一个或多个命令

您可能已经注意到，如果您创建一个单独的命令，如第一个示例所示

import typer

app = typer.Typer()


@app.command()
def main(name: str):
    print(f"Hello {name}")


if __name__ == "__main__":
    app()

Typer 足够智能，可以创建一个 CLI 应用程序，其中单个函数作为主 CLI 应用程序，而不是作为命令/子命令

// Without a CLI argument
$ python main.py

Usage: main.py [OPTIONS] NAME
Try "main.py --help" for help.

Error: Missing argument 'NAME'.

// With the NAME CLI argument
$ python main.py Camila

Hello Camila

// Asking for help
$ python main.py

Usage: main.py [OPTIONS] NAME

Options:
  --install-completion  Install completion for the current shell.
  --show-completion     Show completion for the current shell, to copy it or customize the installation.
  --help                Show this message and exit.

提示

请注意，它不会显示命令 main，即使函数名称是 main。

但是，如果您添加多个命令，Typer 将为每个命令创建一个 CLI 命令

import typer

app = typer.Typer()


@app.command()
def create():
    print("Creating user: Hiro Hamada")


@app.command()
def delete():
    print("Deleting user: Hiro Hamada")


if __name__ == "__main__":
    app()

这里有 2 个命令 create 和 delete

// Check the help
$ python main.py --help

Usage: main.py [OPTIONS] COMMAND [ARGS]...

Options:
  --install-completion  Install completion for the current shell.
  --show-completion     Show completion for the current shell, to copy it or customize the installation.
  --help                Show this message and exit.

Commands:
  create
  delete

// Test the commands
$ python main.py create

Creating user: Hiro Hamada

$ python main.py delete

Deleting user: Hiro Hamada

一个命令和一个回调

如果你想创建一个只有一个命令的 CLI 应用程序，但你仍然希望它是一个命令/子命令，你可以只添加一个回调

import typer

app = typer.Typer()


@app.command()
def create():
    print("Creating user: Hiro Hamada")


@app.callback()
def callback():
    pass


if __name__ == "__main__":
    app()

现在你的 CLI 程序将有一个单独的命令。

检查它

// Check the help
$ python main.py --help

// Notice the single command create
Usage: main.py [OPTIONS] COMMAND [ARGS]...

Options:
  --install-completion  Install completion for the current shell.
  --show-completion     Show completion for the current shell, to copy it or customize the installation.
  --help                Show this message and exit.

Commands:
  create

// Try it
$ python main.py create

Creating user: Hiro Hamada

使用回调进行文档记录

现在你正在使用回调来获得一个单独的命令，你也可以用它来为你的应用程序添加文档

import typer

app = typer.Typer()


@app.command()
def create():
    print("Creating user: Hiro Hamada")


@app.callback()
def callback():
    """
    Creates a single user Hiro Hamada.

    In the next version it will create 5 users more.
    """


if __name__ == "__main__":
    app()

现在回调中的文档字符串将用作帮助文本

$ python main.py --help

// Notice the help text from the docstring
Usage: main.py [OPTIONS] COMMAND [ARGS]...

  Creates a single user Hiro Hamada.

  In the next version it will create 5 users more.

Options:
  --install-completion  Install completion for the current shell.
  --show-completion     Show completion for the current shell, to copy it or customize the installation.
  --help                Show this message and exit.

Commands:
  create

// And it still works the same, the callback does nothing
$ python main.py create

Creating user: Hiro Hamada