In this tutorial, I will explain what does mean the PHP resource and we are going to cover all PHP examples regarding this concept to be easily understandable.
Anyway, the PHP resource is referring to all external accesses which are all external resources that have information or data needed to be manipulated through the main source code, such as database connections, files, documents, streams, or sockets.
Before getting started, you have to look at the get_resource_type callback.
Get Resource Type Function
This is a predefined function, used to help developers see the type of resource during their development stage.
Anyway, the get_resource_type takes a resource type as a parameter. And it returns the name of the resource type as a string value.
The pattern of this callback would as the following code.
<?php get_resource_type( $resource ); ?>
In the following sections, I am going to cover the common resource’s type using get_resource_type with a PHP example.
Using PHP Resource with Database Connection
In the past and before PHP 5.5, you were able to use the get_resource_type with the SQL connection function –
mysql_connect(). because it was returning a resource type. But currently, this function is deprecated and
mysqli_connect() is the alternative.
But we could not able to use the get_resource_type with –
mysqli because this callback is returning an object data type.
So before PHP5.5, you were able to use the following code.
<?php $mysql= mysql_connect(); echo get_resource_type( $mysql ); // mysql link ?>
Using PHP Resource with an External File
In the following example, I will use the fopen() predefined function to get the resource value of the external file. Then will pass it into the get_resource_type callback to see what resource type will print.
<?php $file = fopen("text", "w"); echo $file; // Resource id #5 echo get_resource_type( $file ); // stream ?>
If you need to read more detail, you have to navigate to this link.
In this tutorial, you understood what does mean PHP resource, get_resource_type and saw examples for database, file, and stream.
If you need more details, navigate to the PHP data Types tutorial.