// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"fmt"
	"time"

你只需要 **在每个工程中操作一次**，而不是每次工作时都操作。

///

//// tab | `venv`

你可以使用 Python 自带的 `venv` 模块来创建一个虚拟环境。

<div class="termy">

```console
$ python -m venv .venv
```

</div>

/// details | 上述命令的含义

* `python`: 使用名为 `python` 的程序
* `-m`: 以脚本的方式调用一个模块，我们将告诉它接下来使用哪个模块
* `venv`: 使用名为 `venv` 的模块，这个模块通常随 Python 一起安装
* `.venv`: 在新目录 `.venv` 中创建虚拟环境

///

////

//// tab | `uv`

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

你會看到子應用程式的自動 API 文件，只包含它自己的*路徑操作*，而且都在正確的子路徑前綴 `/subapi` 之下：

<img src="/img/tutorial/sub-applications/image02.png">

如果你嘗試在任一介面中互動，它們都會正常運作，因為瀏覽器能與各自的應用程式或子應用程式通訊。

### 技術細節：`root_path` { #technical-details-root-path }

當你像上面那樣掛載子應用程式時，FastAPI 會使用 ASGI 規範中的一個機制 `root_path`，將子應用程式的掛載路徑告知它。

如此一來，子應用程式就會知道在文件 UI 使用該路徑前綴。

而且子應用程式也能再掛載自己的子應用程式，一切都能正確運作，因為 FastAPI 會自動處理所有這些 `root_path`。

// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"math"
	"net/http"
	"os"