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import errno
import socket
import threading
from redis.exceptions import ConnectionError, ResponseError, InvalidResponse
# Jython doesn't define socket.SOL_TCP, but works fine with it's value, 6
try:
SOL_TCP = socket.SOL_TCP
except AttributeError:
SOL_TCP = 6
class BaseConnection(object):
"Manages TCP communication to and from a Redis server"
def __init__(self, host='localhost', port=6379, db=0, password=None,
socket_timeout=None):
self.host = host
self.port = port
self.db = db
self.password = password
self.socket_timeout = socket_timeout
self._sock = None
self._fp = None
def connect(self, redis_instance):
"Connects to the Redis server if not already connected"
if self._sock:
return
try:
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.settimeout(self.socket_timeout)
sock.connect((self.host, self.port))
except socket.error, e:
# args for socket.error can either be (errno, "message")
# or just "message"
if len(e.args) == 1:
error_message = "Error connecting to %s:%s. %s." % \
(self.host, self.port, e.args[0])
else:
error_message = "Error %s connecting %s:%s. %s." % \
(e.args[0], self.host, self.port, e.args[1])
raise ConnectionError(error_message)
sock.setsockopt(SOL_TCP, socket.TCP_NODELAY, 1)
self._sock = sock
self._fp = sock.makefile('r')
redis_instance._setup_connection()
def disconnect(self):
"Disconnects from the Redis server"
if self._sock is None:
return
try:
self._sock.close()
except socket.error:
pass
self._sock = None
self._fp = None
def send(self, command, redis_instance):
"Send ``command`` to the Redis server. Return the result."
self.connect(redis_instance)
try:
self._sock.sendall(command)
except socket.error, e:
if e.args[0] == errno.EPIPE:
self.disconnect()
if len(e.args) == 1:
_errno, errmsg = 'UNKNOWN', e.args[0]
else:
_errno, errmsg = e.args
raise ConnectionError("Error %s while writing to socket. %s." % \
(_errno, errmsg))
def read(self, length=None):
"""
Read a line from the socket is length is None,
otherwise read ``length`` bytes
"""
try:
if length is not None:
return self._fp.read(length)
return self._fp.readline()
except socket.error, e:
self.disconnect()
if e.args and e.args[0] == errno.EAGAIN:
raise ConnectionError("Error while reading from socket: %s" % \
e.args[1])
return ''
class PythonConnection(BaseConnection):
def read_response(self, command_name, catch_errors):
response = self.read()[:-2] # strip last two characters (\r\n)
if not response:
self.disconnect()
raise ConnectionError("Socket closed on remote end")
# server returned a null value
if response in ('$-1', '*-1'):
return None
byte, response = response[0], response[1:]
# server returned an error
if byte == '-':
if response.startswith('ERR '):
response = response[4:]
raise ResponseError(response)
# single value
elif byte == '+':
return response
# int value
elif byte == ':':
return long(response)
# bulk response
elif byte == '$':
length = int(response)
if length == -1:
return None
response = length and self.read(length) or ''
self.read(2) # read the \r\n delimiter
return response
# multi-bulk response
elif byte == '*':
length = int(response)
if length == -1:
return None
if not catch_errors:
return [self.read_response(command_name, catch_errors)
for i in range(length)]
else:
# for pipelines, we need to read everything,
# including response errors. otherwise we'd
# completely mess up the receive buffer
data = []
for i in range(length):
try:
data.append(
self.read_response(command_name, catch_errors)
)
except Exception, e:
data.append(e)
return data
raise InvalidResponse("Unknown response type for: %s" % command_name)
class HiredisConnection(BaseConnection):
def connect(self, redis_instance):
if self._sock == None:
self._reader = hiredis.Reader(
protocolError=InvalidResponse,
replyError=ResponseError)
super(HiredisConnection, self).connect(redis_instance)
def disconnect(self):
if self._sock:
self._reader = None
super(HiredisConnection, self).disconnect()
def read_response(self, command_name, catch_errors):
response = self._reader.gets()
while response is False:
buffer = self._sock.recv(4096)
if not buffer:
self.disconnect()
raise ConnectionError("Socket closed on remote end")
self._reader.feed(buffer)
response = self._reader.gets()
if isinstance(response, ResponseError):
raise response
return response
try:
import hiredis
Connection = HiredisConnection
except ImportError:
Connection = PythonConnection
class ConnectionPool(threading.local):
"Manages a list of connections on the local thread"
def __init__(self, connection_class=None):
self.connections = {}
self.connection_class = connection_class or Connection
def make_connection_key(self, host, port, db):
"Create a unique key for the specified host, port and db"
return '%s:%s:%s' % (host, port, db)
def get_connection(self, host, port, db, password, socket_timeout):
"Return a specific connection for the specified host, port and db"
key = self.make_connection_key(host, port, db)
if key not in self.connections:
self.connections[key] = self.connection_class(
host, port, db, password, socket_timeout)
return self.connections[key]
def get_all_connections(self):
"Return a list of all connection objects the manager knows about"
return self.connections.values()
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