gettype() Returns a string value representing the data type of a variable var_dump() Prints details about the variable it is given

Convert Boolean Text To Boolean Strings always evaluate to boolean true unless they have a value that's considered "empty" by PHP.  FILTER_VALIDATE_BOOLEAN provides a solution though: $UploadsEnabled = "false"; $UploadsEnabled = filter_var($UploadsEnabled, FILTER_VALIDATE_BOOLEAN); Convert Bytes To UInt32 $handle = fopen("myfile.bin", "rb"); $Contents = fread($handle, 20); $FileByteArray = unpack("C*",$Contents); //<<<Warning the outputted array starts from [1] […]

Variables Any variable used inside a function is by default limited to the local function scope. If you want to access a variable used outside of the function you need to declare it as global within the function: Defines No need to declare a define as global in functions, any function can simply use it

Warning When Using Superglobal Variables Hackers often use these to try and inject code etc.  When accessing superglobal variables ensure you sanitise them.  E.g. $CameFromPage = htmlentities($_SERVER[‘HTTP_REFERER’]); //htmlentities() converts things like < > ” \ etc into HTML strings like &lt; so they become harmless. Superglobal Variables Always available in all scopes $GLOBALS References all […]

Constants define (“MY_ROOT_PATH”, “/usr/local/httpdocs/”); Then to use $PathToUse = MY_ROOT_PATH; PHP Magic Constants __LINE__ The current line number of the file. __FILE__ The full path and filename of the file. If used inside an include, the name of the included file is returned. Since PHP 4.0.2, __FILE__ always contains an absolute path with symlinks resolved […]

Variables General Variable names must start with a ‘$’ character (to allow the php parser to work as fast as possible by instantly know it is a variable). A variable name must start with a letter of the alphabet or and underscore ‘_’. Variable names may only contain: ‘a’ – ‘z’, ‘A’ – ‘Z’ and […]