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:
47			self.log.debug("Executing query %s" % self.mogrify(query, replacements))
48
49		return self.cursor.execute(query, replacements)
50
51	def fetchall(self, query, *args):
52		"""
53		Fetch all rows for a query
54		:param query:  Query
55		:param args: Replacement values
56		:return list: The result rows, as a list
57		"""
58		self.query(query, *args)
59		try:
60			return self.cursor.fetchall()
61		except AttributeError:
62			return []
63
64	def fetchone(self, query, *args):
65		"""
66		Fetch one result row
67
68		:param query: Query
69		:param args: Replacement values
70		:return: The row, as a dictionary, or None if there were no rows
71		"""
72		self.query(query, *args)
73		try:
74			return self.cursor.fetchone()
75		except pymysql.ProgrammingError:
76			self.commit()
77			return None
78
79	def commit(self):
80		"""
81		Commit the current transaction
82
83		This is required for UPDATE etc to stick around.
84		"""
85		self.connection.commit()
86
87	def rollback(self):
88		"""
89		Roll back the current transaction
90		"""
91		self.connection.rollback()
92
93	def close(self):
94		"""
95		Close connection
96
97		Running queries after this is probably a bad idea!
98		"""
99		self.connection.close()