add one_or_404 method to BaseQuery

docs/queries.rst

@@ -116,11 +116,15 @@ Queries in Views
 
 If you write a Flask view function it's often very handy to return a 404
 error for missing entries.  Because this is a very common idiom,
-Flask-SQLAlchemy provides a helper for this exact purpose.  Instead of
-:meth:`~sqlalchemy.orm.query.Query.get` one can use
-:meth:`~Query.get_or_404` and instead of 
-:meth:`~sqlalchemy.orm.query.Query.first` :meth:`~Query.first_or_404`.
-This will raise 404 errors instead of returning `None`::
+Flask-SQLAlchemy provides helpers for this exact purpose.
+
+Instead of :meth:`~sqlalchemy.orm.query.Query.get` one can use
+:meth:`~Query.get_or_404`, instead of 
+:meth:`~sqlalchemy.orm.query.Query.first` use :meth:`~Query.first_or_404`,
+and instead of :meth:`~sqlalchemy.orm.query.Query.one_or_none` use 
+:meth:`~Query.one_or_404`.
+
+These methods will raise 404 errors instead of returning `None`::
 
     @app.route('/user/<username>')
     def show_user(username):

flask_sqlalchemy/__init__.py

@@ -426,6 +426,14 @@ def first_or_404(self):
         if rv is None:
             abort(404)
         return rv
+
+    def one_or_404(self):
+        """Like :meth:`one_or_none` but aborts with 404 if not found instead of returning ``None``."""
+
+        rv = self.one_or_none()
+        if rv is None:
+            abort(404)
+        return rv
 
     def paginate(self, page=None, per_page=None, error_out=True):
         """Returns ``per_page`` items from page ``page``.