将Geofire与现有的Firebase数据库集成 [英] Integrating Geofire with existing firebase database

问题描述

我已经查看了 Geofire 的github Fish示例，但是仍不清楚如何在我的应用程序中实现它.我的用例:我的应用程序向登录用户显示事件/事件.当前在我的应用程序中，我在firebase ref(events)上有firebase侦听器.

I have gone through the github Fish examples for Geofire but still unclear of how to implement it within my app. My use case: My app shows events/meetups to logged in users. Currently within my app I have firebase listener at a firebase ref(events).

database.ref('events').orderByChild('startTime').on('value', (snapshot) => { 
 const feed = snapshot.val() || {}
})

当前，在初始加载时，客户端应用会在事件ref处获取整个对象，然后将每个事件数据显示在表中(每行一个事件)给用户.

Currently, at the initial load, the client app fetches the entire object at the events ref and then each of the events data is displayed to the user in a table(each row an event).

我了解，通过geofire，我可以使用set()函数来保存每个事件键及其地理位置[lat，lng].然后使用查询，我可以检索属于用户当前位置(html5地理位置)指定半径范围内的事件键列表.但是，由于键没有附加数据，我该怎么办?我是否要在事件"引用中为每个事件键设置单独的打开"侦听器?然后显示事件数据?

I understand that with geofire I can use the set() function to save each event key along with its geolocation[lat, lng]. And then using query I can retrieve the list of the event keys that fall within the specified radius to users current location(html5 geolocation). But What do I do with the keys, since there is no data attached to them, do I set individual "on" listeners for each event key at the Events ref? and then display the events data?

推荐答案

使用Geofire时，最终会在JSON树中出现两个分支:一个分支包含对象的地理数据，另一个分支包含实际数据.

When you use Geofire, you end up with two branches in your JSON tree: one with the geodata for objects and one with the actual data.

objects
  objectId1: { ... }
  objectId2: { ... }
  objectId3: { ... }      
geodata
  objectId1: { ... }
  objectId2: { ... }
  objectId3: { ... }

当您针对 geodata 节点触发GeoQuery时，您将获得属于该查询范围的对象的键.因此，例如 objectId2 和 objectId3 .

When you fire a GeoQuery against the geodata node, you get back the keys of the objects that fall within the range of that query. So for example objectId2 and objectId3.

然后，您可以使用该键在 objects 下查找相应的JSON对象.例如，当使用 key_entered :

You then use that key to look up the corresponding JSON object under objects. For example when using key_entered:

geoQuery.on("key_entered", function(key, location, distance) {
  console.log(key + " entered query at " + location + " (" + distance + " km from center)");
  ref.child("objects").child(key).once("value", function(snapshot) {
    console.log(snapshot.val());
  });
});

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