Chapter 8 and register_globals off

Oregon · August 25th, 2003, 04:32 PM

I've had fun with the workarounds on the book examples in Chapter 8 (that work fine with register_globals on), adjusting them to work with register_globals off.

In the Using Cookies... example on page 283, I either couldn't get the cookies to set, or I just couldn't access them as array elements.
By assigning the cookie as a regular variable (say, "font_type"), I could read the cookie by accessing the (persisting) $HTTP_COOKIE_VARS[font_type] variable. This variable wouldn't let me access an array element (ie. $HTTP_COOKIE_VARS[font[type]]).

I'm new to PHP, so maybe I'm missing something, but it looks to me that the register_globals variable is quite infused in the supporting code? I've used session_register() and had strange results and had to rely on the super global variables
(ie $_SESSION[type_sel]) to gain persistence.

Has anyone else seen the same thing? I tried to stay as close to the original example code as possible. My stuff's working, but it's not what I thought it would look like.

The GLOBALS array in the page count example, with the format as:
$GLOBALS["view${whichpage}count"], doesn't work with register_globals off.

I noticed that the super global variable:
$_SESSION['view${whichpage}count'] looks like it should work, but it doesn't. For example:

for ($i = 1;$i <= 4;$i ++) {
 $_SESSION['whichpage[$i]'] = 0;
 // this really only sets $whichpage and not it's elements...
 $_SESSION['view${i}count'] = 0; // same here.

For what it's worth, this is my workaround on the page_count example,
with register_globals off:

<?
session_start();
if ($_SESSION['status'] != "underway") {
 $_SESSION['view1count'] = 0;
 $_SESSION['view2count'] = 0;
 $_SESSION['view3count'] = 0;
 $_SESSION['view4count'] = 0;
 $status = "underway";
 $_SESSION['status'] = $status;
}
?>

<?
// page_count.php
// this doesn't work exactly like the original. the results are the same though.

echo "<html><head><title>Web Page Hit Counter</title></head><body></body>";

$whichpage = $_GET['whichpage'];
if ($whichpage) {
 echo "You are currently on page $whichpage. \n";
 switch ($whichpage) {
 case $whichpage = 1:
 $_SESSION['view1count']++;
 break;
 case $whichpage = 2:
 $_SESSION['view2count']++;
 break;
 case $whichpage = 3:
 $_SESSION['view3count']++;
 break;
 case $whichpage = 4:
 $_SESSION['view4count']++;
 default:
 break;
 }
}

for ($i = 1; $i<=4; $i++) {
 if ($whichpage == $i) {
 echo "<a href=\"$PHP_SELF?".SID."&whichpage=$i\">Page $i</a>";
 }
 else {
 echo "<a href=\"$PHP_SELF?".SID."&whichpage=$i\">Page $i</a>";
 }
 switch ($whichpage) {
 case $whichpage = 1:
 $page_count = $_SESSION['view1count'];
 $_SESSION['page1count'] = "$page_count times.";
 break;
 case $whichpage = 2:
 $page_count = $_SESSION['view2count'];
 $_SESSION['page2count'] = "$page_count times.";
 break;
 case $whichpage = 3:
 $page_count = $_SESSION['view3count'];
 $_SESSION['page3count'] = "$page_count times.";
 break;
 case $whichpage = 4:
 $page_count = $_SESSION['view4count'];
 $_SESSION['page4count'] = "$page_count times.";
 break;
 default:
 break;
 }
 $page_string[1] = $_SESSION['page1count'];
 $page_string[2] = $_SESSION['page2count'];
 $page_string[3] = $_SESSION['page3count'];
 $page_string[4] = $_SESSION['page4count'];
 echo " which you have chosen ";
 echo " $page_string[$i] \n";
}
echo "\n\n \n\n";
echo "</body></html>";

?>

richard.york · August 30th, 2003, 01:33 PM

Hi Oregon,

In the Using Cookies... example on page 283, I either couldn't get the cookies to set, or I just couldn't access them as array elements.
By assigning the cookie as a regular variable (say, "font_type"), I could read the cookie by accessing the (persisting) $HTTP_COOKIE_VARS[font_type] variable. This variable wouldn't let me access an array element (ie. $HTTP_COOKIE_VARS[font[type]]).

As far as this goes you should set up sub-elements in the proper array syntax.

$HTTP_COOKIE_VARS[font[type]]
should be
$_COOKIE["font"]["type"];
Because what you're really trying to do is create a multi-dimensional array.
This would correspond to
$font["type"] with the register_globals directive turned on.

Try to avoid the deprecated globals, i.e. HTTP_*_VARS
Stick with the one word capitalized superglobal array names like $_POST, $_GET, $_COOKIE... etc.

All code can be transformed to work with the register_globals directive being turned off! So don't get discouraged if what appears to be a sound theory doesn't immediately work out.

$PHP_SELF should also be changed to $_SERVER["PHP_SELF"];

I realize also that Beginning PHP4 has used the single '<?' opening statement throughout many of the books examples but this should be avoided too. Always use '<?php' which is 1.) XML compliant and 2.) Gauranteed to be portable, as the '<?' opening delimiter is not always turned on in php.ini.

Code:

<?php
session_start();
if ($_SESSION['status'] != "underway") {
   $_SESSION['view1count'] = 0;
   $_SESSION['view2count'] = 0;
   $_SESSION['view3count'] = 0;
   $_SESSION['view4count'] = 0;
   $_SESSION['status'] = "underway";
}
?>

<?php
// page_count.php
// this doesn't work exactly like the original. the results are the same though.

echo "<html><head><title>Web Page Hit Counter</title></head><body></body>";

Another of the many blunders of the PHP4 book is its inability to show explicit examples, using if($_GET["whichpage"]) is a bad idea... you should be more explicit.

Use the empty() function which checks for null value and the isset() function which checks for a variable's existence.
Ok let's walk through your code and have a look at some of your mistakes.


if (isset($_GET["whichpage"]) && !empty($_GET['whichpage'])) {

    echo "<b>You are currently on page {$_GET['whichpage'}.</b><br><br>\n";

    switch ($_GET['whichpage') {

        # Since the switch control structure is already looking at the value
        # of $_GET["whichpage"], including the comparision operator in the 
        # case statement is not neccessary.  
        # Actually in your code you use the assignment operator which 
        # would not provide the desired result, you're just overwriting the value of $whichpage
        # I also like to stick with the superglobal array throughout a script
        # In the long run it makes things much easier to understand

        case 1:
            $_SESSION['view1count']++;
            break;

        case 2:
            $_SESSION['view2count']++;
            break;

        case 3:
            $_SESSION['view3count']++;
            break;

        case 4:
            $_SESSION['view4count']++;
            break;

        default:

    }

}

for ($i = 1; $i<=4; $i++) {

    /* Sometimes in a windows enviornment the $_SERVER["PHP_SELF"] variable does not have a value.  This workaround will fix that */

    if (!isset($_SERVER["PHP_SELF"]) || empty($_SERVER["PHP_SELF"])) {

        $_SERVER["PHP_SELF"] = $_SERVER["SCRIPT_NAME"];

    }


    if ($_GET["whichpage"] == $i) {

        echo "<b><a href=\"{$_SERVER["PHP_SELF"]}?".SID."&whichpage=$i\">Page $i</a></b>";

    } else {

        echo "<a href=\"{$_SERVER["PHP_SELF"]}?".SID."&whichpage=$i\">Page $i</a>";

    }

       switch ($_GET["whichpage"]) {

         case 1:

            # don't write more code than you have to
            $_SESSION['page1count'] = $_SESSION['view1count']." times.";
                  break;

        case 2:

                  $_SESSION['page2count'] = $_SESSION['view2count']." times.";
                  break;

        case 3:

            $_SESSION['page3count'] = $_SESSION['view3count']" times.";
            break;

        case 4:

            $_SESSION['page4count'] = $_SESSION['view4count']." times.";
            break;

        default:
            #No need to break; the default statement as there is not another statement to fall through to

       }

    $page_string[1] = $_SESSION['page1count'];
    $page_string[2] = $_SESSION['page2count'];
    $page_string[3] = $_SESSION['page3count'];
    $page_string[4] = $_SESSION['page4count'];

    echo " which you have chosen ";
    # Get used to using curly syntax in everything!  
    echo " {$page_string[$i]}<br>\n";
}

echo "\n\n \n\n";
echo "</body></html>";

I have no idea if this completely fixes your code, I just fixed all the obvious errors that I saw. Much of what you wrote could be much more easily accomplished with a loop.

Your code could be written in this simplified equivilent (minus the errors!):

Code:

<?php

session_start();

    if ($_SESSION["status"] != "underway") {

        $_SESSION["view1count"] = 0;
        $_SESSION["view2count"] = 0;
        $_SESSION["view3count"] = 0;
        $_SESSION["view4count"] = 0;
        $_SESSION["status"]     = "underway";

    }

    if (isset($_GET["whichpage"]) && !empty($_GET["whichpage"])) {

        echo "<b>You are currently on page {$_GET["whichpage"}.</b><br><br>\n";   

        if (!isset($_SERVER["PHP_SELF"]) || empty($_SERVER["PHP_SELF"])) {

            $_SERVER["PHP_SELF"] = $_SERVER["SCRIPT_NAME"];

        }

        for ($i = 1; $i <= 4; $i++;) {                    

            if ($_GET["whichpage"] == $i) {

                $_SESSION["view{$i}count"]++;

                $_SESSION["page{$i}count"] = $_SESSION["view{$i}count"]." times.";
                echo "<b><a href=\"{$_SERVER["PHP_SELF"]}?".SID."&whichpage=$i\">Page $i</a></b> | ";


            } else {

                echo "<a href=\"{$_SERVER["PHP_SELF"]}?".SID."&whichpage=$i\">Page $i</a>";

            }

            $page_string[$i] = $_SESSION['page{$i}count'];

            echo " which you have chosen ";
            echo " {$page_string[$i]}<br>\n";

        }        

    }

?>

Try that out and let me know how it goes.

: )
Rich

:::::::::::::::::::::::::::::::::
Smiling Souls
http://www.smilingsouls.net
:::::::::::::::::::::::::::::::::

MikeCassidy · July 24th, 2005, 01:16 PM

I'm not sure anyone is still reading the forum BUT this code will not let you ever get started:

session_start();

if ($_SESSION["status"] != "underway") {

$_SESSION["view1count"] = 0;
$_SESSION["view2count"] = 0;
$_SESSION["view3count"] = 0;
$_SESSION["view4count"] = 0;
$_SESSION["status"] = "underway";

}

if (isset($_GET["whichpage"]) && !empty($_GET["whichpage"])) {

When you start whichpage is empty so you never start the program.
I changed it to:

 if (isset($_GET["whichpage"]) || ($_SESSION["status"] == "underway")) {

and everything is nifty.
Complete code:

<?php

session_start();
header("Cache-control: private"); // IE 6 Fix.

 if ($_SESSION["status"] != "underway") {
 $_SESSION["view1count"] = 0;
 $_SESSION["view2count"] = 0;
 $_SESSION["view3count"] = 0;
 $_SESSION["view4count"] = 0;
 $_SESSION["status"] = "underway";

 }

 if (isset($_GET["whichpage"]) || ($_SESSION["status"] == "underway")) {

 echo "You are currently on page {$_GET["whichpage"]} . \n";

 if (!isset($_SERVER["PHP_SELF"]) || empty($_SERVER["PHP_SELF"])) {

 $_SERVER["PHP_SELF"] = $_SERVER["SCRIPT_NAME"];

 }

 for ($i = 1; $i <= 4; $i++) {
 if ($_GET["whichpage"] == $i) {

 $_SESSION["view{$i}count"]++;

 $_SESSION["page{$i}count"] = $_SESSION["view{$i}count"]." times.";
 echo "<a href=\"{$_SERVER["PHP_SELF"]}?".SID."&whichpage=$i\">Page $i</a> | ";

 } else {

 echo "<a href=\"{$_SERVER["PHP_SELF"]}?".SID."&whichpage=$i\">Page $i</a>";

 }

 $page_string[$i] = $_SESSION["page{$i}count"];

 echo " which you have chosen ";
 echo " $page_string[$i] \n";

 }

 }

?>

jerryschwartz · July 26th, 2005, 03:26 PM

This example, like every other one I've tried, is riddled with problems. It uses a deprecated way of setting session variables, and the second if statement (which is supposed to put the current page in bold) is just wrong.

I bought the book last week, and wish I could get my money back.