Merge pull request #398 from python-cmd2/remove_dynamic_redirectors

Remove cmd2.Cmd.redirector for #381

Author: kotfu

CHANGELOG.md

@@ -29,6 +29,7 @@
     * Deleted ``cmd_with_subs_completer``, ``get_subcommands``, and ``get_subcommand_completer``
         * Replaced by default AutoCompleter implementation for all commands using argparse
     * Deleted support for old method of calling application commands with ``cmd()`` and ``self``
+    * ``cmd2.redirector`` is no longer supported. Output redirection can only be done with '>' or '>>'
 * Python 2 no longer supported
     * ``cmd2`` now supports Python 3.4+
 

cmd2/cmd2.py

@@ -338,7 +338,6 @@ class Cmd(cmd.Cmd):
     # Attributes used to configure the StatementParser, best not to change these at runtime
     blankLinesAllowed = False
     multiline_commands = []
-    redirector = '>'        # for sending output to file
     shortcuts = {'?': 'help', '!': 'shell', '@': 'load', '@@': '_relative_load'}
     aliases = dict()
     terminators = [';']
@@ -1149,29 +1148,26 @@ def _redirect_complete(self, text, line, begidx, endidx, compfunc):
 
             if len(raw_tokens) > 1:
 
-                # Build a list of all redirection tokens
-                all_redirects = constants.REDIRECTION_CHARS + ['>>']
-
                 # Check if there are redirection strings prior to the token being completed
                 seen_pipe = False
                 has_redirection = False
 
                 for cur_token in raw_tokens[:-1]:
-                    if cur_token in all_redirects:
+                    if cur_token in constants.REDIRECTION_TOKENS:
                         has_redirection = True
 
-                        if cur_token == '|':
+                        if cur_token == constants.REDIRECTION_PIPE:
                             seen_pipe = True
 
                 # Get token prior to the one being completed
                 prior_token = raw_tokens[-2]
 
                 # If a pipe is right before the token being completed, complete a shell command as the piped process
-                if prior_token == '|':
+                if prior_token == constants.REDIRECTION_PIPE:
                     return self.shell_cmd_complete(text, line, begidx, endidx)
 
                 # Otherwise do path completion either as files to redirectors or arguments to the piped process
-                elif prior_token in all_redirects or seen_pipe:
+                elif prior_token in constants.REDIRECTION_TOKENS or seen_pipe:
                     return self.path_complete(text, line, begidx, endidx)
 
                 # If there were redirection strings anywhere on the command line, then we
@@ -1820,7 +1816,7 @@ def _redirect_output(self, statement):
 
             # 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.pipe_to), stdin=subproc_stdin)
+                self.pipe_proc = subprocess.Popen(statement.pipe_to, stdin=subproc_stdin)
             except Exception as ex:
                 # Restore stdout to what it was and close the pipe
                 self.stdout.close()
@@ -1834,24 +1830,30 @@ def _redirect_output(self, statement):
                 raise ex
         elif statement.output:
             if (not statement.output_to) and (not can_clip):
-                raise EnvironmentError('Cannot redirect to paste buffer; install ``xclip`` and re-run to enable')
+                raise EnvironmentError("Cannot redirect to paste buffer; install 'pyperclip' and re-run to enable")
             self.kept_state = Statekeeper(self, ('stdout',))
             self.kept_sys = Statekeeper(sys, ('stdout',))
             self.redirecting = True
             if statement.output_to:
+                # going to a file
                 mode = 'w'
-                if statement.output == 2 * self.redirector:
+                # statement.output can only contain
+                # REDIRECTION_APPEND or REDIRECTION_OUTPUT
+                if statement.output == constants.REDIRECTION_APPEND:
                     mode = 'a'
                 sys.stdout = self.stdout = open(os.path.expanduser(statement.output_to), mode)
             else:
+                # going to a paste buffer
                 sys.stdout = self.stdout = tempfile.TemporaryFile(mode="w+")
-                if statement.output == '>>':
+                if statement.output == constants.REDIRECTION_APPEND:
                     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.
+        """Handles restoring state after output redirection as well as
+        the actual pipe operation if present.
 
-        :param statement: Statement object which contains the parsed input from the user
+        :param statement: Statement object which contains the parsed
+                          input from the user
         """
         # If we have redirected output to a file or the clipboard or piped it to a shell command, then restore state
         if self.kept_state is not None:

cmd2/constants.py

@@ -4,9 +4,14 @@
 
 import re
 
-# Used for command parsing, tab completion and word breaks. Do not change.
+# Used for command parsing, output redirection, tab completion and word
+# breaks. Do not change.
 QUOTES = ['"', "'"]
-REDIRECTION_CHARS = ['|', '>']
+REDIRECTION_PIPE = '|'
+REDIRECTION_OUTPUT = '>'
+REDIRECTION_APPEND = '>>'
+REDIRECTION_CHARS = [REDIRECTION_PIPE, REDIRECTION_OUTPUT]
+REDIRECTION_TOKENS = [REDIRECTION_PIPE, REDIRECTION_OUTPUT, REDIRECTION_APPEND]
 
 # Regular expression to match ANSI escape codes
 ANSI_ESCAPE_RE = re.compile(r'\x1b[^m]*m')

cmd2/parsing.py

@@ -45,7 +45,8 @@ class Statement(str):
                             redirection, if any
     :type suffix:           str or None
     :var pipe_to:           if output was piped to a shell command, the shell command
-    :type pipe_to:          str or None
+                            as a list of tokens
+    :type pipe_to:          list
     :var output:            if output was redirected, the redirection token, i.e. '>>'
     :type output:           str or None
     :var output_to:         if output was redirected, the destination, usually a filename
@@ -283,39 +284,42 @@ def parse(self, rawinput: str) -> Statement:
                 argv = tokens
                 tokens = []
 
+        # check for a pipe to a shell process
+        # if there is a pipe, everything after the pipe needs to be passed
+        # to the shell, even redirected output
+        # this allows '(Cmd) say hello | wc > countit.txt'
+        try:
+            # find the first pipe if it exists
+            pipe_pos = tokens.index(constants.REDIRECTION_PIPE)
+            # save everything after the first pipe as tokens
+            pipe_to = tokens[pipe_pos+1:]
+            # remove all the tokens after the pipe
+            tokens = tokens[:pipe_pos]
+        except ValueError:
+            # no pipe in the tokens
+            pipe_to = None
+
         # check for output redirect
         output = None
         output_to = None
         try:
-            output_pos = tokens.index('>')
-            output = '>'
+            output_pos = tokens.index(constants.REDIRECTION_OUTPUT)
+            output = constants.REDIRECTION_OUTPUT
             output_to = ' '.join(tokens[output_pos+1:])
             # remove all the tokens after the output redirect
             tokens = tokens[:output_pos]
         except ValueError:
             pass
 
         try:
-            output_pos = tokens.index('>>')
-            output = '>>'
+            output_pos = tokens.index(constants.REDIRECTION_APPEND)
+            output = constants.REDIRECTION_APPEND
             output_to = ' '.join(tokens[output_pos+1:])
             # remove all tokens after the output redirect
             tokens = tokens[:output_pos]
         except ValueError:
             pass
 
-        # check for pipes
-        try:
-            # find the first pipe if it exists
-            pipe_pos = tokens.index('|')
-            # save everything after the first pipe
-            pipe_to = ' '.join(tokens[pipe_pos+1:])
-            # remove all the tokens after the pipe
-            tokens = tokens[:pipe_pos]
-        except ValueError:
-            # no pipe in the tokens
-            pipe_to = None
-
         if terminator:
             # whatever is left is the suffix
             suffix = ' '.join(tokens)

docs/freefeatures.rst

@@ -100,26 +100,8 @@ As in a Unix shell, output of a command can be redirected:
   - appended to a file with ``>>``, as in ``mycommand args >> filename.txt``
   - piped (``|``) as input to operating-system commands, as in
     ``mycommand args | wc``
-  - sent to the paste buffer, ready for the next Copy operation, by
-    ending with a bare ``>``, as in ``mycommand args >``..  Redirecting
-    to paste buffer requires software to be installed on the operating
-    system, pywin32_ on Windows or xclip_ on \*nix.
+  - sent to the operating system paste buffer, by ending with a bare ``>``, as in ``mycommand args >``. You can even append output to the current contents of the paste buffer by ending your command with ``>>``.
 
-If your application depends on mathematical syntax, ``>`` may be a bad
-choice for redirecting output - it will prevent you from using the
-greater-than sign in your actual user commands.  You can override your
-app's value of ``self.redirector`` to use a different string for output redirection::
-
-    class MyApp(cmd2.Cmd):
-        redirector = '->'
-
-::
-
-    (Cmd) say line1 -> out.txt
-    (Cmd) say line2 ->-> out.txt
-    (Cmd) !cat out.txt
-    line1
-    line2
 
 .. note::
 
@@ -136,8 +118,8 @@ app's value of ``self.redirector`` to use a different string for output redirect
    arguments after them from the command line arguments accordingly.  But output from a command will not be redirected
    to a file or piped to a shell command.
 
-.. _pywin32: http://sourceforge.net/projects/pywin32/
-.. _xclip: http://www.cyberciti.biz/faq/xclip-linux-insert-files-command-output-intoclipboard/
+If you need to include any of these redirection characters in your command,
+you can enclose them in quotation marks, ``mycommand 'with > in the argument'``.
 
 Python
 ======

docs/unfreefeatures.rst

@@ -10,13 +10,17 @@ commands whose names are listed in the
 parameter ``app.multiline_commands``.  These
 commands will be executed only
 after the user has entered a *terminator*.
-By default, the command terminators is
+By default, the command terminator is
 ``;``; replacing or appending to the list
 ``app.terminators`` allows different
 terminators.  A blank line
 is *always* considered a command terminator
 (cannot be overridden).
 
+In multiline commands, output redirection characters
+like ``>`` and ``|`` are part of the command
+arguments unless they appear after the terminator.
+
 
 Parsed statements
 =================

tests/test_cmd2.py

@@ -1430,7 +1430,7 @@ def test_clipboard_failure(capsys):
     # Make sure we got the error output
     out, err = capsys.readouterr()
     assert out == ''
-    assert 'Cannot redirect to paste buffer; install ``xclip`` and re-run to enable' in err
+    assert "Cannot redirect to paste buffer; install 'pyperclip' and re-run to enable" in err
 
 
 class CmdResultApp(cmd2.Cmd):

tests/test_parsing.py

@@ -159,7 +159,7 @@ def test_parse_simple_pipe(parser, line):
     assert statement.command == 'simple'
     assert not statement.args
     assert statement.argv == ['simple']
-    assert statement.pipe_to == 'piped'
+    assert statement.pipe_to == ['piped']
 
 def test_parse_double_pipe_is_not_a_pipe(parser):
     line = 'double-pipe || is not a pipe'
@@ -177,7 +177,7 @@ def test_parse_complex_pipe(parser):
     assert statement.argv == ['command', 'with', 'args,', 'terminator']
     assert statement.terminator == '&'
     assert statement.suffix == 'sufx'
-    assert statement.pipe_to == 'piped'
+    assert statement.pipe_to == ['piped']
 
 @pytest.mark.parametrize('line,output', [
     ('help > out.txt', '>'),
@@ -227,9 +227,9 @@ def test_parse_pipe_and_redirect(parser):
     assert statement.argv == ['output', 'into']
     assert statement.terminator == ';'
     assert statement.suffix == 'sufx'
-    assert statement.pipe_to == 'pipethrume plz'
-    assert statement.output == '>'
-    assert statement.output_to == 'afile.txt'
+    assert statement.pipe_to == ['pipethrume', 'plz', '>', 'afile.txt']
+    assert not statement.output
+    assert not statement.output_to
 
 def test_parse_output_to_paste_buffer(parser):
     line = 'output to paste buffer >> '
@@ -240,8 +240,9 @@ def test_parse_output_to_paste_buffer(parser):
     assert statement.output == '>>'
 
 def test_parse_redirect_inside_terminator(parser):
-    """The terminator designates the end of the commmand/arguments portion.  If a redirector
-    occurs before a terminator, then it will be treated as part of the arguments and not as a redirector."""
+    """The terminator designates the end of the commmand/arguments portion.
+    If a redirector occurs before a terminator, then it will be treated as
+    part of the arguments and not as a redirector."""
     line = 'has > inside;'
     statement = parser.parse(line)
     assert statement.command == 'has'
@@ -385,7 +386,7 @@ def test_parse_alias_pipe(parser, line):
     statement = parser.parse(line)
     assert statement.command == 'help'
     assert not statement.args
-    assert statement.pipe_to == 'less'
+    assert statement.pipe_to == ['less']
 
 def test_parse_alias_terminator_no_whitespace(parser):
     line = 'helpalias;'