Provide a way to display CLI-LDAP relation

Since some LDAP attributes have their cli_name value defined,
so they can be more user friendly, it can be difficult for user to find
out which attributes do the parameteres given to CLI really represent.
This patch provides new command, which will take another IPA command as
and argument and display attributes which given command takes and what
LDAP attributes are they mapped to.

https://fedorahosted.org/freeipa/ticket/447

ipalib/cli.py

@@ -47,7 +47,7 @@ import plugable
 import util
 from errors import PublicError, CommandError, HelpError, InternalError, NoSuchNamespaceError, ValidationError, NotFound, NotConfiguredError
 from constants import CLI_TAB
-from parameters import Password, Bytes, File
+from parameters import Password, Bytes, File, Str
 from text import _
 from ipapython.version import API_VERSION
 
@@ -767,6 +767,30 @@ class help(frontend.Local):
                     print '  %s  %s' % (to_cli(c.name).ljust(mcl), c.summary)
             print "\n"
 
+class show_mappings(frontend.Command):
+    takes_args = (
+        Str('command_name',
+            label=_('Command name'),
+        ),
+    )
+    has_output = tuple()
+
+    def run(self, command_name):
+        command_name = from_cli(command_name)
+        if command_name not in self.Command:
+            raise CommandError(name=command_name)
+        params = self.Command[command_name].options
+        out = [('Parameter','LDAP attribute'),
+               ('=========','==============')]
+        mcl = len(out[0][0])
+        for param in params():
+            if param.exclude and 'webui' in param.exclude:
+                continue
+            out.append((param.cli_name, param.param_spec))
+            mcl = max(mcl,len(param.cli_name))
+        for item in out:
+            print to_cli(item[0]).ljust(mcl)+' : '+item[1]
+
 
 class console(frontend.Command):
     """Start the IPA interactive Python console."""
@@ -1045,6 +1069,7 @@ cli_plugins = (
     textui,
     console,
     help,
+    show_mappings,
 )