# -*- coding: utf-8 -*- from __future__ import unicode_literals import os import sys import time import codecs import curses import webbrowser import subprocess import curses.ascii from curses import textpad from contextlib import contextmanager from tempfile import NamedTemporaryFile import six from kitchen.text.display import textual_width_chop from . import exceptions from .objects import LoadScreen, Color try: # Added in python 3.4+ from html import unescape except ImportError: from six.moves import html_parser unescape = html_parser.HTMLParser().unescape class Terminal(object): MIN_HEIGHT = 10 MIN_WIDTH = 20 # ASCII code ESCAPE = 27 RETURN = 10 SPACE = 32 def __init__(self, stdscr, ascii=False): self.stdscr = stdscr self.ascii = ascii self.loader = LoadScreen(self) self._display = None @property def up_arrow(self): symbol = '^' if self.ascii else '▲' attr = curses.A_BOLD | Color.GREEN return symbol, attr @property def down_arrow(self): symbol = 'v' if self.ascii else '▼' attr = curses.A_BOLD | Color.RED return symbol, attr @property def neutral_arrow(self): symbol = '>' if self.ascii else '‣' attr = curses.A_BOLD return symbol, attr @property def timestamp_sep(self): symbol = 'o' if self.ascii else '•' attr = curses.A_BOLD return symbol, attr @property def guilded(self): symbol = '*' if self.ascii else '✪' attr = curses.A_BOLD | Color.YELLOW return symbol, attr @property def stickied(self): text = '[stickied]' attr = Color.GREEN return text, attr @property def vline(self): return getattr(curses, 'ACS_VLINE', ord('|')) @property def display(self): """ Use a number of methods to guess if the default webbrowser will open in the background as opposed to opening directly in the terminal. """ if self._display is None: if sys.platform == 'darwin': # OSX doesn't always set DISPLAY so we can't use this to check display = True else: display = bool(os.environ.get("DISPLAY")) # Use the convention defined here to parse $BROWSER # https://docs.python.org/2/library/webbrowser.html console_browsers = ['www-browser', 'links', 'links2', 'elinks', 'lynx', 'w3m'] if "BROWSER" in os.environ: user_browser = os.environ["BROWSER"].split(os.pathsep)[0] if user_browser in console_browsers: display = False if webbrowser._tryorder: if webbrowser._tryorder[0] in console_browsers: display = False self._display = display return self._display @staticmethod def flash(): return curses.flash() @staticmethod def addch(window, y, x, ch, attr): """ Curses addch() method that fixes a major bug in python 3.4. See http://bugs.python.org/issue21088 """ if sys.version_info[:3] == (3, 4, 0): y, x = x, y window.addch(y, x, ch, attr) def getch(self): return self.stdscr.getch() @staticmethod @contextmanager def suspend(): """ Suspend curses in order to open another subprocess in the terminal. """ try: curses.endwin() yield finally: curses.doupdate() @contextmanager def no_delay(self): """ Temporarily turn off character delay mode. In this mode, getch will not block while waiting for input and will return -1 if no key has been pressed. """ try: self.stdscr.nodelay(1) yield finally: self.stdscr.nodelay(0) def get_arrow(self, likes): """ Curses does define constants for symbols (e.g. curses.ACS_BULLET). However, they rely on using the curses.addch() function, which has been found to be buggy and a general PITA to work with. By defining them as unicode points they can be added via the more reliable curses.addstr(). http://bugs.python.org/issue21088 """ if likes is None: return self.neutral_arrow elif likes: return self.up_arrow else: return self.down_arrow def clean(self, string, n_cols=None): """ Required reading! http://nedbatchelder.com/text/unipain.html Python 2 input string will be a unicode type (unicode code points). Curses will accept unicode if all of the points are in the ascii range. However, if any of the code points are not valid ascii curses will throw a UnicodeEncodeError: 'ascii' codec can't encode character, ordinal not in range(128). If we encode the unicode to a utf-8 byte string and pass that to curses, it will render correctly. Python 3 input string will be a string type (unicode code points). Curses will accept that in all cases. However, the n character count in addnstr will not be correct. If code points are passed to addnstr, curses will treat each code point as one character and will not account for wide characters. If utf-8 is passed in, addnstr will treat each 'byte' as a single character. Reddit's api sometimes chokes and double-encodes some html characters Praw handles the initial decoding, but we need to do a second pass just to make sure. See https://github.com/michael-lazar/rtv/issues/96 Example: &amp; -> returned directly from reddit's api & -> returned after PRAW decodes the html characters & -> returned after our second pass, this is the true value """ if n_cols is not None and n_cols <= 0: return '' if isinstance(string, six.text_type): string = unescape(string) if self.ascii: if isinstance(string, six.binary_type): string = string.decode('utf-8') string = string.encode('ascii', 'replace') return string[:n_cols] if n_cols else string else: if n_cols: string = textual_width_chop(string, n_cols) if isinstance(string, six.text_type): string = string.encode('utf-8') return string def add_line(self, window, text, row=None, col=None, attr=None): """ Unicode aware version of curses's built-in addnstr method. Safely draws a line of text on the window starting at position (row, col). Checks the boundaries of the window and cuts off the text if it exceeds the length of the window. """ # The following arg combos must be supported to conform with addnstr # (window, text) # (window, text, attr) # (window, text, row, col) # (window, text, row, col, attr) cursor_row, cursor_col = window.getyx() row = row if row is not None else cursor_row col = col if col is not None else cursor_col max_rows, max_cols = window.getmaxyx() n_cols = max_cols - col - 1 if n_cols <= 0: # Trying to draw outside of the screen bounds return text = self.clean(text, n_cols) params = [] if attr is None else [attr] window.addstr(row, col, text, *params) def show_notification(self, message, timeout=None): """ Overlay a message box on the center of the screen and wait for input. Params: message (list or string): List of strings, one per line. timeout (float): Optional, maximum length of time that the message will be shown before disappearing. """ if isinstance(message, six.string_types): message = [message] n_rows, n_cols = self.stdscr.getmaxyx() box_width = max(len(m) for m in message) + 2 box_height = len(message) + 2 # Cut off the lines of the message that don't fit on the screen box_width = min(box_width, n_cols) box_height = min(box_height, n_rows) message = message[:box_height-2] s_row = (n_rows - box_height) // 2 s_col = (n_cols - box_width) // 2 window = curses.newwin(box_height, box_width, s_row, s_col) window.erase() window.border() for index, line in enumerate(message, start=1): self.add_line(window, line, index, 1) window.refresh() ch, start = -1, time.time() with self.no_delay(): while timeout is None or time.time() - start < timeout: ch = self.getch() if ch != -1: break time.sleep(0.01) window.clear() del window self.stdscr.touchwin() self.stdscr.refresh() return ch def open_browser(self, url): """ Open the given url using the default webbrowser. The preferred browser can specified with the $BROWSER environment variable. If not specified, python webbrowser will try to determine the default to use based on your system. For browsers requiring an X display, we call webbrowser.open_new_tab(url) and redirect stdout/stderr to devnull. This is a workaround to stop firefox from spewing warning messages to the console. See http://bugs.python.org/issue22277 for a better description of the problem. For console browsers (e.g. w3m), RTV will suspend and display the browser window within the same terminal. This mode is triggered either when 1. $BROWSER is set to a known console browser, or 2. $DISPLAY is undefined, indicating that the terminal is running headless There may be other cases where console browsers are opened (xdg-open?) but are not detected here. """ if self.display: command = "import webbrowser; webbrowser.open_new_tab('%s')" % url args = [sys.executable, '-c', command] with self.loader('Opening page in a new window'), \ open(os.devnull, 'ab+', 0) as null: p = subprocess.Popen(args, stdout=null, stderr=null) # Give the browser 5 seconds to open a new tab. Because the # display is set, calling webbrowser should be non-blocking. # If it blocks or returns an error, something went wrong. try: start = time.time() while time.time() - start < 10: code = p.poll() if code == 0: break # Success elif code is not None: raise exceptions.BrowserError( 'Browser exited with status=%s' % code) time.sleep(0.01) else: raise exceptions.BrowserError('Timeout opening browser') finally: # Can't check the loader exception because the oauth module # supersedes this loader and we need to always kill the # process if escape is pressed try: p.terminate() except OSError: pass else: with self.suspend(): webbrowser.open_new_tab(url) def open_pager(self, data): """ View a long block of text using the system's default pager. The data string will be piped directly to the pager. """ pager = os.getenv('PAGER') or 'less' try: with self.suspend(): p = subprocess.Popen([pager], stdin=subprocess.PIPE) p.stdin.write(self.clean(data)) p.stdin.close() try: p.wait() except KeyboardInterrupt: p.terminate() except OSError: self.show_notification('Could not open pager %s' % pager) def open_editor(self, data=''): """ Open a temporary file using the system's default editor. The data string will be written to the file before opening. This function will block until the editor has closed. At that point the file will be read and and lines starting with '#' will be stripped. """ with NamedTemporaryFile(prefix='rtv-', suffix='.txt', mode='wb') as fp: fp.write(self.clean(data)) fp.flush() editor = os.getenv('RTV_EDITOR') or os.getenv('EDITOR') or 'nano' try: with self.suspend(): p = subprocess.Popen([editor, fp.name]) try: p.wait() except KeyboardInterrupt: p.terminate() except OSError: self.show_notification('Could not open file with %s' % editor) # Open a second file object to read. This appears to be necessary # in order to read the changes made by some editors (gedit). w+ # mode does not work! with codecs.open(fp.name, 'r', 'utf-8') as fp2: text = ''.join(line for line in fp2 if not line.startswith('#')) text = text.rstrip() return text def text_input(self, window, allow_resize=False): """ Transform a window into a text box that will accept user input and loop until an escape sequence is entered. If the escape key (27) is pressed, cancel the textbox and return None. Otherwise, the textbox will wait until it is full (^j, or a new line is entered on the bottom line) or the BEL key (^g) is pressed. """ window.clear() # Set cursor mode to 1 because 2 doesn't display on some terminals curses.curs_set(1) # Keep insert_mode off to avoid the recursion error described here # http://bugs.python.org/issue13051 textbox = textpad.Textbox(window) textbox.stripspaces = 0 def validate(ch): "Filters characters for special key sequences" if ch == self.ESCAPE: raise exceptions.EscapeInterrupt() if (not allow_resize) and (ch == curses.KEY_RESIZE): raise exceptions.EscapeInterrupt() # Fix backspace for iterm if ch == curses.ascii.DEL: ch = curses.KEY_BACKSPACE return ch # Wrapping in an exception block so that we can distinguish when the # user hits the return character from when the user tries to back out # of the input. try: out = textbox.edit(validate=validate) if isinstance(out, six.binary_type): out = out.decode('utf-8') except exceptions.EscapeInterrupt: out = None curses.curs_set(0) return self.strip_textpad(out) def prompt_input(self, prompt, key=False): """ Display a text prompt at the bottom of the screen. Params: prompt (string): Text prompt that will be displayed key (bool): If true, grab a single keystroke instead of a full string. This can be faster than pressing enter for single key prompts (e.g. y/n?) """ n_rows, n_cols = self.stdscr.getmaxyx() attr = curses.A_BOLD | Color.CYAN prompt = self.clean(prompt, n_cols-1) # Create a new window to draw the text at the bottom of the screen, # so we can erase it when we're done. prompt_win = curses.newwin(1, len(prompt)+1, n_rows-1, 0) self.add_line(prompt_win, prompt, attr=attr) prompt_win.refresh() # Create a separate window for text input input_win = curses.newwin(1, n_cols-len(prompt), n_rows-1, len(prompt)) input_win.attrset(attr) if key: curses.curs_set(1) ch = self.getch() # We can't convert the character to unicode, because it may return # Invalid values for keys that don't map to unicode characters, # e.g. F1 text = ch if ch != self.ESCAPE else None curses.curs_set(0) else: text = self.text_input(input_win) prompt_win.clear() input_win.clear() del prompt_win del input_win self.stdscr.touchwin() self.stdscr.refresh() return text def prompt_y_or_n(self, prompt): """ Wrapper around prompt_input for simple yes/no queries. """ ch = self.prompt_input(prompt, key=True) if ch in (ord('Y'), ord('y')): return True elif ch in (ord('N'), ord('n'), None): return False else: self.flash() return False @staticmethod def strip_textpad(text): """ Attempt to intelligently strip excess whitespace from the output of a curses textpad. """ if text is None: return text # Trivial case where the textbox is only one line long. if '\n' not in text: return text.rstrip() # Allow one space at the end of the line. If there is more than one # space, assume that a newline operation was intended by the user stack, current_line = [], '' for line in text.split('\n'): if line.endswith(' '): stack.append(current_line + line.rstrip()) current_line = '' else: current_line += line stack.append(current_line) # Prune empty lines at the bottom of the textbox. for item in stack[::-1]: if len(item) == 0: stack.pop() else: break out = '\n'.join(stack) return out