# Middleware (Проміжний шар)

У **FastAPI** можна додавати middleware (проміжний шар).

"Middleware" — це функція, яка працює з кожним **запитом** перед його обробкою будь-якою конкретною *операцією шляху* (*path operation*), а також з кожною **відповіддю** перед її поверненням.

* Middleware отримує кожен **запит**, що надходить до Вашого застосунку.
* Може виконати певні дії із цим **запитом** або запустити необхідний код.

Estos `examples` específicos de **OpenAPI** van en otra sección en la especificación de OpenAPI. Van en los **detalles para cada *path operation***, no dentro de cada JSON Schema.

Y Swagger UI ha soportado este campo particular de `examples` por un tiempo. Así que, puedes usarlo para **mostrar** diferentes **ejemplos en la interfaz de documentación**.

        double avgOpTimeNs = totalTime.get() / (double) operations.get();

        System.out.printf("Encryption Byte Tracking Performance: %d ops in %.2f ms%n", operations.get(), overallTimeMs);
        System.out.printf("  Avg atomic operation time: %.2f ns%n", avgOpTimeNs);

        // Verify lock-free performance (allowing for JVM overhead)
        assertTrue(avgOpTimeNs < 5000, "Atomic operations should be reasonably fast (no lock contention)");

    /**
     * Select the least busy channel based on pending operations
     */
    LEAST_LOADED,

    /**
     * Weighted random selection based on channel scores
     */
    WEIGHTED_RANDOM,

    /**
     * Affinity-based selection for related operations
     */
    AFFINITY_BASED,

    /**
     * Adaptive selection based on operation type and performance
     */
    ADAPTIVE

If you pass a "callable" as a dependency in **FastAPI**, it will analyze the parameters for that "callable", and process them in the same way as the parameters for a *path operation function*. Including sub-dependencies.

That also applies to callables with no parameters at all. The same as it would be for *path operation functions* with no parameters.

Then, we can change the dependency "dependable" `common_parameters` from above to the class `CommonQueryParams`:

    }

    /**
     * Sets the number of bytes remaining to be written in a sequence of write operations.
     *
     * @param remainingBytes the remainingBytes to set
     */
    public void setRemainingBytes(final int remainingBytes) {
        this.remainingBytes = remainingBytes;
    }

    /**
     * Sets the write operation flags.
     *
     * @param writeFlags the writeFlags to set
     */

///

Este parámetro no crea ese endpoint / *path operation*, pero declara que la URL `/token` será la que el cliente deberá usar para obtener el token. Esa información se usa en OpenAPI, y luego en los sistemas de documentación interactiva del API.

Pronto también crearemos la verdadera *path operation*.

/// info | Información

  }

  /**
   * Returns an immutable copy of the provided table.
   *
   * <p>The {@link Table#cellSet()} iteration order of the provided table determines the iteration
   * ordering of all views in the returned table. Note that some views of the original table and the
   * copied table may have different iteration orders. For more control over the ordering, create a

    "tax": 3.2
}
```

## Recap { #recap }

You can add multiple body parameters to your *path operation function*, even though a request can only have a single body.

But **FastAPI** will handle it, give you the correct data in your function, and validate and document the correct schema in the *path operation*.

You can also declare singular values to be received as part of the body.

    public static class ShareEnumAll extends DcerpcMessage {

        @Override
        public int getOpnum() {
            return 0x0f;
        }

        /**
         * The return value of the operation.
         */
        public int retval;
        /**
         * The name of the server.
         */
        public String servername;
        /**
         * The information level to return.