Source code for coloredlogs.converter

# Program to convert text with ANSI escape sequences to HTML.
#
# Author: Peter Odding <peter@peterodding.com>
# Last Change: October 9, 2016
# URL: https://coloredlogs.readthedocs.io

"""Convert text with ANSI escape sequences to HTML."""

# Standard library modules.
import codecs
import os
import pipes
import re
import subprocess
import tempfile

# External dependencies.
from humanfriendly.terminal import clean_terminal_output

# Portable color codes from http://en.wikipedia.org/wiki/ANSI_escape_code#Colors.
EIGHT_COLOR_PALETTE = (
    'black',
    'red',
    'rgb(78, 154, 6)',  # green
    'rgb(196, 160, 0)',  # yellow
    'blue',
    'rgb(117, 80, 123)',  # magenta
    'cyan',
    'white',
)

# Regular expression that matches strings we want to convert. Used to separate
# all special strings and literal output in a single pass (this allows us to
# properly encode the output without resorting to nasty hacks).
token_pattern = re.compile('(https?://\\S+|www\\.\\S+|\x1b\\[.*?m)', re.UNICODE)


[docs]def capture(command, encoding='UTF-8'): """ Capture the output of an external command as if it runs in an interactive terminal. :param command: The command name and its arguments (a list of strings). :param encoding: The encoding to use to decode the output (a string). :returns: The output of the command. This function runs an external command under ``script`` (emulating an interactive terminal) to capture the output of the command as if it was running in an interactive terminal (including ANSI escape sequences). """ with open(os.devnull, 'wb') as dev_null: # We start by invoking the `script' program in a form that is supported # by the Linux implementation [1] but fails command line validation on # the Mac OS X (BSD) implementation [2]: The command is specified # using the -c option and the typescript file is /dev/null. # # [1] http://man7.org/linux/man-pages/man1/script.1.html # [2] https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man1/script.1.html command_line = ['script', '-qc', ' '.join(map(pipes.quote, command)), '/dev/null'] script = subprocess.Popen(command_line, stdout=subprocess.PIPE, stderr=dev_null) stdout, stderr = script.communicate() if script.returncode == 0: # If `script' succeeded we assume that it understood our command line # invocation which means it's the Linux implementation (in this case # we can use standard output instead of a temporary file). output = stdout.decode(encoding) else: # If `script' failed we assume that it didn't understand our command # line invocation which means it's the Mac OS X (BSD) implementation # (in this case we need a temporary file because the command line # interface requires it). fd, temporary_file = tempfile.mkstemp(prefix='coloredlogs-', suffix='-capture.txt') try: command_line = ['script', '-q', temporary_file] + list(command) subprocess.Popen(command_line, stdout=dev_null, stderr=dev_null).wait() with codecs.open(temporary_file, 'r', encoding) as handle: output = handle.read() finally: os.unlink(temporary_file) # Clean up backspace and carriage return characters and the 'erase line' # ANSI escape sequence and return the output as a Unicode string. return u'\n'.join(clean_terminal_output(output))
[docs]def convert(text): """ Convert text with ANSI escape sequences to HTML. :param text: The text with ANSI escape sequences (a string). :returns: The text converted to HTML (a string). """ output = [] for token in token_pattern.split(text): if token.startswith(('http://', 'https://', 'www.')): url = token if '://' not in token: url = 'http://' + url text = url.partition('://')[2] token = u'<a href="%s" style="color: inherit;">%s</a>' % (html_encode(url), html_encode(text)) elif token.startswith('\x1b['): ansi_codes = token[2:-1].split(';') if ansi_codes == ['0']: token = '</span>' else: styles = [] for code in ansi_codes: if code == '1': styles.append('font-weight: bold;') elif code.startswith('3') and len(code) == 2: styles.append('color: %s;' % EIGHT_COLOR_PALETTE[int(code[1])]) if styles: token = '<span style="%s">' % ' '.join(styles) else: token = '' else: token = html_encode(token) token = encode_whitespace(token) output.append(token) return ''.join(output)
[docs]def encode_whitespace(text): """ Encode whitespace so that web browsers properly render it. :param text: The plain text (a string). :returns: The text converted to HTML (a string). The purpose of this function is to encode whitespace in such a way that web browsers render the same whitespace regardless of whether 'preformatted' styling is used (by wrapping the text in a ``<pre>...</pre>`` element). """ text = text.replace('\r\n', '\n') text = text.replace('\n', '<br>\n') text = text.replace(' ', '&nbsp;') return text
[docs]def html_encode(text): """ Encode characters with a special meaning as HTML. :param text: The plain text (a string). :returns: The text converted to HTML (a string). """ text = text.replace('&', '&amp;') text = text.replace('<', '&lt;') text = text.replace('>', '&gt;') text = text.replace('"', '&quot;') return text