PHP Include

Without understanding much about the details of PHP, you can save yourself a great deal of time with the use of the PHP include command. include takes a file name and simply inserts that file's contents into the script that issued the include command.

Why is this a cool thing? Well, first of all, this means that you can type up a common header or menu file that you want all your web pages to include. When you add a new page to your site, instead of having to update the links on several web pages, you can simply change the Menu file.


An Include Example

Say we wanted to create a common menu file that all our pages will use. A common practice for naming files that are to be included is to use the ".php" extension. Since we want to create a common menu let's save it as "menu.php".

menu.php Code:
< html>
< body>
Home -
About Us -
Links -
Contact Us


Save the above file as "menu.php". Now create a new file, "index.php" in the same directory as "menu.php". Here we will take advantage of the include command to add our common menu.
index.php Code:

This is my home page that uses a common menu to save me time when I add
new pages to my website!

< /body>
< /html>

And we would do the same thing for "about.php", "links.php", and "contact.php". Just think how terrible it would be if you had 15 or more pages with a common menu and you decided to add another web page to that site. You would have to go in and manually edit every single file to add this new page, but with include files you simply have to change "menu.php" and all your problems are solved. Avoid such troublesome occasions with a simple include file.
What do Visitors See?

If we were to use the include command to insert a menu on each of our web pages, what would the visitor see if they viewed the source of "index.php"? Well, because the include command is pretty much the same as copying and pasting, the visitors would see:
View Source of index.php to a Visitor:

< html>
< body>
Home -
About Us -
Links -
Contact Us

This is my home page that uses a common menu to save me time when I add
new pages to my website!

< /body>
< /html>

The visitor would actually see all the HTML code as one long line of HTML code, because we have not inserted any new line characters. We did some formatting above to make it easier to read. We will be discussing new line characters later.

Passing JavaScript variables to PHP

JavaScript is mainly used as a client side scripting language, while PHP is a server side technology. Unlike Java or ASP.Net, PHP doesn't have tools to make it work client side. That is why you need to combine JavaScript and PHP scripts to develop powerful web-applications.

One of the frequent problems is defining visitor’s screen resolution using JavaScript tools and passing this data to PHP-script. The following script provides solution for this problem:



Copy and paste this code snippet in the text editor, save it as index.htm and run it in your browser. After this code has been executed, a user is automatically redirected to the main.php page where screen resolution is displayed in the browser window.

The main.php looks as follows:


echo "

Screen Resolution:

";
echo "Width : ".$_GET['width']."
";
echo "Height : ".$_GET['height']."
";
?>

How to Get the Current Page URL in PHP

Sometimes, you might want to get the current page URL that is shown in the browser URL window. For example if you want to let your visitors submit a blog post to Digg you need to get that same exact URL. There are plenty of other reasons as well. Here is how you can do that.

Add the following code to a page:

function curPageURL() {
$pageURL = 'http';
if ($_SERVER["HTTPS"] == "on") {$pageURL .= "s";}
$pageURL .= "://";
if ($_SERVER["SERVER_PORT"] != "80") {
$pageURL .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
} else {
$pageURL .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
}
return $pageURL;
}
?>

You can now get the current page URL using the line:

echo curPageURL();
?>
Sometimes it is needed to get the page name only. The following example shows how to do it:


function curPageName() {
return substr($_SERVER["SCRIPT_NAME"],strrpos($_SERVER["SCRIPT_NAME"],"/")+1);
}

echo "The current page name is ".curPageName();
?>

PHP: Dynamic Image Generation

Creating images on the fly can be a very useful skill. PHP has some built-in image generation functions, further more, to generate new images or edit existing images on the fly using PHP, we need to have the GD library installed. In this tutorial we will show you how to get quite interesting and useful effects using image handling functions. We will review two practical tasks: creating security images (captcha) on the fly and building a bar chart using numerical values retrieved from MySQL database.


Creating security images on the fly

At first, have a look at the following script that creates captcha image. Next, we will consider each step of image generation in details.


//Send a generated image to the browser
create_image();
exit();

function create_image()
{
//Let's generate a totally random string using md5
$md5 = md5(rand(0,999));
//We don't need a 32 character long string so we trim it down to 5
$pass = substr($md5, 10, 5);

//Set the image width and height
$width = 100;
$height = 20;

//Create the image resource
$image = ImageCreate($width, $height);

//We are making three colors, white, black and gray
$white = ImageColorAllocate($image, 255, 255, 255);
$black = ImageColorAllocate($image, 0, 0, 0);
$grey = ImageColorAllocate($image, 204, 204, 204);

//Make the background black
ImageFill($image, 0, 0, $black);

//Add randomly generated string in white to the image
ImageString($image, 3, 30, 3, $pass, $white);

//Throw in some lines to make it a little bit harder for any bots to break
ImageRectangle($image,0,0,$width-1,$height-1,$grey);
imageline($image, 0, $height/2, $width, $height/2, $grey);
imageline($image, $width/2, 0, $width/2, $height, $grey);

//Tell the browser what kind of file is come in
header("Content-Type: image/jpeg");

//Output the newly created image in jpeg format
ImageJpeg($image);

//Free up resources
ImageDestroy($image);
}
?>
To create a new image or edit an existing one, we need to create image identifier. In the preceding example we created an empty canvas by calling ImageCreate() function, passing it width and height of a new image as a parameters. Another way to do it is to read the existing image from the file. Depending on the file format you can do it using one of the following functions: ImageCreateFromPNG(), ImageCreateFromGIF(), ImageCreateFromJPEG(). Parameter of each function is a file name.

Then, we need to choose colors to be used while painting. For this we can use ImageColorAllocate() function and image identifiers for red, green, and blue (RGB) components of necessary color will be passed as parameters.

On the next step, we will generate our image. First, using ImageFill() function we will create black background. Parameters of this function are: image identifier, initial coordinates of the area to be filled and fill color. Then, we will use ImageString() function to add text to the image. Its parameters are – image identifier, font, coordinates for the first text position and text color. Finally, we will draw two lines and a rectangular to protect our image a little bit. Please note, that the final point of the rectangular has the following coordinates: $width-1 and $height-1. If they were equal to $width and $height, than the rectangular would have exceeded canvas frame.

When we had created the image, we can output it either to a browser, or to a file. Our example shows how to output it to the browser. We need to inform the browser, that we will output the image, not the text or html-code. To do it, call Header() function, setting image MIME-type. It’s worth mentioning that Header() function can not be executed if HTTP header has already been sent. After sending the header we can output our image using ImageJpeg() function, passing it image identifier as a parameter.

When we have finished working with the image we need to free up resources using ImageDestroy() function.

Building a bar chart

In the example below, using graphic functions we will build a bar chart based on the values stored in MySQL database. In our case, values represent poll results.

In this example we will use poll database. To create it run the following SQL script in your MySQL server:
CREATE DATABASE `poll`;
USE poll;

CREATE TABLE `results` (
book_type VARCHAR(50),
num_votes INT
);

INSERT INTO `results` values
('Classic', 15),
('Fantasy', 7),
('Humor', 32),
('Mystery', 12),
('Poetry', 25);

Script building a bar chart is quite long, so let's divide it into two parts and discuss them separately. The first part of the script connects to MySQL database and requests data that will be represented in the bar chart.

//Querying the database to get poll results

//connection to the database
$dbhandle = mysql_connect("localhost", "root", "")
or die("Unable to connect to MySQL");

//select a database to work with
$selected = mysql_select_db("poll",$dbhandle)
or die("Could not select examples");

//execute the SQL query and return records
$result = mysql_query("SELECT * FROM results");

$num_poller = mysql_num_rows($result);
$total_votes = 0;

//fetch the data from the database
while ($row = mysql_fetch_array($result)) {
$total_votes += $row{'num_votes'}; //calculating total number of votes
}

//nulling the pointer $result
mysql_data_seek($result,0);

//close the connection
mysql_close($dbhandle);

In the second part of the script first of all we will calculate variables needed to build the chart. Then, we prepare primary image and actually output data. Results for each genre are picked from the database one by one, percentage of votes is calculated, and then bars and explanatory notes are outputted.

In this script we are using TrueType fonts to get anti-aliased text. Functions that work with the TrueType fonts have its own peculiarities. First, you need to point where the fonts are located. For this, system variable GDFONTPATH is set. Then, we need to set the font name. TrueType fonts are rendered using ImageTTFText().

We have already discussed above all functions used for drawing, the code has been commented and is quite clear, so you shouldn’t have any trouble.

//Tell gd2, where your fonts reside
putenv('GDFONTPATH=C:\WINDOWS\Fonts');
$font = 'arial';

//Set starting point for drawing
$y = 50;

//Specify constant values
$width = 700; //Image width in pixels
$bar_height = 20; //Bars height
$height = $num_poller * $bar_height * 1.5 + 70; //Calculating image height
$bar_unit = ($width - 400) / 100; //Distance on the bar chart standing for 1 unit

//Create the image resource
$image = ImageCreate($width, $height);

//We are making four colors, white, black, blue and red
$white = ImageColorAllocate($image, 255, 255, 255);
$black = ImageColorAllocate($image, 0, 0, 0);
$red = ImageColorAllocate($image, 255, 0, 0);
$blue = imagecolorallocate($image,0,0,255);

//Create image background
ImageFill($image,$width,$height,$white);
//Draw background shape
ImageRectangle($image, 0, 0, $width-1, $height-1, $black);
//Output header
ImageTTFText($image, 16, 0, $width/3 + 50, $y - 20, $black, $font, 'Poll Results');

while ($row = mysql_fetch_object($result)) {
if ($total_votes > 0)
$percent = intval(round(($row->num_votes/$total_votes)*100));
else
$percent = 0;

//Output header for a particular value
ImageTTFText($image,12,0,10, $y+($bar_height/2), $black, $font, $row->book_type);
//Output percentage for a particular value
ImageTTFText($image, 12, 0, 170, $y + ($bar_height/2),$red,$font,$percent.'%');

$bar_length = $percent * $bar_unit;

//Draw a shape that corresponds to 100%
ImageRectangle($image, $bar_length+221, $y-2, (220+(100*$bar_unit)), $y+$bar_height, $black);
//Output a bar for a particular value
ImageFilledRectangle($image,220,$y-2,220+$bar_length, $y+$bar_height, $blue);
//Output the number of votes
ImageTTFText($image, 12, 0, 250+100*$bar_unit, $y+($bar_height/2), $black, $font, $row->num_votes.' votes cast.');

//Going down to the next bar
$y = $y + ($bar_height * 1.5);

}

//Tell the browser what kind of file is come in
header("Content-Type: image/jpeg");

//Output the newly created image in jpeg format
ImageJpeg($image);

//Free up resources
ImageDestroy($image);
?>

Using dynamically generated images on the other pages

Since the header can be sent only once and it is the only way to tell the browser that you are going to send image, it is not so easy to insert automatically generated images to the regular pages. There are three ways to do it:

* The whole page can consist of the image.
* You can save image in the file and then refer to it using HTML descriptor.
* You can put a script producing image in HTML descriptor, e.g.:

Stored Procedures in MySQL

The programmers and developers all over the world are celebrating the existence of MySQL 5.0 for a good reason. The version has finally paved the way for using stored procedures with this popular open source database. The stored procedures are hoarded at database server in the form of commands and SQL statements and could be invoked for any type of application. Thus, there is advantage for programmers to shed away the need of creating their own SQL; a tiresome job.

Without taking much of the time, let us understand the syntax for utilizing the procedures:

1.

2.
CREATE ProcedureCREATE [DEFINER = { user | CURRENT_USER }]PROCEDURE sp_name ([proc_parameter[,…]])
3.

4.
[characteristic …] routine_body
5.

6.
IN the above syntax, the parameters are specified AS IN, OUT OR INOUT. However, IN case of CREATE FUNCTION displayed below, the only parameter allowed IS IN.
7.

8.
CREATE
9.

10.
[DEFINER = { user | CURRENT_USER }]
11.

12.
FUNCTION sp_name ([func_parameter[,…]])
13.

14.
RETURNS type
15.

16.
[characteristic …] routine_body

Return statement is included in the syntax for a function and it specifies the return type of the function. Routine body is included to define a valid SQL statement. The syntax contains characteristic to provide information regarding nature of data. This may include attributes like CONTAINS SQL, NO SQL, READS SQL DATA and MODIFIES SQL DATA.

Alter Procedure

This statement is used to modify or alter the characteristics possessed by a stored procedure. Here is the syntax:

1.

2.
ALTER {PROCEDURE | FUNCTION} sp_name [characteristic …]

It offers you the advantage to bring in more than one change in the characteristics of stored procedures.

Drop Procedure

In order to remove a stored procedure, there is provision of DROP statement in MySQL database. The syntax for this takes the following shape:

1.

2.
DROP {PROCEDURE | FUNCTION} [IF EXISTS] sp_name

IF EXISTS is used to check the existence of specified procedure or function. It saves the statement from generating an error in case the procedure or function doesn’t exist.

Other Statements For Procedures

Apart from those mentioned above, there are other statements used for stored procedures. Here is the list o these statements:

* Show Create Procedure – It is used to return the text of a stored procedure, which was defined previously using Create syntax. In the similar manner, there is Show Create Function statement to accomplish this task for stored function.
* Show Procedure Status – It is used to return the characteristic of the specified stored procedure. These characteristics include name, type, creation date and so on. You may use Show Function Status also.
* CALL – It is used to invoke the stored procedure created using Create Procedure statement.
* Begin End – It is used to specify multiple statements for carrying out different types of operations and executions.
* Declare – It is used to help programmers in declaring and defining local variables, conditions, procedures and so on.
* SET – This statement is used to modify the values of local as well as global variables.

Also, there are condition statements like IF THEN ELSE, WHILE, CASE WHEN amongst others, which could be employed to operate these procedures.

Thus, MySQL stored procedures are tools for better performance, secure environment, providing ease of maintenance and also, for optimization.