New filter: regex (#1028)

telegram/ext/filters.py

@@ -17,6 +17,8 @@
 # You should have received a copy of the GNU Lesser Public License
 # along with this program.  If not, see [http://www.gnu.org/licenses/].
 """This module contains the Filters for use with the MessageHandler class."""
+
+import re
 from telegram import Chat
 from future.utils import string_types
 
@@ -171,6 +173,33 @@ class Filters(object):
     command = _Command()
     """:obj:`Filter`: Messages starting with ``/``."""
 
+    class regex(BaseFilter):
+        """
+        Filters updates by searching for an occurence of ``pattern`` in the message text.
+        The ``re.search`` function is used to determine whether an update should be filtered.
+        Refer to the documentation of the ``re`` module for more information.
+
+        Note: Does not allow passing groups or a groupdict like the ``RegexHandler`` yet,
+        but this will probably be implemented in a future update, gradually phasing out the
+        RegexHandler (see https://github.com/python-telegram-bot/python-telegram-bot/issues/835).
+
+        Examples:
+            Example ``CommandHandler("start", deep_linked_callback, Filters.regex('parameter'))``
+
+        Args:
+            pattern (:obj:`str` | :obj:`Pattern`): The regex pattern.
+        """
+
+        def __init__(self, pattern):
+            self.pattern = re.compile(pattern)
+            self.name = 'Filters.regex({})'.format(self.pattern)
+
+        # TODO: Once the callback revamp (#1026) is done, the regex filter should be able to pass
+        # the matched groups and groupdict to the context object.
+
+        def filter(self, message):
+            return bool(self.pattern.search(message.text))
+
     class _Reply(BaseFilter):
         name = 'Filters.reply'
 

tests/test_filters.py

@@ -22,6 +22,7 @@ import pytest
 
 from telegram import Message, User, Chat, MessageEntity
 from telegram.ext import Filters, BaseFilter
+import re
 
 
 @pytest.fixture(scope='function')
@@ -51,6 +52,22 @@ class TestFilters(object):
         message.text = '/test'
         assert Filters.command(message)
 
+    def test_filters_regex(self, message):
+        message.text = '/start deep-linked param'
+        assert Filters.regex(r'deep-linked param')(message)
+        message.text = '/help'
+        assert Filters.regex(r'help')(message)
+        message.text = '/help'
+        assert Filters.regex('help')(message)
+
+        message.text = 'test'
+        assert not Filters.regex(r'fail')(message)
+        assert Filters.regex(r'test')(message)
+        assert Filters.regex(re.compile(r'test'))(message)
+
+        message.text = 'i love python'
+        assert Filters.regex(r'.\b[lo]{2}ve python')(message)
+
     def test_filters_reply(self, message):
         another_message = Message(1, User(1, 'TestOther', False), datetime.datetime.now(),
                                   Chat(0, 'private'))