How to use a variable in 2 different Php files? - php

Question

I have am creating a Website that showes Visitors Info. Users are able to visit the page and use Textarea to pick a name for their URL, and the name will be saved as a table in mysql database..
I am using the $name variable in my first php file which is a replacement for the text "visitor_tracking". But today I noticed that there is also another php file and more sql codes, and once again I can see that this file also has the "visitor_tracking" text used in the sql code.
But I think I failed big time, because I simply dont know how to replace the "visitor_tracking" text with my the variable name called $name.
<?php
//define our "maximum idle period" to be 30 minutes
$mins = 30;
//set the time limit before a session expires
ini_set ("session.gc_maxlifetime", $mins * 60);
session_start();
$ip_address = $_SERVER["REMOTE_ADDR"];
$page_name = $_SERVER["SCRIPT_NAME"];
$query_string = $_SERVER["QUERY_STRING"];
$current_page = $page_name."?".$query_string;
//connect to the database using your database settings
include("db_connect.php");
if(isset($_SESSION["tracking"])){
//update the visitor log in the database, based on the current visitor
//id held in $_SESSION["visitor_id"]
$visitor_id = isset($_SESSION["visitor_id"])?$_SESSION["visitor_id"]:0;
if($_SESSION["current_page"] != $current_page)
{
$sql = "INSERT INTO visitor_tracking
(ip_address, page_name, query_string, visitor_id)
VALUES ('$ip_address', '$page_name', '$query_string', '$visitor_id')";
if(!mysql_query($sql)){
echo "Failed to update visitor log";
}
$_SESSION["current_page"] = $current_page;
}
} else {
//set a session variable so we know that this visitor is being tracked
//insert a new row into the database for this person
$sql = "INSERT INTO visitor_tracking
(ip_address, page_name, query_string)
VALUES ('$ip_address', '$page_name', '$query_string')";
if(!mysql_query($sql)){
echo "Failed to add new visitor into tracking log";
$_SESSION["tracking"] = false;
} else {
//find the next available visitor_id for the database
//to assign to this person
$_SESSION["tracking"] = true;
$entry_id = mysql_insert_id();
$lowest_sql = mysql_query("SELECT MAX(visitor_id) as next FROM visitor_tracking");
$lowest_row = mysql_fetch_array($lowest_sql);
$lowest = $lowest_row["next"];
if(!isset($lowest))
$lowest = 1;
else
$lowest++;
//update the visitor entry with the new visitor id
//Note, that we do it in this way to prevent a "race condition"
mysql_query("UPDATE visitor_tracking SET visitor_id = '$lowest' WHERE entry_id = '$entry_id'");
//place the current visitor_id into the session so we can use it on
//subsequent visits to track this person
$_SESSION["visitor_id"] = $lowest;
//save the current page to session so we don't track if someone just refreshes the page
$_SESSION["current_page"] = $current_page;
}
}
Here is a very short part of the script:
I really hope I can get some help to replace the "visitor_tracking" text with the Variable $name...I tried to replace the text with '$name' and used also different qoutes, but didnt work for me...
And this is the call that I used in my 2nd php file that reads from my first php file:
include 'myfile1.php';
echo $var;
But dont know if thats correct too. I cant wait to hear what I am doing wrong.
Thank you very much in advance
PS Many thanks to Prix for helping me with the first php file!

Answer 1

first you need to start session in both pages. it should be the first thing you do in page before writing anything to page output buffer.
In first page you need to assign the value to a session variable. if you don't start session with session_start you don't have a session and value in $_SESSION will not be available.
<?php
session_start(); // first thing in page
?>
<form action="" method="post" >
...
<td><input type="text" name="gname" id="text" value=""></td>
...
</form>
<?PHP
if (isset($_POST['submit'])) {
$name = $_POST['gname'];
//...
//Connect to database and create table
//...
$_SESSION['gname'] = $name;
...
// REMOVE THIS Duplicate -> mysql_query($sql,$conn);
}
?>
in second page again you need to start session first. Before reading a $_SESSION variable you need to check if it has a value (avoid errors or warnings). next read the value and do whatever you want to do with it.
<?php
session_start(); // first thing in page
...
if(isset($_SESSION['gname'])){
// Read the variable from session
$SomeVar = $_SESSION['gname'];
// Do whatever you want with this value
}
?>
By the way,
In your second page, I couldn't find the variable $name.
The way you are creating your table has serious security issue and least of your problems will be a bad table name which cannot be created. read about SQL injection if you are interested to know why.
in your first page you are running $SQL command twice and it will try to create table again which will fail.
Your if statement is finishing before creating table. What if the form wasn't submitted or it $_POST['gname'] was emptY?
there are so many errors in your second page too.