MysqlInterface.cxx

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#include "MysqlInterface.h"
 
#include <cstring>
#include <iostream>
#include <mysql.h>
#include <unistd.h>
 
using namespace std;
 
MysqlInterface::MysqlInterface() {}
 
MysqlInterface::~MysqlInterface() {}
 
int MysqlInterface::connect() {
  if ( m_reuseConnection ) connect( m_dbHost, m_dbUser, m_dbPasswd, m_dbPort );
  return 0;
}
 
int MysqlInterface::connect( std::string host, std::string user, std::string passwd,
                             int port ) {
  try
  {
    m_conn = new MYSQL;
    mysql_init( m_conn );
    MYSQL* ret      = 0;
    int    iattempt = 0;
    for ( iattempt = 0; iattempt < 3; iattempt++ )
    {
      ret = mysql_real_connect( m_conn, host.c_str(), user.c_str(), passwd.c_str(),
                                m_dbName.c_str(), port, NULL, 0 );
      if ( ret != 0 )
      { // Everything is fine.  Put out an info message
        std::cout << "DatabaseSvc: Connected to MySQL database" << std::endl;
        break;
      }
      else
      {
        std::cout << "Couldn't connect to MySQL database. Trying again." << std::endl;
        sleep( 1 );
      }
    }
 
    if ( ret == 0 && iattempt == 2 ) throw (char*)mysql_error( m_conn );
 
  } catch ( std::exception& e )
  {
 
    cerr << "Error in MySQL session initialization!" << endl;
    cerr << "*** std::exception caught:" << endl;
    cerr << "***  error message:" << e.what() << endl;
    return -1;
 
  } catch ( ... )
  { return -1; }
 
  m_isConnected = true;
  return 0;
}
 
int MysqlInterface::select_db( std::string dbname ) {
  int ret = mysql_select_db( m_conn, dbname.c_str() );
  if ( ret != 0 )
  {
    disconnect();
    // Try to re-connect
    sleep( 5 );
    ret = connect( m_dbHost, m_dbUser, m_dbPasswd, m_dbPort );
    if ( ret == 0 ) { ret = mysql_select_db( m_conn, dbname.c_str() ); }
    if ( ret != 0 ) { throw std::exception(); }
  }
  return 0;
}
 
int MysqlInterface::query( std::string dbname, std::string sql ) {
  if ( !m_reuseConnection ) connect( m_dbHost, m_dbUser, m_dbPasswd, m_dbPort );
 
  try
  {
    // check database name
    if ( m_dbName != dbname )
    {
      m_dbName = dbname;
      select_db( m_dbName );
    }
 
    int status = mysql_real_query( m_conn, sql.c_str(), sql.length() );
    if ( status )
    {
      //        if(mysql_errno(m_conn)==2006){
      //  std::cerr << "MySQL error 2006: MySQL server has gone away"<< std::endl;
      std::cerr << "MySQL error: MySQL server has gone away" << std::endl;
      disconnect();
      // Try to re-connect
      sleep( 5 );
      int ret = connect( m_dbHost, m_dbUser, m_dbPasswd, m_dbPort );
      if ( ret == 0 )
      {
        std::cout << "Connected to MySQL database " << std::endl;
        select_db( m_dbName );
        status = mysql_real_query( m_conn, sql.c_str(), sql.length() );
      }
      //  }
 
      if ( status )
      {
        cerr << "Query " << sql << " failed: " << mysql_error( m_conn ) << endl;
        return -1;
      }
    }
  } catch ( ... )
  {
    cerr << "Could not execute query: " << mysql_error( m_conn ) << endl;
    return -1;
  }
 
  if ( !m_reuseConnection ) disconnect();
 
  return 0;
}
 
int MysqlInterface::query( std::string dbname, std::string sql,
                           DatabaseRecordVector& records ) {
  if ( !m_reuseConnection ) connect( m_dbHost, m_dbUser, m_dbPasswd, m_dbPort );
 
  records.clear();
 
  try
  {
    // check database name
    if ( m_dbName != dbname )
    {
      m_dbName = dbname;
      select_db( m_dbName );
    }
 
    int status = mysql_real_query( m_conn, sql.c_str(), sql.length() );
    if ( status )
    {
      //    if(mysql_errno(m_conn)==2006){
      //         std::cerr << "MySQL error 2006: MySQL server has gone away"<< std::endl;
      std::cerr << "MySQL error: MySQL server has gone away" << std::endl;
      disconnect();
      // Try to re-connect
      sleep( 5 );
      int ret = connect( m_dbHost, m_dbUser, m_dbPasswd, m_dbPort );
      if ( ret == 0 )
      {
        std::cout << "Connected to MySQL database " << std::endl;
        select_db( m_dbName );
        status = mysql_real_query( m_conn, sql.c_str(), sql.length() );
      }
      // }
 
      if ( status )
      {
        cerr << "Query " << sql << " failed: " << mysql_error( m_conn ) << endl;
        return -1;
      }
    }
 
    MYSQL_RES* result = mysql_store_result( m_conn );
 
    if ( result )
    {
      int num_fields = mysql_num_fields( result );
 
      if ( num_fields > 0 )
      {
        MYSQL_FIELD* fields;
        fields = mysql_fetch_fields( result );
 
        MYSQL_ROW row;
        while ( ( row = mysql_fetch_row( result ) ) )
        {
          unsigned long* lengths;
          lengths               = mysql_fetch_lengths( result );
          DatabaseRecord* dbrec = new DatabaseRecord;
          int             field;
          for ( field = 0; field < num_fields; field++ )
          {
            if ( row[field] != 0 )
            {
              unsigned long field_len = lengths[field];
              char*         new_record;
              if ( fields[field].type == FIELD_TYPE_BLOB )
              {
                new_record = new char[field_len];
                memcpy( new_record, row[field], field_len );
              }
              else // strings
              {
                new_record = new char[field_len + 1];
                strcpy( new_record, row[field] );
              }
 
              ( *dbrec )[fields[field].name] = new_record;
            }
            else { ( *dbrec )[fields[field].name] = nullptr; }
          }
          records.push_back( dbrec );
        }
      }
      mysql_free_result( result );
      if ( !m_reuseConnection ) disconnect();
 
      return records.size();
    }
  } catch ( ... )
  {
    cerr << "Could not execute query: " << mysql_error( m_conn ) << endl;
    if ( !m_reuseConnection ) disconnect();
    return -1;
  }
 
  if ( !m_reuseConnection ) disconnect();
 
  return 0;
}
 
int MysqlInterface::disconnect() {
  if ( m_conn )
  {
    mysql_close( m_conn );
    delete m_conn;
    m_conn = NULL;
  }
  m_isConnected = false;
  return 0;
}