how to submit a form to another page in wordpress plugin

Question

I am developing a wordpress plugin , which submits a form to another page. But when I try to submit the form to another page , then that page returns some php error. My form code is below

echo "<form action='".plugins_url()."/wp_voting_poll/frontend_poll_process.php'     method='post'>";
echo "<input type='hidden' name='hide' value='$ques' />";
        $total_vote_count = $wpdb->get_var( "SELECT COUNT(*) FROM $table_result WHERE question_uid='$ques'" );
        if($ques!=""){
        echo "<table>";

        foreach($ans_data as $ans_res){

         //   $ans=$ans_res->answer;
         $answer_id=$ans_res->id;
         $type=$ans_res->answer_type;


               $vote_count = $wpdb->get_var( "SELECT COUNT(*) FROM $table_result WHERE answer_id='$answer_id'" );
                if($vote_count==0){
                    error_reporting(0);
                }
                $vote_percent=($vote_count*100)/$total_vote_count;
             echo "<tr> <td>";  
           echo "<div class='answer_div'>";    
               if($type==1){
             echo "<div class='input'><input type='radio' name='ans_name[]' value='$answer_id'/>".$ans_res->answer."<br/></div>";
             }
             elseif($type==0){

             echo "<div class='input'><input type='checkbox' name='ans_name[]' value='$answer_id'/>".$ans_res->answer."<br/></div>";
             }
             if($backend==0){
             echo "</td> <td>";


             echo "<h4> total vote counted $vote_percent% </h4>";

            // echo "<img src='$url' width='$width_img'/>";
             $bar=$vote_percent*5.9;
             echo "<img src='$url' height='10' width='$bar' />";        

             echo "</td></tr>";
             }
        }
        echo "</table>";

        echo "<input type='submit' value='Submit vote' />";
        echo "</form>";

And this is my code of another page , which should process the form . But unfortunately it returns php error.

<?php

require_once("function_ip.php");
$vote_result=$_POST['ans_name'];
$uid=uniqid();
global $wpdb;
$table_vote=$wpdb->prefix."poll_answer_result";
$count=count($vote_result);
 $hidden=$_POST['hide'];

$ans_data=$wpdb->get_results("SELECT  * FROM $table_vote WHERE question_id='$hidden'" );

if($count>0){
foreach($vote_result as $vote_arr){

    $wpdb->insert($table_vote,
                array('answer_id' => $vote_arr,
                      'ip' =>get_client_ip(),  
                      'question_uid' => $hidden
                        ));
 }

}

?>

Answer 1

Wordpress has a generic handler to deal with all forms - admin-post.php.

If you include a hidden field in your form called action, you can then hook in to a function of your choice with all the goodness of wordpress included.

echo "<form action='".get_admin_url()."admin-post.php' method='post'>";

    echo "<input type='hidden' name='action' value='submit-form' />";
    echo "<input type='hidden' name='hide' value='$ques' />";

    { Enter the rest of your first block of code from above here }

echo "</form>";

And then in your functions.php file (or any other php file that you have included via functions.php), you can use this method.

add_action('admin_post_submit-form', '_handle_form_action'); // If the user is logged in
add_action('admin_post_nopriv_submit-form', '_handle_form_action'); // If the user in not logged in
function _handle_form_action(){

    { Enter your second block of code from above here }

}

I'm not sure if you require a redirect once you reach your desired destination, but that can be easily accounted for if you do.

And one final question - is this form on the front end, or in the admin area? Not that it should make a difference that this answer, I'm just curious...