php - pdo 样式的数据表 - 将数据库连接注入(inject)导致错误的类

Question

我正在尝试将我的数据库连接注入(inject)到这个用于数据表的 pdo 样式类中。我收到: fatal error :在第 82 行的/home/test/public_html/assets/data-tables/test-pdo.php 中的非对象上调用成员函数 prepare()

测试pdo.php

<?php

/*
 * Script:    DataTables server-side script for PHP and MySQL
 * Copyright: 2012 - John Becker, Beckersoft, Inc.
 * Copyright: 2010 - Allan Jardine
 * License:   GPL v2 or BSD (3-point)
 */

define('INCLUDE_CHECK',true);

// These files can be included only if INCLUDE_CHECK is defined
require '/home/test/public_html/assets/functions/connect.php';

//inject bd connection into class
class TableData {
    /** @var \PDO */
    protected $_db;

    public function __construct(\PDO $_db) {
         $this->pdo = $_db;
    }

    public function get($table, $index_column, $columns) {

        // Paging
        $sLimit = "";
        if ( isset( $_GET['iDisplayStart'] ) && $_GET['iDisplayLength'] != '-1' ) {
            $sLimit = "LIMIT ".intval( $_GET['iDisplayStart'] ).", ".intval( $_GET['iDisplayLength'] );
        }

        // Ordering
        $sOrder = "";
        if ( isset( $_GET['iSortCol_0'] ) ) {
            $sOrder = "ORDER BY  ";
            for ( $i=0 ; $i<intval( $_GET['iSortingCols'] ) ; $i++ ) {
                if ( $_GET[ 'bSortable_'.intval($_GET['iSortCol_'.$i]) ] == "true" ) {
                    $sortDir = (strcasecmp($_GET['sSortDir_'.$i], 'ASC') == 0) ? 'ASC' : 'DESC';
                    $sOrder .= "`".$columns[ intval( $_GET['iSortCol_'.$i] ) ]."` ". $sortDir .", ";
                }
            }

            $sOrder = substr_replace( $sOrder, "", -2 );
            if ( $sOrder == "ORDER BY" ) {
                $sOrder = "";
            }
        }

        /* 
         * Filtering
         * NOTE this does not match the built-in DataTables filtering which does it
         * word by word on any field. It's possible to do here, but concerned about efficiency
         * on very large tables, and MySQL's regex functionality is very limited
         */
        $sWhere = "";
        if ( isset($_GET['sSearch']) && $_GET['sSearch'] != "" ) {
            $sWhere = "WHERE (";
            for ( $i=0 ; $i<count($columns) ; $i++ ) {
                if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" ) {
                    $sWhere .= "`".$columns[$i]."` LIKE :search OR ";
                }
            }
            $sWhere = substr_replace( $sWhere, "", -3 );
            $sWhere .= ')';
        }

        // Individual column filtering
        for ( $i=0 ; $i<count($columns) ; $i++ ) {
            if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' ) {
                if ( $sWhere == "" ) {
                    $sWhere = "WHERE ";
                }
                else {
                    $sWhere .= " AND ";
                }
                $sWhere .= "`".$columns[$i]."` LIKE :search".$i." ";
            }
        }

        // SQL queries get data to display
        $sQuery = "SELECT SQL_CALC_FOUND_ROWS `".str_replace(" , ", " ", implode("`, `", $columns))."` FROM `".$table."` ".$sWhere." ".$sOrder." ".$sLimit;
        $statement = $this->_db->prepare($sQuery);

        // Bind parameters
        if ( isset($_GET['sSearch']) && $_GET['sSearch'] != "" ) {
            $statement->bindValue(':search', '%'.$_GET['sSearch'].'%', PDO::PARAM_STR);
        }
        for ( $i=0 ; $i<count($columns) ; $i++ ) {
            if ( isset($_GET['bSearchable_'.$i]) && $_GET['bSearchable_'.$i] == "true" && $_GET['sSearch_'.$i] != '' ) {
                $statement->bindValue(':search'.$i, '%'.$_GET['sSearch_'.$i].'%', PDO::PARAM_STR);
            }
        }

        $statement->execute();
        $rResult = $statement->fetchAll();

        $iFilteredTotal = current($this->_db->query('SELECT FOUND_ROWS()')->fetch());

        // Get total number of rows in table
        $sQuery = "SELECT COUNT(`".$index_column."`) FROM `".$table."`";
        $iTotal = current($this->_db->query($sQuery)->fetch());

        // Output
        $output = array(
            "sEcho" => intval($_GET['sEcho']),
            "iTotalRecords" => $iTotal,
            "iTotalDisplayRecords" => $iFilteredTotal,
            "aaData" => array()
        );

        // Return array of values
        foreach($rResult as $aRow) {
            $row = array();         
            for ( $i = 0; $i < count($columns); $i++ ) {
                if ( $columns[$i] == "version" ) {
                    // Special output formatting for 'version' column
                    $row[] = ($aRow[ $columns[$i] ]=="0") ? '-' : $aRow[ $columns[$i] ];
                }
                else if ( $columns[$i] != ' ' ) {
                    $row[] = $aRow[ $columns[$i] ];
                }
            }
            $output['aaData'][] = $row;
        }

        echo json_encode( $output );
    }

}

header('Pragma: no-cache');
header('Cache-Control: no-store, no-cache, must-revalidate');

// Create instance of TableData class
//$table_data = new TableData();
$table_data = new TableData($db);

// Get the data
//$table_data->get('table_name', 'index_column', array('column1', 'column2', 'columnN'));
$table_data->get('accounts', 'account_id', array('account_id', 'account_username', 'account_password', 'account_email'));


?>

和我在网站其余部分使用的 connect.php。我正在尝试按照建议将 $db 连接从这里注入(inject)到上面的类中。

<?php

if(!defined('INCLUDE_CHECK')) die('You are not allowed to execute this file directly');

// db config
$db_host        = 'localhost';
$db_database    = 'dbname';
$db_user        = 'dbuser';
$db_pass        = 'dbpass'; 

//db connection
try {
    $db = new PDO("mysql:host=$db_host;dbname=$db_database;charset=utf8", $db_user, $db_pass, array(PDO::ATTR_EMULATE_PREPARES => false, PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::ATTR_PERSISTENT => true));
}
catch(PDOException $e) {
    error_log("Failed to connect to database: ".$e->getMessage());
}

?>

Answer 1

在您的构造函数中，您具有以下内容:

public function __construct(\PDO $_db) {
     $this->pdo = $_db;
}

不过，您的实例变量是:

protected $_db;

所以你应该将构造函数更改为:

public function __construct(\PDO $_db) {
     $this->_db = $_db;
}