试图弄清楚如何在使用 axios get 请求获取消息的 useEffect 中以正确的方式使用 socket.io
Trying to figure out how to use socket.io the correct way in a useEffect that is using an axios get request to fetch messages
到目前为止,我一直停留在我的 useEffect 上,它获取所有当前消息并相应地呈现状态。截至目前,在刷新页面之前它不会呈现新状态。
const Home = ({ user, logout }) => {
const history = useHistory();
const socket = useContext(SocketContext);
const [conversations, setConversations] = useState([]);
const [activeConversation, setActiveConversation] = useState(null);
const classes = useStyles();
const [isLoggedIn, setIsLoggedIn] = useState(false);
const addSearchedUsers = (users) => {
const currentUsers = {};
// make table of current users so we can lookup faster
conversations.forEach((convo) => {
currentUsers[convo.otherUser.id] = true;
});
const newState = [...conversations];
users.forEach((user) => {
// only create a fake convo if we don't already have a convo with this user
if (!currentUsers[user.id]) {
let fakeConvo = { otherUser: user, messages: [] };
newState.push(fakeConvo);
}
});
setConversations(newState);
};
const clearSearchedUsers = () => {
setConversations((prev) => prev.filter((convo) => convo.id));
};
const saveMessage = async (body) => {
const { data } = await axios.post("/api/messages", body);
return data;
};
const sendMessage = (data, body) => {
socket.emit("new-message", {
message: data.message,
recipientId: body.recipientId,
sender: data.sender,
});
};
const postMessage = async (body) => {
try {
const data = await saveMessage(body);
if (!body.conversationId) {
addNewConvo(body.recipientId, data.message);
} else {
addMessageToConversation(data);
}
sendMessage(data, body);
} catch (error) {
console.error(error);
}
};
const addNewConvo = useCallback(
(recipientId, message) => {
conversations.forEach((convo) => {
if (convo.otherUser.id === recipientId) {
convo.messages.push(message);
convo.latestMessageText = message.text;
convo.id = message.conversationId;
}
});
setConversations(conversations);
},
[setConversations, conversations],
);
const addMessageToConversation = useCallback(
(data) => {
// if sender isn't null, that means the message needs to be put in a brand new convo
const { message, sender = null } = data;
if (sender !== null) {
const newConvo = {
id: message.conversationId,
otherUser: sender,
messages: [message],
};
newConvo.latestMessageText = message.text;
setConversations((prev) => [newConvo, ...prev]);
}
conversations.forEach((convo) => {
console.log('hi', message.conversationId)
if (convo.id === message.conversationId) {
const convoCopy = { ...convo }
convoCopy.messages.push(message);
convoCopy.latestMessageText = message.text;
console.log('convo', convoCopy)
} else {
return convo
}
});
setConversations(conversations);
},
[setConversations, conversations],
);
const setActiveChat = useCallback((username) => {
setActiveConversation(username);
}, []);
const addOnlineUser = useCallback((id) => {
setConversations((prev) =>
prev.map((convo) => {
if (convo.otherUser.id === id) {
const convoCopy = { ...convo };
convoCopy.otherUser = { ...convoCopy.otherUser, online: true };
return convoCopy;
} else {
return convo;
}
}),
);
}, []);
const removeOfflineUser = useCallback((id) => {
setConversations((prev) =>
prev.map((convo) => {
if (convo.otherUser.id === id) {
const convoCopy = { ...convo };
convoCopy.otherUser = { ...convoCopy.otherUser, online: false };
return convoCopy;
} else {
return convo;
}
}),
);
}, []);
// Lifecycle
useEffect(() => {
// Socket init
socket.on("add-online-user", addOnlineUser);
socket.on("remove-offline-user", removeOfflineUser);
socket.on("new-message", addMessageToConversation);
return () => {
// before the component is destroyed
// unbind all event handlers used in this component
socket.off("add-online-user", addOnlineUser);
socket.off("remove-offline-user", removeOfflineUser);
socket.off("new-message", addMessageToConversation);
};
}, [addMessageToConversation, addOnlineUser, removeOfflineUser, socket]);
useEffect(() => {
// when fetching, prevent redirect
if (user?.isFetching) return;
if (user && user.id) {
setIsLoggedIn(true);
} else {
// If we were previously logged in, redirect to login instead of register
if (isLoggedIn) history.push("/login");
else history.push("/register");
}
}, [user, history, isLoggedIn]);
useEffect(() => {
const fetchConversations = async () => {
try {
const { data } = await axios.get("/api/conversations");
setConversations(data);
} catch (error) {
console.error(error);
}
};
if (!user.isFetching) {
fetchConversations();
}
}, [user]);
const handleLogout = async () => {
if (user && user.id) {
await logout(user.id);
}
};
return (
<>
<Button onClick={handleLogout}>Logout</Button>
<Grid container component="main" className={classes.root}>
<CssBaseline />
<SidebarContainer
conversations={conversations}
user={user}
clearSearchedUsers={clearSearchedUsers}
addSearchedUsers={addSearchedUsers}
setActiveChat={setActiveChat}
/>
<ActiveChat
activeConversation={activeConversation}
conversations={conversations}
user={user}
postMessage={postMessage}
/>
</Grid>
</>
);
};
这是我工作的主要部分,该项目在我开始时有起始代码,并被告知不要接触后端,所以我知道前端代码有问题。我觉得我错过了一些对 socket.io 很重要的东西
import { io } from 'socket.io-client';
import React from 'react';
export const socket = io(window.location.origin);
socket.on('connect', () => {
console.log('connected to server');
});
export const SocketContext = React.createContext();
这就是我设置 socket.io 的方式,如果有人能指出正确的方向,那就太好了。我一直在尽可能多地阅读 socket.io,但仍然很迷茫。
基于后端正常工作的假设...
const addNewConvo = useCallback(
(recipientId, message) => {
conversations.forEach((convo) => {
if (convo.otherUser.id === recipientId) {
convo.messages.push(message);
convo.latestMessageText = message.text;
convo.id = message.conversationId;
}
});
setConversations(conversations);
},
[setConversations, conversations],
);
setConversations(conversations);
这是使用状态变量设置状态的错误方法,因此它不会执行任何操作。可能是为什么您的代码在刷新之前不会更改。
建议的修复:
const addNewConvo = useCallback(
(recipientId, message) => {
setConversations(previousState => previousState.map(convo => {
if (convo.otherUser.id === recipientId) {
convo.messages.push(message)
convo.latestMessageText = message.text;
convo.id = message.conversationId;
return convo
}
return convo
}))
},
[setConversations, conversations],
);
注意:由于我对消息进行了深度复制,因此甚至可以更有效地完成上述操作
到目前为止,我一直停留在我的 useEffect 上,它获取所有当前消息并相应地呈现状态。截至目前,在刷新页面之前它不会呈现新状态。
const Home = ({ user, logout }) => {
const history = useHistory();
const socket = useContext(SocketContext);
const [conversations, setConversations] = useState([]);
const [activeConversation, setActiveConversation] = useState(null);
const classes = useStyles();
const [isLoggedIn, setIsLoggedIn] = useState(false);
const addSearchedUsers = (users) => {
const currentUsers = {};
// make table of current users so we can lookup faster
conversations.forEach((convo) => {
currentUsers[convo.otherUser.id] = true;
});
const newState = [...conversations];
users.forEach((user) => {
// only create a fake convo if we don't already have a convo with this user
if (!currentUsers[user.id]) {
let fakeConvo = { otherUser: user, messages: [] };
newState.push(fakeConvo);
}
});
setConversations(newState);
};
const clearSearchedUsers = () => {
setConversations((prev) => prev.filter((convo) => convo.id));
};
const saveMessage = async (body) => {
const { data } = await axios.post("/api/messages", body);
return data;
};
const sendMessage = (data, body) => {
socket.emit("new-message", {
message: data.message,
recipientId: body.recipientId,
sender: data.sender,
});
};
const postMessage = async (body) => {
try {
const data = await saveMessage(body);
if (!body.conversationId) {
addNewConvo(body.recipientId, data.message);
} else {
addMessageToConversation(data);
}
sendMessage(data, body);
} catch (error) {
console.error(error);
}
};
const addNewConvo = useCallback(
(recipientId, message) => {
conversations.forEach((convo) => {
if (convo.otherUser.id === recipientId) {
convo.messages.push(message);
convo.latestMessageText = message.text;
convo.id = message.conversationId;
}
});
setConversations(conversations);
},
[setConversations, conversations],
);
const addMessageToConversation = useCallback(
(data) => {
// if sender isn't null, that means the message needs to be put in a brand new convo
const { message, sender = null } = data;
if (sender !== null) {
const newConvo = {
id: message.conversationId,
otherUser: sender,
messages: [message],
};
newConvo.latestMessageText = message.text;
setConversations((prev) => [newConvo, ...prev]);
}
conversations.forEach((convo) => {
console.log('hi', message.conversationId)
if (convo.id === message.conversationId) {
const convoCopy = { ...convo }
convoCopy.messages.push(message);
convoCopy.latestMessageText = message.text;
console.log('convo', convoCopy)
} else {
return convo
}
});
setConversations(conversations);
},
[setConversations, conversations],
);
const setActiveChat = useCallback((username) => {
setActiveConversation(username);
}, []);
const addOnlineUser = useCallback((id) => {
setConversations((prev) =>
prev.map((convo) => {
if (convo.otherUser.id === id) {
const convoCopy = { ...convo };
convoCopy.otherUser = { ...convoCopy.otherUser, online: true };
return convoCopy;
} else {
return convo;
}
}),
);
}, []);
const removeOfflineUser = useCallback((id) => {
setConversations((prev) =>
prev.map((convo) => {
if (convo.otherUser.id === id) {
const convoCopy = { ...convo };
convoCopy.otherUser = { ...convoCopy.otherUser, online: false };
return convoCopy;
} else {
return convo;
}
}),
);
}, []);
// Lifecycle
useEffect(() => {
// Socket init
socket.on("add-online-user", addOnlineUser);
socket.on("remove-offline-user", removeOfflineUser);
socket.on("new-message", addMessageToConversation);
return () => {
// before the component is destroyed
// unbind all event handlers used in this component
socket.off("add-online-user", addOnlineUser);
socket.off("remove-offline-user", removeOfflineUser);
socket.off("new-message", addMessageToConversation);
};
}, [addMessageToConversation, addOnlineUser, removeOfflineUser, socket]);
useEffect(() => {
// when fetching, prevent redirect
if (user?.isFetching) return;
if (user && user.id) {
setIsLoggedIn(true);
} else {
// If we were previously logged in, redirect to login instead of register
if (isLoggedIn) history.push("/login");
else history.push("/register");
}
}, [user, history, isLoggedIn]);
useEffect(() => {
const fetchConversations = async () => {
try {
const { data } = await axios.get("/api/conversations");
setConversations(data);
} catch (error) {
console.error(error);
}
};
if (!user.isFetching) {
fetchConversations();
}
}, [user]);
const handleLogout = async () => {
if (user && user.id) {
await logout(user.id);
}
};
return (
<>
<Button onClick={handleLogout}>Logout</Button>
<Grid container component="main" className={classes.root}>
<CssBaseline />
<SidebarContainer
conversations={conversations}
user={user}
clearSearchedUsers={clearSearchedUsers}
addSearchedUsers={addSearchedUsers}
setActiveChat={setActiveChat}
/>
<ActiveChat
activeConversation={activeConversation}
conversations={conversations}
user={user}
postMessage={postMessage}
/>
</Grid>
</>
);
};
import { io } from 'socket.io-client';
import React from 'react';
export const socket = io(window.location.origin);
socket.on('connect', () => {
console.log('connected to server');
});
export const SocketContext = React.createContext();
这就是我设置 socket.io 的方式,如果有人能指出正确的方向,那就太好了。我一直在尽可能多地阅读 socket.io,但仍然很迷茫。
基于后端正常工作的假设...
const addNewConvo = useCallback(
(recipientId, message) => {
conversations.forEach((convo) => {
if (convo.otherUser.id === recipientId) {
convo.messages.push(message);
convo.latestMessageText = message.text;
convo.id = message.conversationId;
}
});
setConversations(conversations);
},
[setConversations, conversations],
);
setConversations(conversations);
这是使用状态变量设置状态的错误方法,因此它不会执行任何操作。可能是为什么您的代码在刷新之前不会更改。
建议的修复:
const addNewConvo = useCallback(
(recipientId, message) => {
setConversations(previousState => previousState.map(convo => {
if (convo.otherUser.id === recipientId) {
convo.messages.push(message)
convo.latestMessageText = message.text;
convo.id = message.conversationId;
return convo
}
return convo
}))
},
[setConversations, conversations],
);
注意:由于我对消息进行了深度复制,因此甚至可以更有效地完成上述操作