Clamp mark titles to 255 chars before DB writes

Author: homoludens

README.md

@@ -2,6 +2,11 @@ Flaskmarks
 ===============
 Simple (and self educational) [Flask](http://flask.pocoo.org/) & [SQLAlchemy](http://www.sqlalchemy.org/) based bookmark and RSS feed app.
 
+Recent Technical Changes
+========================
+- `Mark.title` is now clamped to 255 characters at the model layer before database writes.
+- This prevents PostgreSQL errors like `value too long for type character varying(255)` across API, quickadd async metadata updates, imports, and UI edits.
+
 Features
 ========
 "Flaskmarks" is a bookmark managing application. Its purpose is to be a all-in-one bookmark and RSS feed repository. Storing all bookmarks and RSS feeds in one place and make them accessible from all platforms and devices. This is by no means an original idea, but this is an interpretation of the problem.
@@ -62,7 +67,8 @@ GROQ_API_KEY=your-groq-api-key
 Generate a bcrypt password hash (useful for manual database updates):
 
 ```bash
-python -c "from flaskmarks import create_app; from flaskmarks.core.extensions import bcrypt; app=create_app(); with app.app_context(): print(bcrypt.generate_password_hash('YOUR_PASSWORD').decode('utf-8'))"
+python -c "from flaskmarks import create_app; from flaskmarks.core.extensions import bcrypt; app=create_app(); ctx=app.app_context(); ctx.push(); print(bcrypt.generate_password_hash('YOUR_PASSWORD').decode('utf-8')); ctx.pop()"
+
 ```
 
 ## Development with Docker

flaskmarks/models/mark.py

@@ -9,7 +9,7 @@
 from sqlalchemy import event, Column, Text, Computed
 from sqlalchemy.sql import func
 # from sqlalchemy.dialects.mysql import LONGTEXT
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import relationship, validates
 from sqlalchemy.dialects.postgresql import TSVECTOR
 from pgvector.sqlalchemy import Vector
 # from sqlalchemy_fulltext import FullText
@@ -75,6 +75,7 @@ class Mark(db.Model):
 
     valid_types = ['bookmark', 'feed', 'youtube']
     valid_feed_types = ['feed', 'youtube']
+    max_title_length = 255
 
     def __init__(self, owner_id: int, created: dt | None = None) -> None:
         """
@@ -123,6 +124,18 @@ def insert_from_import(self, data: dict[str, Any]) -> None:
     def __repr__(self) -> str:
         return f'<Mark {self.title!r}>'
 
+    @staticmethod
+    def clamp_title_length(value: Any) -> str | None:
+        """Ensure titles always fit in the DB column constraint."""
+        if value is None:
+            return None
+        return str(value)[:Mark.max_title_length]
+
+    @validates('title')
+    def validate_title_length(self, key: str, value: Any) -> str | None:
+        """Clamp title before any insert/update so DB writes cannot overflow."""
+        return self.clamp_title_length(value)
+
     def get_embedding_text(self) -> str:
         """
         Generate the text to be embedded for this mark.