[RESOLVED] Making Code Reusable and Robust

[StevenJ]

Hi,

I come from a background in C and sed/awk/unix so please be patient with me 🙂

I am trying to make the code I have written more robust, and more modular so that I can re-use many elements (and hopefully speed things up).

I tend to do design in Dreamweaver, and then once happy with the layout/template - I use dreamweaver to create connections etc to the DB so that I can print out records and repeating regions. I then use text editors to "improve" the php to the extent of my knowledge.

That siad, I am now trying to make a function that simply retruns a filename from a database......

One thing that I can't see to understand is the following function.

 image_lib.php
require_once('../Connections/gall_db_con.php');

function get_last_image () {
mysql_select_db($database_gall_db_con, $gall_db_con);
	$query_latest_image = "SELECT id, filename, image_name, protect, active FROM es_img_images WHERE protect = 'N' AND active = 'Y' ORDER BY es_img_images.filename DESC LIMIT 1";
	$latest_image = mysql_query($query_latest_image, $gall_db_con) or die(mysql_error());
	$row_latest_image = mysql_fetch_assoc($latest_image);
	$totalRows_latest_image = mysql_num_rows($latest_image);

mysql_free_result($latest_image);
return ($row_latest_image['filename']);
}

now when I call the function as below, I get a raft of errors:

$a = get_last_image();
echo $a ;

Notice: Undefined variable: database_gall_db_con in E:\es_gallery\includes\image_lib.php on line 6

Notice: Undefined variable: gall_db_con in E:\es_gallery\includes\image_lib.php on line 6

Warning: mysql_select_db(): supplied argument is not a valid MySQL-Link resource in E:\es_gallery\includes\image_lib.php on line 6

Notice: Undefined variable: gall_db_con in E:\es_gallery\includes\image_lib.php on line 8

Warning: mysql_query(): supplied argument is not a valid MySQL-Link resource in E:\es_gallery\includes\image_lib.php on line 8

but yet when I include the following line as pasrt of the function

include('../Connections/gall_db_con.php');

it works 😕 now I undertsand how it works, a little - but I wish to create about 20 functions that all return different images from the database, I surely I don't need to use the include('../Connections/gall_db_con.php'); in each function?

would it also be possible to move the mysql_select_db to outside the function? becuase I only ever select the one database?

regards

StevenJ

[sfullman]

This is a pretty simple one - you need to declare

function whatever(){
//make vars accessible
global $database_gall_db_con, $gall_db_con, [... etc.] ;

}

in php you declare global to make something accessible inside a function, otherwise the function doesn't see ANY variables. The exception is $SESSION['whatever'] (session variables), and $POST['asdf'], $COOKIE['asdf'], $GET['asdf'] (query string variables). Also for the vars above, you could have used $GLOBALS['database_gall_db_con'] vs just $database_gall_db_con.

To get an idea of globals, view a page like this:

<?php
echo "<pre>";
//will show entire var environment
print_r($GLOBALS);

?>

One final thing, you can't declare a part of an array global like $myArray['node1'], only $myArray;

Samuel

[StevenJ]

fantastic sfullman!

thanks.

I did try making the variable global in the inc file:
../Connections/gall_db_con.php

but that produced an error.

so simply, all I need to do,

global $variable_in_inc_file ;

and it's available to the function........

thanks v much.