Magic Functions in PHP
- All function starts with double underscore(__)
- PHP reserves all function names starting with __
- It allows to define class functionality without needing to duplicate code.
- It can be defined inside the class only.
- It can be triggered at any point of code(event).
- Magic functions will never directly be called by the programmer – actually, PHP will call the function ‘behind the scenes’. This is why they are called ‘magic’ functions – because they are never directly called, and they allow the programmer to do some pretty powerful things
- __construct(): It called at creation of objects.
- __destruct() : it called when all reference of objects are removed/object explicitly destroyed.
- __set(): It called when you try to set a property that is not accessible(not defined/public). If __set is used to set a property that is not exist, the new property will be public. If it is used on a property that is not public, the accessibility will not change.
- __get():It called when try to access non accessible properties . Non-accessible means either the property is not defined or not public.If property is not defined then __get will be called from both inside and outside of the class context.You could even use it to set properties from outside the class.
- __call(): It called when try to access not defined method.
- __sleep(): It called when object is serialized with PHP’s serialize.It can be used to clean object before serialization.
- __wakeup():It called when object is un-serialized with PHP’s un-serialize.It can be used to reestablish resource like db connection.
- __toString(): It called when you try to access object in string context. It cannot throw an exception-results in fatal error .If you will get any exceptions inside the __toSting then you need to handle inside itself.
- __isset(): It called when isset is called on inaccessible property.
- __unset(): It called when try to unset a non-accessible value.
- __clone(): If clone is called on object that contains other object, both the clone and original contains same object.
- __invoke(): It allows to treat an object like a function.
- __autoload(): It allow to auto load files automatically without require/require_once functions.
- Magic code is hard to document and understand.
- Magic methods do not support type hinting. One of the greatest advantages of using functions to set properties is that you can use type hinting.
- Makes sure that the user property will always contain a valid user object or null.
- IDEs do not support magic methods.
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