# -*- coding: utf-8 -*- from __future__ import unicode_literals import os import sys import time import shlex import codecs import curses import logging import threading import webbrowser import subprocess import curses.ascii from curses import textpad from multiprocessing import Process from contextlib import contextmanager from tempfile import NamedTemporaryFile import six from kitchen.text.display import textual_width_chop from . import exceptions, mime_parsers from .theme import Theme, ThemeList from .objects import LoadScreen try: # Fix only needed for versions prior to python 3.6 from mailcap_fix import mailcap except ImportError: import mailcap try: # Added in python 3.4+ from html import unescape except ImportError: from six.moves import html_parser unescape = html_parser.HTMLParser().unescape _logger = logging.getLogger(__name__) class Terminal(object): MIN_HEIGHT = 10 MIN_WIDTH = 20 # ASCII codes ESCAPE = 27 RETURN = 10 SPACE = 32 def __init__(self, stdscr, config): self.stdscr = stdscr self.config = config self.loader = LoadScreen(self) self.theme = None # Initialized by term.set_theme() self.theme_list = ThemeList() self._display = None self._mailcap_dict = mailcap.getcaps() self._term = os.environ.get('TERM') # This is a hack, the MIME parsers should be stateless # but we need to load the imgur credentials from the config mime_parsers.ImgurApiMIMEParser.CLIENT_ID = config['imgur_client_id'] @property def up_arrow(self): return '^' if self.config['ascii'] else '▲' @property def down_arrow(self): return 'v' if self.config['ascii'] else '▼' @property def neutral_arrow(self): return 'o' if self.config['ascii'] else '•' @property def guilded(self): return '*' if self.config['ascii'] else '✪' @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': # OS X won't set $DISPLAY unless xQuartz is installed. # If you're using OS X and you want to access a terminal # browser, you need to set it manually via $BROWSER. # See issue #166 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(): """ Flash the screen to indicate that an action was invalid. """ return curses.flash() @staticmethod def curs_set(val): """ Change the cursor visibility, may fail for some terminals with limited cursor support. """ try: curses.curs_set(val) except: pass @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): """ Wait for a keypress and return the corresponding character code (int). """ 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, self.attr('NeutralVote') elif likes: return self.up_arrow, self.attr('Upvote') else: return self.down_arrow, self.attr('Downvote') 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.config['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) @staticmethod def add_space(window): """ Shortcut for adding a single space to a window at the current position """ row, col = window.getyx() _, max_cols = window.getmaxyx() n_cols = max_cols - col - 1 if n_cols <= 0: # Trying to draw outside of the screen bounds return window.addstr(row, col, ' ') def show_notification(self, message, timeout=None, style='Info'): """ 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. style (str): The theme element that will be applied to the notification window """ assert style in ('Info', 'Warning', 'Error', 'Success') if isinstance(message, six.string_types): message = message.splitlines() n_rows, n_cols = self.stdscr.getmaxyx() v_offset, h_offset = self.stdscr.getbegyx() 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 + v_offset s_col = (n_cols - box_width) // 2 + h_offset window = curses.newwin(box_height, box_width, s_row, s_col) window.bkgd(str(' '), self.attr('Notice{0}'.format(style))) 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_link(self, url): """ Open a media link using the definitions from the user's mailcap file. Most urls are parsed using their file extension, but special cases exist for websites that are prevalent on reddit such as Imgur and Gfycat. If there are no valid mailcap definitions, RTV will fall back to using the default webbrowser. RTV checks for certain mailcap fields to determine how to open a link: - If ``copiousoutput`` is specified, the curses application will be paused and stdout will be piped to the system pager. - If `needsterminal`` is specified, the curses application will yield terminal control to the subprocess until it has exited. - Otherwise, we assume that the subprocess is meant to open a new x-window, and we swallow all stdout output. Examples: Stream youtube videos with VLC Browse images and imgur albums with feh Watch .webm videos through your terminal with mplayer View images directly in your terminal with fbi or w3m Play .mp3 files with sox player Send HTML pages your pager using to html2text ...anything is possible! """ if not self.config['enable_media']: return self.open_browser(url) try: with self.loader('Checking link', catch_exception=False): command, entry = self.get_mailcap_entry(url) except exceptions.MailcapEntryNotFound: return self.open_browser(url) _logger.info('Executing command: %s', command) needs_terminal = 'needsterminal' in entry copious_output = 'copiousoutput' in entry if needs_terminal or copious_output: # Blocking, pause rtv until the process returns with self.suspend(): os.system('clear') p = subprocess.Popen( [command], stderr=subprocess.PIPE, universal_newlines=True, shell=True) _, stderr = p.communicate() if copious_output: six.moves.input('Press any key to continue') code = p.poll() if code != 0: _logger.warning(stderr) self.show_notification( 'Program exited with status={0}\n{1}'.format( code, stderr.strip()), style='Error') else: # Non-blocking, open a background process with self.loader('Opening page', delay=0): p = subprocess.Popen( [command], shell=True, universal_newlines=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE) # Wait a little while to make sure that the command doesn't # exit with an error. This isn't perfect, but it should be good # enough to catch invalid commands. time.sleep(1.0) code = p.poll() if code is not None and code != 0: _, stderr = p.communicate() raise exceptions.BrowserError( 'Program exited with status={0}\n{1}'.format( code, stderr.strip())) # Spin off a thread with p.communicate() to avoid subprocess # hang when the stodout/stderr PIPE gets filled up. This # behavior was discovered when opening long gifs with mpv # because mpv sends a progress bar to stderr. # https://thraxil.org/users/anders/posts/2008/03/13/ threading.Thread(target=p.communicate).start() def get_mailcap_entry(self, url): """ Search through the mime handlers list and attempt to find the appropriate command to open the provided url with. Will raise a MailcapEntryNotFound exception if no valid command exists. Params: url (text): URL that will be checked Returns: command (text): The string of the command that should be executed in a subprocess to open the resource. entry (dict): The full mailcap entry for the corresponding command """ for parser in mime_parsers.parsers: if parser.pattern.match(url): # modified_url may be the same as the original url, but it # could also be updated to point to a different page, or it # could refer to the location of a temporary file with the # page's downloaded content. try: modified_url, content_type = parser.get_mimetype(url) except Exception as e: # If Imgur decides to change its html layout, let it fail # silently in the background instead of crashing. _logger.warning('parser %s raised an exception', parser) _logger.exception(e) raise exceptions.MailcapEntryNotFound() if not content_type: _logger.info('Content type could not be determined') raise exceptions.MailcapEntryNotFound() elif content_type == 'text/html': _logger.info('Content type text/html, deferring to browser') raise exceptions.MailcapEntryNotFound() command, entry = mailcap.findmatch( self._mailcap_dict, content_type, filename=modified_url) if not entry: _logger.info('Could not find a valid mailcap entry') raise exceptions.MailcapEntryNotFound() return command, entry # No parsers matched the url raise exceptions.MailcapEntryNotFound() 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 open a new subprocess and redirect stdout/stderr to devnull. This is a workaround to stop BackgroundBrowsers (e.g. xdg-open, any BROWSER command ending in "&"), 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. These cases are still unhandled and will probably be broken if we incorrectly assume that self.display=True. """ if self.display: with self.loader('Opening page in a new window'): def open_url_silent(url): # This used to be done using subprocess.Popen(). # It was switched to multiprocessing.Process so that we # can re-use the webbrowser instance that has been patched # by RTV. It's also safer because it doesn't inject # python code through the command line. null = open(os.devnull, 'ab+', 0) sys.stdout, sys.stderr = null, null webbrowser.open_new_tab(url) p = Process(target=open_url_silent, args=(url,)) p.start() # Give the browser 7 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: p.join(7) if p.is_alive(): raise exceptions.BrowserError( 'Timeout waiting for browser to open') finally: # This will be hit on the browser timeout, but also if the # user presses the ESC key. We always want to kill the # webbrowser process if it hasn't opened the tab and # terminated by now. 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' command = shlex.split(pager) try: with self.suspend(): _logger.debug('Running command: %s', command) p = subprocess.Popen(command, stdin=subprocess.PIPE) try: p.communicate(data.encode('utf-8')) except KeyboardInterrupt: p.terminate() except OSError as e: _logger.exception(e) self.show_notification('Could not open pager %s' % pager) @contextmanager def open_editor(self, data=''): """ Open a file for editing using the system's default editor. After the file has been altered, the text will be read back and lines starting with '#' will be stripped. If an error occurs inside of the context manager, the file will be preserved. Otherwise, the file will be deleted when the context manager closes. Params: data (str): If provided, text will be written to the file before opening it with the editor. Returns: text (str): The text that the user entered into the editor. """ with NamedTemporaryFile(prefix='rtv_', suffix='.txt', delete=False) as fp: # Create a tempory file and grab the name, but close immediately so # we can re-open using the right encoding filepath = fp.name with codecs.open(filepath, 'w', 'utf-8') as fp: fp.write(data) _logger.info('File created: %s', filepath) editor = (os.getenv('RTV_EDITOR') or os.getenv('VISUAL') or os.getenv('EDITOR') or 'nano') command = shlex.split(editor) + [filepath] try: with self.suspend(): _logger.debug('Running command: %s', command) p = subprocess.Popen(command) try: p.communicate() except KeyboardInterrupt: p.terminate() except OSError as e: _logger.exception(e) self.show_notification('Could not open file with %s' % editor) with codecs.open(filepath, 'r', 'utf-8') as fp: text = ''.join(line for line in fp if not line.startswith('#')) text = text.rstrip() try: yield text except exceptions.TemporaryFileError: # All exceptions will cause the file to *not* be removed, but these # ones should also be swallowed _logger.info('Caught TemporaryFileError') self.show_notification('Post saved as: %s' % filepath) else: # If no errors occurred, try to remove the file try: os.remove(filepath) except OSError: _logger.warning('Could not delete: %s', filepath) else: _logger.info('File deleted: %s', filepath) def open_urlview(self, data): """ Pipe a block of text to urlview, which displays a list of urls contained in the text and allows the user to open them with their web browser. """ urlview = os.getenv('RTV_URLVIEWER') or 'urlview' command = shlex.split(urlview) try: with self.suspend(): _logger.debug('Running command: %s', command) p = subprocess.Popen(command, stdin=subprocess.PIPE) try: p.communicate(input=data.encode('utf-8')) except KeyboardInterrupt: p.terminate() code = p.poll() if code == 1: # Clear the "No URLs found." message from stdout sys.stdout.write("\033[F") sys.stdout.flush() if code == 1: self.show_notification('No URLs found') except OSError as e: _logger.exception(e) self.show_notification( 'Failed to open {0}'.format(urlview)) 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 self.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 self.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() v_offset, h_offset = self.stdscr.getbegyx() ch, attr = str(' '), self.attr('Prompt') 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. s_row = v_offset + n_rows - 1 s_col = h_offset prompt_win = curses.newwin(1, len(prompt) + 1, s_row, s_col) prompt_win.bkgd(ch, attr) self.add_line(prompt_win, prompt) prompt_win.refresh() # Create a separate window for text input s_col = h_offset + len(prompt) input_win = curses.newwin(1, n_cols - len(prompt), s_row, s_col) input_win.bkgd(ch, attr) input_win.refresh() if key: self.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 self.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(' ') or not line: 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 def clear_screen(self): """ In the beginning this always called touchwin(). However, a bug was discovered in tmux when TERM was set to `xterm-256color`, where only part of the screen got redrawn when scrolling. tmux automatically sets TERM to `screen-256color`, but many people choose to override this in their tmux.conf or .bashrc file which can cause issues. Using clearok() instead seems to fix the problem, with the trade off of slightly more expensive screen refreshes. Update: It was discovered that using clearok() introduced a separate bug for urxvt users in which their screen flashed when scrolling. Heuristics were added to make it work with as many configurations as possible. It's still not perfect (e.g. urxvt + xterm-256color) will screen flash, but it should work in all cases if the user sets their TERM correctly. Reference: https://github.com/michael-lazar/rtv/issues/343 https://github.com/michael-lazar/rtv/issues/323 """ if self._term != 'xterm-256color': self.stdscr.touchwin() else: self.stdscr.clearok(True) def attr(self, element): """ Shortcut for fetching the color + attribute code for an element. """ # The theme must be initialized before calling this assert self.theme is not None return self.theme.get(element) @staticmethod def check_theme(theme): """ Check if the given theme is compatible with the terminal """ terminal_colors = curses.COLORS if curses.has_colors() else 0 if theme.required_colors > terminal_colors: return False elif theme.required_color_pairs > curses.COLOR_PAIRS: return False else: return True def set_theme(self, theme=None): """ Check that the terminal supports the provided theme, and applies the theme to the terminal if possible. If the terminal doesn't support the theme, this falls back to the default theme. The default theme only requires 8 colors so it should be compatible with any terminal that supports basic colors. """ terminal_colors = curses.COLORS if curses.has_colors() else 0 if theme is None: theme = Theme(use_color=bool(terminal_colors)) elif theme.required_color_pairs > curses.COLOR_PAIRS: _logger.warning( 'Theme %s requires %s color pairs, but TERM %s only ' 'supports %s color pairs, switching to default theme', theme.name, theme.required_color_pairs, self._term, curses.COLOR_PAIRS) theme = Theme() elif theme.required_colors > terminal_colors: _logger.warning( 'Theme %s requires %s colors, but TERM %s only ' 'supports %s colors, switching to default theme', theme.name, theme.required_colors, self._term, curses.COLORS) theme = Theme() theme.bind_curses() self.theme = theme # Apply the default color to the whole screen self.stdscr.bkgd(str(' '), self.attr('Normal'))