PHP How to use File Inclusion

You can include the content of a PHP file into another PHP file before the server executes it. There are two PHP functions which can be used to included one PHP file into another PHP file.
  • The include() Function
  • The require() Function
This is a strong point of PHP which helps in creating functions, headers, footers, or elements that can be reused on multiple pages. This will help developers to make it easy to change the layout of complete website with minimal effort. If there is any change required then instead of changing thousand of files just change included file.

The include() Function

The include() function takes all the text in a specified file and copies it into the file that uses the include function. If there is any problem in loading a file then the include() function generates a warning but the script will continue execution.
Assume you want to create a common menu for your website. Then create a file menu.php with the following content.
<a href="http://www.tutorialspoint.com/index.htm">Home</a> - 
<a href="http://www.tutorialspoint.com/ebxml">ebXML</a> - 
<a href="http://www.tutorialspoint.com/ajax">AJAX</a> - 
<a href="http://www.tutorialspoint.com/perl">PERL</a> <br />
Now create as many pages as you like and include this file to create header. For example now your test.php file can have following content.
<html>
<body>
<?php include("menu.php"); ?>
<p>This is an example to show how to include PHP file!</p>
</body>
</html>
This will produce following result

This is an example to show how to include PHP file. You can include menu.php file in as many as files you like!

The require() Function

The require() function takes all the text in a specified file and copies it into the file that uses the include function. If there is any problem in loading a file then the require() function generates a fatal error and halt the execution of the script.
So there is no difference in require() and include() except they handle error conditions. It is recommended to use the require() function instead of include(), because scripts should not continue executing if files are missing or misnamed.
You can try using above example with require() function and it will generate same result. But if you will try following two examples where file does not exist then you will get different results.
<html>
<body>
<?php include("xxmenu.php"); ?>
<p>This is an example to show how to include wrong PHP file!</p>
</body>
</html>
This will produce following result
This is an example to show how to include wrong PHP file!
Now lets try same example with require() function.
<html>
<body>
<?php require("xxmenu.php"); ?>
<p>This is an example to show how to include wrong PHP file!</p>
</body>
</html>
This time file execution halts and nothing is displayed.
NOTE: You may get plain warning messages or fatal error messages or nothing at all. This depends on your PHP Server configuration.

Comments

Post a Comment

Popular posts from this blog

LINUX Move and copy files using SSH

Often you will need to move one or more files/folders or copy them to a different location. You can do so easily using an SSH connection. The commands which you would need to use are mv (short from move) and cp (short from copy). The mv command syntax looks like this: mv configuration.php-dist configuration.php By issuing the above command we will move (rename) the file configuration.php-dist to configuration.php. You can also use mv to move a whole directory and its content: mv includes/* ./ This will move all files (and folders) in the includes/ directory to the current working directory. In some cases however, we will need to only update the files and move only files that were changed, which we can do by passing ‘ -u ’ as argument to the command: mv -u includes/* admin/includes The copy (cp) command works the same way as mv, but instead of moving the files/folders it copies them. For example: cp configuration.php-dist configuration.php The command will copy the co
Read more

PHP Predefined Variables

PHP provides a large number of predefined variables to any script which it runs.PHP provides an additional set of predefined arrays containing variables from the web server the environment, and user input. These new arrays are called superglobals: All the following variables are automatically available in every scope. PHP Superglobals: Variable Description $GLOBALS Contains a reference to every variable which is currently available within the global scope of the script. The keys of this array are the names of the global variables. $_SERVER This is an array containing information such as headers, paths, and script locations. The entries in this array are created by the web server. There is no guarantee that every web server will provide any of these. See next section for a complete list of all the SERVER variables. $_GET An associative array of variables passed to the current script via the HTTP GET method. $_POST An associative array of variable
Read more

Java : Variables Declaring

[1]. Java Variables Variables are containers for storing data values. In Java, there are different types of variables, for example: String - stores text, such as "Hello". String values are surrounded by double quotes int - stores integers (whole numbers), without decimals, such as 123 or -123 float - stores floating point numbers, with decimals, such as 19.99 or -19.99 char - stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotes boolean - stores values with two states: true or false [2]. Declaring (Creating) Variables To create a variable, you must specify the type and assign it a value: Syntax type variable = value ; Where type is one of Java's types (such as int or String), and variable is the name of the variable (such as x or name). The equal sign is used to assign values to the variable. To create a variable that should store text, look at the following example: Example Create a variable called  name  of type  Stri
Read more