Retrieving and Filtering GET and POST requests with JRequest::getVar
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Summary[edit]
When writing any web application, it is crucial that you filter input data before using it. Joomla! provides a set of filtering libraries to help you accomplish this.
JRequest 'getVar' method[edit]
To retrieve GET/POST request data, Joomla! uses the getVar method of the JRequest class (JRequest::getVar()).
Retrieving Data
If you have a form variable named 'address', you would want to use this code to get it:
EXAMPLE:
$address = JRequest::getVar('address');
Unless other parameters are set, all HTML and trailing whitespace will be filtered out.
The DEFAULT Parameter
If you want to specify a default value in the event that 'address' is not in the request or is unset, use this code:
EXAMPLE:
$address = JRequest::getVar('address', 'Address is empty'); echo $address; // Address is empty
The SOURCE Parameter
Frequently, you will expect your variable to be found in a specific portion of the HTTP request (POST, GET, etc...). If this is the case, you should specify which portion; this will slightly increase your extension's security. If you expect 'address' to only be in POST, use this code to enforce that:
EXAMPLE:
$address = JRequest::getVar('address', 'default value goes here', 'post');
The VARIABLE TYPE Parameter
The fourth parameter of getVar() can be used to specify certain filters to force validation of specific value types for the variable.
EXAMPLE:
$address = JRequest::getVar('address', 'default value goes here', 'post','variable type');
Here is a list of types you can validate:
- INT
- INTEGER
- FLOAT
- DOUBLE
- BOOL
- BOOLEAN
- WORD
- ALNUM
- CMD
- BASE64
- STRING
- ARRAY
- PATH
- USERNAME
The FILTER MASK Parameter
Finally, there are some mask constants you can pass in as the fifth parameter that allow you to bypass portions of the filtering:
EXAMPLE:
$address = JRequest::getVar('address', 'default value goes here', 'post','validation type','mask type');
- JREQUEST_NOTRIM - prevents trimming of whitespace
- JREQUEST_ALLOWRAW - bypasses filtering
- JREQUEST_ALLOWHTML - allows most HTML. If this is not passed in, HTML is stripped out by default.
Definition[edit]
The class JRequest is defined in the following location.
libraries\joomla\environment\request.php
The JRequest api page can be found here.
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