<div class="screenshot">
<img src="/img/tutorial/request-form-models/image01.png">
</div>

## Forbid Extra Form Fields { #forbid-extra-form-fields }

In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.

/// note

This is supported since FastAPI version `0.114.0`. 🤓

///

    this.leafNodeCode = leafNodeCode;
  }

  char getLeafNodeCode() {
    return leafNodeCode;
  }

  char getInnerNodeCode() {
    return innerNodeCode;
  }

  /** Returns a PublicSuffixType of the right type according to the given code */
  static PublicSuffixType fromCode(char code) {
    for (PublicSuffixType value : values()) {
      if (value.getInnerNodeCode() == code || value.getLeafNodeCode() == code) {

 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>, maybe: It might no longer be
 *       necessary there, since we have stopped using the {@code @ParametersAreNonnullByDefault}
 *       annotations that {@code ParametricNullness} was counteracting.
 * </ul>
 *

   */

  @Override
  public void write(char[] cbuf, int off, int len) throws IOException {
    checkNotClosed();
    // It turns out that creating a new String is usually as fast, or faster
    // than wrapping cbuf in a light-weight CharSequence.
    target.append(new String(cbuf, off, len));
  }

  /*
   * Override a few functions for performance reasons to avoid creating unnecessary strings.
   */

  @Override

 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>, maybe: It might no longer be
 *       necessary there, since we have stopped using the {@code @ParametersAreNonnullByDefault}
 *       annotations that {@code ParametricNullness} was counteracting.
 * </ul>
 *

 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>, maybe: It might no longer be
 *       necessary there, since we have stopped using the {@code @ParametersAreNonnullByDefault}
 *       annotations that {@code ParametricNullness} was counteracting.
 * </ul>
 *

 *       href="https://github.com/google/guava/issues/6126#issuecomment-1204399671">treats it
 *       identically to {@code Nullable}</a> as of version 0.9.9.
 *   <li><a href="https://developers.google.com/j2objc">J2ObjC</a>, maybe: It might no longer be
 *       necessary there, since we have stopped using the {@code @ParametersAreNonnullByDefault}
 *       annotations that {@code ParametricNullness} was counteracting.
 * </ul>
 *

   * stream is longer, its extra elements will be ignored.
   *
   * <p>Note that if you are calling {@link Stream#forEach} on the resulting stream, you might want
   * to consider using {@link #forEachPair} instead of this method.
   *
   * <p><b>Performance note:</b> The resulting stream is not <a

# 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 }

certificate.

The trusted roots don't need to be the same for client and server when using client authentication.
Clients might rely on the platform certificates and servers might use a private
organization-specific certificate authority.

By default `HeldCertificate` instances expire after 24 hours. Use `duration()` to adjust.