# Source files generated by annotation processors appear directly
# under the root of srcjars jars created by bazel, rather than under
# the maven-style src/main/java subdirectory.
#

/**
 * A generic JUnit test which tests {@code forEach} operations on a collection. Can't be invoked
 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@Ignore("test runners must not instantiate and run this directly, only via suites we build")
// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.

```Python
contents = myfile.file.read()
```

/// note | "`async` Technical Details"

When you use the `async` methods, **FastAPI** runs the file methods in a threadpool and awaits for them.

///

/// note | "Starlette Technical Details"

You can use the `TestClient` class to test FastAPI applications without creating an actual HTTP and socket connection, just communicating directly with the FastAPI code.

Read more about it in the [FastAPI docs for Testing](https://fastapi.tiangolo.com/tutorial/testing/).

You can import it directly from `fastapi.testclient`:

```python
from fastapi.testclient import TestClient
```

		field.ValueOf = func(ctx context.Context, value reflect.Value) (interface{}, bool) {
			fieldValue := reflect.Indirect(value).Field(fieldIndex)
			return fieldValue.Interface(), fieldValue.IsZero()
		}
	default:
		field.ValueOf = func(ctx context.Context, v reflect.Value) (interface{}, bool) {
			v = reflect.Indirect(v)
			for _, fieldIdx := range field.StructField.Index {
				if fieldIdx >= 0 {
					v = v.Field(fieldIdx)