cmd2.utils¶
Settings¶
- class cmd2.utils.Settable(name: str, val_type: Union[Type[Any], Callable[[Any], Any]], description: str, settable_object: object, *, settable_attrib_name: Optional[str] = None, onchange_cb: Optional[Callable[[str, cmd2.utils._T, cmd2.utils._T], Any]] = None, choices: Optional[Iterable[Any]] = None, choices_provider: Optional[Union[cmd2.argparse_custom.ChoicesProviderFuncBase, cmd2.argparse_custom.ChoicesProviderFuncWithTokens]] = None, completer: Optional[Union[cmd2.argparse_custom.CompleterFuncBase, cmd2.argparse_custom.CompleterFuncWithTokens]] = None)¶
Used to configure an attribute to be settable via the set command in the CLI
- __init__(name: str, val_type: Union[Type[Any], Callable[[Any], Any]], description: str, settable_object: object, *, settable_attrib_name: Optional[str] = None, onchange_cb: Optional[Callable[[str, cmd2.utils._T, cmd2.utils._T], Any]] = None, choices: Optional[Iterable[Any]] = None, choices_provider: Optional[Union[cmd2.argparse_custom.ChoicesProviderFuncBase, cmd2.argparse_custom.ChoicesProviderFuncWithTokens]] = None, completer: Optional[Union[cmd2.argparse_custom.CompleterFuncBase, cmd2.argparse_custom.CompleterFuncWithTokens]] = None) → None¶
Settable Initializer
- Parameters
name – name of the instance attribute being made settable
val_type – callable used to cast the string value from the command line into its proper type and even validate its value. Setting this to bool provides tab completion for true/false and validation using str_to_bool(). The val_type function should raise an exception if it fails. This exception will be caught and printed by Cmd.do_set().
description – string describing this setting
settable_object – object to which the instance attribute belongs (e.g. self)
settable_attrib_name – name which displays to the user in the output of the set command. Defaults to name if not specified.
onchange_cb –
optional function or method to call when the value of this settable is altered by the set command. (e.g. onchange_cb=self.debug_changed)
- Cmd.do_set() passes the following 3 arguments to onchange_cb:
param_name: str - name of the changed parameter old_value: Any - the value before being changed new_value: Any - the value after being changed
The following optional settings provide tab completion for a parameter’s values. They correspond to the same settings in argparse-based tab completion. A maximum of one of these should be provided.
- Parameters
choices – iterable of accepted values
choices_provider – function that provides choices for this argument
completer – tab completion function that provides choices for this argument
- get_value() → Any¶
Get the value of the settable attribute :return:
- set_value(value: Any) → Any¶
Set the settable attribute on the specified destination object :param value: New value to set :return: New value that the attribute was set to
Quote Handling¶
- cmd2.utils.is_quoted(arg: str) → bool¶
Checks if a string is quoted
- Parameters
arg – the string being checked for quotes
- Returns
True if a string is quoted
- cmd2.utils.quote_string(arg: str) → str¶
Quote a string
- cmd2.utils.quote_string_if_needed(arg: str) → str¶
Quote a string if it contains spaces and isn’t already quoted
- cmd2.utils.strip_quotes(arg: str) → str¶
Strip outer quotes from a string.
Applies to both single and double quotes.
- Parameters
arg – string to strip outer quotes from
- Returns
same string with potentially outer quotes stripped
- cmd2.utils.quote_specific_tokens(tokens: List[str], tokens_to_quote: List[str]) → None¶
Quote specific tokens in a list
- Parameters
tokens – token list being edited
tokens_to_quote – the tokens, which if present in tokens, to quote
- cmd2.utils.unquote_specific_tokens(tokens: List[str], tokens_to_unquote: List[str]) → None¶
Unquote specific tokens in a list
- Parameters
tokens – token list being edited
tokens_to_unquote – the tokens, which if present in tokens, to unquote
IO Handling¶
- class cmd2.utils.StdSim(inner_stream: Union[TextIO, cmd2.utils.StdSim], *, echo: bool = False, encoding: str = 'utf-8', errors: str = 'replace')¶
Class to simulate behavior of sys.stdout or sys.stderr. Stores contents in internal buffer and optionally echos to the inner stream it is simulating.
- write(s: str) → None¶
Add str to internal bytes buffer and if echo is True, echo contents to inner stream
- Parameters
s – String to write to the stream
- getvalue() → str¶
Get the internal contents as a str
- getbytes() → bytes¶
Get the internal contents as bytes
- read(size: Optional[int] = - 1) → str¶
Read from the internal contents as a str and then clear them out
- Parameters
size – Number of bytes to read from the stream
- readbytes() → bytes¶
Read from the internal contents as bytes and then clear them out
- clear() → None¶
Clear the internal contents
- isatty() → bool¶
StdSim only considered an interactive stream if echo is True and inner_stream is a tty.
- property line_buffering: bool¶
Handle when the inner stream doesn’t have a line_buffering attribute which is the case when running unit tests because pytest sets stdout to a pytest EncodedFile object.
- class cmd2.utils.ByteBuf(std_sim_instance: cmd2.utils.StdSim)¶
Used by StdSim to write binary data and stores the actual bytes written
- write(b: bytes) → None¶
Add bytes to internal bytes buffer and if echo is True, echo contents to inner stream.
- class cmd2.utils.ProcReader(proc: subprocess.Popen, stdout: Union[cmd2.utils.StdSim, TextIO], stderr: Union[cmd2.utils.StdSim, TextIO])¶
Used to capture stdout and stderr from a Popen process if any of those were set to subprocess.PIPE. If neither are pipes, then the process will run normally and no output will be captured.
- send_sigint() → None¶
Send a SIGINT to the process similar to if <Ctrl>+C were pressed
- terminate() → None¶
Terminate the process
- wait() → None¶
Wait for the process to finish
Tab Completion¶
- class cmd2.utils.CompletionMode(value)¶
Enum for what type of tab completion to perform in cmd2.Cmd.read_input()
- NONE¶
Tab completion will be disabled during read_input() call. Use of custom up-arrow history supported.
- COMMANDS¶
read_input() will tab complete cmd2 commands and their arguments. cmd2’s command line history will be used for up arrow if history is not provided. Otherwise use of custom up-arrow history supported.
- CUSTOM¶
read_input() will tab complete based on one of its following parameters (choices, choices_provider, completer, parser). Use of custom up-arrow history supported
- class cmd2.utils.CustomCompletionSettings(parser: argparse.ArgumentParser, *, preserve_quotes: bool = False)¶
Used by cmd2.Cmd.complete() to tab complete strings other than command arguments
- __init__(parser: argparse.ArgumentParser, *, preserve_quotes: bool = False) → None¶
Initializer
- Parameters
parser – arg parser defining format of string being tab completed
preserve_quotes – if True, then quoted tokens will keep their quotes when processed by ArgparseCompleter. This is helpful in cases when you’re tab completing flag-like tokens (e.g. -o, –option) and you don’t want them to be treated as argparse flags when quoted. Set this to True if you plan on passing the string to argparse with the tokens still quoted.
Text Alignment¶
- cmd2.utils.align_text(text: str, alignment: cmd2.utils.TextAlignment, *, fill_char: str = ' ', width: Optional[int] = None, tab_width: int = 4, truncate: bool = False) → str¶
Align text for display within a given width. Supports characters with display widths greater than 1. ANSI style sequences do not count toward the display width. If text has line breaks, then each line is aligned independently.
There are convenience wrappers around this function: align_left(), align_center(), and align_right()
- Parameters
text – text to align (can contain multiple lines)
alignment – how to align the text
fill_char – character that fills the alignment gap. Defaults to space. (Cannot be a line breaking character)
width – display width of the aligned text. Defaults to width of the terminal.
tab_width – any tabs in the text will be replaced with this many spaces. if fill_char is a tab, then it will be converted to one space.
truncate – if True, then each line will be shortened to fit within the display width. The truncated portions are replaced by a ‘…’ character. Defaults to False.
- Returns
aligned text
- Raises
TypeError if fill_char is more than one character (not including ANSI style sequences)
- Raises
ValueError if text or fill_char contains an unprintable character
- Raises
ValueError if width is less than 1
- cmd2.utils.align_left(text: str, *, fill_char: str = ' ', width: Optional[int] = None, tab_width: int = 4, truncate: bool = False) → str¶
Left align text for display within a given width. Supports characters with display widths greater than 1. ANSI style sequences do not count toward the display width. If text has line breaks, then each line is aligned independently.
- Parameters
text – text to left align (can contain multiple lines)
fill_char – character that fills the alignment gap. Defaults to space. (Cannot be a line breaking character)
width – display width of the aligned text. Defaults to width of the terminal.
tab_width – any tabs in the text will be replaced with this many spaces. if fill_char is a tab, then it will be converted to one space.
truncate – if True, then text will be shortened to fit within the display width. The truncated portion is replaced by a ‘…’ character. Defaults to False.
- Returns
left-aligned text
- Raises
TypeError if fill_char is more than one character (not including ANSI style sequences)
- Raises
ValueError if text or fill_char contains an unprintable character
- Raises
ValueError if width is less than 1
- cmd2.utils.align_right(text: str, *, fill_char: str = ' ', width: Optional[int] = None, tab_width: int = 4, truncate: bool = False) → str¶
Right align text for display within a given width. Supports characters with display widths greater than 1. ANSI style sequences do not count toward the display width. If text has line breaks, then each line is aligned independently.
- Parameters
text – text to right align (can contain multiple lines)
fill_char – character that fills the alignment gap. Defaults to space. (Cannot be a line breaking character)
width – display width of the aligned text. Defaults to width of the terminal.
tab_width – any tabs in the text will be replaced with this many spaces. if fill_char is a tab, then it will be converted to one space.
truncate – if True, then text will be shortened to fit within the display width. The truncated portion is replaced by a ‘…’ character. Defaults to False.
- Returns
right-aligned text
- Raises
TypeError if fill_char is more than one character (not including ANSI style sequences)
- Raises
ValueError if text or fill_char contains an unprintable character
- Raises
ValueError if width is less than 1
- cmd2.utils.align_center(text: str, *, fill_char: str = ' ', width: Optional[int] = None, tab_width: int = 4, truncate: bool = False) → str¶
Center text for display within a given width. Supports characters with display widths greater than 1. ANSI style sequences do not count toward the display width. If text has line breaks, then each line is aligned independently.
- Parameters
text – text to center (can contain multiple lines)
fill_char – character that fills the alignment gap. Defaults to space. (Cannot be a line breaking character)
width – display width of the aligned text. Defaults to width of the terminal.
tab_width – any tabs in the text will be replaced with this many spaces. if fill_char is a tab, then it will be converted to one space.
truncate – if True, then text will be shortened to fit within the display width. The truncated portion is replaced by a ‘…’ character. Defaults to False.
- Returns
centered text
- Raises
TypeError if fill_char is more than one character (not including ANSI style sequences)
- Raises
ValueError if text or fill_char contains an unprintable character
- Raises
ValueError if width is less than 1
- cmd2.utils.truncate_line(line: str, max_width: int, *, tab_width: int = 4) → str¶
Truncate a single line to fit within a given display width. Any portion of the string that is truncated is replaced by a ‘…’ character. Supports characters with display widths greater than 1. ANSI style sequences do not count toward the display width.
If there are ANSI style sequences in the string after where truncation occurs, this function will append them to the returned string.
This is done to prevent issues caused in cases like: truncate_line(fg.blue + hello + fg.reset, 3) In this case, “hello” would be truncated before fg.reset resets the color from blue. Appending the remaining style sequences makes sure the style is in the same state had the entire string been printed. align_text() relies on this behavior when preserving style over multiple lines.
- Parameters
line – text to truncate
max_width – the maximum display width the resulting string is allowed to have
tab_width – any tabs in the text will be replaced with this many spaces
- Returns
line that has a display width less than or equal to width
- Raises
ValueError if text contains an unprintable character like a newline
- Raises
ValueError if max_width is less than 1
Miscellaneous¶
- cmd2.utils.str_to_bool(val: str) → bool¶
Converts a string to a boolean based on its value.
- Parameters
val – string being converted
- Returns
boolean value expressed in the string
- Raises
ValueError if the string does not contain a value corresponding to a boolean value
- cmd2.utils.categorize(func: Union[Callable[[...], Any], Iterable[Callable[[...], Any]]], category: str) → None¶
Categorize a function.
The help command output will group the passed function under the specified category heading
- Parameters
func – function or list of functions to categorize
category – category to put it in
- Example
>>> import cmd2 >>> class MyApp(cmd2.Cmd): >>> def do_echo(self, arglist): >>> self.poutput(' '.join(arglist) >>> >>> cmd2.utils.categorize(do_echo, "Text Processing")
For an alternative approach to categorizing commands using a decorator, see
with_category()
- cmd2.utils.remove_duplicates(list_to_prune: List[cmd2.utils._T]) → List[cmd2.utils._T]¶
Removes duplicates from a list while preserving order of the items.
- Parameters
list_to_prune – the list being pruned of duplicates
- Returns
The pruned list
- cmd2.utils.alphabetical_sort(list_to_sort: Iterable[str]) → List[str]¶
Sorts a list of strings alphabetically.
For example: [‘a1’, ‘A11’, ‘A2’, ‘a22’, ‘a3’]
To sort a list in place, don’t call this method, which makes a copy. Instead, do this:
my_list.sort(key=norm_fold)
- Parameters
list_to_sort – the list being sorted
- Returns
the sorted list
- cmd2.utils.natural_sort(list_to_sort: Iterable[str]) → List[str]¶
Sorts a list of strings case insensitively as well as numerically.
For example: [‘a1’, ‘A2’, ‘a3’, ‘A11’, ‘a22’]
To sort a list in place, don’t call this method, which makes a copy. Instead, do this:
my_list.sort(key=natural_keys)
- Parameters
list_to_sort – the list being sorted
- Returns
the list sorted naturally