from typing import Optional

from fastapi import FastAPI, Security
from fastapi.security import OAuth2PasswordBearer
from fastapi.testclient import TestClient

app = FastAPI()

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/token", auto_error=False)


@app.get("/items/")
async def read_items(token: Optional[str] = Security(oauth2_scheme)):
    if token is None:
        return {"msg": "Create an account first"}
    return {"token": token}

# Apache Maven Upgrade Script
#
# Environment Variable Prerequisites
#
#   JAVA_HOME           (Optional) Points to a Java installation.
#   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
#   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.
# -----------------------------------------------------------------------------

            UpgradeOptions options = mock(UpgradeOptions.class);
            when(options.modelVersion()).thenReturn(Optional.of("4.1.0"));
            when(options.all()).thenReturn(Optional.empty());
            UpgradeContext context = createMockContext(options);

            UpgradeResult result = strategy.doApply(context, pomMap);

        return delegate.getExecutionId();
    }

    @Override
    public String getGoal() {
        return delegate.getGoal();
    }

    @Override
    public Optional<XmlNode> getConfiguration() {
        return Optional.of(delegate.getConfiguration()).map(Xpp3Dom::getDom);
    }

    @Override
    public String toString() {
        return delegate.toString();
    }

@REM Apache Maven Upgrade Script
@REM
@REM Environment Variable Prerequisites
@REM
@REM   JAVA_HOME           (Optional) Points to a Java installation.
@REM   MAVEN_OPTS          (Optional) Java runtime options used when Maven is executed.
@REM   MAVEN_SKIP_RC       (Optional) Flag to disable loading of mavenrc files.
@REM -----------------------------------------------------------------------------

            return "UNRESOLVED";
        }

        @Override
        public String id() {
            return "UNRESOLVED";
        }

        @Override
        public Optional<String> option() {
            return Optional.empty();
        }

        @Override
        public String[] option(Iterable<? extends Path> paths) {
            return new String[0];
        }
    };

    /**

package org.apache.maven.cling.invoker.cisupport;

import java.util.Optional;

import org.apache.maven.api.cli.cisupport.CIInfo;

/**
 * Service interface to detect CI system process runs on, if any.
 *
 * @since 4.0.0
 */
public interface CIDetector {
    /**
     * Returns non-empty optional with CI information, if CI is detected, empty otherwise.
     */
    Optional<CIInfo> detectCI();

이 응용 프로그램을 예로 들어보겠습니다:

{* ../../docs_src/query_params_str_validations/tutorial001.py hl[9] *}

쿼리 매개변수 `q`는 `Optional[str]` 자료형입니다. 즉, `str` 자료형이지만 `None` 역시 될 수 있음을 뜻하고, 실제로 기본값은 `None`이기 때문에 FastAPI는 이 매개변수가 필수가 아니라는 것을 압니다.

/// note | 참고

FastAPI는 `q`의 기본값이 `= None`이기 때문에 필수가 아님을 압니다.

`Optional[str]`에 있는 `Optional`은 FastAPI가 사용하는게 아니지만, 편집기에게 더 나은 지원과 오류 탐지를 제공하게 해줍니다.

///

## 추가 검증

     * @param result Outcome of the current Maven build.
     * @return A {@link BuildResumptionData} instance or {@link Optional#empty()} if resuming the build is not possible.
     */
    Optional<BuildResumptionData> determineBuildResumptionData(MavenExecutionResult result);

from typing import Optional

import pytest
from fastapi import Cookie, FastAPI, Header, Path, Query
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/hidden_cookie")
async def hidden_cookie(
    hidden_cookie: Optional[str] = Cookie(default=None, include_in_schema=False),
):
    return {"hidden_cookie": hidden_cookie}


@app.get("/hidden_header")
async def hidden_header(