InputEditor Class Reference

Public Member Functions
	__init__ (self, str editor_command=None, str initial_content=None, str commentlines_start_with="#")
	input (self)
	get_editor_command (self)

Public Attributes
	editor_command_list = shlex.split(editor_command_string, posix=True)
	command line for the editor, split to separate executable name command line arguments
	initial_content = initial_content
	initial content of the editor window
	comment_string = commentlines_start_with
	string which starts comments in the file

Protected Member Functions
	_remove_comment_lines (self, a_string)
	_default_environment_editor (self)
	_prompt_for_editor (self)

Detailed Description

Class to get user input via opening a temporary file in a text editor.

It is an alternative to the python commands ``input()`` or ``sys.stdin.readlines`` and is
similar to the behaviour of ``git commit`` for editing commit messages.  By using an editor
instead of the command line, the user is motivated to give expressive multi-line input,
leveraging the full text editing capabilities of his editor.  This function cannot be used for
example in interactive terminal scripts, whenever detailed user input is required.

Heavily inspired by the code in this blog post:
https://chase-seibert.github.io/blog/2012/10/31/python-fork-exec-vim-raw-input.html

Parameters:
    editor_command: Editor to open for user input.  If ``None``, get
        default editor from environment variables.  It should be the name
        of a shell executable and can contain command line arguments.
    initial_content: Initial string to insert into the temporary file that
        is opened for user input.  Can be used for default input or to
        insert comment lines with instructions.
    commentlines_start_with: Optionally define string with which comment
        lines start

Definition at line 316 of file terminal_utils.py.

Constructor & Destructor Documentation

__init__()

__init__	(		self,
		str	editor_command = None,
		str	initial_content = None,
		str	commentlines_start_with = "#" )

Constructor

Definition at line 340 of file terminal_utils.py.

                 commentlines_start_with: str = "#"):
        """Constructor"""
        # Use provided editor command or editor command from environment variables
        editor_command_string = editor_command or self._default_environment_editor()
        ## command line for the editor, split to separate executable name command line arguments
        self.editor_command_list = shlex.split(editor_command_string, posix=True)
        # check if editor executable exists and if not, prompt for new editor command
        if shutil.which(self.editor_command_list[0]) is None:
            self._prompt_for_editor()
 
        ## initial content of the editor window
        self.initial_content = initial_content
        ## string which starts comments in the file
        self.comment_string = commentlines_start_with
 

Member Function Documentation

_default_environment_editor()

_default_environment_editor ( self )

protected

Return editor from environment variables. If not existing, return vi(m) as default.

Definition at line 396 of file terminal_utils.py.

    def _default_environment_editor(self):
        """
        Return editor from environment variables. If not existing, return vi(m) as default.
        """
        editor_command = (os.environ.get('VISUAL') or os.environ.get('EDITOR') or
                          'vim' or 'vi')
        return editor_command
 

_prompt_for_editor()

_prompt_for_editor ( self )

protected

Ask user to provide editor command

Definition at line 404 of file terminal_utils.py.

    def _prompt_for_editor(self):
        """
        Ask user to provide editor command
        """
        # Prompt user for editor command until one is found which exists in PATH
        while True:
            new_editor_command_string = input("Use editor: ")
            new_editor_command_list = shlex.split(new_editor_command_string, posix=True)
 
            if shutil.which(new_editor_command_list[0]) is not None:
                self.editor_command_list = new_editor_command_list
                return self.editor_command_list
 
            else:
                print(f"Editor '{self.editor_command_list[0]}' not found in $PATH.")

_remove_comment_lines()

_remove_comment_lines ( self, a_string )

protected

Remove lines from string that start with a comment character and return modified version.

Definition at line 386 of file terminal_utils.py.

    def _remove_comment_lines(self, a_string):
        """
        Remove lines from string that start with a comment character and return modified version.
        """
        if self.comment_string is not None:
            a_string = "\n".join(
                [line for line in a_string.splitlines()
                 if not line.startswith(self.comment_string)]).strip()
        return a_string
 

get_editor_command()

get_editor_command

(

self

)

Get editor shell command string used for user input.

Definition at line 381 of file terminal_utils.py.

    def get_editor_command(self):
        """Get editor shell command string used for user input."""
        # Construct string from list which holds the executable and args
        return " ".join(self.editor_command_list)
 

input()

input

(

self

)

Get user input via editing a temporary file in an editor. If opening the editor fails, fall
back to command line input

Definition at line 358 of file terminal_utils.py.

    def input(self):
        """
        Get user input via editing a temporary file in an editor. If opening the editor fails, fall
        back to command line input
        """
        try:
            with tempfile.NamedTemporaryFile(mode='r+') as tmpfile:
                if self.initial_content:
                    tmpfile.write(self.initial_content)
                    tmpfile.flush()
                subprocess.check_call(self.editor_command_list + [tmpfile.name])
                tmpfile.seek(0)
                input_string = tmpfile.read().strip()
            input_string = self._remove_comment_lines(input_string)
 
        except (FileNotFoundError, subprocess.CalledProcessError):
            # If editor not found or other problem with subprocess call, fall back to terminal input
            print(f"Could not open {self.get_editor_command()}.")
            print("Try to set your $VISUAL or $EDITOR environment variables properly.\n")
            sys.exit(1)
 
        return input_string
 

Member Data Documentation

comment_string

comment_string = commentlines_start_with

string which starts comments in the file

Definition at line 356 of file terminal_utils.py.

editor_command_list

editor_command_list = shlex.split(editor_command_string, posix=True)

command line for the editor, split to separate executable name command line arguments

Definition at line 348 of file terminal_utils.py.

initial_content

initial_content = initial_content

initial content of the editor window

Definition at line 354 of file terminal_utils.py.

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The documentation for this class was generated from the following file:

• framework/scripts/terminal_utils.py