使用Firebase过期URL

Question

有人如何创建指向Firebase数据的临时URL，但数据（和URL）会在特定时间后即5分钟或15分钟后被销毁？

Answer 1

根据数据的存储方式，有几种不同的选择可以按时间戳删除数据。

假设数据是未排序的，并且您已经将时间戳存储为每个记录中的一个字段，那么您可以简单地从第一条记录开始读取并删除它们，直到找到您想要保留的一条：

<script>
var FB = new Firebase(YOUR_URL);
var childRef = FB.child( TABLE_WITH_RECORDS_TO_DELETE );
var oneWeekAgo = new Date().getTime()-1000*60*60*24*7; // one week ago

var fx = function(snapshot) { // keep a ref to this so we can call off later
   var v = snapshot.val();
   if( v.expires_on_date < oneWeekAgo ) {
      // delete the record
      snapshot.ref().remove();
   }
   else {
      // we found the first keeper, so we are done
      childRef.off('child_added', fx);
   }
}

// fetched records and test to see how old they are
childRef.on('childAdded', fx);
</script>

如果数据是按时间戳排序的，您可以按照如下方式检索和删除它们：

var FB = new Firebase(YOUR_URL);
var childRef = FB.child( TABLE_WITH_RECORDS_TO_DELETE );
var oneWeekAgoMinusOne = new Date().getTime()-1000*60*60*24*7-1; // one week ago

// fetched using endAt, so only retrieving older than 1 week
childRef.endAt( oneWeekAgoMinusOne ).on('childAdded', function(snapshot) {
    // delete the record
   snapshot.ref().remove();
});