From 8f1cdf7a6eb9d91283e153a2aeffae492ba879bb Mon Sep 17 00:00:00 2001
From: Emily Frost <emfrost@posteo.net>
Date: Mon, 6 Jun 2022 07:38:55 -0500
Subject: [PATCH] Classified the loose functions in metadata.py

---
 metadata.py | 138 +++++++++++++++++++++++++---------------------------
 1 file changed, 66 insertions(+), 72 deletions(-)

diff --git a/metadata.py b/metadata.py
index 1305535..526b535 100644
--- a/metadata.py
+++ b/metadata.py
@@ -14,20 +14,8 @@ import sqlalchemy.orm
 # TODO: l o g g i n g
 HASH_CHUNK_SIZE = 10485760 # 10mb
 
-db_session = None
-
-_db_session_maker = sqlalchemy.orm.sessionmaker()
-_engine = None
-_configured = False
 _SQLBase = sqlalchemy.ext.declarative.declarative_base()
 
-class MetadataDBSessionException(Exception):
-	'''This exception is raised when something goes wrong with a database session.'''
-
-
-def _uuidgen():
-	return str(uuid.uuid4())
-
 '''
 Metadata ORM classes for SQLAlchemy. For a detailed description of each piece of data, refer to
 metadata/README.md
@@ -112,63 +100,69 @@ class Image(_SQLBase):
 				)
 			)
 
-
-'''
-# TODO: I was attempting to avoid writing a class to see if I could, but it is not worth the clunk.
-Rewrite these functions into a class.
-'''
-
-def configure(db_path):
-	'''
-	Configure and initialize the database for the entire module.
-	Currently, only SQLite is supported.
-
-	db_path: Path for the SQLite database
-	'''
-	_engine = sqlalchemy.create_engine('sqlite:///%s' % db_path)
-
-	_SQLBase.metadata.create_all(_engine)
-	_db_session_maker.configure(bind=_engine)
-	_configured = True
-
-def search(session, table_object, **constraints):
-	'''
-	Search the database for entries matching the given constraints.
-
-	session: SQLAlchemy session, presumably from get_db_session
-	table_object: SQLAlchemy ORM table object, defined in the file above
-	constraints: key-value pairs to match against specific fields in the database
-				Note: Currently, only the query.ilike method is supported. This is intended to
-				eventually support the entire range of available filters.
-	'''
-	query = session.query(table_object)
-
-	for key, value in constraints.items():
-		query = query.filter(getattr(table_object, key).ilike('%%%s%%' % value))
-
-	item_list = []
-	for item in query:
-		item_list.append(item)
-
-	return item_list
-
-@contextlib.contextmanager
-def get_db_session():
-	'''Get a SQLAlchemy database session with a proper context object. '''
-	# TODO: There's probably a more reliable way of knowing whether the database was configured.
-	if not _configured:
-		raise MetadataDBSessionException('Tried to get session without configuring a database.')
-
-	session = _db_session_maker()
-	try:
-		yield session
-
-	except:
-		# TODO: Decide which exceptions to handle/eat here and which ones belong in UI.
-		#   This one is okay to put off until you start really building UI.
-		session.rollback()
-		raise
-	else:
-		session.commit()
-	finally:
-		session.close()
+class hashdb:
+	_engine = None
+
+	# TODO: db_path's default should be set here, not in frontend.
+	def __init__(self, db_path):
+		'''
+		Configure and initialize the database for the entire module.
+		Currently, only SQLite is supported.
+
+		db_path: Path for the SQLite database
+		'''
+		self._engine = sqlalchemy.create_engine('sqlite:///%s' % db_path)
+
+		_SQLBase.metadata.create_all(self._engine)
+		self._session_maker.configure(bind=self._engine)
+
+	def search(self, table_object, **constraints):
+		'''
+		Search the database for entries matching the given constraints.
+
+		table_object: SQLAlchemy ORM table object, defined in the file above
+		constraints: key-value pairs to match against specific fields in the database
+					Note: Currently, only the query.ilike method is supported. This is intended to
+					eventually support the entire range of available filters.
+		'''
+
+		with self._get_db_session() as session:
+			# TODO: Consider making this return data recursively on items that reference other
+			#	tables.
+			query = session.query(table_object)
+
+			for key, value in constraints.items():
+				query = query.filter(getattr(table_object, key).ilike('%%%s%%' % value))
+
+			item_list = []
+			for item in query:
+				item_list.append(item)
+
+		return item_list
+
+	def import_json(self, json_file):
+		'''
+		Import metadata from a json file.
+		'''
+
+		# json files can be large, but not too large for ram
+		# do not exit on invalid metadata, log the error and skip the object
+		pass
+
+	@contextlib.contextmanager
+	def _get_db_session():
+		'''Get a SQLAlchemy database session with a proper context object. '''
+
+		session = sqlalchemy.orm.sessionmaker()
+		try:
+			yield session
+
+		except:
+			# TODO: Decide which exceptions to handle/eat here and which ones belong in UI.
+			#   This one is okay to put off until you start really building UI.
+			session.rollback()
+			raise
+		else:
+			session.commit()
+		finally:
+			session.close()