begin cli work

cli/db.py

@@ -0,0 +1,46 @@
+import psycopg2
+import psycopg2.extras
+from loguru import logger
+
+
+class NoDataFoundException(Exception): pass
+
+class TooMuchDataFoundException(Exception): pass
+
+
+def execDatabaseOperation(dbh, func, params):
+    cur = None
+    try:
+        with dbh.cursor(cursor_factory = psycopg2.extras.RealDictCursor) as cur:
+            params["params"] = [ v if not v=='' else None for v in params["params"] ]
+            logger.debug("edo: {}".format(str(params)))
+            return func(cur, params)
+    except psycopg2.Error as err:
+        raise Exception("Error when working on cursor: {}".format(err))
+
+
+
+def _opGetMany(cursor, params):
+    items = []
+    cursor.execute(params["statement"], params["params"])
+    for itemObj in cursor:
+        logger.debug("item received {}".format(str(itemObj)))
+        items.append(itemObj)
+    return items
+
+def dbGetMany(dbh, params):
+    return execDatabaseOperation(dbh, _opGetMany, params)
+
+def _opGetOne(cursor, params):
+    cursor.execute(params["statement"], params["params"])
+    itemObj = cursor.fetchone()
+    logger.debug(f"item received: {itemObj}")
+    if not itemObj:
+        raise NoDataFoundException
+    dummyObj = cursor.fetchone()
+    if dummyObj:
+        raise TooMuchDataFoundException
+    return itemObj
+
+def dbGetOne(dbh, params):
+    return execDatabaseOperation(dbh, _opGetOne, params)