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Dave — Tue, 07 Sep 2010 00:59:32 +0000

PC Desk

Desk that also doubles as acomputer. Designed by Sung-kyu Nam.

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Some useful PHP functions

Admin — Fri, 16 Apr 2010 01:10:58 +0000

Recently, I have noticed that I use the same exact functions over and over again in PHP. I’ve actually set-up a complete function list that I tend to include in all of my projects. Here is an overview of some of them.

Let’s connect

You will need to connect to your database from time to time. It is important to do that in most projects that deal with MySQL, and you’ll probably do it frequently, on every page. Now, you can either delete that “function CustomConnect” and the braces and simply include() this part as a file orrr, just add this to your function list and call it up whenever you need it:

function CustomConnect () {

// MySQL variables
$host = 'localhost';
$user = 'username';
$pass = 'password';
$db = 'database';

//connect
global $connection;
$connection = mysql_connect($host, $user, $pass) or die ("Unable to connect!");
//database select
mysql_select_db($db) or die ("Unable to select database!");
}

I have used this function numerous times before and yes, it works. This is the standard MySQL connection. I set up the variable $connection as global so that variable can be used outside of the function. Why do we need that? You will need that for your mysql_close() function where you will use $connection as your argument variable (inside the parentheses). That will, obviously, close the connection to the mysql database.

Change the username, password, and database according to your own website. Tweak the function as needed. I found it bare-boned and just as I need it for my purposes but you can add default variables, make it more of a “function” if you catch my drift.

Let’s Authenticate

Authentication is essential when creating an admin-side for a website. What does it mean? It means that PHP checks if you are, indeed, the logged in user, and if you have permission to see the site. The PHP is rather simple but effective!

function Authenticate () {
session_start();

if (!$_SESSION['auth'] == 1 || isset($_GET['logout'])) {
    // check if authentication was performed
    // else die with error
	session_destroy();
	header("Location: login.php");
}

}

First, we start a session, this tells the server that we are going to use a session. Next, with an “if” loop, we check if the session variable “auth” is set to one, change this however you need to to indicate that a user is logged in. The $_SESSION[''] variable, if you did not know already, stores variable and information between pages. That means that you don’t need to keep using a “post” form to pass the data along. All of it is there in the session, and can be called up whenever.

As you can see, if either the authentication is not set or the $_GET['logout'] variable is set, you will be redirected to login.php. Basically, this is how you log out! You can set up a button or a link to make this work.

This, again, is a bare-boned function. You can add global variables to call on the session variable username or other information.

Let’s Validate

This part is a bit harder.The way I validate is lengthy and redundant, very redundant. Perhaps even wasteful but it works for me and I can sleep soundly because everything is validate correctly. I set up SEVERAL functions to do this:


function isEmailAddress($value) {
        return eregi('^([a-z0-9])+([\.a-z0-9_-])*@([a-z0-9_-])+(\.[a-z0-9_-]+)*\.([a-z]{2,6})$', $value);
    }

function isAlpha($value) {
        return preg_match('/^[a-zA-Z]+$/', $value);
    }
function Alphanum ($value) {
		return preg_match("/^[a-z0-9]+([\\s]{1}[a-z0-9]|[a-z0-9])+$/i", $value);
	}

function name ($var) {
	if (!isAlpha($var)){
	return TRUE;
	}
}

function email ($var) {
	if (!isset($var)){
	return TRUE;
	}
	if (empty($var)){
	return TRUE;
	}
	if (trim($var) == ''){
	return TRUE;
	}
	if (isEmailAddress($var) == 0){
	return TRUE;
	}
}
function message ($var) {
	if (!isset($var)){
	return TRUE;
	}
	if (empty($var)){
	return TRUE;
	}
	if (trim($var) == ''){
	return TRUE;
	}

I told you it was lengthy! All these functions are essential, you may combine some of the “if” statements together with an || or && but I like to keep them separate. As you can see, there are two separate functions above that check for an e-mail address, this is done with pattern recognition. The next function isAlpha does the same but only for alpha characters, Alphanum does the same except that it includes numeric characters. The next three functions (name, email, and message) combine these along with a few “if” statements that check that data has, indeed been submitted via empty($var), trim($var), and other functions already included within PHP. Notice that you will be returned a TRUE value for all of these, meaning that if something is wrong, the result will be true. Use it like this:

if (message($_GET['submittedmessage'])) { echo "Something is wrong";}

And that’s it. If something is wrong, PHP will be echo out “Something is wrong”.

Let’s show some stuff

I like to keep handy one other function that deals with showing the latest entries in a MySQL database. I call it the “ShowComments” function because that is what I originally used it for. You will have to set up this function for each site you’ll use (ie. the rows and stuff like that) but here is what mine generally looks like:

function ShowComments ($var, $where = '') {

$query = "SELECT * FROM database_name $where ORDER BY id DESC";

    // execute query
    $result = mysql_query($query) or die ("Error in query: $query. ".mysql_error());

	if (mysql_num_rows($result) > 0) {
				$x = 1;
		while($row = mysql_fetch_row($result) AND $x <= $var) :
			$link = $_SERVER['PHP_SELF']."?id=".$row[0];
       		echo "To: ".stripslashes($row[1])."";
        	echo "" .stripslashes($row[2])."";
			echo "permalink  ";
			echo substr($row[3], 0, 10)."";
			echo "
			";
			$x++;
		endwhile;
	}
}

I used this function on one of my latest projects (so ignore the id’s). You can add another parameter into the function to change table names on the go but I usually use this for only one table, such as comments, or a feed. I added the $where part so that I can pick out specific rows rather than just all of them at once. Note that you will have to write the entire “where” statement ie. WHERE id=4 not just id=4, okay? Good.

Here’s an example of how I used it:

Notice how I used it two separate times. Once to show the fave latest comments, the second time to show one specific comment with a specific (escaped) id.

Well, this is it. I hope these functions gave you some insight on how you can speed up your work!

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Just a little stupid Javascript App

Admin — Sun, 21 Mar 2010 18:56:37 +0000

Remember how I promised I would learn Javascript so many times in the past? Well, I finally got around to learning some of the basics. And just like I did with PHP when I was learning it, I decided to create a simple application. I could not come up with a good idea so my friend suggested one and within a couple of hours I finished it.

Here is the demo. I received some positive feedback from a lot of people so I thought I’d show how I, first of all, made it and how it helped me learn Javascript.

The Concept

Okay, the concept was to create a site wherein one would receive advice to a question with a general advice quote or whatever else. Basically, a sentence or two that would guide the user. It works in a similar way as one of my older projects Only A Quote, except this is pure javascript, no databases, and no php at all.

The idea is to set up variables, actually strings, that contain the quotes. One string = one quote. And then access these strings randomly. The access has to be inside the HTML (ie. no refreshing) and I want the text to fade out and fade back in with the advice quote.

Another thing I wanted to do was to have the answer appear in a teacup, etc. I’ll explain some of the basic CSS to do that, and same with how to create the cup in photoshop (I hate doing in-depth photoshop tutorials)

Variables

Believe it or not, I stored all of the quotes in a single variable, a single array actually. Here is how you go about it:

var answer = new Array();

answer[0] = "Never miss an opportunity to make others happy, even if you have to leave them alone in order to do it.";

answer[1] = "You can tell more about a person by what he says about others than you can by what others say about him. ";

answer[2] = "Seek freedom and become captive of your desires.  Seek discipline and find your liberty.";

You can add as many answers as you wish, the only thing you have to do is follow the format: answer[next number] = “Answer text”;

Also, to initialize a variable just add the “var” in front of the variable name, an equal sign and the variable contents. Since this is an array I defined variable as an array by adding “new Array()”.

Text and the Form

The next thing we have to do is create the text field we want to dynamically change and the form to initialize several functions that will change the text, and do the fading.

This is the easiest part:

What's your cup of tea?

The paragraph Id-ed “Ans” is the place where the answer will appear. I created a form with an “onclick” event that points to the “TextStuff()” function. You can use basically anything for the onclick button. A div with an onclick, a textfield, anything at all but a button is rather convenient so I used that. You don’t have to Id anything other than the paragraph.

Functions

Next, let’s create a function that will change the text. I’m going to call it “message()”.

function message() {
var ArrayLength = answer.length;
var r=Math.floor(Math.random()*ArrayLength);
document.getElementById('Ans').innerHTML = answer[r];

}

Let me explain this.First, I created a new variable that will get the number of array elements in my array. You can use the “.length” on any variable. For a string, the return value will be the number of characters. For an array, it will get the number of elements. The next variable “r” creates a random number with “Math.floor(Math.random()*number)”, you can replace “number” with any number that will be the ceiling for the random integer. For example, if you put 5 there, the random number will be between 0 and 5. By using putting “ArrayLength” there, you won’t have to keep changing this value if you add new quotes.

The last part basically means “in this document getElementById called (‘Ans’) and do innerHTML so that answer[r] is the new value for the element with the ‘Ans’ Id”. This will change the text within the paragraph Id-ed Ans.

The Fade Function

The next big thing I tackled was fading the text in and out. The problem here is is that I could not find a regular javascript function that could do this and I’m not skilled enough to figure it out myself. I took a shortcut and used JQuery.

Put that in your header to include the latest JQuery version.
Next, we will use the fadeIn and fadeOut JQuery functions. First, did you notice how the previous function I created is called “message()” while the onclick function is called “TextStuff()”? Well, here is where we create our “TextStuff()” function.

function TextStuff() {
$("p").fadeOut("slow");
var t=setTimeout("message()", 2000);
}

Okay, first of all. JQuery functions do not work the same as regular javascript functions because JQuery is a framework and it has its own rules. Let me explain how this particular instance works. “$(“element“).fadeOut(speed, function to call);” I used the “p” (paragraph) element but you can use any other, even an #id. There are several speed settings such as “slow”, “fast”, or you can just put milliseconds there.

Second, I set the “message()” function to execute 2000 milliseconds (2 seconds) after the text fades out. the setTimeout function does this latent execution. You can replace the 2000 with any number you want.

Next I added a fadeIn function into the message() function.

$("p").fadeIn("slow");

Just put this at beginning of the function before the ArrayLength variable.

Where to put all this stuff

This is the easy part. Put the functions in the header along with the call to the JQuery script. You can put the variable there as well or you can create a .js file with all the answers and call onto that like so:

Don’t use the