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Diffstat (limited to 'python/click/decorators.py')
| -rw-r--r-- | python/click/decorators.py | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/python/click/decorators.py b/python/click/decorators.py new file mode 100644 index 0000000..c57c530 --- /dev/null +++ b/python/click/decorators.py @@ -0,0 +1,311 @@ +import sys +import inspect + +from functools import update_wrapper + +from ._compat import iteritems +from ._unicodefun import _check_for_unicode_literals +from .utils import echo +from .globals import get_current_context + + +def pass_context(f): + """Marks a callback as wanting to receive the current context + object as first argument. + """ + def new_func(*args, **kwargs): + return f(get_current_context(), *args, **kwargs) + return update_wrapper(new_func, f) + + +def pass_obj(f): + """Similar to :func:`pass_context`, but only pass the object on the + context onwards (:attr:`Context.obj`). This is useful if that object + represents the state of a nested system. + """ + def new_func(*args, **kwargs): + return f(get_current_context().obj, *args, **kwargs) + return update_wrapper(new_func, f) + + +def make_pass_decorator(object_type, ensure=False): + """Given an object type this creates a decorator that will work + similar to :func:`pass_obj` but instead of passing the object of the + current context, it will find the innermost context of type + :func:`object_type`. + + This generates a decorator that works roughly like this:: + + from functools import update_wrapper + + def decorator(f): + @pass_context + def new_func(ctx, *args, **kwargs): + obj = ctx.find_object(object_type) + return ctx.invoke(f, obj, *args, **kwargs) + return update_wrapper(new_func, f) + return decorator + + :param object_type: the type of the object to pass. + :param ensure: if set to `True`, a new object will be created and + remembered on the context if it's not there yet. + """ + def decorator(f): + def new_func(*args, **kwargs): + ctx = get_current_context() + if ensure: + obj = ctx.ensure_object(object_type) + else: + obj = ctx.find_object(object_type) + if obj is None: + raise RuntimeError('Managed to invoke callback without a ' + 'context object of type %r existing' + % object_type.__name__) + return ctx.invoke(f, obj, *args, **kwargs) + return update_wrapper(new_func, f) + return decorator + + +def _make_command(f, name, attrs, cls): + if isinstance(f, Command): + raise TypeError('Attempted to convert a callback into a ' + 'command twice.') + try: + params = f.__click_params__ + params.reverse() + del f.__click_params__ + except AttributeError: + params = [] + help = attrs.get('help') + if help is None: + help = inspect.getdoc(f) + if isinstance(help, bytes): + help = help.decode('utf-8') + else: + help = inspect.cleandoc(help) + attrs['help'] = help + _check_for_unicode_literals() + return cls(name=name or f.__name__.lower().replace('_', '-'), + callback=f, params=params, **attrs) + + +def command(name=None, cls=None, **attrs): + r"""Creates a new :class:`Command` and uses the decorated function as + callback. This will also automatically attach all decorated + :func:`option`\s and :func:`argument`\s as parameters to the command. + + The name of the command defaults to the name of the function. If you + want to change that, you can pass the intended name as the first + argument. + + All keyword arguments are forwarded to the underlying command class. + + Once decorated the function turns into a :class:`Command` instance + that can be invoked as a command line utility or be attached to a + command :class:`Group`. + + :param name: the name of the command. This defaults to the function + name with underscores replaced by dashes. + :param cls: the command class to instantiate. This defaults to + :class:`Command`. + """ + if cls is None: + cls = Command + def decorator(f): + cmd = _make_command(f, name, attrs, cls) + cmd.__doc__ = f.__doc__ + return cmd + return decorator + + +def group(name=None, **attrs): + """Creates a new :class:`Group` with a function as callback. This + works otherwise the same as :func:`command` just that the `cls` + parameter is set to :class:`Group`. + """ + attrs.setdefault('cls', Group) + return command(name, **attrs) + + +def _param_memo(f, param): + if isinstance(f, Command): + f.params.append(param) + else: + if not hasattr(f, '__click_params__'): + f.__click_params__ = [] + f.__click_params__.append(param) + + +def argument(*param_decls, **attrs): + """Attaches an argument to the command. All positional arguments are + passed as parameter declarations to :class:`Argument`; all keyword + arguments are forwarded unchanged (except ``cls``). + This is equivalent to creating an :class:`Argument` instance manually + and attaching it to the :attr:`Command.params` list. + + :param cls: the argument class to instantiate. This defaults to + :class:`Argument`. + """ + def decorator(f): + ArgumentClass = attrs.pop('cls', Argument) + _param_memo(f, ArgumentClass(param_decls, **attrs)) + return f + return decorator + + +def option(*param_decls, **attrs): + """Attaches an option to the command. All positional arguments are + passed as parameter declarations to :class:`Option`; all keyword + arguments are forwarded unchanged (except ``cls``). + This is equivalent to creating an :class:`Option` instance manually + and attaching it to the :attr:`Command.params` list. + + :param cls: the option class to instantiate. This defaults to + :class:`Option`. + """ + def decorator(f): + # Issue 926, copy attrs, so pre-defined options can re-use the same cls= + option_attrs = attrs.copy() + + if 'help' in option_attrs: + option_attrs['help'] = inspect.cleandoc(option_attrs['help']) + OptionClass = option_attrs.pop('cls', Option) + _param_memo(f, OptionClass(param_decls, **option_attrs)) + return f + return decorator + + +def confirmation_option(*param_decls, **attrs): + """Shortcut for confirmation prompts that can be ignored by passing + ``--yes`` as parameter. + + This is equivalent to decorating a function with :func:`option` with + the following parameters:: + + def callback(ctx, param, value): + if not value: + ctx.abort() + + @click.command() + @click.option('--yes', is_flag=True, callback=callback, + expose_value=False, prompt='Do you want to continue?') + def dropdb(): + pass + """ + def decorator(f): + def callback(ctx, param, value): + if not value: + ctx.abort() + attrs.setdefault('is_flag', True) + attrs.setdefault('callback', callback) + attrs.setdefault('expose_value', False) + attrs.setdefault('prompt', 'Do you want to continue?') + attrs.setdefault('help', 'Confirm the action without prompting.') + return option(*(param_decls or ('--yes',)), **attrs)(f) + return decorator + + +def password_option(*param_decls, **attrs): + """Shortcut for password prompts. + + This is equivalent to decorating a function with :func:`option` with + the following parameters:: + + @click.command() + @click.option('--password', prompt=True, confirmation_prompt=True, + hide_input=True) + def changeadmin(password): + pass + """ + def decorator(f): + attrs.setdefault('prompt', True) + attrs.setdefault('confirmation_prompt', True) + attrs.setdefault('hide_input', True) + return option(*(param_decls or ('--password',)), **attrs)(f) + return decorator + + +def version_option(version=None, *param_decls, **attrs): + """Adds a ``--version`` option which immediately ends the program + printing out the version number. This is implemented as an eager + option that prints the version and exits the program in the callback. + + :param version: the version number to show. If not provided Click + attempts an auto discovery via setuptools. + :param prog_name: the name of the program (defaults to autodetection) + :param message: custom message to show instead of the default + (``'%(prog)s, version %(version)s'``) + :param others: everything else is forwarded to :func:`option`. + """ + if version is None: + if hasattr(sys, '_getframe'): + module = sys._getframe(1).f_globals.get('__name__') + else: + module = '' + + def decorator(f): + prog_name = attrs.pop('prog_name', None) + message = attrs.pop('message', '%(prog)s, version %(version)s') + + def callback(ctx, param, value): + if not value or ctx.resilient_parsing: + return + prog = prog_name + if prog is None: + prog = ctx.find_root().info_name + ver = version + if ver is None: + try: + import pkg_resources + except ImportError: + pass + else: + for dist in pkg_resources.working_set: + scripts = dist.get_entry_map().get('console_scripts') or {} + for script_name, entry_point in iteritems(scripts): + if entry_point.module_name == module: + ver = dist.version + break + if ver is None: + raise RuntimeError('Could not determine version') + echo(message % { + 'prog': prog, + 'version': ver, + }, color=ctx.color) + ctx.exit() + + attrs.setdefault('is_flag', True) + attrs.setdefault('expose_value', False) + attrs.setdefault('is_eager', True) + attrs.setdefault('help', 'Show the version and exit.') + attrs['callback'] = callback + return option(*(param_decls or ('--version',)), **attrs)(f) + return decorator + + +def help_option(*param_decls, **attrs): + """Adds a ``--help`` option which immediately ends the program + printing out the help page. This is usually unnecessary to add as + this is added by default to all commands unless suppressed. + + Like :func:`version_option`, this is implemented as eager option that + prints in the callback and exits. + + All arguments are forwarded to :func:`option`. + """ + def decorator(f): + def callback(ctx, param, value): + if value and not ctx.resilient_parsing: + echo(ctx.get_help(), color=ctx.color) + ctx.exit() + attrs.setdefault('is_flag', True) + attrs.setdefault('expose_value', False) + attrs.setdefault('help', 'Show this message and exit.') + attrs.setdefault('is_eager', True) + attrs['callback'] = callback + return option(*(param_decls or ('--help',)), **attrs)(f) + return decorator + + +# Circular dependencies between core and decorators +from .core import Command, Group, Argument, Option |