Emit user-catchable exceptions instead of just ValueError where possi…

…ble (Closes: #45)

django_slack/exceptions.py

@@ -0,0 +1,45 @@
+class SlackException(ValueError):
+    pass
+
+class ChannelNotFound(SlackException):
+    pass
+
+class IsArchived(SlackException):
+    pass
+
+class MsgTooLong(SlackException):
+    pass
+
+class NoText(SlackException):
+    pass
+
+class RateLimited(SlackException):
+    pass
+
+class NotAuthed(SlackException):
+    pass
+
+class InvalidAuth(SlackException):
+    pass
+
+class TokenRevoked(SlackException):
+    pass
+
+class AccountInactive(SlackException):
+    pass
+
+class UserIsBot(SlackException):
+    pass
+
+LABEL_TO_EXCEPTION = {
+    'channel_not_found': ChannelNotFound,
+    'is_archived': IsArchived,
+    'msg_too_long': MsgTooLong,
+    'no_text': NoText,
+    'rate_limited': RateLimited,
+    'not_authed': NotAuthed,
+    'invalid_auth': InvalidAuth,
+    'token_revoked': TokenRevoked,
+    'account_inactive': AccountInactive,
+    'user_is_bot': UserIsBot,
+}

django_slack/utils.py

@@ -2,6 +2,7 @@
 
 from django.utils.module_loading import import_string
 
+from .exceptions import LABEL_TO_EXCEPTION, SlackException
 from .app_settings import app_settings
 
 class Backend(object):
@@ -13,10 +14,12 @@ def validate(self, content_type, content):
             result = json.loads(content)
 
             if not result['ok']:
-                raise ValueError(result['error'])
+                klass = LABEL_TO_EXCEPTION.get(result['error'], SlackException)
+
+                raise klass(result['error'])
 
         elif content != 'ok':
-            raise ValueError(content)
+            raise SlackException(content)
 
 def get_backend():
     """