You can add code to be run with the `request`,  before any *path operation* receives it.

And also after the `response` is generated, before returning it.

For example, you could add a custom header `X-Process-Time` containing the time in seconds that it took to process the request and generate a response:

```Python hl_lines="10  12-13"
{!../../docs_src/middleware/tutorial001.py!}
```

/// tip

// Code generated by "stringer -type=format -trimprefix=format untar.go"; DO NOT EDIT.

package cmd

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[formatUnknown-0]
	_ = x[formatGzip-1]
	_ = x[formatZstd-2]
	_ = x[formatLZ4-3]
	_ = x[formatS2-4]
	_ = x[formatBZ2-5]
}

// Code generated by "stringer -type lcEventSrc -trimprefix lcEventSrc_ bucket-lifecycle-audit.go"; DO NOT EDIT.

package cmd

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[lcEventSrc_None-0]
	_ = x[lcEventSrc_Heal-1]
	_ = x[lcEventSrc_Scanner-2]
	_ = x[lcEventSrc_Decom-3]

// Code generated by "stringer -type Action lifecycle.go"; DO NOT EDIT.

package lifecycle

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[NoneAction-0]
	_ = x[DeleteAction-1]
	_ = x[DeleteVersionAction-2]
	_ = x[TransitionAction-3]
	_ = x[TransitionVersionAction-4]

// Code generated by "stringer -type=scannerMetric -trimprefix=scannerMetric data-scanner-metric.go"; DO NOT EDIT.

package cmd

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[scannerMetricReadMetadata-0]
	_ = x[scannerMetricCheckMissing-1]
	_ = x[scannerMetricSaveUsage-2]

// Code generated by "stringer -type=storageMetric -trimprefix=storageMetric xl-storage-disk-id-check.go"; DO NOT EDIT.

package cmd

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[storageMetricMakeVolBulk-0]
	_ = x[storageMetricMakeVol-1]
	_ = x[storageMetricListVols-2]

// Code generated by "stringer -type=STSErrorCode -trimprefix=Err sts-errors.go"; DO NOT EDIT.

package cmd

import "strconv"

func _() {
	// An "invalid array index" compiler error signifies that the constant values have changed.
	// Re-run the stringer command to generate them again.
	var x [1]struct{}
	_ = x[ErrSTSNone-0]
	_ = x[ErrSTSAccessDenied-1]
	_ = x[ErrSTSMissingParameter-2]
	_ = x[ErrSTSInvalidParameterValue-3]

							<src>${project.build.directory}/generated-packaging/deb/env/fess</src>
							<dst>/etc/default/fess</dst>
							<mapper>
								<type>perm</type>
								<user>root</user>
								<group>root</group>
							</mapper>
						</data>
						<!-- Add init.d files -->
						<data>
							<type>file</type>
							<src>${project.build.directory}/generated-packaging/deb/init.d/fess</src>

		i, test := i, test
		func() {
			defer recoverTest(i, test.ShouldPass, t)
			key := GenerateKey(test.ExtKey[:], test.Random)
			if [32]byte(key) == [32]byte{} {
				t.Errorf("Test %d: generated key is zero key", i) // check that we generate random and unique key
			}
		}()
	}
}

var generateIVTests = []struct {
	Random     io.Reader
	ShouldPass bool
}{
	{Random: nil, ShouldPass: true},              // 0

import org.apache.commons.cli.Option;
import org.junit.jupiter.api.Test;

import static java.util.Objects.nonNull;

/**
 * Pseudo test to generate documentation fragment about supported CLI options. TODO such documentation generation code
 * should not be necessary as unit test but should be run during site generation (Velocity? Doxia macro?)
 */
class CLIManagerDocumentationTest {
    private static final String LS = System.lineSeparator();