Package: typer
Typer, build great CLIs. Easy to code. Based on Python type hints.Documentation:https://typer.tiangolo.comSource Code:https://github.com/tiangolo/typerTyper is a library for buildingCLIapplications that users willlove usingand developers willlove creating. Based on Python 3.6+ type hints.The key features are:Intuitive to write: Great editor support.Completioneverywhere. Less time debugging. Designed to be easy to use and learn. Less time reading docs.Easy to use: It's easy to use for the final users. Automatic help, and automatic completion for all shells.Short: Minimize code duplication. Multiple features from each parameter declaration. Fewer bugs.Start simple: The simplest example adds only 2 lines of code to your app:1 import, 1 function call.Grow large: Grow in complexity as much as you want, create arbitrarily complex trees of commands and groups of subcommands, with options and arguments.FastAPI of CLIsTyperisFastAPI's little sibling.And it's intended to be the FastAPI of CLIs.RequirementsPython 3.6+Typerstands on the shoulders of a giant. Its only internal dependency isClick.Installation$pipinstall"typer[all]"---> 100%Successfully installed typerNote: that will includeRich. Rich is the recommended library todisplayinformation on the terminal, it is optional, but when installed, it's deeply integrated intoTyperto display beautiful output.ExampleThe absolute minimumCreate a filemain.pywith:importtyperdefmain(name:str):print(f"Hello{name}")if__name__=="__main__":typer.run(main)Run itRun your application:// Run your application$pythonmain.py// You get a nice error, you are missing NAMEUsage: main.py [OPTIONS] NAMETry 'main.py --help' for help.╭─ Error ───────────────────────────────────────────╮│ Missing argument 'NAME'.                          │╰───────────────────────────────────────────────────╯// You get a --help for free$pythonmain.py--helpUsage: main.py [OPTIONS] NAME╭─ Arguments ───────────────────────────────────────╮│ *    name      TEXT  [default: None] [required]   |╰───────────────────────────────────────────────────╯╭─ Options ─────────────────────────────────────────╮│ --help          Show this message and exit.       │╰───────────────────────────────────────────────────╯// Now pass the NAME argument$pythonmain.pyCamilaHello Camila// It works! 🎉Note: auto-completion works when you create a Python package and run it with--install-completionor when you useTyper CLI.Example upgradeThis was the simplest example possible.Now let's see one a bit more complex.An example with two subcommandsModify the filemain.py.Create atyper.Typer()app, and create two subcommands with their parameters.importtyperapp=typer.Typer()@app.command()defhello(name:str):print(f"Hello{name}")@app.command()defgoodbye(name:str,formal:bool=False):ifformal:print(f"Goodbye Ms.{name}. Have a good day.")else:print(f"Bye{name}!")if__name__=="__main__":app()And that will:Explicitly create atyper.Typerapp.The previoustyper.runactually creates one implicitly for you.Add two subcommands with@app.command().Execute theapp()itself, as if it was a function (instead oftyper.run).Run the upgraded exampleCheck the new help:$pythonmain.py--helpUsage: main.py [OPTIONS] COMMAND [ARGS]...╭─ Options ─────────────────────────────────────────╮│ --install-completion          Install completion  ││                               for the current     ││                               shell.              ││ --show-completion             Show completion for ││                               the current shell,  ││                               to copy it or       ││                               customize the       ││                               installation.       ││ --help                        Show this message   ││                               and exit.           │╰───────────────────────────────────────────────────╯╭─ Commands ────────────────────────────────────────╮│ goodbye                                           ││ hello                                             │╰───────────────────────────────────────────────────╯// When you create a package you get ✨ auto-completion ✨ for free, installed with --install-completion// You have 2 subcommands (the 2 functions): goodbye and helloNow check the help for thehellocommand:$pythonmain.pyhello--helpUsage: main.py hello [OPTIONS] NAME╭─ Arguments ───────────────────────────────────────╮│ *    name      TEXT  [default: None] [required]   │╰───────────────────────────────────────────────────╯╭─ Options ─────────────────────────────────────────╮│ --help          Show this message and exit.       │╰───────────────────────────────────────────────────╯And now check the help for thegoodbyecommand:$pythonmain.pygoodbye--helpUsage: main.py goodbye [OPTIONS] NAME╭─ Arguments ───────────────────────────────────────╮│ *    name      TEXT  [default: None] [required]   │╰───────────────────────────────────────────────────╯╭─ Options ─────────────────────────────────────────╮│ --formal    --no-formal      [default: no-formal] ││ --help                       Show this message    ││                              and exit.            │╰───────────────────────────────────────────────────╯// Automatic --formal and --no-formal for the bool option 🎉Now you can try out the new command line application:// Use it with the hello command$pythonmain.pyhelloCamilaHello Camila// And with the goodbye command$pythonmain.pygoodbyeCamilaBye Camila!// And with --formal$pythonmain.pygoodbye--formalCamilaGoodbye Ms. Camila. Have a good day.RecapIn summary, you declareoncethe types of parameters (CLI argumentsandCLI options) as function parameters.You do that with standard modern Python types.You don't have to learn a new syntax, the methods or classes of a specific library, etc.Just standardPython 3.6+.For example, for anint:total:intor for aboolflag:force:boolAnd similarly forfiles,paths,enums(choices), etc. And there are tools to creategroups of subcommands, add metadata, extravalidation, etc.You get: great editor support, includingcompletionandtype checkseverywhere.Your users get: automatic--help,auto-completionin their terminal (Bash, Zsh, Fish, PowerShell) when they install your package or when usingTyper CLI.For a more complete example including more features, see theTutorial - User Guide.Optional DependenciesTyper usesClickinternally. That's the only dependency.But you can also install extras:rich: and Typer will show nicely formatted errors automatically.shellingham: and Typer will automatically detect the current shell when installing completion.Withshellinghamyou can just use--install-completion.Withoutshellingham, you have to pass the name of the shell to install completion for, e.g.--install-completion bash.You can installtyperwithrichandshellinghamwithpip install typer[all].LicenseThis project is licensed under the terms of the MIT license.