from typing import Any, Generic, List, Optional, TextIO, TypeVar, Union, overload
from . import get_console
from .console import Console
from .text import Text, TextType
PromptType = TypeVar("PromptType")
DefaultType = TypeVar("DefaultType")
[docs]class PromptError(Exception):
"""Exception base class for prompt related errors."""
[docs]class InvalidResponse(PromptError):
"""Exception to indicate a response was invalid. Raise this within process_response() to indicate an error
and provide an error message.
Args:
message (Union[str, Text]): Error message.
"""
def __init__(self, message: TextType) -> None:
self.message = message
def __rich__(self) -> TextType:
return self.message
[docs]class PromptBase(Generic[PromptType]):
"""Ask the user for input until a valid response is received. This is the base class, see one of
the concrete classes for examples.
Args:
prompt (TextType, optional): Prompt text. Defaults to "".
console (Console, optional): A Console instance or None to use global console. Defaults to None.
password (bool, optional): Enable password input. Defaults to False.
choices (List[str], optional): A list of valid choices. Defaults to None.
show_default (bool, optional): Show default in prompt. Defaults to True.
show_choices (bool, optional): Show choices in prompt. Defaults to True.
"""
response_type: type = str
validate_error_message = "[prompt.invalid]Please enter a valid value"
illegal_choice_message = (
"[prompt.invalid.choice]Please select one of the available options"
)
prompt_suffix = ": "
choices: Optional[List[str]] = None
def __init__(
self,
prompt: TextType = "",
*,
console: Optional[Console] = None,
password: bool = False,
choices: Optional[List[str]] = None,
show_default: bool = True,
show_choices: bool = True,
) -> None:
self.console = console or get_console()
self.prompt = (
Text.from_markup(prompt, style="prompt")
if isinstance(prompt, str)
else prompt
)
self.password = password
if choices is not None:
self.choices = choices
self.show_default = show_default
self.show_choices = show_choices
@classmethod
@overload
def ask(
cls,
prompt: TextType = "",
*,
console: Optional[Console] = None,
password: bool = False,
choices: Optional[List[str]] = None,
show_default: bool = True,
show_choices: bool = True,
default: DefaultType,
stream: Optional[TextIO] = None,
) -> Union[DefaultType, PromptType]:
...
@classmethod
@overload
def ask(
cls,
prompt: TextType = "",
*,
console: Optional[Console] = None,
password: bool = False,
choices: Optional[List[str]] = None,
show_default: bool = True,
show_choices: bool = True,
stream: Optional[TextIO] = None,
) -> PromptType:
...
[docs] @classmethod
def ask(
cls,
prompt: TextType = "",
*,
console: Optional[Console] = None,
password: bool = False,
choices: Optional[List[str]] = None,
show_default: bool = True,
show_choices: bool = True,
default: Any = ...,
stream: Optional[TextIO] = None,
) -> Any:
"""Shortcut to construct and run a prompt loop and return the result.
Example:
>>> filename = Prompt.ask("Enter a filename")
Args:
prompt (TextType, optional): Prompt text. Defaults to "".
console (Console, optional): A Console instance or None to use global console. Defaults to None.
password (bool, optional): Enable password input. Defaults to False.
choices (List[str], optional): A list of valid choices. Defaults to None.
show_default (bool, optional): Show default in prompt. Defaults to True.
show_choices (bool, optional): Show choices in prompt. Defaults to True.
stream (TextIO, optional): Optional text file open for reading to get input. Defaults to None.
"""
_prompt = cls(
prompt,
console=console,
password=password,
choices=choices,
show_default=show_default,
show_choices=show_choices,
)
return _prompt(default=default, stream=stream)
[docs] def render_default(self, default: DefaultType) -> Text:
"""Turn the supplied default in to a Text instance.
Args:
default (DefaultType): Default value.
Returns:
Text: Text containing rendering of default value.
"""
return Text(f"({default})", "prompt.default")
[docs] def make_prompt(self, default: DefaultType) -> Text:
"""Make prompt text.
Args:
default (DefaultType): Default value.
Returns:
Text: Text to display in prompt.
"""
prompt = self.prompt.copy()
prompt.end = ""
if self.show_choices and self.choices:
_choices = "/".join(self.choices)
choices = f"[{_choices}]"
prompt.append(" ")
prompt.append(choices, "prompt.choices")
if (
default != ...
and self.show_default
and isinstance(default, (str, self.response_type))
):
prompt.append(" ")
_default = self.render_default(default)
prompt.append(_default)
prompt.append(self.prompt_suffix)
return prompt
[docs] def check_choice(self, value: str) -> bool:
"""Check value is in the list of valid choices.
Args:
value (str): Value entered by user.
Returns:
bool: True if choice was valid, otherwise False.
"""
assert self.choices is not None
return value.strip() in self.choices
[docs] def process_response(self, value: str) -> PromptType:
"""Process response from user, convert to prompt type.
Args:
value (str): String typed by user.
Raises:
InvalidResponse: If ``value`` is invalid.
Returns:
PromptType: The value to be returned from ask method.
"""
value = value.strip()
try:
return_value: PromptType = self.response_type(value)
except ValueError:
raise InvalidResponse(self.validate_error_message)
if self.choices is not None and not self.check_choice(value):
raise InvalidResponse(self.illegal_choice_message)
return return_value
[docs] def on_validate_error(self, value: str, error: InvalidResponse) -> None:
"""Called to handle validation error.
Args:
value (str): String entered by user.
error (InvalidResponse): Exception instance the initiated the error.
"""
self.console.print(error)
[docs] def pre_prompt(self) -> None:
"""Hook to display something before the prompt."""
@overload
def __call__(self, *, stream: Optional[TextIO] = None) -> PromptType:
...
@overload
def __call__(
self, *, default: DefaultType, stream: Optional[TextIO] = None
) -> Union[PromptType, DefaultType]:
...
def __call__(self, *, default: Any = ..., stream: Optional[TextIO] = None) -> Any:
"""Run the prompt loop.
Args:
default (Any, optional): Optional default value.
Returns:
PromptType: Processed value.
"""
while True:
self.pre_prompt()
prompt = self.make_prompt(default)
value = self.get_input(self.console, prompt, self.password, stream=stream)
if value == "" and default != ...:
return default
try:
return_value = self.process_response(value)
except InvalidResponse as error:
self.on_validate_error(value, error)
continue
else:
return return_value
[docs]class Prompt(PromptBase[str]):
"""A prompt that returns a str.
Example:
>>> name = Prompt.ask("Enter your name")
"""
response_type = str
[docs]class IntPrompt(PromptBase[int]):
"""A prompt that returns an integer.
Example:
>>> burrito_count = IntPrompt.ask("How many burritos do you want to order")
"""
response_type = int
validate_error_message = "[prompt.invalid]Please enter a valid integer number"
[docs]class FloatPrompt(PromptBase[int]):
"""A prompt that returns a float.
Example:
>>> temperature = FloatPrompt.ask("Enter desired temperature")
"""
response_type = float
validate_error_message = "[prompt.invalid]Please enter a number"
[docs]class Confirm(PromptBase[bool]):
"""A yes / no confirmation prompt.
Example:
>>> if Confirm.ask("Continue"):
run_job()
"""
response_type = bool
validate_error_message = "[prompt.invalid]Please enter Y or N"
choices: List[str] = ["y", "n"]
[docs] def render_default(self, default: DefaultType) -> Text:
"""Render the default as (y) or (n) rather than True/False."""
yes, no = self.choices
return Text(f"({yes})" if default else f"({no})", style="prompt.default")
[docs] def process_response(self, value: str) -> bool:
"""Convert choices to a bool."""
value = value.strip().lower()
if value not in self.choices:
raise InvalidResponse(self.validate_error_message)
return value == self.choices[0]
if __name__ == "__main__": # pragma: no cover
from rich import print
if Confirm.ask("Run [i]prompt[/i] tests?", default=True):
while True:
result = IntPrompt.ask(
":rocket: Enter a number between [b]1[/b] and [b]10[/b]", default=5
)
if result >= 1 and result <= 10:
break
print(":pile_of_poo: [prompt.invalid]Number must be between 1 and 10")
print(f"number={result}")
while True:
password = Prompt.ask(
"Please enter a password [cyan](must be at least 5 characters)",
password=True,
)
if len(password) >= 5:
break
print("[prompt.invalid]password too short")
print(f"password={password!r}")
fruit = Prompt.ask("Enter a fruit", choices=["apple", "orange", "pear"])
print(f"fruit={fruit!r}")
else:
print("[b]OK :loudly_crying_face:")