pkg reflect, func StructOf([]StructField) Type
pkg reflect, method (StructTag) Lookup(string) (string, bool)
pkg runtime, func CallersFrames([]uintptr) *Frames
pkg runtime, func KeepAlive(interface{})
pkg runtime, func SetCgoTraceback(int, unsafe.Pointer, unsafe.Pointer, unsafe.Pointer)
pkg runtime, method (*Frames) Next() (Frame, bool)
pkg runtime, type Frame struct
pkg runtime, type Frame struct, Entry uintptr
pkg runtime, type Frame struct, File string

So we have a dedicated thread for every socket that just reads frames and dispatches them.

The reader thread must never run application-layer code. Otherwise one slow stream can hold up the entire connection.

# Query Parameter Models { #query-parameter-models }

If you have a group of **query parameters** that are related, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

# General - How To - Recipes { #general-how-to-recipes }

Here are several pointers to other places in the docs, for general or frequent questions.

## Filter Data - Security { #filter-data-security }

To ensure that you don't return more data than you should, read the docs for [Tutorial - Response Model - Return Type](../tutorial/response-model.md){.internal-link target=_blank}.

## Documentation Tags - OpenAPI { #documentation-tags-openapi }

            """
        ),
    ] = _Unset,
    decimal_places: Annotated[
        Union[int, None],
        Doc(
            """
            Maximum number of decimal places allowed for numbers.
            """
        ),
    ] = _Unset,
    examples: Annotated[
        Optional[list[Any]],
        Doc(
            """
            Example values for this field.

# Header Parameter Models { #header-parameter-models }

If you have a group of related **header parameters**, you can create a **Pydantic model** to declare them.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

import com.google.common.annotations.J2ktIncompatible;
import java.io.Closeable;
import java.io.Flushable;
import java.io.IOException;
import java.io.Writer;
import org.jspecify.annotations.Nullable;

/**
 * Writer that places all output on an {@link Appendable} target. If the target is {@link Flushable}
 * or {@link Closeable}, flush()es and close()s will also be delegated to the target.
 *
 * @author Alan Green
 * @author Sebastian Kanthak

				return nil, err
			}
			continue
		}
		data, _ = json.Marshal(cfg)
		break
	}
	if osIsPermission(err) {
		logger.Info("Older config found but is not readable %s, proceeding to read config from other places", err)
	}
	if osIsNotExist(err) || osIsPermission(err) || len(data) == 0 {
		data, err = readConfig(GlobalContext, objAPI, configFile)
		if err != nil {
			// when config.json is not found, then we freshly initialize.

{* ../../docs_src/security/tutorial003_an_py310.py hl[82:85] *}

#### Sobre `**user_dict` { #about-user-dict }

`UserInDB(**user_dict)` significa:

*Pasa las claves y valores de `user_dict` directamente como argumentos clave-valor, equivalente a:*

```Python
UserInDB(
    username = user_dict["username"],
    email = user_dict["email"],
    full_name = user_dict["full_name"],

`Header` es una clase "hermana" de `Path`, `Query` y `Cookie`. También hereda de la misma clase común `Param`.

Pero recuerda que cuando importas `Query`, `Path`, `Header`, y otros de `fastapi`, en realidad son funciones que retornan clases especiales.

///

/// info | Información

Para declarar headers, necesitas usar `Header`, porque de otra forma los parámetros serían interpretados como parámetros de query.

///