Refactored pager support to not rely on pydoc

click/_compat.py

@@ -9,6 +9,9 @@
 PY2 = sys.version_info[0] == 2
 
 
+_ansi_re = re.compile('\033\[((?:\d|;)*)([a-zA-Z])')
+
+
 def _make_text_stream(stream, encoding, errors):
  if encoding is None:
  encoding = get_best_encoding(stream)
@@ -427,7 +430,7 @@ def __repr__(self):
  return repr(self._f)
 
 
-_auto_wrap_for_ansi = lambda x: x
+auto_wrap_for_ansi = None
 
 
 try:
@@ -438,14 +441,11 @@ def __repr__(self):
  from weakref import WeakKeyDictionary
  _ansi_stream_wrappers = WeakKeyDictionary()
 
- def _auto_wrap_for_ansi(stream):
+ def auto_wrap_for_ansi(stream):
  cached = _ansi_stream_wrappers.get(stream)
  if cached is not None:
  return cached
- try:
- strip = not stream.isatty()
- except Exception:
- strip = True
+ strip = not isatty(stream)
  rv = colorama.AnsiToWin32(stream, strip=strip).stream
  try:
  _ansi_stream_wrappers[stream] = rv
@@ -454,6 +454,17 @@ def _auto_wrap_for_ansi(stream):
  return rv
 
 
+def strip_ansi(value):
+ return _ansi_re.sub('', value)
+
+
+def isatty(stream):
+ try:
+ return stream.isatty()
+ except Exception:
+ return False
+
+
 binary_streams = {
  'stdin': get_binary_stdin,
  'stdout': get_binary_stdout,

click/_termui_impl.py

@@ -10,9 +10,11 @@
  :license: BSD, see LICENSE for more details.
 """
 import os
+import sys
 import time
 import math
-from ._compat import get_text_stdout, range_type, PY2
+from ._compat import get_text_stdout, range_type, PY2, isatty, open_stream, \
+ strip_ansi
 from .utils import echo
 
 
@@ -224,3 +226,60 @@ def next(self):
  if not PY2:
  __next__ = next
  del next
+
+
+def pager(text):
+ """Decide what method to use for paging through text."""
+ stdout = get_text_stdout()
+ if not isatty(sys.stdin) or not isatty(stdout):
+ return _nullpager(stdout, text)
+ if 'PAGER' in os.environ:
+ if sys.platform == 'win32':
+ return _tempfilepager(strip_ansi(text), os.environ['PAGER'])
+ elif os.environ.get('TERM') in ('dumb', 'emacs'):
+ return _pipepager(strip_ansi(text), os.environ['PAGER'])
+ else:
+ return _pipepager(text, os.environ['PAGER'])
+ if os.environ.get('TERM') in ('dumb', 'emacs'):
+ return _nullpager(stdout, text)
+ if sys.platform == 'win32' or sys.platform.startswith('os2'):
+ return _tempfilepager(strip_ansi(text), 'more <')
+ if hasattr(os, 'system') and os.system('(less) 2>/dev/null') == 0:
+ return _pipepager(text, 'less')
+
+ import tempfile
+ fd, filename = tempfile.mkstemp()
+ os.close(fd)
+ try:
+ if hasattr(os, 'system') and os.system('more "%s"' % filename) == 0:
+ return _pipepager(text, 'more')
+ return _nullpager(stdout, text)
+ finally:
+ os.unlink(filename)
+
+
+def _pipepager(text, cmd):
+ """Page through text by feeding it to another program."""
+ pipe = os.popen(cmd, 'w')
+ try:
+ pipe.write(text)
+ pipe.close()
+ except IOError:
+ pass
+
+
+def _tempfilepager(text, cmd):
+ """Page through text by invoking a program on a temporary file."""
+ import tempfile
+ filename = tempfile.mktemp()
+ with open_stream(filename, 'w')[1] as f:
+ f.write(text)
+ try:
+ os.system(cmd + ' "' + filename + '"')
+ finally:
+ os.unlink(filename)
+
+
+def _nullpager(stream, text):
+ """Simply print unformatted text. This is the ultimate fallback."""
+ stream.write(strip_ansi(text))

click/termui.py

@@ -175,12 +175,8 @@ def echo_via_pager(text):
  encoding = get_best_encoding(sys.stdout)
  text = text.encode(encoding, 'replace')
 
- # Pydoc's pager is badly broken with LANG=C on Python 3 to the point
- # where it will corrupt the terminal. http://bugs.python.org/issue21398
- # I don't feel like reimplementing it given that it works on Python 2
- # and seems reasonably stable otherwise.
- import pydoc
- pydoc.pager(text)
+ from ._termui_impl import pager
+ return pager(text + '\n')
 
 
 def progressbar(iterable=None, length=None, label=None, show_eta=True,

click/utils.py

@@ -4,7 +4,7 @@
 
 from ._compat import text_type, open_stream, get_streerror, string_types, \
  PY2, get_best_encoding, binary_streams, text_streams, filename_to_ui, \
- _auto_wrap_for_ansi
+ auto_wrap_for_ansi, strip_ansi, isatty
 
 if not PY2:
  from ._compat import _find_binary_writer
@@ -223,7 +223,6 @@ def echo(message=None, file=None, nl=True):
  """
  if file is None:
  file = sys.stdout
- file = _auto_wrap_for_ansi(file)
 
  if message is not None and not isinstance(message, echo_native_types):
  message = text_type(message)
@@ -242,6 +241,16 @@ def echo(message=None, file=None, nl=True):
  binary_file.write(b'\n')
  binary_file.flush()
  return
+
+ # If we have colorama support we wrap the stream to handle colors
+ # for us. In case colorama is not supported and our output stream
+ # is not a terminal, we strip the ansi codes ourselves.
+ if auto_wrap_for_ansi is not None:
+ file = auto_wrap_for_ansi(file)
+ elif message and not isatty(file):
+ message = strip_ansi(message)
+
+ if message:
  file.write(message)
  if nl:
  file.write('\n')

tests/test_utils.py

@@ -7,8 +7,9 @@ def test_echo(runner):
  click.echo(b'\x44\x44')
  click.echo(42, nl=False)
  click.echo(b'a', nl=False)
+ click.echo('\x1b[31mx\x1b[39m', nl=False)
  bytes = out.getvalue()
- assert bytes == b'\xe2\x98\x83\nDD\n42a'
+ assert bytes == b'\xe2\x98\x83\nDD\n42ax'
 
 
 def test_filename_formatting():