如何记住上次访问的项目

Question

我一直在试验这段代码。 $srv 检查自己的地址。因此，如果我们在 /_test.php?id=45 中，代码将执行。这是 header.php 中的代码 > 每个站点都包含 header.php。

if ( $srv == '/_test.php')
{   
    $aid = $_GET['id'];
    $numLastViewed = 5 ; 
    $lastViewedLocation = $_SESSION['lastViewed'];
    //check if first element of array exist
    if (isset($lastViewedLocation[0])) {
    //look for last set index
        for($i = 1;$i < $numLastViewed; ++$i){
            //when found > save it to var
            if(isset($lastViewedLocation[$i]))
            {
                $takenIndex = $i;                   
            }           
        }
        //check if array is full 
        if($takenIndex < $numLastViewed)
        {   //push element on end of array 
            array_push($lastViewedLocation, $aid);
            $_SESSION['lastViewed'] = $lastViewedLocation;
        }else
        {//delete first item and add current item to end of array
            $sub = array_shift($lastViewedLocation);
            array_push($lastViewedLocation, $aid);
            $_SESSION['lastViewed'] = $lastViewedLocation;
        }

    }else
    {   //if first element doesn't exist > save it to session
        array_push($lastViewedLocation, $aid);
        $_SESSION['lastViewed'] = $lastViewedLocation;  
    }       
}

在此之后，我尝试将会话数组保存到变量并在其他文件的屏幕上打印。使用以下代码：

$lastViewedLocation = $_SESSION['lastViewed'];
            foreach($lastViewedLocation as $lastViewedAtt) {
            echo $lastViewedAtt;
            }

没用。

Answer 1

我尝试用 var_dump 检查我的数组。据说它是NULL。所以在开始时删除了 if 子句，这样代码肯定会执行，所以至少会话将在零索引上设置 $aid 。但它仍然是 NULL。

这里我得出的结论是 $aid 没有通过，所以我把代码从 header.php 放到 _test.php 文件中，代码实际上在那里工作。但我做了一些调整 > 当数组填充了 5 个元素时，代码没有停止。所以我稍微调整了一下。以下是工作版本。谢谢大家的意见。

                            if (isset($_SESSION['lastViewed'])) {
                                $lastViewedLocation = $_SESSION['lastViewed'];
                                $numLastViewed = 5;     
                                $takenIndex = count($lastViewedLocation);       
                                //check if array is full 
                                if($takenIndex < $numLastViewed)
                                {   //push element on end of array 
                                    array_push($lastViewedLocation, $aid);
                                    $_SESSION['lastViewed'] = $lastViewedLocation;
                                }else
                                {//delete first item and add current item to end of array
                                    $sub = array_shift($lastViewedLocation);
                                    array_push($lastViewedLocation, $aid);
                                    $_SESSION['lastViewed'] = $lastViewedLocation;
                                }

                            }else
                            {   //if first element doesn't exist > save it to session
                                $_SESSION['lastViewed']= array(0 => '$aid');

                            }

使用此代码，数组就像具有给定限制的队列。元素一个一个地进入队列，直到数组中的元素数量达到限制。然后删除队列中的第一个元素，并将新元素添加到队列的末尾。这一直持续到会话被销毁。

如何记住上次访问的项目

How to remember last visited items

php

arrays

queue

session