custom_json_decode.php

	function custom_json_decode(&$contents=NULL, $normalize_contents=true, $force_array=true){
		
		//---------------decode contents---------------------
		
		$decoded_contents=NULL;
		
		if(is_string($contents)){
			
			$decoded_contents=json_decode($contents,$force_array);
		
		}
		
		//---------------normalize contents---------------------
		
		if($normalize_contents===true){
			
			if(is_string($decoded_contents)){
				
				if($decoded_contents==='NULL'||$decoded_contents==='null'){
					
					$contents=NULL;
				}
				elseif($decoded_contents==='FALSE'||$decoded_contents==='false'){
					
					$contents=false;
				}
			}
			elseif(!is_null($decoded_contents)){
				
				$contents=$decoded_contents;
			}
		}
		else{
			
			//---------------validation contents---------------------
			
			$contents=$decoded_contents;
		}
		
		return $contents;
	}

Use

$none_json_str='hello';

//------------decoding a none json str---------------

$contents=custom_json_decode($none_json_str); // returns 'hello'

//------------checking a none json str---------------

custom_json_decode($none_json_str,false);

$valid_json=false;

if(!is_null($none_json_str)){

    $valid_json=true;

}