diff options
| -rwxr-xr-x | cmd2.py | 63 | ||||
| -rw-r--r-- | docs/install.rst | 7 |
2 files changed, 47 insertions, 23 deletions
@@ -17,9 +17,8 @@ Redirection to file with >, >>; input from file with < Easy transcript-based testing of applications (see examples/example.py) Bash-style ``select`` available -Note that redirection with > and | will only work if `self.stdout.write()` -is used in place of `print`. The standard library's `cmd` module is -written to use `self.stdout.write()`, +Note that redirection with > and | will only work if `self.poutput()` +is used in place of `print`. - Catherine Devlin, Jan 03 2008 - catherinedevlin.blogspot.com @@ -62,6 +61,7 @@ from six.moves import zip # If using Python 2.7, try to use the subprocess32 package backported from Python 3.2 due to various improvements # NOTE: The feature to pipe output to a shell command won't work correctly in Python 2.7 without this try: + # noinspection PyPackageRequirements import subprocess32 as subprocess except ImportError: import subprocess @@ -306,6 +306,7 @@ def options(option_list, arg_desc="arg"): # Can we access the clipboard? Should always be true on Windows and Mac, but only sometimes on Linux +# noinspection PyUnresolvedReferences try: if six.PY3 and sys.platform.startswith('linux'): # Avoid extraneous output to stderr from xclip when clipboard is empty at cost of overwriting clipboard contents @@ -559,12 +560,26 @@ class Cmd(cmd.Cmd): # Make sure settable parameters are sorted alphabetically by key self.settable = collections.OrderedDict(sorted(self.settable.items(), key=lambda t: t[0])) - def poutput(self, msg): - """Convenient shortcut for self.stdout.write(); adds newline if necessary.""" + def poutput(self, msg, end='\n'): + """Convenient shortcut for self.stdout.write(); by default adds newline to end if not already present. + + Also handles BrokenPipeError exceptions for when a commands's output has been piped to another process and + that process terminates before than command is finished executing. + + :param msg: str - message to print to current stdout + :param end: str - string appended after the end of the message, default a newline + """ if msg: - self.stdout.write(msg) - if msg[-1] != '\n': - self.stdout.write('\n') + try: + self.stdout.write(msg) + if not msg.endswith(end): + self.stdout.write(end) + except BrokenPipeError: + # This occurs if a command's output is being piped to another process and that process closes before the + # command is finished. We intentionally don't print a warning message here since we know that stdout + # will be restored by the _restore_output() method. If you would like your application to print a + # warning message, then override this method. + pass def perror(self, errmsg, exception_type=None, traceback_war=True): """ Print error message to sys.stderr and if debug is true, print an exception Traceback if one exists. @@ -776,7 +791,7 @@ class Cmd(cmd.Cmd): # Create a pipe with read and write sides read_fd, write_fd = os.pipe() - # Make sure that self.stdout.write() expects unicode strings in Python 3 and byte strings in Python 2 + # Make sure that self.poutput() expects unicode strings in Python 3 and byte strings in Python 2 write_mode = 'w' read_mode = 'r' if six.PY2: @@ -789,7 +804,7 @@ class Cmd(cmd.Cmd): # noinspection PyTypeChecker subproc_stdin = io.open(read_fd, read_mode) - # If you don't set shell=True, subprocess failure will throw an exception + # We want Popen to raise an exception if it fails to open the process. Thus we don't set shell to True. try: self.pipe_proc = subprocess.Popen(shlex.split(statement.parsed.pipeTo), stdin=subproc_stdin) except Exception as ex: @@ -815,7 +830,7 @@ class Cmd(cmd.Cmd): else: sys.stdout = self.stdout = tempfile.TemporaryFile(mode="w+") if statement.parsed.output == '>>': - self.stdout.write(get_paste_buffer()) + self.poutput(get_paste_buffer()) def _restore_output(self, statement): """Handles restoring state after output redirection as well as the actual pipe operation if present. @@ -830,7 +845,10 @@ class Cmd(cmd.Cmd): write_to_paste_buffer(self.stdout.read()) # Close the file or pipe that stdout was redirected to - self.stdout.close() + try: + self.stdout.close() + except BrokenPipeError: + pass # If we were piping output to a shell command, then close the subprocess the shell command was running in if self.pipe_proc is not None: @@ -943,7 +961,7 @@ class Cmd(cmd.Cmd): except EOFError: line = 'eof' else: - self.stdout.write(safe_prompt) + self.poutput(safe_prompt, end='') self.stdout.flush() line = self.stdin.readline() if not len(line): @@ -986,7 +1004,7 @@ class Cmd(cmd.Cmd): # If echo is on and in the middle of running a script, then echo the line to the output if self.echo and self._current_script_dir is not None: - self.stdout.write(line + '\n') + self.poutput(line + '\n') # Run the command along with all associated pre and post hooks stop = self.onecmd_plus_hooks(line) @@ -1007,7 +1025,7 @@ class Cmd(cmd.Cmd): # noinspection PyUnusedLocal def do_cmdenvironment(self, args): """Summary report of interactive parameters.""" - self.stdout.write(""" + self.poutput(""" Commands are case-sensitive: {} Commands may be terminated with: {} Arguments at invocation allowed: {} @@ -1065,7 +1083,7 @@ class Cmd(cmd.Cmd): cmds_doc.append(command) else: cmds_undoc.append(command) - self.stdout.write("%s\n" % str(self.doc_leader)) + self.poutput("%s\n" % str(self.doc_leader)) self.print_topics(self.doc_header, cmds_doc, 15, 80) self.print_topics(self.misc_header, list(help_dict.keys()), 15, 80) self.print_topics(self.undoc_header, cmds_undoc, 15, 80) @@ -1074,7 +1092,7 @@ class Cmd(cmd.Cmd): def do_shortcuts(self, args): """Lists shortcuts (aliases) available.""" result = "\n".join('%s: %s' % (sc[0], sc[1]) for sc in sorted(self.shortcuts)) - self.stdout.write("Shortcuts for other commands:\n{}\n".format(result)) + self.poutput("Shortcuts for other commands:\n{}\n".format(result)) # noinspection PyUnusedLocal def do_eof(self, arg): @@ -1119,9 +1137,8 @@ class Cmd(cmd.Cmd): result = fulloptions[response - 1][0] break except (ValueError, IndexError): - self.stdout.write("{!r} isn't a valid choice. Pick a number " - "between 1 and {}:\n".format( - response, len(fulloptions))) + self.poutput("{!r} isn't a valid choice. Pick a number between 1 and {}:\n".format(response, + len(fulloptions))) return result @options([make_option('-l', '--long', action="store_true", help="describe function of parameter")]) @@ -1172,7 +1189,7 @@ class Cmd(cmd.Cmd): else: val = cast(current_val, val) setattr(self, param_name, val) - self.stdout.write('%s - was: %s\nnow: %s\n' % (param_name, current_val, val)) + self.poutput('%s - was: %s\nnow: %s\n' % (param_name, current_val, val)) if current_val != val: try: onchange_hook = getattr(self, '_onchange_%s' % param_name) @@ -1535,7 +1552,7 @@ Paths or arguments that contain spaces must be enclosed in quotes if opts.script: self.poutput(hi) else: - self.stdout.write(hi.pr()) + self.poutput(hi.pr()) def _last_matching(self, arg): """Return the last item from the history list that matches arg. Or if arg not provided, return last item. @@ -1839,7 +1856,7 @@ Script should contain one command per line, just like command would be typed in # Print the intro, if there is one, right after the preloop if self.intro is not None: - self.stdout.write(str(self.intro) + "\n") + self.poutput(str(self.intro) + "\n") # And then call _cmdloop() to enter the main loop self._cmdloop() diff --git a/docs/install.rst b/docs/install.rst index 6d293176..1edba409 100644 --- a/docs/install.rst +++ b/docs/install.rst @@ -124,3 +124,10 @@ If you wish to permanently uninstall ``cmd2``, this can also easily be done with pip uninstall cmd2 +Extra requirement for Python 2.7 only +------------------------------------- +If you want to be able to pipe the output of commands to a shell command on Python 2.7, then you will need one +additional package installed: + + * subprocess32 + |