[英]Notifications with Socket.io - how to emit to a specific user/recipient?
我想實現一個簡單的通知系統。 當user1
喜歡user2
的帖子時, user2
應該會收到來自user1
的實時通知。
這是客戶端 function(Redux 操作)的一部分,其中有人喜歡一個帖子:
.then(() => {
const socket = require("socket.io-client")(
"http://localhost:5000"
);
socket.emit("like", user, post);
});
這是服務器套接字user1
,在用戶 1 喜歡用戶user2
的帖子后創建通知:
io.on("connection", (socket) => {
socket.on("like", async (user, post) => {
if (!post.post.likedBy.includes(user.user._id)) {
const Notification = require("./models/Notification");
let newNotification = new Notification({
notification: `${user.user.username} liked your post!`,
sender: user.user._id,
recipient: post.post.by._id,
read: false,
});
await newNotification.save();
io.emit("notification");
}
});
});
這是創建通知后的客戶端 function:
socket.on("notification", () => {
console.log("liked");
});
現在的問題是console.log('liked')
出現在user1
和user2
上。 我怎樣才能只發送給收到通知的用戶? socket.io 如何找到收到user1
通知的特定user2
?
您應該像這樣存儲所有用戶的列表(數組或對象):
(請注意,當用戶connects
或leaves
套接字服務器時,列表必須更新)
// an example of structure in order to store the users
const users = [
{
id: 1,
socket: socket
},
// ...
];
然后你可以定位帖子所有者並向他發送這樣的通知:
// assuming the the 'post' object contains the id of the owner
const user = users.find(user => user.id == post.user.id);
// (or depending of the storage structure)
// const user = users[post.user.id]
user.socket.emit('notification');
這里有一個例子:
const withObject = {};
const withArray = [];
io.on('connection', socket => {
const user = { socket : socket };
socket.on('data', id => {
// here you do as you want, if you want to store just their socket or another data, in this example I store their id and socket
user.id = id;
withObject[id] = user;
withArray[id] = user;
// or withArray.push(user);
});
socket.on('disconnect', () => {
delete withObject[user.id];
delete withArray[user.id];
// or let index = users.indexOf(user);
// if(index !=== -1) users.splice(index, 1);
});
});
有很多方法可以實現我要解釋的內容,但主要思想是將套接字與其他索引(例如用戶 ID)鏈接起來,以便稍后在代碼中檢索它。
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