PHP Books left me in the dark?

dpoincelot

Hi, I've ben studying PHP for a few months now. I read two books about building basic applications and recently built a literature library with great success.

HOWEVER, after importing the file over to the server, my page was filled with errors about variables being undefined. This was a bit puzzling to me since the application worked fine on my laptop. I did some searching and discovered the "isset function", something my books didn't even discuss. My question is, why didn't I need this "isset" function on my laptop and do I have to use "isset" everywhere a new variable is listed in the code? For example, I have a switch statement that isn't working, do I need to use "isset" since the variable is being passed through the URL, like so?

switch (isset($HTTP_GET_VARS["mod"]))

Man those books left me in the dark on this one.

Thanks any help,
Dan

cgraz

Are you using different versions of PHP on your lap top and where the site is now?

I can't answer your isset() question or about the variables being undefined, but if you are using a different version of php, you can try

$_GET_['mod']

I'm not quite sure of the version numbers, but I think older versions of PHP used $HTTP_GET_VARS and newer versions now use $_GET.

I could be wrong here--hopefully someone will correct me if I am. 😉

Cgraz

marcnyc

As a beginner myself, I have never used isset() but it's always good to know what you are working on, so I'd suggest you upload a file to your server that contains the code

<? phpinfo() ?>

and compare it with the one on your laptop. [MANUAL]phpinfo[/MANUAL] will give you all info about your server configuration!

planetsim

No cgraz you are quite right there. Why do a phpinfo();

When you can just do phpversion();
which just tells what version you have. Im not entirely sure when the $_GET came in but

4.0.6 was i think the last to use HTTP_GET_VARS

cgraz

Thanks planetsim. I was pretty sure, but didn't want to give anyone wrong information.

Thanks for the confirmation. 😉

Cgraz

Jedi_Legend

Originally posted by planetsim
No cgraz you are quite right there. Why do a phpinfo();

When you can just do phpversion();
which just tells what version you have. Im not entirely sure when the $_GET came in but

4.0.6 was i think the last to use HTTP_GET_VARS

It's always good to do php_info() anyway, as it gives you a lot more useful information than phpversion().

I do believe HTTP_GET_VARS wasn't changed until version 4.1.0 and I think it is still supported by the latest versions.

dpoincelot

Hi guys,

I'm using version 4.2.3 both on the laptop and on the server. The only difference is that I'm running Apache on the laptop and IIS on the server.

I tried changing HTTP_GET_VARS to GET, but that still didn't work. The only thing that seems to work is using isset() or empty() and validate all variables. The below code works, but its a real pain to implement throughout the page:

if (!empty($HTTP_GET_VARS["mod"])) {
$mod = $HTTP_GET_VARS["mod"];
} else {
$mod = "";
}

switch ($mod) {

Any ideas on how to avoid this approach, it seems like I'm doing something wrong?

Even a statement as simple as this isn't working:

$rowset = $dbclass->database_sql("SELECT * FROM lit_library WHERE id = '$id'");
while ($rows = mssql_fetch_array($rowset)) {
$lit_id = $rows[id];
$lit_title = $rows[title];
$lit_category = $rows[category];
$lit_subcategory = $rows[subcategory];
$lit_date = $rows[date_entered];
$lit_description = $rows[description];
$lit_state = $rows[state_province];
$lit_website = $rows[website];
$lit_document = $rows[document];
$lit_archive = $rows[archive];
}

It says "Use of undefined constant" for all the $row variables?

Please Help!

Thanks

dpoincelot

o.k. figured out one part, this:

Needed to have quotes, for some reason the laptop let me get away without them, should have been $lit_id = $rows["id"];

Slowly but surely...

Fubear

The problem with the undeclared variable errors lies in the server config.

If you try to use a variable without declaring it, you will get a NOTICE error. The server on IIS reports all errors as a default i believe, where the apache server is set to ignore them.

To fix:
error_reporting (E_ALL ^ E_NOTICE);

basically saying "Report all errors except Notice errors"

dpoincelot

Is it then considered poor technique to turn the error checking off? Is the right way to initialized variables?
Thanks, Dan

Fubear

There is no right or wrong way to write PHP, there is only style.

I prefer to "IF (!$var)" than "IF(!isset($var))"

Notice errors are non-critical errors, and only inform you of 'improper' programming techniques such as undeclared variables, but in an environment such as PHP it shouldnt impact the overall operation of your code.

I with ALL errors on your are forced to write in a 'safer' style, but it wont make much of a differance to what your code is doing (but you may pickup some bad programming habits should you migrate to another language).

Write in the style you feel most comfortable with.