Safe Function Call
Safely call a function, class method, or object method in a manner that doesn’t generate errors if those plugins cease to exist. Various helper functions are provided that provide handy variations of this theme: _sfc() : Safely call a function and get its return value _sfce() : Safely call a functio
Safely call a function, class method, or object method in a manner that doesn’t generate errors if those plugins cease to exist.
Various helper functions are provided that provide handy variations of this theme:
- _sfc() : Safely call a function and get its return value
- _sfce() : Safely call a function and echo its return value
- _sfcf() : Safely call a function; if it doesn’t exist, then a fallback function (if specified) is called
- _sfcm() : Safely call a function; if it doesn’t exist, then echo a message (if provided)
Let’s assume you had something like this in a template:
<?php list_cities( 'Texas', 3 ); ?>
If you deactivated the plugin that provided list_cities() , your site would generate an error when that template is accessed.
You can instead use _sfc() , which is provided by this plugin to call other functions, like so:
<?php _sfc( 'list_cities', 'Texas', 3 ); ?>
That will simply do nothing if the list_cities() function is not available.
If you’d rather display a message when the function does not exist, use _sfcm() instead, like so:
<?php _sfcm( 'list_cities', 'The cities listing is temporarily disabled.', 'Texas', 3 ); ?>
In this case, if list_cities() is not available, the text “The cities listing is temporarily disabled.” will be displayed.
If you’d rather call another function when the function does not exist, use _sfcf() instead, like so:
<?php function unavailable_function_handler( $function_name ) { echo "The function $function_name is not available."; } _sfcf( 'nonexistent_function', 'unavailable_function_handler' ); ?>
In the event you want to safely call a function and echo its value, you can use _sfce() like so:
<?php _sfce( 'largest_city', 'Tx' ); ?>
Which is roughly equivalent to doing :
<?php if function_exists( 'largest_city' ) { echo largest_city( 'Tx' ); } ?>
Filter invocation method
To further prevent issues in your code should this plugin itself become deactivated, you can use indirect filter invocation to call the plugin functions. Each function has an associated filter with the same name as the function. Simply use apply_filters() to invoke that function instead of calling the function directly.
