# Extending OpenAPI

There are some cases where you might need to modify the generated OpenAPI schema.

In this section you will see how.

## The normal process

The normal (default) process, is as follows.

A `FastAPI` application (instance) has an `.openapi()` method that is expected to return the OpenAPI schema.

## About "Form Fields"

The way HTML forms (`<form></form>`) sends the data to the server normally uses a "special" encoding for that data, it's different from JSON.

**FastAPI** will make sure to read that data from the right place instead of JSON.

/// note | "Technical Details"

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

            ul.append(li)
        })
    }

    setupTermynal();
    showRandomAnnouncement('announce-left', 5000)
    showRandomAnnouncement('announce-right', 10000)
}
document$.subscribe(() => {
    main()

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package bandwidth

import (
	"sync"
	"sync/atomic"
	"time"
)

const (
	// betaBucket is the weight used to calculate exponential moving average
	betaBucket = 0.1 // Number of averages considered = 1/(1-betaObject)
)

// bucketMeasurement captures the bandwidth details for one bucket
type bucketMeasurement struct {

	MinK8SVersion               = 28
	UnSupportedK8SVersionLogMsg = "\nThe Kubernetes version %s is not supported by Istio %s. The minimum supported Kubernetes version is 1.%d.\n" +
		"Proceeding with the installation, but you might experience problems. " +
		"See https://istio.io/latest/docs/releases/supported-releases/ for a list of supported versions.\n"
)

// CheckKubernetesVersion checks if this Istio version is supported in the k8s version

                            <la:message key="labels.dict_protwords_title"/>
                        </h1>
                    </div>
                    <div class="col-sm-6">
                        <ol class="breadcrumb float-sm-right">
                            <li class="breadcrumb-item"><la:link href="/admin/dict">
                                <la:message key="labels.dict_list_link"/>
                            </la:link></li>

But you can return a `JSONResponse` directly from your *path operations*.

It might be useful, for example, to return custom headers or cookies.

## Return a `Response`

In fact, you can return any `Response` or any sub-class of it.

/// tip

`JSONResponse` itself is a sub-class of `Response`.

   * of {@link CombinedFuture}, the user-supplied callback usually has its own references to inputs.
   */
  /*
   * In certain circumstances, this field might theoretically not be visible to an afterDone() call
   * triggered by cancel(). For details, see the comments on the fields of TimeoutFuture.
   */
  @CheckForNull @LazyInit

					symmetry = uint64(len(p.Seq))%ss == 0
				} else {
					symmetry = ss%uint64(len(p.Seq)) == 0
				}
			}
		}
		// With no arg patterns, it is expected that user knows
		// the right symmetry, so either ellipses patterns are
		// provided (recommended) or no ellipses patterns.
		if _, ok := newSetCounts[ss]; !ok && (symmetry || argPatterns == nil) {
			newSetCounts[ss] = struct{}{}
		}
	}

        ArtifactResolutionResult result = resolve(request);

        // We have collected all the problems so let's mimic the way the old code worked and just blow up right here.
        // That's right lets just let it rip right here and send a big incomprehensible blob of text at unsuspecting
        // users. Bad dog!

        resolutionErrorHandler.throwErrors(request, result);

        return result;
    }