X-Git-Url: https://git.llucax.com/software/pymin.git/blobdiff_plain/f2571fe7b62abfa67f4b805c266869058647afff..f3eaf59b7f33ce2ab39f853834460e92d2e1ca76:/pymin/dispatcher.py

diff --git a/pymin/dispatcher.py b/pymin/dispatcher.py
index 7e9ef60..0d28cb3 100644
--- a/pymin/dispatcher.py
+++ b/pymin/dispatcher.py
@@ -7,7 +7,11 @@ It's based on Zope or Cherrypy dispatching (but implemented from the scratch)
 and translates commands to functions/objects/methods.
 """
 
-__ALL__ = ('Error', 'HandlerError', 'CommandNotFoundError', 'Handler',
+import re
+import inspect
+import logging ; log = logging.getLogger('pymin.dispatcher')
+
+__all__ = ('Error', 'HandlerError', 'CommandNotFoundError', 'Handler',
             'Dispatcher', 'handler', 'is_handler', 'get_help')
 
 class Error(RuntimeError):
@@ -19,7 +23,16 @@ class Error(RuntimeError):
     command - is the command that raised the exception, expressed as a list of
               paths (or subcommands).
     """
-    pass
+
+    def __init__(self, message):
+        r"Initialize the Error object. See class documentation for more info."
+        self.message = message
+
+    def __unicode__(self):
+        return self.message
+
+    def __str__(self):
+        return unicode(self).encode('utf-8')
 
 class HandlerError(Error):
     r"""HandlerError(command) -> HandlerError instance :: Base handlers error.
@@ -37,25 +50,104 @@ class CommandError(Error):
     """
 
     def __init__(self, command):
-        r"""Initialize the object.
-
-        See class documentation for more info.
-        """
+        r"Initialize the object, see class documentation for more info."
         self.command = command
 
-    def __str__(self):
-        return 'Command error: "%s"' % self.command
+    def __unicode__(self):
+        return u'Error in command "%s".' % u' '.join(self.command)
+
+class WrongArgumentsError(CommandError):
+    r"""WrongArgumentsError(handler, error) -> WrongArgumentsError instance.
+
+    This exception is raised when an empty command string is received.
+    """
+
+    def __init__(self, handler, error):
+        r"Initialize the object, see class documentation for more info."
+        self.handler = handler
+        self.error = error
+
+    args_re = re.compile(r'\w+\(\) takes (.+) (\d+) \w+ \((\d+) given\)')
+
+    extra_kw_re = re.compile(r'\w+\(\) got an unexpected keyword argument (.+)')
+
+    dup_kw_re = re.compile(r'\w+\(\) got multiple values for keyword argument '
+                            r"'(.+)'")
+
+    def format(self):
+        r"format() -> unicode - Format a TypeError to adapt it to a command."
+        m = self.args_re.match(unicode(self.error))
+        if m:
+            (quant, n_ok, n_bad)  = m.groups()
+            n_ok = int(n_ok)
+            n_bad = int(n_bad)
+            n_ok -= 1
+            n_bad -= 1
+            pl = ''
+            if n_ok != 1:
+                pl = 's'
+            return u'takes %s %s argument%s, %s given' \
+                        % (quant, n_ok, pl, n_bad)
+        m = self.extra_kw_re.match(unicode(self.error))
+        if m:
+            (kw,)  = m.groups()
+            return u'got an unexpected keyword argument %s' % kw
+        m = self.dup_kw_re.match(unicode(self.error))
+        if m:
+            (kw,)  = m.groups()
+            return u'got multiple values for argument %s' % kw
+        return u'got wrong arguments'
+
+    def __unicode__(self):
+        return u'Command "%s" %s.' % (self.handler.__name__, self.format())
+
+class CommandNotSpecifiedError(CommandError):
+    r"""CommandNotSpecifiedError() -> CommandNotSpecifiedError instance.
+
+    This exception is raised when an empty command string is received.
+    """
+
+    def __init__(self):
+        r"Initialize the object, see class documentation for more info."
+        pass
+
+    def __unicode__(self):
+        return u'Command not specified.'
+
+class CommandIsAHandlerError(CommandError):
+    r"""CommandIsAHandlerError() -> CommandIsAHandlerError instance.
+
+    This exception is raised when a command is a handler containing commands
+    instead of a command itself.
+    """
+
+    def __unicode__(self):
+        command = ' '.join(self.command)
+        return u'"%s" is a handler, not a command (type "%s help" for help).' \
+                    % (command, command)
+
+class CommandNotInHandlerError(CommandError):
+    r"""CommandNotInHandlerError() -> CommandNotInHandlerError instance.
+
+    This exception is raised when a command parent is a hanlder containing
+    commands, but the command itself is not found.
+    """
+
+    def __unicode__(self):
+        return u'Command "%(c)s" not found in handler "%(h)s" ' \
+                u'(type "%(h)s help" for help).' \
+                        % dict(c=u' '.join(self.command[-1:]),
+                                h=u' '.join(self.command[0:-1]))
 
 class CommandNotFoundError(CommandError):
-    r"""CommandNotFoundError(command) -> CommandNotFoundError instance.
+    r"""CommandNotFoundError(command[, handler]) -> CommandNotFoundError object.
 
     This exception is raised when the command received can't be dispatched
     because there is no handlers to process it.
     """
 
-    def __str__(self):
-        return 'Command not found: "%s"' % ' '.join(
-                                                repr(c) for c in self.command)
+    def __unicode__(self):
+        return u'Command "%s" not found.' % u' '.join(self.command)
 
 class ParseError(CommandError):
     r"""ParseError(command[, desc]) -> ParseError instance
@@ -75,8 +167,26 @@ class ParseError(CommandError):
         self.command = command
         self.desc = desc
 
-    def __str__(self):
-        return 'Syntax error, %s: %s' % (self.desc, self.command)
+    def __unicode__(self):
+        return u'Syntax error, %s: %s' % (self.desc, self.command)
+
+class HelpNotFoundError(Error):
+    r"""HelpNotFoundError(command) -> HelpNotFoundError instance.
+
+    This exception is raised when a help command can't find the command
+    asked for help.
+    """
+
+    def __init__(self, command):
+        r"""Initialize the object.
+
+        See class documentation for more info.
+        """
+        self.command = command
+
+    def __unicode__(self):
+        return u"Can't get help for '%s', command not found." % self.command
+
 
 def handler(help):
     r"""handler(help) -> function wrapper :: Mark a callable as a handler.
@@ -85,36 +195,74 @@ def handler(help):
 
     help - Help string for the handler.
     """
-    def wrapper(f):
-        if not help:
-            raise TypeError("'help' should not be empty")
-        f._dispatcher_help = help
-        return f
-    return wrapper
+    if not help:
+        raise TypeError("'help' should not be empty")
+    def make_wrapper(f):
+        log.debug('handler(): Decorating %s()', f.__name__)
+        # Here comes the tricky part:
+        # We need to make our wrapped function to accept any number of
+        # positional and keyword arguments, but checking for the correct
+        # arguments and raising an exception in case the arguments doesn't
+        # match.
+        # So we create a dummy function, with the same signature as the
+        # wrapped one, so we can check later (at "dispatch-time") if the
+        # real function call will be successful. If the dummy function don't
+        # raise a TypeError, the arguments are just fine.
+        env = dict()
+        argspec = inspect.getargspec(f)
+        signature = inspect.formatargspec(*argspec)
+        # The dummy function
+        exec "def f%s: pass" % signature in env
+        signature_check = env['f']
+        # The wrapper to check the signature at "dispatch-time"
+        def wrapper(*args, **kwargs):
+            # First we check if the arguments passed are OK.
+            try:
+                signature_check(*args, **kwargs)
+            except TypeError, e:
+                # If not, we raise an appropriate error.
+                raise WrongArgumentsError(f, e)
+            # If they are fine, we call the real function
+            return f(*args, **kwargs)
+        # Some flag to mark our handlers for simple checks
+        wrapper._dispatcher_handler = True
+        # The help string we asked for in the first place =)
+        wrapper.handler_help = help
+        # We store the original signature for better help generation
+        wrapper.handler_argspec = argspec
+        # And some makeup, to make our wrapper look like the original function
+        wrapper.__name__ = f.__name__
+        wrapper.__dict__.update(f.__dict__)
+        # We add a hint in the documentation
+        wrapper.__doc__ = "Pymin handler with signature: %s%s" \
+                            % (wrapper.__name__, signature)
+        if f.__doc__ is not None:
+            wrapper.__doc__ += "\n\n" + f.__doc__
+        wrapper.__module__ = f.__module__
+        return wrapper
+    return make_wrapper
 
 def is_handler(handler):
     r"is_handler(handler) -> bool :: Tell if a object is a handler."
-    return callable(handler) and hasattr(handler, '_dispatcher_help')
-
-def get_help(handler):
-    r"get_help(handler) -> unicode :: Get a handler's help string."
-    if not is_handler(handler):
-        raise TypeError("'%s' should be a handler" % handler.__name__)
-    return handler._dispatcher_help
+    return callable(handler) and hasattr(handler, '_dispatcher_handler') \
+                and handler._dispatcher_handler
 
 class Handler:
     r"""Handler() -> Handler instance :: Base class for all dispatcher handlers.
 
     All dispatcher handlers should inherit from this class to have some extra
-    commands, like help.
+    commands, like help. You should override the 'handler_help' attribute to a
+    nice help message describing the handler.
     """
 
-    @handler(u'List available commands.')
+    handler_help = u'Undocumented handler'
+
+    @handler(u'List available commands')
     def commands(self):
         r"""commands() -> generator :: List the available commands."""
         return (a for a in dir(self) if is_handler(getattr(self, a)))
 
-    @handler(u'Show available commands with their help.')
+    @handler(u'Show available commands with their help')
     def help(self, command=None):
         r"""help([command]) -> unicode/dict :: Show help on available commands.
 
@@ -123,14 +271,33 @@ class Handler:
         and values are the help strings.
         """
         if command is None:
-            return dict((a, get_help(getattr(self, a)))
-                        for a in dir(self) if is_handler(getattr(self, a)))
-        if not hasattr(self, command):
-            raise CommandNotFoundError(command)
-        handler = getattr(self, command)
-        if not is_handler(handler):
-            raise CommandNotFoundError(command)
-        return get_help(handler)
+            d = dict()
+            for a in dir(self):
+                h = getattr(self, a)
+                if a == 'parent': continue # Skip parents in SubHandlers
+                if is_handler(h) or isinstance(h, Handler):
+                    d[a] = h.handler_help
+            return d
+        # A command was specified
+        if command == 'parent': # Skip parents in SubHandlers
+            raise HelpNotFoundError(command)
+        if not hasattr(self, command.encode('utf-8')):
+            raise HelpNotFoundError(command)
+        handler = getattr(self, command.encode('utf-8'))
+        if not is_handler(handler) and not hasattr(handler, 'handler_help'):
+            raise HelpNotFoundError(command)
+        return handler.handler_help
+
+    def handle_timer(self):
+        r"""handle_timer() -> None :: Do periodic tasks.
+
+        By default we do nothing but calling handle_timer() on subhandlers.
+        """
+        for a in dir(self):
+            if a == 'parent': continue # Skip parents in SubHandlers
+            h = getattr(self, a)
+            if isinstance(h, Handler):
+                h.handle_timer()
 
 def parse_command(command):
     r"""parse_command(command) -> (args, kwargs) :: Parse a command.
@@ -158,6 +325,8 @@ def parse_command(command):
     arguments is preserved and if there are multiple keyword arguments with
     the same key, the last value is the winner (all other values are lost).
 
+    The command should be a unicode string.
+
     Examples:
 
     >>> parse_command('hello world')
@@ -185,6 +354,12 @@ def parse_command(command):
     ([u'=hello'], {})
     >>> parse_command(r'\thello')
     ([u'\thello'], {})
+    >>> parse_command(r'hello \n')
+    ([u'hello', u'\n'], {})
+    >>> parse_command(r'hello \nmundo')
+    ([u'hello', u'\nmundo'], {})
+    >>> parse_command(r'test \N')
+    ([u'test', None], {})
     >>> parse_command(r'\N')
     ([None], {})
     >>> parse_command(r'none=\N')
@@ -209,9 +384,23 @@ def parse_command(command):
     escape = False
     keyword = None
     state = SEP
+    def register_token(buff, keyword, seq, dic):
+        if buff == r'\N':
+            buff = None
+        if keyword is not None:
+            dic[keyword.encode('utf-8')] = buff
+            keyword = None
+        else:
+            seq.append(buff)
+        buff = u''
+        return (buff, keyword)
     for n, c in enumerate(command):
         # Escaped character
         if escape:
+            # Not yet registered the token
+            if state == SEP and buff:
+                (buff, keyword) = register_token(buff, keyword, seq, dic)
+                state = TOKEN
             for e in escaped_chars:
                 if c == e:
                     buff += eval(u'"\\' + e + u'"')
@@ -236,14 +425,7 @@ def parse_command(command):
                     keyword = buff
                     buff = u''
                     continue
-                if buff == r'\N':
-                    buff = None
-                if keyword is not None: # Value found
-                    dic[str(keyword)] = buff
-                    keyword = None
-                else: # Normal parameter found
-                    seq.append(buff)
-                buff = u''
+                (buff, keyword) = register_token(buff, keyword, seq, dic)
             state = TOKEN
         # Getting a token
         if state == TOKEN:
@@ -285,12 +467,7 @@ def parse_command(command):
         raise ParseError(command,
                         u'keyword argument (%s) without value' % keyword)
     if buff:
-        if buff == r'\N':
-            buff = None
-        if keyword is not None:
-            dic[str(keyword)] = buff
-        else:
-            seq.append(buff)
+        register_token(buff, keyword, seq, dic)
     return (seq, dic)
 
 class Dispatcher:
@@ -318,9 +495,7 @@ class Dispatcher:
     'arg1', 'arg 2', arg=3) will be called. The handler "tree" can be as
     complex and deep as you want.
 
-    If some command can't be dispatched (because there is no root handler
-    or there is no matching callable attribute), a CommandNotFoundError
-    is raised.
+    If some command can't be dispatched, a CommandError subclass is raised.
     """
 
     def __init__(self, root):
@@ -328,49 +503,79 @@ class Dispatcher:
 
         See Dispatcher class documentation for more info.
         """
+        log.debug(u'Dispatcher(%r)', root)
         self.root = root
 
     def dispatch(self, route):
         r"""dispatch(route) -> None :: Dispatch a command string.
 
         This method searches for a suitable callable object in the routes
-        "tree" and call it, or raises a CommandNotFoundError if the command
+        "tree" and call it, or raises a CommandError subclass if the command
         can't be dispatched.
+
+        route - *unicode* string with the command route.
         """
+        log.debug('Dispatcher.dispatch(%r)', route)
         command = list()
         (route, kwargs) = parse_command(route)
+        log.debug(u'Dispatcher.dispatch: route=%r, kwargs=%r', route, kwargs)
         if not route:
-            raise CommandNotFoundError(command)
+            log.debug(u'Dispatcher.dispatch: command not specified')
+            raise CommandNotSpecifiedError()
         handler = self.root
         while not is_handler(handler):
+            log.debug(u'Dispatcher.dispatch: handler=%r, route=%r',
+                        handler, route)
             if len(route) is 0:
+                if isinstance(handler, Handler):
+                    log.debug(u'Dispatcher.dispatch: command is a handler')
+                    raise CommandIsAHandlerError(command)
+                log.debug(u'Dispatcher.dispatch: command not found')
                 raise CommandNotFoundError(command)
             command.append(route[0])
-            if not hasattr(handler, route[0]):
+            log.debug(u'Dispatcher.dispatch: command=%r', command)
+            if route[0] == 'parent':
+                log.debug(u'Dispatcher.dispatch: is parent => not found')
+                raise CommandNotFoundError(command)
+            if not hasattr(handler, route[0].encode('utf-8')):
+                if isinstance(handler, Handler) and len(command) > 1:
+                    log.debug(u'Dispatcher.dispatch: command not in handler')
+                    raise CommandNotInHandlerError(command)
+                log.debug(u'Dispatcher.dispatch: command not found')
                 raise CommandNotFoundError(command)
-            handler = getattr(handler, route[0])
+            handler = getattr(handler, route[0].encode('utf-8'))
             route = route[1:]
-        return handler(*route, **kwargs)
+        log.debug(u'Dispatcher.dispatch: %r is a handler, calling it with '
+                    u'route=%r, kwargs=%r', handler, route, kwargs)
+        r = handler(*route, **kwargs)
+        log.debug(u'Dispatcher.dispatch: handler returned %s', r)
+        return r
 
 
 if __name__ == '__main__':
 
-    @handler(u"test: Print all the arguments, return nothing.")
+    logging.basicConfig(
+        level   = logging.DEBUG,
+        format  = '%(asctime)s %(levelname)-8s %(message)s',
+        datefmt = '%H:%M:%S',
+    )
+
+    @handler(u"test: Print all the arguments, return nothing")
     def test_func(*args):
         print 'func:', args
 
     class TestClassSubHandler(Handler):
-        @handler(u"subcmd: Print all the arguments, return nothing.")
+        @handler(u"subcmd: Print all the arguments, return nothing")
         def subcmd(self, *args):
             print 'class.subclass.subcmd:', args
 
     class TestClass(Handler):
-        @handler(u"cmd1: Print all the arguments, return nothing.")
+        @handler(u"cmd1: Print all the arguments, return nothing")
         def cmd1(self, *args):
             print 'class.cmd1:', args
-        @handler(u"cmd2: Print all the arguments, return nothing.")
-        def cmd2(self, *args):
-            print 'class.cmd2:', args
+        @handler(u"cmd2: Print all the arguments, return nothing")
+        def cmd2(self, arg1, arg2):
+            print 'class.cmd2:', arg1, arg2
         subclass = TestClassSubHandler()
 
     class RootHandler(Handler):
@@ -379,25 +584,74 @@ if __name__ == '__main__':
 
     d = Dispatcher(RootHandler())
 
-    d.dispatch(r'''func arg1 arg2 arg3 "fourth 'argument' with \", a\ttab and\n\\n"''')
-    print 'inst commands:', tuple(d.dispatch('inst commands'))
-    print 'inst help:', d.dispatch('inst help')
-    d.dispatch('inst cmd1 arg1 arg2 arg3 arg4')
-    d.dispatch('inst cmd2 arg1 arg2')
-    print 'inst subclass help:', d.dispatch('inst subclass help')
-    d.dispatch('inst subclass subcmd arg1 arg2 arg3 arg4 arg5')
+    r = d.dispatch(r'''func arg1 arg2 arg3 "fourth 'argument' with \", a\ttab and\n\\n"''')
+    assert r is None
+    r = list(d.dispatch('inst commands'))
+    r.sort()
+    assert r == ['cmd1', 'cmd2', 'commands', 'help']
+    print 'inst commands:', r
+    r = d.dispatch('inst help')
+    assert r == {
+                'commands': u'List available commands',
+                'subclass': u'Undocumented handler',
+                'cmd1': u'cmd1: Print all the arguments, return nothing',
+                'cmd2': u'cmd2: Print all the arguments, return nothing',
+                'help': u'Show available commands with their help'
+    }
+    print 'inst help:', r
+    r = d.dispatch('inst cmd1 arg1 arg2 arg3 arg4')
+    assert r is None
+    r = d.dispatch('inst cmd2 arg1 arg2')
+    assert r is None
+    r = d.dispatch('inst subclass help')
+    assert r == {
+                'subcmd': u'subcmd: Print all the arguments, return nothing',
+                'commands': u'List available commands',
+                'help': u'Show available commands with their help'
+    }
+    print 'inst subclass help:', r
+    r = d.dispatch('inst subclass subcmd arg1 arg2 arg3 arg4 arg5')
+    assert r is None
     try:
         d.dispatch('')
-    except CommandNotFoundError, e:
+        assert False, 'It should raised a CommandNotSpecifiedError'
+    except CommandNotSpecifiedError, e:
         print 'Not found:', e
     try:
         d.dispatch('sucutrule piquete culete')
+        assert False, 'It should raised a CommandNotFoundError'
     except CommandNotFoundError, e:
         print 'Not found:', e
     try:
         d.dispatch('inst cmd3 arg1 arg2 arg3')
-    except CommandNotFoundError, e:
+        assert False, 'It should raised a CommandNotInHandlerError'
+    except CommandNotInHandlerError, e:
+        print 'Not found:', e
+    try:
+        d.dispatch('inst')
+        assert False, 'It should raised a CommandIsAHandlerError'
+    except CommandIsAHandlerError, e:
         print 'Not found:', e
+    try:
+        d.dispatch('inst cmd2 "just one arg"')
+        assert False, 'It should raised a WrongArgumentsError'
+    except WrongArgumentsError, e:
+        print 'Bad arguments:', e
+    try:
+        d.dispatch('inst cmd2 arg1 arg2 "an extra argument"')
+        assert False, 'It should raised a WrongArgumentsError'
+    except WrongArgumentsError, e:
+        print 'Bad arguments:', e
+    try:
+        d.dispatch('inst cmd2 arg1 arg2 arg3="unexpected keyword arg"')
+        assert False, 'It should raised a WrongArgumentsError'
+    except WrongArgumentsError, e:
+        print 'Bad arguments:', e
+    try:
+        d.dispatch('inst cmd2 arg1 arg2 arg2="duplicated keyword arg"')
+        assert False, 'It should raised a WrongArgumentsError'
+    except WrongArgumentsError, e:
+        print 'Bad arguments:', e
     print
     print
 
@@ -428,6 +682,12 @@ if __name__ == '__main__':
     assert p == ([u'=hello'], {}), p
     p = parse_command(r'\thello')
     assert p == ([u'\thello'], {}), p
+    p = parse_command(r'hello \n')
+    assert p == ([u'hello', u'\n'], {}), p
+    p = parse_command(r'hello \nmundo')
+    assert p == ([u'hello', u'\nmundo'], {}), p
+    p = parse_command(r'test \N')
+    assert p == ([u'test', None], {}), p
     p = parse_command(r'\N')
     assert p == ([None], {}), p
     p = parse_command(r'none=\N')
@@ -440,14 +700,12 @@ if __name__ == '__main__':
     assert p == ([u'\\None'], {}), p
     try:
         p = parse_command('hello=')
+        assert False, p + ' should raised a ParseError'
     except ParseError, e:
         pass
-    else:
-        assert False, p + ' should raised a ParseError'
     try:
         p = parse_command('"hello')
+        assert False, p + ' should raised a ParseError'
     except ParseError, e:
         pass
-    else:
-        assert False, p + ' should raised a ParseError'