Vamos primeiro ver como o aplicativo da API normal se pareceria antes de adicionar o callback.

Ele terá uma *operação de rota* que receberá um corpo `Invoice`, e um parâmetro de consulta `callback_url` que conterá a URL para o callback.

Essa parte é bastante normal, a maior parte do código provavelmente já é familiar para você:

{* ../../docs_src/openapi_callbacks/tutorial001.py hl[9:13,36:53] *}

/// tip | Dica

        assertEquals(result, duplicateHostHelper.convert(url));

        url = "http://foo.com/";
        result = "http://www.foo.com/";
        assertEquals(result, duplicateHostHelper.convert(url));

        url = "http://foo.com:8080/";
        result = "http://www.foo.com:8080/";
        assertEquals(result, duplicateHostHelper.convert(url));

        url = "http://mail.bar.com/";

    Converter<String, Number> converter = Converter.<String, Number>from(forward, backward);

    assertNull(converter.convert(null));
    assertNull(converter.reverse().convert(null));

    assertEquals((Integer) 5, converter.convert("5"));
    assertEquals("5", converter.reverse().convert(5));
  }

  // Null-passthrough violates our nullness annotations, so we don't support it under J2KT.
  @J2ktIncompatible

      return Ascii.toLowerCase(word);
    }

    @Override
    String convert(CaseFormat format, String s) {
      if (format == LOWER_UNDERSCORE) {
        return s.replace('-', '_');
      }
      if (format == UPPER_UNDERSCORE) {
        return Ascii.toUpperCase(s.replace('-', '_'));
      }
      return super.convert(format, s);
    }
  },

  /** C++ variable naming convention, e.g., "lower_underscore". */

import jcifs.Address;
import jcifs.CIFSContext;
import jcifs.NetbiosAddress;
import jcifs.NetbiosName;

/**
 * This class represents a NetBIOS over TCP/IP address. Under normal
 * conditions, users of jCIFS need not be concerned with this class as
 * name resolution and session services are handled internally by the smb package.
 *
 *
 *  * Applications can use the methods <code>getLocalHost</code>,
 * <code>getByName</code>, and

      return Ascii.toLowerCase(word);
    }

    @Override
    String convert(CaseFormat format, String s) {
      if (format == LOWER_UNDERSCORE) {
        return s.replace('-', '_');
      }
      if (format == UPPER_UNDERSCORE) {
        return Ascii.toUpperCase(s.replace('-', '_'));
      }
      return super.convert(format, s);
    }
  },

  /** C++ variable naming convention, e.g., "lower_underscore". */

     *
     * @param o
     *            the object to convert
     * @return the converted {@link Long}
     */
    public static Long toLong(final Object o) {
        return toLong(o, null);
    }

    /**
     * Converts the given object to a {@link Long}.
     *
     * @param o
     *            the object to convert
     * @param pattern
     *            the pattern string

     * @param src
     *            The source object to convert.
     * @return The converted {@link Date}.
     */
    public static Date toDate(final Object src) {
        return toDate(src, null, LocaleUtil.getDefault());
    }

    /**
     * Converts the given object to a {@link Date}.
     *
     * @param src
     *            The source object to convert.
     * @param pattern

    assertThat(converter.convert("1")).isEqualTo(1);
    assertThat(converter.convert("0")).isEqualTo(0);
    assertThat(converter.convert("-1")).isEqualTo(-1);
    assertThat(converter.convert("0xff")).isEqualTo(255);
    assertThat(converter.convert("0xFF")).isEqualTo(255);
    assertThat(converter.convert("-0xFF")).isEqualTo(-255);
    assertThat(converter.convert("#0000FF")).isEqualTo(255);

    assertThat(converter.convert("1.0")).isEqualTo(1.0);
    assertThat(converter.convert("0.0")).isEqualTo(0.0);
    assertThat(converter.convert("-1.0")).isEqualTo(-1.0);
    assertThat(converter.convert("1")).isEqualTo(1.0);
    assertThat(converter.convert("0")).isEqualTo(0.0);
    assertThat(converter.convert("-1")).isEqualTo(-1.0);
    assertThat(converter.convert("1e6")).isEqualTo(1e6);