how can i pass json from php to js and manipulate it?

Question

here is what i want to do

1. i use codeigniter directory_map() function to map a folder save it as $map;

     $map = directory_map($this->rootdir.$this->session->userdata('user_name')); 

2. then i encode the $map and echo it out

     echo $dir = json_encode($map); 

3. what i want is save the $dir somehow.so when user open one of the folder i can use js to get the folder's content from the saved $dir json file, instead of communicate to server.if this make sense then how can i save the $dir json file or how to get it in the js file.

is there a better way to do that?

Answer 1

I personally use the method mentioned here , which is basically along the following outline:

Update: (I think I confused you a bit) The following is Javascript code

//Global object to store the cache
cache = {};
function makeRequest(requested_data){
   request_hash = hash(requested_data);
   if (cache[request_hash]){
       handleData(cache[request_hash]);
   }
   else{
       //Make Ajax call, get data response back and store it in the cache
       request_hash = hash(requested_data);
       cache[request_hash] = data;
       handleData(data);
   }
}

Note: for hash() , you can use any hashing algorithm out there, you don't really need a cryptography-level hash, just something to create a basic signature. I use the Javascript implementation of Java's hashCode()