Move url-transformation application to TopicSchema

This was only being done when a new topic was created before, which
meant that if a topic's link was edited, the new link wouldn't go
through the transformation process (and we do want it to).

tildes/tildes/models/topic/topic.py

@@ -32,7 +32,6 @@ from tildes.lib.id import id_to_id36
 from tildes.lib.markdown import convert_markdown_to_safe_html
 from tildes.lib.string import convert_to_url_slug
 from tildes.lib.url import get_domain_from_url, is_tweet
-from tildes.lib.url_transform import apply_url_transformations
 from tildes.metrics import incr_counter
 from tildes.models import DatabaseModel
 from tildes.models.group import Group
@@ -208,7 +207,7 @@ class Topic(DatabaseModel):
         """Create a new link topic."""
         new_topic = cls._create_base_topic(group, author, title)
         new_topic.topic_type = TopicType.LINK
-        new_topic.link = apply_url_transformations(link)
+        new_topic.link = link
         new_topic.original_url = link
 
         incr_counter("topics", type="link")

tildes/tildes/schemas/topic.py

@@ -11,6 +11,7 @@ from marshmallow import pre_load, Schema, validates, validates_schema, Validatio
 from marshmallow.fields import DateTime, List, Nested, String, URL
 import sqlalchemy_utils
 
+from tildes.lib.url_transform import apply_url_transformations
 from tildes.schemas.fields import Enum, ID36, Ltree, Markdown, SimpleString
 from tildes.schemas.group import GroupSchema
 from tildes.schemas.user import UserSchema
@@ -118,6 +119,9 @@ class TopicSchema(Schema):
         if not parsed.scheme:
             data["link"] = "http://" + data["link"]
 
+        # run the link through the url-transformation process
+        data["link"] = apply_url_transformations(data["link"])
+
         return data
 
     @validates_schema