register a custom help action that knows how to print the list of commands available and a help command to generate help for the other commands

2 files changed, 49 insertions, 13 deletions

diff --git a/cliff/app.py b/cliff/app.py
index 0610f9e..344d3da 100644
--- a/cliff/app.py
+++ b/cliff/app.py
@@ -7,6 +7,8 @@ import logging.handlers
 import os
 import sys
 
+from .help import HelpAction, HelpCommand
+
 LOG = logging.getLogger(__name__)
 
 
@@ -32,6 +34,7 @@ class App(object):
         :param stderr: Standard error output stream
         """
         self.command_manager = command_manager
+        self.command_manager.add_command('help', HelpCommand)
         self.stdin = stdin or sys.stdin
         self.stdout = stdout or sys.stdout
         self.stderr = stderr or sys.stderr
@@ -68,7 +71,9 @@ class App(object):
             )
         parser.add_argument(
             '-h', '--help',
-            action='help',
+            action=HelpAction,
+            nargs=0,
+            default=self.command_manager,  # tricky
             help="show this help message and exit",
             )
         parser.add_argument(
@@ -79,18 +84,6 @@ class App(object):
             )
         return parser
 
-    def show_verbose_help(self, *args):
-        """Displays the normal syntax info and a list of available subcommands.
-        """
-        self.parser.print_help()
-        print('')
-        print('Commands:')
-        for name, ep in sorted(self.command_manager):
-            factory = ep.load()
-            cmd = factory(self, None)
-            print('  %-13s  %s' % (name, cmd.get_description()))
-        sys.exit(0)
-
     def configure_logging(self):
         """Create logging handlers for any log output.
         """
diff --git a/cliff/help.py b/cliff/help.py
new file mode 100644
index 0000000..f53e61b
--- /dev/null
+++ b/cliff/help.py
@@ -0,0 +1,43 @@
+import argparse
+import sys
+
+from .command import Command
+
+
+class HelpAction(argparse.Action):
+    """Provide a custom action so the -h and --help options
+    to the main app will print a list of the commands.
+
+    The commands are determined by checking the CommandManager
+    instance, passed in as the "default" value for the action.
+    """
+    def __call__(self, parser, namespace, values, option_string=None):
+        parser.print_help()
+        print('')
+        print('Commands:')
+        command_manager = self.default
+        for name, ep in sorted(command_manager):
+            factory = ep.load()
+            cmd = factory(self, None)
+            print('  %-13s  %s' % (name, cmd.get_description()))
+        sys.exit(0)
+
+
+class HelpCommand(Command):
+    def get_parser(self, prog_name):
+        parser = super(HelpCommand, self).get_parser(prog_name)
+        parser.add_argument('cmd',
+                            nargs='*',
+                            help='name of the command',
+                            )
+        return parser
+
+    def run(self, parsed_args):
+        if parsed_args.cmd:
+            cmd_factory, name, search_args = self.app.command_manager.find_command(parsed_args.cmd)
+            cmd = cmd_factory(self.app, search_args)
+            cmd_parser = cmd.get_parser(' '.join([self.app.NAME, name]))
+        else:
+            cmd_parser = self.get_parser(' '.join([self.app.NAME, 'help']))
+        cmd_parser.parse_args(['--help'])
+        return 0