# Dependencies - `Depends()` and `Security()`

## `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()`

Manchmal benötigen Sie den Rückgabewert einer Abhängigkeit innerhalb Ihrer *Pfadoperation-Funktion* nicht wirklich.

Oder die Abhängigkeit gibt keinen Wert zurück.

Aber Sie müssen sie trotzdem ausführen/auflösen.

In diesen Fällen können Sie, anstatt einen Parameter der *Pfadoperation-Funktion* mit `Depends` zu deklarieren, eine `list` von `dependencies` zum *Pfadoperation-Dekorator* hinzufügen.

 * limitations under the License.
 */

package com.google.common.collect;

import static java.util.Arrays.asList;

import com.google.common.base.Function;
import com.google.common.collect.Multiset.Entry;
import com.google.common.collect.testing.SetTestSuiteBuilder;
import com.google.common.collect.testing.TestStringSetGenerator;

 * **Route**: address, proxy, socketAddress
 * **TlsVersion**: javaName

#### Renamed Functions

* **Headers.of()**: for symmetry with `listOf()`, `setOf()`, etc., we’ve replaced
  `Headers.of(String...)` with `headersOf(vararg String)`.

#### Extension Functions

We’ve migrated from static functions to extension functions where we think they fit.

| Java                                | Kotlin                          |

# `Response` class

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*.

Read more about it in the [FastAPI docs about returning a custom Response](https://fastapi.tiangolo.com/advanced/response-directly/#returning-a-custom-response)

  }

  // enum singleton pattern
  private enum TrimStringFunction implements Function<String, String> {
    INSTANCE;

    @Override
    public String apply(String string) {
      return whitespace().trimFrom(string);
    }
  }

  public void testCompose() {
    Function<String, String> trim = TrimStringFunction.INSTANCE;
    Predicate<String> equalsFoo = Predicates.equalTo("Foo");

 * limitations under the License.
 */

package com.google.common.collect;

import static java.util.Arrays.asList;

import com.google.common.base.Function;
import com.google.common.collect.testing.SafeTreeSet;
import com.google.common.collect.testing.SetTestSuiteBuilder;
import com.google.common.collect.testing.TestStringSetGenerator;

	// baseDir is not honored in windows platform
	return os.MkdirAll(dirPath, perm)
}

// readDirFn applies the fn() function on each entries at dirPath, doesn't recurse into
// the directory itself, if the dirPath doesn't exist this function doesn't return
// an error.
func readDirFn(dirPath string, filter func(name string, typ os.FileMode) error) error {
	// Ensure we don't pick up files as directories.

var commitRE = /^(?:\d+:)?([0-9a-f]{6,40})$/; // e.g "8486:ab29d2698a47" or "ab29d2698a47"
var gerritChangeIdRE = /^I[0-9a-f]{4,40}$/; // e.g. Id69c00d908d18151486007ec03da5495b34b05f5
var pkgRE = /^[a-z0-9_\/]+$/;

function urlForInput(t) {
    if (!t) {
        return null;
    }

    if (numericRE.test(t)) {
        if (t < 150000) {
            // We could use the golang.org/cl/ handler here, but

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

package com.google.common.collect;

import com.google.common.base.Function;
import com.google.common.collect.testing.Helpers.NullsBeforeTwo;
import com.google.common.collect.testing.SafeTreeMap;
import com.google.common.collect.testing.SortedMapTestSuiteBuilder;