531 lines
16 KiB
Python
531 lines
16 KiB
Python
import re
|
|
import warnings
|
|
from . import err
|
|
|
|
|
|
#: Regular expression for :meth:`Cursor.executemany`.
|
|
#: executemany only supports simple bulk insert.
|
|
#: You can use it to load large dataset.
|
|
RE_INSERT_VALUES = re.compile(
|
|
r"\s*((?:INSERT|REPLACE)\b.+\bVALUES?\s*)"
|
|
+ r"(\(\s*(?:%s|%\(.+\)s)\s*(?:,\s*(?:%s|%\(.+\)s)\s*)*\))"
|
|
+ r"(\s*(?:ON DUPLICATE.*)?);?\s*\Z",
|
|
re.IGNORECASE | re.DOTALL,
|
|
)
|
|
|
|
|
|
class Cursor:
|
|
"""
|
|
This is the object used to interact with the database.
|
|
|
|
Do not create an instance of a Cursor yourself. Call
|
|
connections.Connection.cursor().
|
|
|
|
See `Cursor <https://www.python.org/dev/peps/pep-0249/#cursor-objects>`_ in
|
|
the specification.
|
|
"""
|
|
|
|
#: Max statement size which :meth:`executemany` generates.
|
|
#:
|
|
#: Max size of allowed statement is max_allowed_packet - packet_header_size.
|
|
#: Default value of max_allowed_packet is 1048576.
|
|
max_stmt_length = 1024000
|
|
|
|
def __init__(self, connection):
|
|
self.connection = connection
|
|
self.warning_count = 0
|
|
self.description = None
|
|
self.rownumber = 0
|
|
self.rowcount = -1
|
|
self.arraysize = 1
|
|
self._executed = None
|
|
self._result = None
|
|
self._rows = None
|
|
|
|
def close(self):
|
|
"""
|
|
Closing a cursor just exhausts all remaining data.
|
|
"""
|
|
conn = self.connection
|
|
if conn is None:
|
|
return
|
|
try:
|
|
while self.nextset():
|
|
pass
|
|
finally:
|
|
self.connection = None
|
|
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, *exc_info):
|
|
del exc_info
|
|
self.close()
|
|
|
|
def _get_db(self):
|
|
if not self.connection:
|
|
raise err.ProgrammingError("Cursor closed")
|
|
return self.connection
|
|
|
|
def _check_executed(self):
|
|
if not self._executed:
|
|
raise err.ProgrammingError("execute() first")
|
|
|
|
def _conv_row(self, row):
|
|
return row
|
|
|
|
def setinputsizes(self, *args):
|
|
"""Does nothing, required by DB API."""
|
|
|
|
def setoutputsizes(self, *args):
|
|
"""Does nothing, required by DB API."""
|
|
|
|
def _nextset(self, unbuffered=False):
|
|
"""Get the next query set."""
|
|
conn = self._get_db()
|
|
current_result = self._result
|
|
if current_result is None or current_result is not conn._result:
|
|
return None
|
|
if not current_result.has_next:
|
|
return None
|
|
self._result = None
|
|
self._clear_result()
|
|
conn.next_result(unbuffered=unbuffered)
|
|
self._do_get_result()
|
|
return True
|
|
|
|
def nextset(self):
|
|
return self._nextset(False)
|
|
|
|
def _escape_args(self, args, conn):
|
|
if isinstance(args, (tuple, list)):
|
|
return tuple(conn.literal(arg) for arg in args)
|
|
elif isinstance(args, dict):
|
|
return {key: conn.literal(val) for (key, val) in args.items()}
|
|
else:
|
|
# If it's not a dictionary let's try escaping it anyways.
|
|
# Worst case it will throw a Value error
|
|
return conn.escape(args)
|
|
|
|
def mogrify(self, query, args=None):
|
|
"""
|
|
Returns the exact string that would be sent to the database by calling the
|
|
execute() method.
|
|
|
|
:param query: Query to mogrify.
|
|
:type query: str
|
|
|
|
:param args: Parameters used with query. (optional)
|
|
:type args: tuple, list or dict
|
|
|
|
:return: The query with argument binding applied.
|
|
:rtype: str
|
|
|
|
This method follows the extension to the DB API 2.0 followed by Psycopg.
|
|
"""
|
|
conn = self._get_db()
|
|
|
|
if args is not None:
|
|
query = query % self._escape_args(args, conn)
|
|
|
|
return query
|
|
|
|
def execute(self, query, args=None):
|
|
"""Execute a query.
|
|
|
|
:param query: Query to execute.
|
|
:type query: str
|
|
|
|
:param args: Parameters used with query. (optional)
|
|
:type args: tuple, list or dict
|
|
|
|
:return: Number of affected rows.
|
|
:rtype: int
|
|
|
|
If args is a list or tuple, %s can be used as a placeholder in the query.
|
|
If args is a dict, %(name)s can be used as a placeholder in the query.
|
|
"""
|
|
while self.nextset():
|
|
pass
|
|
|
|
query = self.mogrify(query, args)
|
|
|
|
result = self._query(query)
|
|
self._executed = query
|
|
return result
|
|
|
|
def executemany(self, query, args):
|
|
"""Run several data against one query.
|
|
|
|
:param query: Query to execute.
|
|
:type query: str
|
|
|
|
:param args: Sequence of sequences or mappings. It is used as parameter.
|
|
:type args: tuple or list
|
|
|
|
:return: Number of rows affected, if any.
|
|
:rtype: int or None
|
|
|
|
This method improves performance on multiple-row INSERT and
|
|
REPLACE. Otherwise it is equivalent to looping over args with
|
|
execute().
|
|
"""
|
|
if not args:
|
|
return
|
|
|
|
m = RE_INSERT_VALUES.match(query)
|
|
if m:
|
|
q_prefix = m.group(1) % ()
|
|
q_values = m.group(2).rstrip()
|
|
q_postfix = m.group(3) or ""
|
|
assert q_values[0] == "(" and q_values[-1] == ")"
|
|
return self._do_execute_many(
|
|
q_prefix,
|
|
q_values,
|
|
q_postfix,
|
|
args,
|
|
self.max_stmt_length,
|
|
self._get_db().encoding,
|
|
)
|
|
|
|
self.rowcount = sum(self.execute(query, arg) for arg in args)
|
|
return self.rowcount
|
|
|
|
def _do_execute_many(
|
|
self, prefix, values, postfix, args, max_stmt_length, encoding
|
|
):
|
|
conn = self._get_db()
|
|
escape = self._escape_args
|
|
if isinstance(prefix, str):
|
|
prefix = prefix.encode(encoding)
|
|
if isinstance(postfix, str):
|
|
postfix = postfix.encode(encoding)
|
|
sql = bytearray(prefix)
|
|
args = iter(args)
|
|
v = values % escape(next(args), conn)
|
|
if isinstance(v, str):
|
|
v = v.encode(encoding, "surrogateescape")
|
|
sql += v
|
|
rows = 0
|
|
for arg in args:
|
|
v = values % escape(arg, conn)
|
|
if isinstance(v, str):
|
|
v = v.encode(encoding, "surrogateescape")
|
|
if len(sql) + len(v) + len(postfix) + 1 > max_stmt_length:
|
|
rows += self.execute(sql + postfix)
|
|
sql = bytearray(prefix)
|
|
else:
|
|
sql += b","
|
|
sql += v
|
|
rows += self.execute(sql + postfix)
|
|
self.rowcount = rows
|
|
return rows
|
|
|
|
def callproc(self, procname, args=()):
|
|
"""Execute stored procedure procname with args.
|
|
|
|
:param procname: Name of procedure to execute on server.
|
|
:type procname: str
|
|
|
|
:param args: Sequence of parameters to use with procedure.
|
|
:type args: tuple or list
|
|
|
|
Returns the original args.
|
|
|
|
Compatibility warning: PEP-249 specifies that any modified
|
|
parameters must be returned. This is currently impossible
|
|
as they are only available by storing them in a server
|
|
variable and then retrieved by a query. Since stored
|
|
procedures return zero or more result sets, there is no
|
|
reliable way to get at OUT or INOUT parameters via callproc.
|
|
The server variables are named @_procname_n, where procname
|
|
is the parameter above and n is the position of the parameter
|
|
(from zero). Once all result sets generated by the procedure
|
|
have been fetched, you can issue a SELECT @_procname_0, ...
|
|
query using .execute() to get any OUT or INOUT values.
|
|
|
|
Compatibility warning: The act of calling a stored procedure
|
|
itself creates an empty result set. This appears after any
|
|
result sets generated by the procedure. This is non-standard
|
|
behavior with respect to the DB-API. Be sure to use nextset()
|
|
to advance through all result sets; otherwise you may get
|
|
disconnected.
|
|
"""
|
|
conn = self._get_db()
|
|
if args:
|
|
fmt = f"@_{procname}_%d=%s"
|
|
self._query(
|
|
"SET %s"
|
|
% ",".join(
|
|
fmt % (index, conn.escape(arg)) for index, arg in enumerate(args)
|
|
)
|
|
)
|
|
self.nextset()
|
|
|
|
q = "CALL {}({})".format(
|
|
procname,
|
|
",".join(["@_%s_%d" % (procname, i) for i in range(len(args))]),
|
|
)
|
|
self._query(q)
|
|
self._executed = q
|
|
return args
|
|
|
|
def fetchone(self):
|
|
"""Fetch the next row."""
|
|
self._check_executed()
|
|
if self._rows is None or self.rownumber >= len(self._rows):
|
|
return None
|
|
result = self._rows[self.rownumber]
|
|
self.rownumber += 1
|
|
return result
|
|
|
|
def fetchmany(self, size=None):
|
|
"""Fetch several rows."""
|
|
self._check_executed()
|
|
if self._rows is None:
|
|
# Django expects () for EOF.
|
|
# https://github.com/django/django/blob/0c1518ee429b01c145cf5b34eab01b0b92f8c246/django/db/backends/mysql/features.py#L8
|
|
return ()
|
|
end = self.rownumber + (size or self.arraysize)
|
|
result = self._rows[self.rownumber : end]
|
|
self.rownumber = min(end, len(self._rows))
|
|
return result
|
|
|
|
def fetchall(self):
|
|
"""Fetch all the rows."""
|
|
self._check_executed()
|
|
if self._rows is None:
|
|
return []
|
|
if self.rownumber:
|
|
result = self._rows[self.rownumber :]
|
|
else:
|
|
result = self._rows
|
|
self.rownumber = len(self._rows)
|
|
return result
|
|
|
|
def scroll(self, value, mode="relative"):
|
|
self._check_executed()
|
|
if mode == "relative":
|
|
r = self.rownumber + value
|
|
elif mode == "absolute":
|
|
r = value
|
|
else:
|
|
raise err.ProgrammingError("unknown scroll mode %s" % mode)
|
|
|
|
if not (0 <= r < len(self._rows)):
|
|
raise IndexError("out of range")
|
|
self.rownumber = r
|
|
|
|
def _query(self, q):
|
|
conn = self._get_db()
|
|
self._clear_result()
|
|
conn.query(q)
|
|
self._do_get_result()
|
|
return self.rowcount
|
|
|
|
def _clear_result(self):
|
|
self.rownumber = 0
|
|
self._result = None
|
|
|
|
self.rowcount = 0
|
|
self.warning_count = 0
|
|
self.description = None
|
|
self.lastrowid = None
|
|
self._rows = None
|
|
|
|
def _do_get_result(self):
|
|
conn = self._get_db()
|
|
|
|
self._result = result = conn._result
|
|
|
|
self.rowcount = result.affected_rows
|
|
self.warning_count = result.warning_count
|
|
self.description = result.description
|
|
self.lastrowid = result.insert_id
|
|
self._rows = result.rows
|
|
|
|
def __iter__(self):
|
|
return self
|
|
|
|
def __next__(self):
|
|
row = self.fetchone()
|
|
if row is None:
|
|
raise StopIteration
|
|
return row
|
|
|
|
def __getattr__(self, name):
|
|
# DB-API 2.0 optional extension says these errors can be accessed
|
|
# via Connection object. But MySQLdb had defined them on Cursor object.
|
|
if name in (
|
|
"Warning",
|
|
"Error",
|
|
"InterfaceError",
|
|
"DatabaseError",
|
|
"DataError",
|
|
"OperationalError",
|
|
"IntegrityError",
|
|
"InternalError",
|
|
"ProgrammingError",
|
|
"NotSupportedError",
|
|
):
|
|
# Deprecated since v1.1
|
|
warnings.warn(
|
|
"PyMySQL errors hould be accessed from `pymysql` package",
|
|
DeprecationWarning,
|
|
stacklevel=2,
|
|
)
|
|
return getattr(err, name)
|
|
raise AttributeError(name)
|
|
|
|
|
|
class DictCursorMixin:
|
|
# You can override this to use OrderedDict or other dict-like types.
|
|
dict_type = dict
|
|
|
|
def _do_get_result(self):
|
|
super()._do_get_result()
|
|
fields = []
|
|
if self.description:
|
|
for f in self._result.fields:
|
|
name = f.name
|
|
if name in fields:
|
|
name = f.table_name + "." + name
|
|
fields.append(name)
|
|
self._fields = fields
|
|
|
|
if fields and self._rows:
|
|
self._rows = [self._conv_row(r) for r in self._rows]
|
|
|
|
def _conv_row(self, row):
|
|
if row is None:
|
|
return None
|
|
return self.dict_type(zip(self._fields, row))
|
|
|
|
|
|
class DictCursor(DictCursorMixin, Cursor):
|
|
"""A cursor which returns results as a dictionary"""
|
|
|
|
|
|
class SSCursor(Cursor):
|
|
"""
|
|
Unbuffered Cursor, mainly useful for queries that return a lot of data,
|
|
or for connections to remote servers over a slow network.
|
|
|
|
Instead of copying every row of data into a buffer, this will fetch
|
|
rows as needed. The upside of this is the client uses much less memory,
|
|
and rows are returned much faster when traveling over a slow network
|
|
or if the result set is very big.
|
|
|
|
There are limitations, though. The MySQL protocol doesn't support
|
|
returning the total number of rows, so the only way to tell how many rows
|
|
there are is to iterate over every row returned. Also, it currently isn't
|
|
possible to scroll backwards, as only the current row is held in memory.
|
|
"""
|
|
|
|
def _conv_row(self, row):
|
|
return row
|
|
|
|
def close(self):
|
|
conn = self.connection
|
|
if conn is None:
|
|
return
|
|
|
|
if self._result is not None and self._result is conn._result:
|
|
self._result._finish_unbuffered_query()
|
|
|
|
try:
|
|
while self.nextset():
|
|
pass
|
|
finally:
|
|
self.connection = None
|
|
|
|
__del__ = close
|
|
|
|
def _query(self, q):
|
|
conn = self._get_db()
|
|
self._clear_result()
|
|
conn.query(q, unbuffered=True)
|
|
self._do_get_result()
|
|
return self.rowcount
|
|
|
|
def nextset(self):
|
|
return self._nextset(unbuffered=True)
|
|
|
|
def read_next(self):
|
|
"""Read next row."""
|
|
return self._conv_row(self._result._read_rowdata_packet_unbuffered())
|
|
|
|
def fetchone(self):
|
|
"""Fetch next row."""
|
|
self._check_executed()
|
|
row = self.read_next()
|
|
if row is None:
|
|
self.warning_count = self._result.warning_count
|
|
return None
|
|
self.rownumber += 1
|
|
return row
|
|
|
|
def fetchall(self):
|
|
"""
|
|
Fetch all, as per MySQLdb. Pretty useless for large queries, as
|
|
it is buffered. See fetchall_unbuffered(), if you want an unbuffered
|
|
generator version of this method.
|
|
"""
|
|
return list(self.fetchall_unbuffered())
|
|
|
|
def fetchall_unbuffered(self):
|
|
"""
|
|
Fetch all, implemented as a generator, which isn't to standard,
|
|
however, it doesn't make sense to return everything in a list, as that
|
|
would use ridiculous memory for large result sets.
|
|
"""
|
|
return iter(self.fetchone, None)
|
|
|
|
def fetchmany(self, size=None):
|
|
"""Fetch many."""
|
|
self._check_executed()
|
|
if size is None:
|
|
size = self.arraysize
|
|
|
|
rows = []
|
|
for i in range(size):
|
|
row = self.read_next()
|
|
if row is None:
|
|
self.warning_count = self._result.warning_count
|
|
break
|
|
rows.append(row)
|
|
self.rownumber += 1
|
|
if not rows:
|
|
# Django expects () for EOF.
|
|
# https://github.com/django/django/blob/0c1518ee429b01c145cf5b34eab01b0b92f8c246/django/db/backends/mysql/features.py#L8
|
|
return ()
|
|
return rows
|
|
|
|
def scroll(self, value, mode="relative"):
|
|
self._check_executed()
|
|
|
|
if mode == "relative":
|
|
if value < 0:
|
|
raise err.NotSupportedError(
|
|
"Backwards scrolling not supported by this cursor"
|
|
)
|
|
|
|
for _ in range(value):
|
|
self.read_next()
|
|
self.rownumber += value
|
|
elif mode == "absolute":
|
|
if value < self.rownumber:
|
|
raise err.NotSupportedError(
|
|
"Backwards scrolling not supported by this cursor"
|
|
)
|
|
|
|
end = value - self.rownumber
|
|
for _ in range(end):
|
|
self.read_next()
|
|
self.rownumber = value
|
|
else:
|
|
raise err.ProgrammingError("unknown scroll mode %s" % mode)
|
|
|
|
|
|
class SSDictCursor(DictCursorMixin, SSCursor):
|
|
"""An unbuffered cursor, which returns results as a dictionary"""
|