In PHP, the term "request" refers to the data that is sent from a client (usually a web browser) to a web server. This data contains information about the action the client wants to perform, such as retrieving a web page, submitting a form, or making an API call. PHP provides several superglobal arrays that allow you to access and work with the request data. The commonly used superglobal arrays for handling request data are:
1. $_GET:
Contains the query parameters or data sent via the URL's query string.
Example: example.com/page.php?id=123
Access the value of id using $_GET['id'].
2. $_POST:
Contains data sent via HTTP POST method from forms or HTTP requests with a content type of "application/x-www-form-urlencoded" or "multipart/form-data".
Access form field values using $_POST['field_name'].
3. $_REQUEST:
Combines the data from $_GET, $_POST, and $_COOKIE.
Allows you to access request data regardless of the request method.
4. $_FILES:
Contains information about uploaded files from an HTML form with the attribute enctype="multipart/form-data".
Provides details such as the file name, temporary file path, size, and error status.
Access uploaded files using $_FILES['file_input_name'].
5. $_COOKIE:
Contains values of cookies sent by the client's browser.
Access cookie values using $_COOKIE['cookie_name'].
6. $_SERVER:
Contains server and execution environment information, including headers, paths, script locations, and more.
Provides information such as the requested URL, request method, server IP address, and user agent.
Access server variables using $_SERVER['variable_name'].
These superglobal arrays allow you to retrieve and work with request data in your PHP scripts. You can access and manipulate the values stored in these arrays based on your application's requirements. It's important to validate and sanitize user input to ensure security and prevent vulnerabilities like SQL injection or cross-site scripting (XSS).
It's worth noting that the values in these superglobal arrays are typically automatically populated by PHP based on the request data received from the client. However, it's good practice to verify the existence of specific keys or perform appropriate checks to handle cases when expected data is missing.