### Casos de uso: servicio externo { #use-cases-external-service }

Un ejemplo podría ser que tienes un proveedor de autenticación externo al que necesitas llamar.

Le envías un token y te devuelve un usuario autenticado.

Although any other parameter declared normally (for example, the body with a Pydantic model) would still be validated, converted, annotated, etc.

But there are specific cases where it's useful to get the `Request` object.

## Use the `Request` object directly { #use-the-request-object-directly }

Let's imagine you want to get the client's IP address/host inside of your *path operation function*.

 * sum that is used for purposes such as collecting statistics, not for fine-grained synchronization
 * control. Under low update contention, the two classes have similar characteristics. But under
 * high contention, expected throughput of this class is significantly higher, at the expense of
 * higher space consumption.
 *

import com.google.common.base.Supplier;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.TreeMap;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Test cases for {@link Tables#newCustomTable}.
 *
 * @author Jared Levy
 */
@GwtCompatible
@NullMarked
public class NewCustomTableTest extends AbstractTableTest<Character> {

  @Override

 *
 * <p>
 * This exception can be thrown when there are problems accessing URLs, files, or any other resources needed for crawling.
 * It includes constructors to handle messages, causes, or both.
 * </p>
 *
 * <p>
 * The log level can be set to DEBUG, INFO, WARN, or ERROR, and the class provides methods to check if a specific log level is enabled.
 * </p>
 *
 * <p>
 * Example usage:
 * </p>

            // Act & Assert
            assertThrows(NullPointerException.class, () -> resp.readBytesWireFormat(null, 0));
        }

        @Test
        @DisplayName("Insufficient buffer causes ArrayIndexOutOfBoundsException")
        void shortBuffer_throwsAIOOBE() {
            // Arrange: length 1 means readInt2 will access index 1 and fail
            byte[] buffer = new byte[1];

# JSON Compatible Encoder { #json-compatible-encoder }

There are some cases where you might need to convert a data type (like a Pydantic model) to something compatible with JSON (like a `dict`, `list`, etc).

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder` { #using-the-jsonable-encoder }

 * way to check an object at runtime to be an instance of a {@link TypeToken}. Instead, caller
 * should use the type safe {@link #putInstance}.
 *
 * <p>Also, if caller suppresses unchecked warnings and passes in an {@code Iterable<String>} for
 * type {@code Iterable<Integer>}, the map won't be able to detect and throw type error.
 *
 * <p>Like any other {@code Map<Class, Object>}, this map may contain entries for primitive types,

 * way to check an object at runtime to be an instance of a {@link TypeToken}. Instead, caller
 * should use the type safe {@link #putInstance}.
 *
 * <p>Also, if caller suppresses unchecked warnings and passes in an {@code Iterable<String>} for
 * type {@code Iterable<Integer>}, the map won't be able to detect and throw type error.
 *
 * <p>Like any other {@code Map<Class, Object>}, this map may contain entries for primitive types,

                  ListFeature.SUPPORTS_SET)
              .createTestSuite());
    }
    return suite;
  }

  // Test generators.  To let the GWT test suite generator access them, they need to be
  // public named classes with a public default constructor.

  public static final class ShortsAsListGenerator extends TestShortListGenerator {
    @Override
    protected List<Short> create(Short[] elements) {
      return asList(elements);