Firebase iOS SDK - 统计连接的用户

Question

我正在使用Firebase iOS SDK构建一个聊天系统，该聊天系统可让我的用户连接到一些随机聊天的“聊天室”。在房间内，我想向他们显示当前连接的人员总数。问题是我不知道该怎么做。连接的用户数量应在特定用户的连接和断开连接时更新。我不知道该从哪里开始，该怎么做。

Answer 1

这是简单的:)

每当用户认证/加入房间它们保存到活跃用户的列表。上述

夫特

let ref = Firebase(url: "<your-firebase-db>") 
ref.observeAuthEventWithBlock { authData in 
    if authData != nil { 
    // 1 - Get the ref 
    let activeUsersRef = Firebase(url: '<your-firebase-db>/activeUsers') 
    // 2 - Create a unique ref 
    let singleUserRef = activeUsersRef.childByAutoId() 
    // 3 - Add them to the list of online users 
    singleUserRef.setValue(authData.providerData["email"]) 
    // 4 - When they drop their connection, remove them 
    singleUserRef.onDisconnectRemoveValue() 
    } 
} 

目标C

Firebase *ref = [[Firebase alloc] initWithUrl: @"<your-firebase-db>"]; 
[ref observeAuthEventWithBlock: ^(FAuthData *authData) { 
    Firebase *activeUsersRef = [[Firebase alloc] initWithUrl: @"<your-firebase-db>/activeUsers"]; 
    Firebase *singleUserRef = [activeUsersRef childByAutoId]; 
    [singleUserRef setValue: @"Whatever-the-key-is"]; 
    [singleUserRef onDisconnectRemoveValue]; 
}]; 

代码段将保持活跃的用户的列表。

现在您只需要显示计数。

斯威夫特

// Listen to the same ref as above 
let activeUsersRef = Firebase(url: 'firebase-db.firebaseio.com/activeUsers') 
activeUsersRef.observeEventType(.Value, withBlock: { (snapshot: FDataSnapshot!) in 
    var count = 0 
    // if the snapshot exists, get the children 
    if snapshot.exists() { 
    count = snapshot.childrenCount 
    } 
}) 

Objective-C的

Firebase *activeUsersRef = [[Firebase alloc] initWithUrl: @"<your-firebase-db>/activeUsers"]; 
[activeUsersRef observeEventType:FEventTypeValue withBlock:^(FDataSnapshot *snapshot) { 
    NSUInteger count = 0; 
    if ([snapshot exists]) { 
    count = snapshot.childrenCount; 
    } 
}];