add Base.as_dict() and Base.json()

Two utility functions for all of our ORM models that will
allow us to easily convert them to Python structures and
JSON data.

Signed-off-by: Kevin Morris <kevr@0cost.org>

aurweb/models/declarative.py

@@ -1,10 +1,40 @@
+import json
+
 from sqlalchemy.ext.declarative import declarative_base
 
 import aurweb.db
 
+from aurweb import util
+
+
+def to_dict(model):
+    return {
+        c.name: getattr(model, c.name)
+        for c in model.__table__.columns
+    }
+
+
+def to_json(model, indent: int = None):
+    return json.dumps({
+        k: util.jsonify(v)
+        for k, v in to_dict(model).items()
+    }, indent=indent)
+
+
 Base = declarative_base()
+
+# Setup __table_args__ applicable to every table.
 Base.__table_args__ = {
     "autoload": True,
     "autoload_with": aurweb.db.get_engine(),
     "extend_existing": True
 }
+
+
+# Setup Base.as_dict and Base.json.
+#
+# With this, declarative models can use .as_dict() or .json()
+# at any time to produce a dict and json out of table columns.
+#
+Base.as_dict = to_dict
+Base.json = to_json