# Advanced Middleware { #advanced-middleware }

In the main tutorial you read how to add [Custom Middleware](../tutorial/middleware.md){.internal-link target=_blank} to your application.

And then you also read how to handle [CORS with the `CORSMiddleware`](../tutorial/cors.md){.internal-link target=_blank}.

In this section we'll see how to use other middlewares.

## Adding ASGI middlewares { #adding-asgi-middlewares }

			return FileInfoVersions{}, err
		}
		versions, err = xlMeta.ListVersions(volume, path, allParts)
	}
	if err == nil && len(versions) == 0 {
		// This special case is needed to handle len(xlMeta.versions) == 0
		versions = []FileInfo{
			{
				Volume:   volume,
				Name:     path,
				Deleted:  true,
				IsLatest: true,
				ModTime:  timeSentinel1970,
			},
		}
	}
	if err != nil {

    This command will be run from the **current working directory**, the same `/code` directory you set above with `WORKDIR /code`.

/// tip

Review what each line does by clicking each number bubble in the code. 👆

///

/// warning

Make sure to **always** use the **exec form** of the `CMD` instruction, as explained below.

///

#### Use `CMD` - Exec Form { #use-cmd-exec-form }

 * specific language governing permissions and limitations
 * under the License.
 */

/**
 * Provides XML-specific services for reading and writing Maven's configuration files
 * and descriptors. These services handle XML parsing, transformation, and serialization
 * while maintaining Maven's model integrity.
 *
 * @since 4.0.0
 */

Some of the options you could use as a TLS Termination Proxy are:

* Traefik (that can also handle certificate renewals)
* Caddy (that can also handle certificate renewals)
* Nginx
* HAProxy

## Let's Encrypt { #lets-encrypt }

Before Let's Encrypt, these **HTTPS certificates** were sold by trusted third parties.

		b.WriteString("| ---- | ---- | ---- | ------ |\n")
		for _, metric := range metrics {
			b.WriteString(metric.TableRow())
		}
		w.Write([]byte(b.String()))
	})
}

func (h *metricsV3Server) handle(path string, isListingRequest bool, buckets []string) http.Handler {
	var notFoundHandler http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "Metrics Resource Not found", http.StatusNotFound)

    public void test_init_withNullSessionId() {
        urlFilter.init(null);
        // Should handle null session ID gracefully
        assertNotNull(urlFilter);
    }

    /**
     * Test initialization with empty session ID
     */
    public void test_init_withEmptySessionId() {
        urlFilter.init("");
        // Should handle empty session ID gracefully
        assertNotNull(urlFilter);
    }

    /**

	github.com/jackc/pgpassfile v1.0.0 // indirect
	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
	github.com/jackc/pgx/v5 v5.7.5 // indirect
	github.com/jackc/puddle/v2 v2.2.2 // indirect
	github.com/jinzhu/inflection v1.0.0 // indirect
	github.com/mattn/go-sqlite3 v1.14.32 // indirect
	github.com/microsoft/go-mssqldb v1.9.3 // indirect
	github.com/pmezard/go-difflib v1.0.0 // indirect

/// note

If you check the new (fake) database `fake_users_db`, you will see how the hashed password looks like now: `"$2b$12$EixZaYVK1fsbw1ZfbX3OXePaWxn96p36WQoeG6Lruj3vjPGga31lW"`.

///

## Handle JWT tokens { #handle-jwt-tokens }

Import the modules installed.

Create a random secret key that will be used to sign the JWT tokens.

To generate a secure random secret key use the command:

<div class="termy">

        shell: bash
        run: |
          mkdir -p ~/.mimir
          cp .github/ci-extensions.xml ~/.m2/extensions.xml
          cp .github/ci-mimir-daemon.properties ~/.mimir/daemon.properties

      - name: Handle Mimir caches
        uses: actions/cache@0400d5f644dc74513175e3cd8d07132dd4860809 # v4
        with:
          path: ~/.mimir/local
          key: mimir-${{ runner.os }}-initial-${{ hashFiles('**/pom.xml') }}