How to handle php notices, warnings and errors in REST api?

Let say, for example, that you are only concerned about fatal run-time errors, fatal compile-time errors and run-time warnings. Set the error reporting to desired level with error_reporting() function.

error_reporting( E_ERROR | E_COMPILE_ERROR | E_WARNING );

Since user-defined error handler ( later below ) can't handle fatal errors, fatal error messages will still be displayed. To avoid that use ini_set() function and set the display_errors to zero.

ini_set( 'display_errors', 0 );

Now create a custom error handler with set_error_handler() to completely bypass PHP error handler for the error types specified ( does not apply to fatal errors ).

/* The following error types cannot be handled with a user defined function:  *  E_ERROR, E_PARSE, E_CORE_ERROR, E_CORE_WARNING, E_COMPILE_ERROR, E_COMPILE_WARNING * The standard PHP error handler is completely bypassed for the error types specified *  unless the callback function returns FALSE. */function exception_error_handler( $severity, $message, $file, $line ) {    if ( !( error_reporting() & $severity ) ) {        // This error code is not included in error_reporting        return;    }    // code for handling errors}set_error_handler( "exception_error_handler" );

Fatal errors can be handled on shutdown with register_shutdown_function(). Shutdown handler is executed after the script is done, or is terminated ( this also applies for errors ). We need to get the information about the last error that occurred ( error_get_last() ), next is to check if this is the type of error that we track ( that it is not really needed here since errors that are not specified in error_reporting won't be triggered, but it can be useful to filter errors ), and lastly, call to exception handler.

function fatal_error_shutdown() {    $last_error = error_get_last();    if ( error_reporting() & $last_error['type'] )        call_user_func_array( 'exception_error_handler', $last_error );}register_shutdown_function( 'fatal_error_shutdown' );

Now you can use custom exception handler to catch unhandled exceptions ( including fatal ones ) and to force the response code ( with header() function ).

Of course you can change HTTP status in PHP:

<?php    header("HTTP/1.1 502 Bad Gateway");?> 

You could change the message and the code, but you must to be careful with standard codes

set_error_handler function is what I missed. I came up with the following code. Any better answer is welcomed.

function jsonErrorHandler(){   if (error_reporting()) {        http_response_code(500);        header('Content-Type: application/json; charset=utf-8');        $response = array_combine(['errno', 'errstr', 'errfile', 'errline', 'errcontext'], func_get_args());        die(json_encode($response));  }}set_error_handler('jsonErrorHandler');