Cutelyst Memcached plugin. More...

#include <Cutelyst/Plugins/Memcached/Memcached>

Inheritance diagram for Cutelyst::Memcached:

Protected Member Functions
bool	setup (Application *app) override

Protected Member Functions inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signal)

bool	isSignalConnected (const QMetaMethod &signal) const const

int	receivers (const char *signal) const const

QObject *	sender () const const

int	senderSignalIndex () const const

virtual void	timerEvent (QTimerEvent *event)

Additional Inherited Members
Public Member Functions inherited from Cutelyst::Plugin
	Plugin (Application *parent)

Public Member Functions inherited from QObject
	QObject (QObject *parent)

QBindable< QString >	bindableObjectName ()

bool	blockSignals (bool block)

const QObjectList &	children () const const

QMetaObject::Connection	connect (const QObject sender, const char signal, const char *method, Qt::ConnectionType type) const const

void	deleteLater ()

void	destroyed (QObject *obj)

bool	disconnect (const char signal, const QObject receiver, const char *method) const const

bool	disconnect (const QObject receiver, const char method) const const

void	dumpObjectInfo () const const

void	dumpObjectTree () const const

QList< QByteArray >	dynamicPropertyNames () const const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name, Qt::FindChildOptions options) const const

QList< T >	findChildren (const QRegularExpression &re, Qt::FindChildOptions options) const const

QList< T >	findChildren (const QString &name, Qt::FindChildOptions options) const const

QList< T >	findChildren (Qt::FindChildOptions options) const const

bool	inherits (const char *className) const const

void	installEventFilter (QObject *filterObj)

bool	isQuickItemType () const const

bool	isWidgetType () const const

bool	isWindowType () const const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const const

void	moveToThread (QThread *targetThread)

QString	objectName () const const

void	objectNameChanged (const QString &objectName)

QObject *	parent () const const

QVariant	property (const char *name) const const

	Q_CLASSINFO (Name, Value)

	Q_EMIT Q_EMIT

	Q_ENUM (...)

	Q_ENUM_NS (...)

	Q_ENUMS (...)

	Q_FLAG (...)

	Q_FLAG_NS (...)

	Q_FLAGS (...)

	Q_GADGET Q_GADGET

	Q_GADGET_EXPORT (EXPORT_MACRO)

	Q_INTERFACES (...)

	Q_INVOKABLE Q_INVOKABLE

	Q_MOC_INCLUDE Q_MOC_INCLUDE

	Q_NAMESPACE Q_NAMESPACE

	Q_NAMESPACE_EXPORT (EXPORT_MACRO)

	Q_OBJECT Q_OBJECT

	Q_PROPERTY (...)

	Q_REVISION Q_REVISION

	Q_SET_OBJECT_NAME (Object)

	Q_SIGNAL Q_SIGNAL

	Q_SIGNALS Q_SIGNALS

	Q_SLOT Q_SLOT

	Q_SLOTS Q_SLOTS

T	qobject_cast (const QObject *object)

T	qobject_cast (QObject *object)

	QT_NO_NARROWING_CONVERSIONS_IN_CONNECT QT_NO_NARROWING_CONVERSIONS_IN_CONNECT

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setObjectName (QAnyStringView name)

void	setParent (QObject *parent)

bool	setProperty (const char *name, const QVariant &value)

bool	setProperty (const char *name, QVariant &&value)

bool	signalsBlocked () const const

int	startTimer (int interval, Qt::TimerType timerType)

int	startTimer (std::chrono::milliseconds interval, Qt::TimerType timerType)

QThread *	thread () const const

Static Public Member Functions inherited from QObject
QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char method, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject sender, PointerToMemberFunction signal, const QObject context, Functor functor, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject sender, PointerToMemberFunction signal, const QObject receiver, PointerToMemberFunction method, Qt::ConnectionType type)

QMetaObject::Connection	connect (const QObject *sender, PointerToMemberFunction signal, Functor functor)

bool	disconnect (const QMetaObject::Connection &connection)

bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char method)

bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method)

bool	disconnect (const QObject sender, PointerToMemberFunction signal, const QObject receiver, PointerToMemberFunction method)

QString	tr (const char sourceText, const char disambiguation, int n)

Public Attributes inherited from QObject
typedef	QObjectList

Properties inherited from QObject
	objectName

Detailed Description

The Memcached plugin for Cutelyst can be used to store, retrieve, delete and modify data on a memcached general-purpose distributed memory caching system. It uses libmemcached to connect to a pool of memcached servers and to perform the caching operations. In order to build this plugin, the libmemcached development and header files have to be present at build time.

Basically all values are stored as QByteArray. So, to store simple types, simply convert them into a QByteArray and vice versa on retrieval. For more complex or custom types you can use QDataStream to serialize them into a QByteArray. For most methods in this plugin there are template functions for convenience that perform this serialization. The requirement to use them is that the types to store and get provide stream operators for QDataStream.

Configuration

The Memcached plugin can be configured in the application configuration file in the Cutelyst_Memcached_Plugin section. It uses the same configuration strings as libmemcached but in lowercase and without the dashes in front and for consistence '-' replaced by '_'. So –BINARY-PROTOCOL will be binary_protocol. To add servers and/or sockets use the servers configuration key. Servers can be added with name, port and weight, separated by ',' - multiple servers are separated by a ';'. To add sockets, use a full path as name. If no configuration has been set or if the servers configuration key is empty, a default server at localhost on port 11211 will be used.

Additional to the configuration options of libmemcached there are some plugin specific options:

compression

Type: bool Default: fase

Enables compression of input values based on qCompress / zlib.

compression_level

Type: integer Default: -1

The compression level used by qCompress(). Valid values are between 0 and 9, with 9 corresponding to the greatest compression. The value 0 corresponds to no compression at all. The default value is -1, which specifies zlib’s default compression.

compression_threshold

Type: integer Default: 100

The compression size threshold in bytes. Only input values bigger than the threshold will be compressed.

encryption_key

Type: string Default: empty

If set and not empty, AES encryption will be enabled for storing data on the memcached servers.

sasl_user

Type: string Default: empty

If set and not empty, SASL authentication will be used to authenticate with the memcached server(s). Note that SASL support has to be enabled when building libmemcached.

sasl_password

Type: string Default: empty

Password used for the SASL authentication with the memcached server(s).

Note: If you want to use non-ASCII key names, you have to enable the binary protocol.

To set default values directly in your application, use setDefaultConfig() or the overloaded constructor taking default values. Configuration values that can not be found in the application configuration file will be looked up for default values in that QVariantMap.

Configuration example

[Cutelyst_Memcached_Plugin]
servers=cache.example.com,11211,2;/path/to/memcached.sock,1
binary_protocol=true
namespace=foobar

Expiration times

Expiration times are set in seconds. If the value is bigger than 30 days, it is interpreted as a unix timestamp.

Logging and return types

Messages from this plugin are logged to the logging category cutelyst.plugin.memcached. All methods provide the possibility to specify a pointer to a Memcached::ReturnType variable that can provide further information about occurred errors if methods return false or empty results.

See also: Logging with Cutelyst

Usage example

#include <Cutelyst/Plugins/Memcached/Memcached>
 
bool MyCutelystApp::init()
{
    // other initialization stuff
    // ...
 
    new Memcached(this);
 
    // maybe more initialization stuff
    //...
}
 
void MyController::index(Context *c)
{
    QVariantList myData = Memcached::get<QVariantList>(QStringLiteral("myKey"));
    if (myData.empty()) {
        QSqlQuery q = CPreparedSqlQuery(QStringLiteral("SELECT * FROM myTable"));
        if (q.exec()) {
            myData = Sql::queryToHashList(q);
            if (!myData.empty()) {
                Memcached::set(QStringLiteral("myKey"), myData, 900);
            }
        }
    }
 
    // present your data
    // ...
}

Build requirements

To build this plugin you need the development and header files for libmemcached and run cmake with -DPLUGIN_MEMCACHED:BOOL=ON.

Unit test

Enabling the build of the Memcached plugin will also enable the unit tests for this plugin. By default, the unit test will start its own memcached instance. Alternatively you can set the CUTELYST_MEMCACHED_TEST_SERVERS environment variable in your build environment to define different servers that you have to start by yourself. The syntax is the same as for adding servers in the configuration file. If you have for examble two servers, one on default location and another one on a unix socket, export the following environment variable befor running the tests:

export CUTELYST_MEMCACHED_TEST_SERVERS=localhost;/tmp/memcached.sock

Since: Cutelyst 1.11.0

Definition at line 166 of file memcached.h.

Member Function Documentation

◆ setup()

bool Memcached::setup ( Application * app )

overrideprotectedvirtual

Reads the configuration and sets up the plugin.

Reimplemented from Cutelyst::Plugin.

Definition at line 45 of file memcached.cpp.

References QString::at(), Cutelyst::Engine::config(), QObject::connect(), QByteArray::constData(), QList::empty(), Cutelyst::Application::engine(), QString::isEmpty(), QStringList::join(), Cutelyst::Application::loadTranslations(), Cutelyst::Application::postForked(), QList::push_back(), QString::replace(), QByteArray::size(), QStringView::split(), QString::startsWith(), QString::toUpper(), and QString::toUtf8().

Protected Member Functions

Additional Inherited Members

Detailed Description

Configuration

Configuration example

Expiration times

Logging and return types

Usage example

Build requirements

Unit test

Member Function Documentation

◆ setup()