twisted.protocols.memcache.MemCacheProtocol

class documentation

class MemCacheProtocol(LineReceiver, TimeoutMixin): (source)

MemCache protocol: connect to a memcached server to store/retrieve values.

Method	`__init__`	Create the protocol.
Method	`add`	Add the given `key`. It must not exist in the server.
Method	`append`	Append given data to the value of an existing key.
Method	`checkAndSet`	Change the content of `key` only if the `cas` value matches the current one associated with the key. Use this to store a value which hasn't been modified since last time you fetched it.
Method	`cmd_CLIENT_ERROR`	An invalid input as been sent.
Method	`cmd_DELETED`	A delete command has completed successfully.
Method	`cmd_END`	This the end token to a get or a stat operation.
Method	`cmd_ERROR`	A non-existent command has been sent.
Method	`cmd_EXISTS`	A `checkAndSet` update has failed.
Method	`cmd_NOT_FOUND`	Manage error response for incr/decr/delete.
Method	`cmd_NOT_STORED`	Manage a specific 'not stored' response to a set operation: this is not an error, but some condition wasn't met.
Method	`cmd_OK`	The last command has been completed.
Method	`cmd_SERVER_ERROR`	An error has happened server-side.
Method	`cmd_STAT`	Reception of one stat line.
Method	`cmd_STORED`	Manage a success response to a set operation.
Method	`cmd_VALUE`	Prepare the reading a value after a get.
Method	`cmd_VERSION`	Read version token.
Method	`connectionLost`	Cause any outstanding commands to fail.
Method	`decrement`	Decrement the value of `key` by given value (default to 1). `key` must be consistent with an int. Return the new value, coerced to 0 if negative.
Method	`delete`	Delete an existing `key`.
Method	`flushAll`	Flush all cached values.
Method	`get`	No summary
Method	`getMultiple`	No summary
Method	`increment`	Increment the value of `key` by given value (default to 1). `key` must be consistent with an int. Return the new value.
Method	`lineReceived`	Receive line commands from the server.
Method	`prepend`	Prepend given data to the value of an existing key.
Method	`rawDataReceived`	Collect data for a get.
Method	`replace`	Replace the given `key`. It must already exist in the server.
Method	`sendLine`	Override sendLine to add a timeout to response.
Method	`set`	Set the given `key`.
Method	`stats`	Get some stats from the server. It will be available as a dict.
Method	`timeoutConnection`	Close the connection in case of timeout.
Method	`version`	Get the version of the server.
Constant	`MAX_KEY_LENGTH`	Undocumented
Instance Variable	`persistentTimeOut`	the timeout period used to wait for a response.
Instance Variable	`timeOut`	Undocumented
Method	`_cancelCommands`	Cancel all the outstanding commands, making them fail with `reason`.
Method	`_get`	Helper method for `get` and `getMultiple`.
Method	`_incrdecr`	Internal wrapper for incr/decr.
Method	`_set`	Internal wrapper for setting values.
Instance Variable	`_bufferLength`	the total amount of bytes in `_getBuffer`.
Instance Variable	`_current`	current list of requests waiting for an answer from the server.
Instance Variable	`_disconnected`	indicate if the connectionLost has been called or not.
Instance Variable	`_getBuffer`	current buffer of data, used to store temporary data when reading in raw mode.
Instance Variable	`_lenExpected`	amount of data expected in raw mode, when reading for a value.

Inherited from LineReceiver:

Method	`clearLineBuffer`	Clear buffered data.
Method	`dataReceived`	Protocol.dataReceived. Translates bytes into lines, and calls lineReceived (or rawDataReceived, depending on mode.)
Method	`lineLengthExceeded`	Called when the maximum line length has been reached. Override if it needs to be dealt with in some special way.
Method	`setLineMode`	Sets the line-mode of this receiver.
Method	`setRawMode`	Sets the raw mode of this receiver. Further data received will be sent to rawDataReceived rather than lineReceived.
Constant	`MAX_LENGTH`	The maximum length of a line to allow (If a sent line is longer than this, the connection is dropped). Default is 16384.
Class Variable	`delimiter`	The line-ending delimiter to use. By default this is `b'\r\n'`.
Instance Variable	`line_mode`	Undocumented
Instance Variable	`_buffer`	Undocumented
Instance Variable	`_busyReceiving`	Undocumented

Inherited from Protocol (via LineReceiver):

Method	`logPrefix`	Return a prefix matching the class name, to identify log messages related to this protocol instance.
Class Variable	`factory`	Undocumented

Inherited from BaseProtocol (via LineReceiver, Protocol):

Method	`connectionMade`	Called when a connection is made.
Method	`makeConnection`	Make a connection to a transport and a server.
Instance Variable	`connected`	Undocumented
Instance Variable	`transport`	Undocumented

Inherited from _PauseableMixin (via LineReceiver):

Method	`pauseProducing`	Undocumented
Method	`resumeProducing`	Undocumented
Method	`stopProducing`	Undocumented
Instance Variable	`paused`	Undocumented

Inherited from TimeoutMixin:

Method	`callLater`	Wrapper around `reactor.callLater` for test purpose.
Method	`resetTimeout`	Reset the timeout count down.
Method	`setTimeout`	Change the timeout period
Method	`__timedOut`	Undocumented
Instance Variable	`__timeoutCall`	Undocumented

def __init__(self, timeOut=60): (source)

Create the protocol.

Parameters
timeOut:`int`	the timeout to wait before detecting that the connection is dead and close it. It's expressed in seconds.

def add(self, key, val, flags=0, expireTime=0): (source)

Add the given key. It must not exist in the server.

Parameters
key:`bytes`	the key to add.
val:`bytes`	the value associated with the key.
flags:`int`	the flags to store with the key.
expireTime:`int`	if different from 0, the relative time in seconds when the key will be deleted from the store.
Returns
`Deferred`	a deferred that will fire with `True` if the operation has succeeded, and `False` with the key already exists.

def append(self, key, val): (source)

Append given data to the value of an existing key.

Parameters
key:`bytes`	The key to modify.
val:`bytes`	The value to append to the current value associated with the key.
Returns
`Deferred`	A deferred that will fire with `True` if the operation has succeeded, `False` otherwise.

def checkAndSet(self, key, val, cas, flags=0, expireTime=0): (source)

Change the content of key only if the cas value matches the current one associated with the key. Use this to store a value which hasn't been modified since last time you fetched it.

Parameters
key:`bytes`	The key to set.
val:`bytes`	The value associated with the key.
cas:`bytes`	Unique 64-bit value returned by previous call of `get`.
flags:`int`	The flags to store with the key.
expireTime:`int`	If different from 0, the relative time in seconds when the key will be deleted from the store.
Returns
`Deferred`	A deferred that will fire with `True` if the operation has succeeded, `False` otherwise.

def cmd_CLIENT_ERROR(self, errText): (source)

An invalid input as been sent.

def cmd_DELETED(self): (source)

A delete command has completed successfully.

def cmd_END(self): (source)

This the end token to a get or a stat operation.

def cmd_ERROR(self): (source)

A non-existent command has been sent.

def cmd_EXISTS(self): (source)

A checkAndSet update has failed.

def cmd_NOT_FOUND(self): (source)

Manage error response for incr/decr/delete.

def cmd_NOT_STORED(self): (source)

Manage a specific 'not stored' response to a set operation: this is not an error, but some condition wasn't met.

def cmd_OK(self): (source)

The last command has been completed.

def cmd_SERVER_ERROR(self, errText): (source)

An error has happened server-side.

def cmd_STAT(self, line): (source)

Reception of one stat line.

def cmd_STORED(self): (source)

Manage a success response to a set operation.

def cmd_VALUE(self, line): (source)

Prepare the reading a value after a get.

def cmd_VERSION(self, versionData): (source)

Read version token.

def connectionLost(self, reason): (source)

from twisted.internet.interfaces.IProtocol

overrides twisted.internet.protocol.Protocol.connectionLost

Cause any outstanding commands to fail.

def decrement(self, key, val=1): (source)

Decrement the value of key by given value (default to 1). key must be consistent with an int. Return the new value, coerced to 0 if negative.

Parameters
key:`bytes`	the key to modify.
val:`int`	the value to decrement.
Returns
`Deferred`	a deferred with will be called back with the new value associated with the key (after the decrement).

def delete(self, key): (source)

Delete an existing key.

Parameters
key:`bytes`	the key to delete.
Returns
`Deferred`	a deferred that will be called back with `True` if the key was successfully deleted, or `False` if not.

def flushAll(self): (source)

Flush all cached values.

Returns
`Deferred`	a deferred that will be called back with `True` when the operation has succeeded.

def get(self, key, withIdentifier=False): (source)

Get the given key. It doesn't support multiple keys. If withIdentifier is set to True, the command issued is a gets, that will return the current identifier associated with the value. This identifier has to be used when issuing checkAndSet update later, using the corresponding method.

Parameters
key:`bytes`	The key to retrieve.
withIdentifier:`bool`	If set to `True`, retrieve the current identifier along with the value and the flags.
Returns
`Deferred`	A deferred that will fire with the tuple (flags, value) if `withIdentifier` is `False`, or (flags, cas identifier, value) if `True`. If the server indicates there is no value associated with `key`, the returned value will be `None` and the returned flags will be `0`.

def getMultiple(self, keys, withIdentifier=False): (source)

Get the given list of keys. If withIdentifier is set to True, the command issued is a gets, that will return the identifiers associated with each values. This identifier has to be used when issuing checkAndSet update later, using the corresponding method.

Parameters
keys:`list` of `bytes`	The keys to retrieve.
withIdentifier:`bool`	If set to `True`, retrieve the identifiers along with the values and the flags.
Returns
`Deferred`	A deferred that will fire with a dictionary with the elements of `keys` as keys and the tuples (flags, value) as values if `withIdentifier` is `False`, or (flags, cas identifier, value) if `True`. If the server indicates there is no value associated with `key`, the returned values will be `None` and the returned flags will be `0`.
Present Since
9.0

def increment(self, key, val=1): (source)

Increment the value of key by given value (default to 1). key must be consistent with an int. Return the new value.

Parameters
key:`bytes`	the key to modify.
val:`int`	the value to increment.
Returns
`Deferred`	a deferred with will be called back with the new value associated with the key (after the increment).

def lineReceived(self, line): (source)

overrides twisted.protocols.basic.LineReceiver.lineReceived

Receive line commands from the server.

def prepend(self, key, val): (source)

Prepend given data to the value of an existing key.

Parameters
key:`bytes`	The key to modify.
val:`bytes`	The value to prepend to the current value associated with the key.
Returns
`Deferred`	A deferred that will fire with `True` if the operation has succeeded, `False` otherwise.

def rawDataReceived(self, data): (source)

overrides twisted.protocols.basic.LineReceiver.rawDataReceived

Collect data for a get.

def replace(self, key, val, flags=0, expireTime=0): (source)

Replace the given key. It must already exist in the server.

Parameters
key:`bytes`	the key to replace.
val:`bytes`	the new value associated with the key.
flags:`int`	the flags to store with the key.
expireTime:`int`	if different from 0, the relative time in seconds when the key will be deleted from the store.
Returns
`Deferred`	a deferred that will fire with `True` if the operation has succeeded, and `False` with the key didn't previously exist.

def sendLine(self, line): (source)

overrides twisted.protocols.basic.LineReceiver.sendLine

Override sendLine to add a timeout to response.

def set(self, key, val, flags=0, expireTime=0): (source)

Set the given key.

Parameters
key:`bytes`	the key to set.
val:`bytes`	the value associated with the key.
flags:`int`	the flags to store with the key.
expireTime:`int`	if different from 0, the relative time in seconds when the key will be deleted from the store.
Returns
`Deferred`	a deferred that will fire with `True` if the operation has succeeded.

def stats(self, arg=None): (source)

Get some stats from the server. It will be available as a dict.

Parameters
arg:`None` or `bytes`	An optional additional string which will be sent along with the stats command. The interpretation of this value by the server is left undefined by the memcache protocol specification.
Returns
`Deferred`	a deferred that will fire with a `dict` of the available statistics.

def timeoutConnection(self): (source)

overrides twisted.protocols.policies.TimeoutMixin.timeoutConnection

Close the connection in case of timeout.

def version(self): (source)

Get the version of the server.

Returns
`Deferred`	a deferred that will fire with the string value of the version.

MAX_KEY_LENGTH: int = (source)

Undocumented

Value

persistentTimeOut: int = (source)

the timeout period used to wait for a response.

timeOut = (source)

overrides twisted.protocols.policies.TimeoutMixin.timeOut

Undocumented

def _cancelCommands(self, reason): (source)

Cancel all the outstanding commands, making them fail with reason.

def _get(self, keys, withIdentifier, multiple): (source)

Helper method for get and getMultiple.

def _incrdecr(self, cmd, key, val): (source)

Internal wrapper for incr/decr.

def _set(self, cmd, key, val, flags, expireTime, cas): (source)

Internal wrapper for setting values.

_bufferLength: int = (source)

the total amount of bytes in _getBuffer.

_current: deque of Command = (source)

current list of requests waiting for an answer from the server.

_disconnected: bool = (source)

indicate if the connectionLost has been called or not.

_getBuffer: list = (source)

current buffer of data, used to store temporary data when reading in raw mode.

_lenExpected: int = (source)

amount of data expected in raw mode, when reading for a value.