Write to file best practices.

spookztar

I have now spent a couple of months with PHP, getting comfy with working with a database back-end, and now the time has come to try storing and accessing information in files.

In ralation to this, I am looking for information on best practices in regards to both easy access of stored information and being practical in how it is stored (not to mention security). I'm sure there's more than a few trade-of's hidden here...

For example: What is the best way to store database parameters and general account access information? Do you do so, in a long row of constants containing the information? such as this?

define (peter madsen, oux76H9K);
define (rachel stevens, khfMJ747);

Is it more practical to park it in an array indiced by usernames, and then search with a loop from an external file?

$accessinfo["peter madsen"] == oux76H9K;
$accessinfo["rachel stevens"] == khfMJ747;

Which way is the easiest/ best/safest way, to access from an external file needing the information to proceed?

Maybe both of the above are redicilous compared to somekind of simple XML file? (I don't know anything about XML)

I know this is really basic stuff, but I just wanna start off on the right foot, before picking up any bad practices.

Spookztar.

NogDog

I generally like to define constants for any configuration values which are ... well ... constant. That way there is no possibility of overwriting such a value by inadvertently using the same variable name.

spookztar

I see, and the way you would access the information when checking is needed, would be with... A while loop? - searching by the first parameter of the constant (the name) and then parking the second into a variable for comparison with a user supplied string? Both strings md5'ed? Or maybe a foreach?

NogDog

Not exactly sure if this is the sort of thing you're looking for, but as an example of what I'm thinking of:

dbconfig.include.php:

<?php
define('DB_HOST', 'localhost');
define('DB_USER', 'nogdog');
define('DB_PASSWORD', 'abcd1234');
define('DB_NAME', 'my_database');

main script:

<?php
require_once 'dbconfig.include.php';
$dbLink = mysql_connect(DB_HOST, DB_USER, DB_PASSWORD) or 
      die('Could not connect to the database.');
mysql_select_db(DB_NAME) or die('Unable to select database');
?>

If what you're really looking for is something more complex, I guess I need more information about what you want to do.

spookztar

Thanx for you example. You're not far off. What about replacing text? If you create a form where people can create a new username and password. How do you do this best so you don't leave the old info still in the file?

Do you ask for the user to fill in the both the old and new username and password in a form, and then use the info to create a matching sting to the one you want to replace in the file, and then put the new string in it's place with a string_replace? Or is it enough to just search on the constants name?

NogDog

What you're describing is something I would use a database for, not a file. Besides the fact that it would be faster and more secure using a DB, unless you're using a text file with an exactly fixed size that never changes, you cannot change parts of it without re-writing the entire file. Thus, as the file increases in size with more and more users, it becomes slower (plus it's just not as elegant as using a database 🙂 ).

Anyway, if you still want to use a file, then the general procedure would be to load the existing content into an array via the [man]file/man function. Then find the array element you need to change, make the change, then overwrite the old file contents with current contents of the array (using [man]implode/man to convert the array back into a single string value).

spookztar

That's exactly the kind of advice I was looking for, thanks. Could you tell me of any types of situations where using a file is the more preferable approach? If no real good reasons exist, I would rather just stop at the basics of file manipulation, and toss myself at getting comfortable XML-RPC and SOAP.