backend.lib.database_mysql

 1"""
 2Database wrapper
 3"""
 4import pymysql.connections as mysqlconnections
 5import pymysql
 6
 7class MySQLDatabase:
 8	"""
 9	Simple database handler for MySQL connections
10
11	4CAT uses PostgreSQL for its database - this MySQL class is available as a
12	convenience for data sources that wish to use the Sphinx full-text search
13	engine via SphinxQL. As such, only methods needed for that (i.e.
14	`fetchall()`) are implemented.
15	"""
16	cursor = None
17	log = None
18
19	def __init__(self, logger=None, dbname=None, user=None, password=None, host=None, port=None):
20		"""
21		Set up database connection
22		"""
23		self.connection = mysqlconnections.Connection(database=dbname, user=user, password=password, host=host, port=port)
24		self.cursor = self.connection.cursor(pymysql.cursors.DictCursor)
25		if logger:
26			self.log = logger
27
28	def mogrify(self, query, replacements):
29		"""
30		Parse a query with replacement variables
31
32		:param str query:  Query
33		:param list replacements:  Replacement variables
34		:return str: Parsed query
35		"""
36		return self.cursor.mogrify(query, replacements)
37
38	def query(self, query, replacements=None):
39		"""
40		Execute a query
41
42		:param string query: Query
43		:param args: Replacement values
44		:return None:
45		"""
46		if self.log: self.log.debug("Executing query %s" % self.mogrify(query, replacements))
47
48		return self.cursor.execute(query, replacements)
49
50	def fetchall(self, query, *args):
51		"""
52		Fetch all rows for a query
53		:param query:  Query
54		:param args: Replacement values
55		:return list: The result rows, as a list
56		"""
57		self.query(query, *args)
58		try:
59			return self.cursor.fetchall()
60		except AttributeError:
61			return []
62
63	def fetchone(self, query, *args):
64		"""
65		Fetch one result row
66
67		:param query: Query
68		:param args: Replacement values
69		:return: The row, as a dictionary, or None if there were no rows
70		"""
71		self.query(query, *args)
72		try:
73			return self.cursor.fetchone()
74		except pymysql.ProgrammingError:
75			self.commit()
76			return None
77
78	def commit(self):
79		"""
80		Commit the current transaction
81
82		This is required for UPDATE etc to stick around.
83		"""
84		self.connection.commit()
85
86	def rollback(self):
87		"""
88		Roll back the current transaction
89		"""
90		self.connection.rollback()
91
92	def close(self):
93		"""
94		Close connection
95
96		Running queries after this is probably a bad idea!
97		"""
98		self.connection.close()