When do items in HTML5 local storage expire?

Question

For how long is data stored in localStorage (as part of DOM Storage in HTML5) available? Can I set an expiration time for the data which I put into localStorage?

Answer 1

????? ???? ?? ?????? ????? ?????? ????????. ???? ????? ????? ????????.

https://developer.mozilla.org/en- ???????? ??????? / ??????? / ???????? / API / ????? / ??????? ??????

??????? ?????? ???? ?? ?????? ?? ???? ?? ?? ????? ??????? ??? ?????? ?? ?? ???? ???? ??? ????. ???? ????? ???????? ?????? ?? ??????? ??????? ?? ?? ??? ????? ??????? ??? ???????? ??????. ??? ?? ????? ?? ?????? ????????. ????? ??? ?????? ???? "??? ?????" ??????? ??? ??? ??????? ?????? ???? ??????.

????? - ?? ??????? ?? ??????? ????? ?? ????? ????? ??????? ??? ?? ???? ???? ????? ???. ???? ??? ????? ????? ????? ???? ?? ?????? ?????? ?? ?? ??? ?? ???? ??? ?????? ??? ?? ??????? ??? ?? ??? ???? ?? ???? ?? ??? ??? ??? ?? ??? ??? ?????????.

Answer 2

???? ?? ????? ??? ?????? ?????? ???? ?? ?????? ?? ????? ?? ??????? ??????

var object = {value: "value", timestamp: new Date().getTime()}
localStorage.setItem("key", JSON.stringify(object));

?????? ????? ????? ??????? ??? ?????? ?????? ??????? ?? ??????? ??????? ???? ??? ?????? ?????? ???? ??????.

var object = JSON.parse(localStorage.getItem("key")),
    dateString = object.timestamp,
    now = new Date().getTime().toString();

compareTime(dateString, now); //to implement

Answer 3

?????? ??????? lscache . ??? ?????? ?? ??? ??????? ?? ???????? ??? ?? ??? ??????? ???? ?????? ??? ??????? ????. ???? ??? ???? ???? ???? ????? ??????? ???? ?? ?????? ??? ?????? ???????? ??????.

??? readme:

lscache.set

Stores the value in localStorage. Expires after specified number of minutes.

Arguments
key (string)
value (Object|string)
time (number: optional)

???? ?? ????? ??????? ??? ??? ?????? ??????? ???????. ???? ??? ????? ?????? ???? ??? ?????.

??? ??? ?? ????? ??? ?? ?????? ?? ???????? ????? ?????? ????? ???? ???? ????? (??? JSON) ??????? ?? ??? ????????.

??????? ??????? ???? ??? ???? ????? ???? ??????? ?????? ??? ??? ????????. ????? ?????? ??? lscache ?? ???? ?? ?????? ?????? ??? ?????? ??? ????? ?????? ????? ??????.

Answer 4

????

?Brynner ??????? ???? ???? ????: ????? ????? ?????? ??? ????????? ?????? ????. ???? ???????? ??? ??? ??? ???? ???? ????? ?? ????????? ?? ??? ???? ????? JSON ???????? ? ?? ?? ????? ??? ????? ??? ?????? ??? ?????? ??????.

???? ???? ???? ?????:

 /*  removeStorage: removes a key from localStorage and its sibling expiracy key
    params:
        key <string>     : localStorage key to remove
    returns:
        <boolean> : telling if operation succeeded
 */
 function removeStorage(name) {
    try {
        localStorage.removeItem(name);
        localStorage.removeItem(name + '_expiresIn');
    } catch(e) {
        console.log('removeStorage: Error removing key ['+ key + '] from localStorage: ' + JSON.stringify(e) );
        return false;
    }
    return true;
}
/*  getStorage: retrieves a key from localStorage previously set with setStorage().
    params:
        key <string> : localStorage key
    returns:
        <string> : value of localStorage key
        null : in case of expired key or failure
 */
function getStorage(key) {

    var now = Date.now();  //epoch time, lets deal only with integer
    // set expiration for storage
    var expiresIn = localStorage.getItem(key+'_expiresIn');
    if (expiresIn===undefined || expiresIn===null) { expiresIn = 0; }

    if (expiresIn < now) {// Expired
        removeStorage(key);
        return null;
    } else {
        try {
            var value = localStorage.getItem(key);
            return value;
        } catch(e) {
            console.log('getStorage: Error reading key ['+ key + '] from localStorage: ' + JSON.stringify(e) );
            return null;
        }
    }
}
/*  setStorage: writes a key into localStorage setting a expire time
    params:
        key <string>     : localStorage key
        value <string>   : localStorage value
        expires <number> : number of seconds from now to expire the key
    returns:
        <boolean> : telling if operation succeeded
 */
function setStorage(key, value, expires) {

    if (expires===undefined || expires===null) {
        expires = (24*60*60);  // default: seconds for 1 day
    } else {
        expires = Math.abs(expires); //make sure it's positive
    }

    var now = Date.now();  //millisecs since epoch time, lets deal only with integer
    var schedule = now + expires*1000; 
    try {
        localStorage.setItem(key, value);
        localStorage.setItem(key + '_expiresIn', schedule);
    } catch(e) {
        console.log('setStorage: Error setting key ['+ key + '] in localStorage: ' + JSON.stringify(e) );
        return false;
    }
    return true;
}

Answer 5

???? ????? ??????? ?????? ?? ??? ????? ???? ?????? ????????? ??????? ?????? ??. ?????? ???????? ????? ??????? ?????? ?? ?????? ???? ????? ???? ????? ??????? ?????? ???? ??????? ?? ???????? ?????? ??? ??????.

???? ???? ?????? ?? ???:

if (!$.cookie('your_key') || !localStorage.getItem('your_key')) {
    //get your_data from server, then...
    localStorage.setItem('your_key', 'your_data' );
    $.cookie('your_key', 1);
} else {
    var your_data = localStorage.getItem('your_key');
}
// do stuff with your_data

???? ?????? ???? ?????? ?? ??????? ?????????? ?????? ??? ????? ???????. ?????? ????? ??????? ?? ????? ?????? ???? ????? ??? ??????? ???? ???????? ?????? ?your_data ?? ???? ?????? ?? ???? ??????.

?????? ?? ??? ???? ?????? ??? ????? ???? ???????? ??????? ???? ???? ?? ????? ????? ???????? ??????? ???? ?????? ??? ????? ????????. ??? ???? ??? ????? ??????? ????? ?? ?? ?? ???? ????? ??? ????? ???? ?? 4K ?? ???? ?????? (???? ???? ??????)? ???? ???????? ?? ?????? ???????? ?????? ??? ?????? ??? ????? ??? ????? ???? ???????? ???????? ?????? ??? ?????? .

Answer 6

???? ???? ???? ???????? ??? sessionStorage

• ??? ??? ??? ??????? ?????? ???? ????? ???? ????? ?????? / ????? ???????
• ?sessionStorage ???? ???? ???? ?? ???? ???? ?????? ?? ??????

?????????? ?????? ???????

sessionStorage.setItem("key","my value");

?????????? ???? ?????? ???

var value = sessionStorage.getItem("key");

???? ??? ??????? ??????

??? ????? ???????? ??

  sessionStorage.key = "my val";
  sessionStorage["key"] = "my val";
  sessionStorage.setItem("key","my value");

??? ??? ?????? ??? ?

  var value = sessionStorage.key;
  var value = sessionStorage["key"];
  var value = sessionStorage.getItem("key");

Answer 7

???? ?????? ?? ???? ???? ?? ????? / ????????.

????? :

????? ????? ??? ?? ????? ???????? ?? ????? ??????? ??????? ??? ?????? ????? ?? ????? ???? ???? ??? ?? ??? ????????. ??? ?? ???? ???????? ????? ???? ??? ???????? ?? ??? ?? ????????? ???? ???? ?????? ??? ??? ?????? ??? ???????.

Answer 8

??? ????? W3C:

????? ????? ??? ?? ????? ???????? ?? ????? ??????? ??????? ??? ?????? ????? ?? ????? ???? ???? ??? ?? ??? ????????. ??? ?? ???? ???????? ????? ???? ??? ???????? ?? ??? ?? ????????? ???? ???? ?????? ??? ??? ?????? ??? ???????.

???? ???? ?? ???? ????????? ?????? ?? ??? ?????? ?????? ????? ?? ???????? setItem (?????? ????)? ???? ?? ????? ??? ????? ?? ????? ????? ???? ?? ???????? ???????.

Answer 9

// Functions
function removeHtmlStorage(name) {
    localStorage.removeItem(name);
    localStorage.removeItem(name+'_time');
}

function setHtmlStorage(name, value, expires) {

    if (expires==undefined || expires=='null') { var expires = 3600; } // default: 1h

    var date = new Date();
    var schedule = Math.round((date.setSeconds(date.getSeconds()+expires))/1000);

    localStorage.setItem(name, value);
    localStorage.setItem(name+'_time', schedule);
}

function statusHtmlStorage(name) {

    var date = new Date();
    var current = Math.round(+date/1000);

    // Get Schedule
    var stored_time = localStorage.getItem(name+'_time');
    if (stored_time==undefined || stored_time=='null') { var stored_time = 0; }

    // Expired
    if (stored_time < current) {

        // Remove
        removeHtmlStorage(name);

        return 0;

    } else {

        return 1;
    }
}

// Status
var cache_status = statusHtmlStorage('cache_name');

// Has Data
if (cache_status == 1) {

    // Get Cache
    var data = localStorage.getItem('cache_name');
    alert(data);

// Expired or Empty Cache
} else {

    // Get Data
    var data = 'Pay in cash :)';
    alert(data);

    // Set Cache (30 seconds)
    if (cache) { setHtmlStorage('cache_name', data, 30); }

}

Answer 10

??? ??? ?? ???????? jStorage ??????? ????? ????? ?? ???? ????? ?????? ?? ????? setTTL ??? jStorage ???????

$.jStorage.set('myLocalVar', "some value");
$.jStorage.setTTL("myLocalVar", 24*60*60*1000); // 24 Hr.

Answer 11

???? ??? ?? ??? ?? ???? ???? ?? ?? ???? ??? ?????? ?????? ??? ??? ??? ???? ??? ??????? ???? ????? ??? ?????? ??????? / ?????? / ????? ??????? ????? ?????? ????? ?? ?????? ???:

https://github.com/RonenNess/ExpiredStorage

Answer 12

????? ???????? ?????? ?localforage:

angular.module('app').service('cacheService', function() {

  return {
    set: function(key, value, expireTimeInSeconds) {
      return localforage.setItem(key, {
        data: value,
        timestamp: new Date().getTime(),
        expireTimeInMilliseconds: expireTimeInSeconds * 1000
      })
    },
    get: function(key) {
      return localforage.getItem(key).then(function(item) {
        if(!item || new Date().getTime() > (item.timestamp + item.expireTimeInMilliseconds)) {
          return null
        } else {
          return item.data
        }
      })
    }
  }

})

Answer 13

? @sebarmeli ?? ????? ?? ?????? ?? ????? ???? ??? ??? ???? ??? ???????? ???? ????? ????? ?????? ?? sessionStorage ?? ??????? ?? ???? ?????? ??????:

???? ?? ???? ??????? (sessionStorage) ???? ????? ??? ????? ????? ?? ?? ???? ???? ?????? ??????. ???? ?????? ????? ?????? ????? ????? ???? ??? ?????? ??? ?????? ??????? ??????????. ???? ???? ?? ????? ????? ????? ?? ????? ???? ???? ????? ??? ????.

MDN: sessionStorage

Answer 14

?????? ????????:

???? ???????? ?? ??? ???? ?? ???? ????? ?? ????? ????? ???? ????? ??????? ?????. ??? ??? ????? ??? ???? ??? ??????? UI ??????? ??? ???????? ??? ????? (??? ????? ??????? ???????? ?????? ??????? ??????????? ??? ??????).

???? ?? ???? ?????? ??????? ???? ???? ?? ???? ???? ????? + ??? ????? ???? ?????? ????? ??? ???.

??????: ??? ?? ???? ???? ??? ??? ????? ??? ??????? ??????? ???? ????

// Addition
if(window.localStorage){
    localStorage.setItem('myapp-' + new Date().getTime(), 'my value');
}

// Removal of all expired items
if(window.localStorage){

    // two mins - (1000 * 60 * 20) would be 20 mins
    var expiryTime = new Date().getTime() - (1000 * 60 * 2);

    var deleteRows = [];
    for(var i=0; i < localStorage.length; i++){
        var key = localStorage.key(i);
        var partsArray = key.split('-');
        // The last value will be a timestamp
        var lastRow = partsArray[partsArray.length - 1];

        if(lastRow && parseInt(lastRow) < expiryTime){
            deleteRows.push(key);
        }
    }
    // delete old data
    for(var j=0; j < deleteRows.length; j++){
        localStorage.removeItem(deleteRows[j]);
    }
}

Answer 15

?????? ?? ???? ??? ????.

var hours = 24; // Reset when storage is more than 24hours
var now = new Date().getTime();
var setupTime = localStorage.getItem('setupTime');
if (setupTime == null) {
     localStorage.setItem('setupTime', now)
} else {
    if(now-setupTime > hours*60*60*1000) {
         localStorage.clear()
         localStorage.setItem('setupTime', now);
    }
}