wp-hooks-guide

Most of the people may gone through many article on filter or action hook, but still can’t get concept on hook of WordPress , then you are on the best place to learn.

Here i am not going to illustrate about basic theoritical meaning of hooks, just i will provide simple demonstration on hooks.

Before starting i hope you guys are clear on working of function of php.

Hooks are actually comes on action as calling and called function.

Lets say : Example1

On functions.php file you had defined a function called sum.

Function add_function ( $input_a, $input_b ) {
$total = sum ($input_a, $input_b);
return $total;

}

Normally to called this function we used

add_function (5,6); //this is calling function 5 and 6 are arguments.

_________

If you understand how the above code execute then there is no any worry, hooks on WordPress also works on the same way.

Somewhere on WordPress templates [take header.php ] you had added calling function as:

do_action (‘sum_the_total’, $argument_1, $argument_2 );
apply_filters (‘sum_the_total’, $argument_1, $argument_2 )

Here sum_the_total is the name of hooks, through which we can run many function at a time with given priority on action hooks/filter_hooks

do_action () and apply_filters () are calling function which functions as above example1 calling functions:
add_function ( 5, 6);

Now we need to defined function on functions.php template, lets say we declared same function as on example1

Example2:

Here $input_a and input_b are parameter which carries value hold by arguments: $argument_1 and $argument_2

Function add_function ( $input_a, $input_b ) {
$total = sum ($input_a, $input_b);
return $total;

}
add_action ( ‘sum_the_total’, ‘add_function’, 12);
add_filter ( ‘sum_the_total’, ‘add_function’, 12);

similarly let’s say:

Function add_function_2 ( $input_a, $input_b ) {
$total = sum ($input_a, $input_b);
return $total;

}
add_action ( ‘sum_the_total’, ‘add_function_2’, 13);
add_filter ( ‘sum_the_total’, ‘add_function’, 12);

Here “sum_the_total” is name of hooks which is defined on do_action which will hooks function add_function and add_function_2. Then execute them as per their priority given:

There on example2 add_function will execute first due to its priority = 12 . [The function with less priority will execute first. ]

Output:

if on header.php file
$argument_1 = 1;
$argument_2 = 2;
echo do_action (‘sum_the_total’, $argument_1, $argument_2 );

Output will be :
3

For reference:

Meaning of hooks by wordpress.org:

do_action()

add_action()

Have a look on difference between filter and action hooks here:
http://zellwk.com/blog/wordpress-actions-and-filters/

Actions and filters are NOT the same thing…

Note: If you require any information or have any question or queries or you have better soution than this then please feel free to contact me at adhsushil7@gmail.com

Thanks

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