```console
// Go to the home directory
$ cd
// Create a directory for all your code projects
$ mkdir code
// Enter into that code directory
$ cd code
// Create a directory for this project
$ mkdir awesome-project
// Enter into that project directory
$ cd awesome-project
```

Result (German):

```console
// Gehe zum Home-Verzeichnis
$ cd

      } catch (ClassNotFoundException runningUnderAndroidOrJava8) {
        /*
         * I'm not sure that we could actually get here for *Android*: I would expect us to enter
         * the POSIX code path instead. And if we tried this code path, we'd have trouble unless we
         * were running under a new enough version of Android to support NIO.
         *

O = MyOrg
OU = MyOU
CN = MyServerName

[v3_req]
subjectAltName = @alt_names

[alt_names]
IP.1 = 127.0.0.1
DNS.1 = localhost
```

Run `openssl` by specifying the configuration file and enter a passphrase if prompted:

```sh
openssl req -new -x509 -nodes -days 730 -keyout private.key -out public.crt -config openssl.conf
```

### 3.3 Use GnuTLS (for Windows) to Generate a Certificate

But in this case, the same **FastAPI** application will handle the API and the authentication.

So, let's review it from that simplified point of view:

* The user types the `username` and `password` in the frontend, and hits `Enter`.
* The frontend (running in the user's browser) sends that `username` and `password` to a specific URL in our API (declared with `tokenUrl="token"`).

OAuth2는 backend 또는 API가 사용자를 인증하는 서버와 독립적일 수 있도록 설계되었습니다.

하지만 이 경우에는 같은 **FastAPI** 애플리케이션이 API와 인증을 모두 처리합니다.

따라서, 단순화된 관점에서 다시 정리해보면:

* 사용자가 frontend에서 `username`과 `password`를 입력하고 `Enter`를 누릅니다.
* frontend(사용자의 브라우저에서 실행됨)는 해당 `username`과 `password`를 우리 API의 특정 URL로 보냅니다(`tokenUrl="token"`로 선언됨).
* API는 `username`과 `password`를 확인하고 "token"으로 응답합니다(아직 아무것도 구현하지 않았습니다).

    withLock {
      while (headersQueue.isEmpty() && errorCode == null) {
        val doReadTimeout = callerIsIdle || doReadTimeout()
        if (doReadTimeout) {
          readTimeout.enter()
        }
        try {
          waitForIo()
        } finally {
          if (doReadTimeout) {
            readTimeout.exitAndThrowIfTimedOut()
          }
        }
      }

 *   <li>isImplicit: Whether to use implicit SSL/TLS encryption.</li>
 *   <li>trustManager: The trust manager to use for SSL/TLS connections ("all", "valid", or "none").</li>
 *   <li>enterLocalPassiveMode: Whether to enter local passive mode.</li>
 *   <li>ftpAuthentications: An array of {@link FtpAuthentication} objects for different FTP URLs.</li>
 * </ul>
 *
 * <p>

        }

        //
        // We enter the session scope right after the MavenSession creation and before any of the
        // AbstractLifecycleParticipant lookups
        // so that @SessionScoped components can be @Injected into AbstractLifecycleParticipants.
        //
        sessionScope.enter();
        MavenChainedWorkspaceReader chainedWorkspaceReader =

<div class="termy">

```console
// Go to the home directory
$ cd
// Create a directory for all your code projects
$ mkdir code
// Enter into that code directory
$ cd code
// Create a directory for this project
$ mkdir awesome-project
// Enter into that project directory
$ cd awesome-project
```

</div>

## Create a Virtual Environment { #create-a-virtual-environment }

現在回頭理解剛剛那些是什麼。

在 OAuth2 中，`password` 是處理安全與身分驗證的其中一種「流程」（flow）。

OAuth2 的設計讓後端或 API 可以獨立於執行使用者驗證的伺服器。

但在這個例子中，同一個 FastAPI 應用會同時處理 API 與驗證。

簡化來看流程如下：

- 使用者在前端輸入 `username` 與 `password`，按下 `Enter`。
- 前端（在使用者的瀏覽器中執行）把 `username` 與 `password` 傳到我們 API 的特定 URL（在程式中宣告為 `tokenUrl="token"`）。
- API 檢查 `username` 與 `password`，並回傳一個「token（權杖）」（我們還沒實作這部分）。
    - 「token（權杖）」就是一段字串，之後可用來識別並驗證此使用者。
    - 通常 token 會設定一段時間後失效。