使用php分页时避免丢失POST数据

Question

I am working on a renting website that transfer date from page to another, for example the user enter a date and some information and when he goes to another page he should find the information that he entered in the first page. Everything works fine except that when I add pagination like this: [1] [2] [3] [4] every time I click on a page number in the pagination the POST data will be lost. For example if I clicked number 2 in the pagination I get this message:

Undefined index: date......

I found some solutions which is using get method but I don't know how to use get method in this situation.

What should I change to my code to avoid losing POST data?

here is my full code:

 <?php
$date= $_POST['date']; // the post data from previous page
$info= $_POST['info']; // the post data from previous page

?>  


<form action="next_page.php" method="post" name="myForm"> 


<input name="date" type="hidden" value="<?php echo $date; ?>" />
<input name="info" type="hidden" value="<?php echo $info; ?>" />




<?php

include(db.php);


$q="select count(*) \"total\"  from users";
$ros1=mysql_query($q,$link);
$row=(mysql_fetch_array($ros1));
$total=$row['total'];
$dis=8;
$total_page=ceil($total/$dis);


$page_cur=(isset($_GET['page']))?$_GET['page']:1;
$k=($page_cur-1)*$dis;

$query="SELECT * FROM cars limit $k,$dis";
$ros=mysql_query($query,$link);

while($row = mysql_fetch_array($ros))
{

 echo  $row["user_id"];

echo  $row["user_name"];

echo  $row["user_email"];
}
for($i=1;$i<=$total_page;$i++){
if($page_cur==$i){
echo ' <input type="button" value="'.$i.'"> ';
}
else{
echo '<a href="carstype.php?page='.$i.'"> <input type="button" value="'.$i.'"> </a>';
}}
?>
<input  type="submit" name="userId" value="' .$row['user_id'] . '" /> 

</form>  

Answer 1

You should store this information somewhere between your http-requests. There are some possible solutions for that:

1. you can store this information in the database
2. in session (temporarily store, if you don't need this data in your database)
3. store in every html page as a hidden field

Answer 2

You can use PHP sessions to store users input on the server:

PHP Sessions

Keep all the data in $_SESSION and read it from there when it's needed in the page. Update the stored values when the users inputs something new.

Answer 3

You should use GET method instead of POST method.

    <?php
$date = $_GET['date']; // the post data from previous page
$info = $_GET['info']; // the post data from previous page
?>  


<form action="next_page.php" method="get" name="myForm"> 


    <input name="date" type="hidden" value="<?php echo $date; ?>" />
    <input name="info" type="hidden" value="<?php echo $info; ?>" />




    <?php
    include(db . php);


    $q = "select count(*) \"total\"  from users";
    $ros1 = mysql_query($q, $link);
    $row = (mysql_fetch_array($ros1));
    $total = $row['total'];
    $dis = 8;
    $total_page = ceil($total / $dis);


    $page_cur = (isset($_GET['page'])) ? $_GET['page'] : 1;
    $k = ($page_cur - 1) * $dis;

    $query = "SELECT * FROM cars limit $k,$dis";
    $ros = mysql_query($query, $link);

    while ($row = mysql_fetch_array($ros)) {

        echo $row["user_id"];

        echo $row["user_name"];

        echo $row["user_email"];
    }
    for ($i = 1; $i <= $total_page; $i++) {
        if ($page_cur == $i) {
            echo ' <input type="button" value="' . $i . '"> ';
        } else {
            echo '<a href="carstype.php?page=' . $i . '&date=' . $date . '&info=' . $info . '"> $i </a>';
        }
    }
    ?>
    <input  type="submit" name="userId" value="' .$row['user_id'] . '" /> 

</form>

Answer 4

A good way in my opinion is to start the seach with a POST form and if the results exceed a limit then construct pagination links which really are post forms incorporating the search keyword and target page in the form of hidden variables.

Passing the search keyword as a get parameter needs care (url encode) because urls have limits on the characters they allow (ascii letters and digits, and characters such as /, ~, -, _ etc ) for example a user might search for something in japanese or greek or use symbols.

Passing the search keyword as a session variable also needs care. Consider this scenario: a user has opened multiple result pages, but all pages will hereafter have access to the last processed session saved keyword. Also storing the search keyword in a session requires coordination by the developer such as when to destroy the session variable etc.