added some helpers in AT_URI

app/at_uri.rb

···
   class InvalidURIError
   end
 
+  TID_PATTERN = /^[234567abcdefghij][234567abcdefghijklmnopqrstuvwxyz]{12}$/
+
   attr_reader :repo, :collection, :rkey
 
   def initialize(uri)
···
 
   def to_s
     @uri
+  end
+
+  def has_valid_tid?
+    @rkey =~ TID_PATTERN
+  end
+
+  def is_post?
+    @collection == 'app.bsky.feed.post' && has_valid_tid?
   end
 end
 

app/importers/base_importer.rb

···
 
   def create_item_for_post(uri)
     post_uri = AT_URI(uri)
-    return if post_uri.collection != 'app.bsky.feed.post' || post_uri.rkey.length != 13
+    return unless post_uri.is_post?
 
     post = Post.find_by(
       user_id: user_id_for_did(post_uri.repo),