# Bigger Applications - Multiple Files { #bigger-applications-multiple-files }

If you are building an application or a web API, it's rarely the case that you can put everything in a single file.

**FastAPI** provides a convenience tool to structure your application while keeping all the flexibility.

/// info

If you come from Flask, this would be the equivalent of Flask's Blueprints.

///

## An example file structure { #an-example-file-structure }

        if (StringUtil.isNotBlank(scriptType)) {
            return scriptType;
        }
        return Constants.DEFAULT_SCRIPT;
    }

    public enum ConfigType {
        WEB("W"), FILE("F"), DATA("D");

        private final String typePrefix;

        ConfigType(final String typePrefix) {
            this.typePrefix = typePrefix;
        }

        public String getTypePrefix() {

            try {
                webConfig = webConfigService.getWebConfig(getWebConfigId()).get();
            } catch (final Exception e) {
                logger.warn("Web Config {} does not exist.", getWebConfigId(), e);
            }
        }
        return webConfig;
    }

    public String getId() {
        return asDocMeta().id();
    }

	claims.SetExpiry(UTCNow().Add(defaultJWTExpiry))
	claims.SetAccessKey(accessKey)
	token := jwtgo.NewWithClaims(jwtgo.SigningMethodHS512, claims)
	return token.SignedString([]byte(secretKey))
}

// Tests web request authenticator.
func TestWebRequestAuthenticate(t *testing.T) {
	ctx, cancel := context.WithCancel(t.Context())
	defer cancel()

	obj, fsDir, err := prepareFS(ctx)
	if err != nil {
		t.Fatal(err)
	}

Keep in mind that dataclasses can't do everything Pydantic models can do.

So, you might still need to use Pydantic models.

But if you have a bunch of dataclasses laying around, this is a nice trick to use them to power a web API using FastAPI. 🤓

///

## Dataclasses in `response_model` { #dataclasses-in-response-model }

You can also use `dataclasses` in the `response_model` parameter:

/// tip | Tipp

Um mehr über Statuscodes zu lernen, und welcher wofür verwendet wird, lesen Sie die <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Status" class="external-link" target="_blank"><abbr title="Mozilla Developer Network – Mozilla-Entwickler-Netzwerk">MDN</abbr> Dokumentation über HTTP-Statuscodes</a>.

///

## Abkürzung, um die Namen zu erinnern

Daher müssen Sie möglicherweise weiterhin Pydantic-Modelle verwenden.

Wenn Sie jedoch eine Menge Datenklassen herumliegen haben, ist dies ein guter Trick, um sie für eine Web-API mithilfe von FastAPI zu verwenden. 🤓

///

## Datenklassen als `response_model`

Sie können `dataclasses` auch im Parameter `response_model` verwenden:

/// tip | Подсказка

Чтобы узнать больше о HTTP кодах статуса и о том, для чего каждый из них предназначен, ознакомьтесь с <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Status" class="external-link" target="_blank">документацией <abbr title="Mozilla Developer Network">MDN</abbr> об HTTP кодах статуса ответа</a>.

///

## Краткие обозначения для запоминания названий кодов

import okhttp3.WebSocketListener
import okhttp3.internal.addHeaderLenient
import okhttp3.internal.http2.ErrorCode
import okhttp3.internal.http2.Settings
import okio.Buffer

/** A scripted response to be replayed by the mock web server. */
public class MockResponse {
  /** Returns the HTTP response line, such as "HTTP/1.1 200 OK". */
  public val status: String

  public val code: Int
    get() {

            covered by testModule.gwt.xml. Maybe I'll try it someday.

            [*] https://code.google.com/p/google-web-toolkit/wiki/ResourceOracle#When_multiple_PathPrefix_es_have_the_same_path
                https://code.google.com/p/google-web-toolkit/issues/detail?id=7581
            -->
          <execution>
            <id>gwt-test</id>
            <goals>
              <goal>test</goal>