J1.5

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 functions[edit]

Under most circumstances, you will want to use member functions the JRequest class to get request variables. The most common case is when you want to use a specific variable found in either the GET or POST portion of the HTTP request. If you have a form variable named 'address', you would want to use this code to get it:

$address = JRequest::getVar('address');

By setting $address this way, getVar() strips out all HTML and trailing whitespace. If you want to specify a default value in the event that 'address' is not in the request or is unset, use this code:

$address = JRequest::getVar('address', 'default value goes here');

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:

$address = JRequest::getVar('address', 'default value goes here', 'post');

The fourth parameter of getVar() can be used to specify certain filters to force validation of specific value types for the variable. Here is a list of types you can validate:

  • INT
  • INTEGER
  • FLOAT
  • DOUBLE
  • BOOL
  • BOOLEAN
  • WORD
  • ALNUM
  • CMD
  • BASE64
  • STRING
  • ARRAY
  • PATH
  • USERNAME

Finally, there are some mask constants you can pass in as the fifth parameter that allow you to bypass portions of the filtering:

  • 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.