html - 如何将到期时间应用于 HTML5 indexeddb 中的键？

Question

在html5 api中的indexedDB中，我可以用它来存储键值对。但是我如何确保在添加某个键值后，1 天后，该键应该自动从数据库中删除。

我想用当前日期时间和到期时间将值包装在一个对象中，当您获得该值时，检查时差，但这是最好的方法吗？

谢谢

Answer 1

是的，正如 Scott Marcus 和 dgrogan 所说的那样。另一个提示:如果您在时间戳上创建索引，则可以在“过期”值的范围内迭代游标，并在打开数据库后删除它们。

const open = indexedDB.open("demo");

open.onupgradeneeded = function () {
  const db = open.result;
  const store = db.createObjectStore("store");
  const index = store.createIndex("timestamp", "timestamp");

  // Populate with some dummy data, with about half from the past:
  for (let id = 0; id < 20; ++id) {
    store.put(
      {
        value: Math.random(),
        timestamp: new Date(Date.now() + (Math.random() - 0.5) * 10000),
      },
      id
    );
  }
};

open.onsuccess = function () {
  const db = open.result;
  const tx = db.transaction("store", "readwrite");
  // Anything in the past:
  const range = IDBKeyRange.upperBound(new Date());

  tx
    .objectStore("store")
    .index("timestamp")
    .openCursor(range).onsuccess = function (e) {
    const cursor = e.target.result;
    if (!cursor) return;
    console.log("deleting: " + cursor.key);
    cursor.delete();
    cursor.continue();
  };

  // This transaction will run after the first commits since
  // it has overlapping scope:
  const tx2 = db.transaction("store");
  tx2.objectStore("store").count().onsuccess = function (e) {
    console.log("records remaining: " + e.target.result);
  };
};