Files
MaxScale/examples/examplefiltersession.hh
2019-05-10 10:31:12 +03:00

79 lines
3.0 KiB
C++

/*
* Copyright (c) 2018 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2022-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#pragma once
#include <maxscale/ccdefs.hh>
#include <maxscale/filter.hh>
class ExampleFilter;
/*
* Defines session-specific data for this filter. An object of this class is created when a client connects
* and deleted on disconnect. The object is only accessed from one thread because sessions are locked to
* a thread when created.
*/
class ExampleFilterSession : public maxscale::FilterSession
{
// Prevent copy-constructor and assignment operator usage
ExampleFilterSession(const ExampleFilterSession&);
ExampleFilterSession& operator=(const ExampleFilterSession&);
public:
~ExampleFilterSession();
// Called when a client session has been closed. Destructor will be called right after.
void close();
/**
* Called by ExampleFilter::newSession() to create the session.
*
* @param pSession pSession The generic MaxScale session object
* @param pFilter The shared filter object
* @return A new session or NULL on failure
*/
static ExampleFilterSession* create(MXS_SESSION* pSession, ExampleFilter& pFilter);
/**
* Handle a query from the client. This is called when the client sends a query and the query has not
* been blocked by any previous component in the query processing chain. The filter should do its own
* processing and then send the query to the next component. If the query comes in multiple packets,
* this is called for each packet.
*
* @param pPacket Packet containing the query, or at least a part of it
* @return 0 on success. This typically depends on the later stages of the query processing chain.
*/
int routeQuery(GWBUF* pPacket);
/**
* Handle a reply from server. The reply typically contains a resultset or a response to a command.
* The filter should do its own processing and then send the query to the next component.
* If the reply comes in multiple packets, this is called for each packet. The processing chain for
* replies is the same as for queries, just walked in the opposite direction.
*
* @param pPacket Packet containing results
* @return 0 on success. This typically depends on the later stages of the reply processing chain.
*/
int clientReply(GWBUF* pPacket);
private:
// Used in the create function
ExampleFilterSession(MXS_SESSION* pSession, ExampleFilter& filter);
ExampleFilter& m_filter; /**< Shared filter data */
uint64_t m_session_id {0}; /**< Session id */
int m_queries {0}; /**< How many queries has this session seen */
int m_replies {0}; /**< How many replies has this session seen */
};