[英]How to create user specific data when user logs in for the first time in realtime firebase database?
我希望代码能够在用户登录时创建特定数据,但如果 firebase 实时数据库中已经存在,则不会创建它。 我使用了以下代码,通过它检查孩子是否已经存在,如果没有,则在 firebase 数据库中创建孩子,但不知何故,代码的行为不正常。 当用户再次登录时,完整的数据部分将被重写。
片段我需要帮助
if (!(checkdata(user.uid))) {
writeUserData(user.uid,user.displayName,user.email,user.photoURL)
}
var database = firebase.database();
function checkdata(userid){
var ref = firebase.database().ref("users");
ref.once("value")
.then(function(snapshot) {
var datapresent = snapshot.hasChild(userid); // true
return datapresent
});
}
function writeUserData(userId, name, email, imageUrl) {
firebase.database().ref('users/' + userId).set({
username: name,
email: email,
profile_picture : imageUrl,
cropdata : []
});
}
完整的JS文件
const signInBtn = document.getElementById('signinbtn');
const signOutBtn = document.getElementById('signoutbtn');
const userDetails = document.getElementById('username');
const auth = firebase.auth();
const provider = new firebase.auth.GoogleAuthProvider();
signInBtn.onclick = () => auth.signInWithPopup(provider);
signOutBtn.onclick = () => auth.signOut();
function toggle(className, displayState){
var elements = document.getElementsByClassName(className)
for (var i = 0; i < elements.length; i++){
elements[i].style.display = displayState;
}
}
auth.onAuthStateChanged(function(user) {
if (user) {
// signed in
toggle('userishere', 'block');
toggle('usernothere', 'none');
//userDetails.innerHTML = `<h3>Hello ${user.displayName}!</h3> <p>User ID: ${user.uid}</p>`;
userDetails.innerHTML = `Hello ${user.displayName}!`
console.log(user)
if (!(checkdata(user.uid))) {
writeUserData(user.uid,user.displayName,user.email,user.photoURL)
}
} else {
// not signed in
toggle('userishere', 'none');
toggle('usernothere', 'block');
userDetails.innerHTML = '';
}
});
var database = firebase.database();
function checkdata(userid){
var ref = firebase.database().ref("users");
ref.once("value")
.then(function(snapshot) {
var datapresent = snapshot.hasChild(userid); // true
return datapresent
});
}
function writeUserData(userId, name, email, imageUrl) {
firebase.database().ref('users/' + userId).set({
username: name,
email: email,
profile_picture : imageUrl,
cropdata : []
});
}
我刚刚找到了解决方案,异步代码没有等待我的 firebase 响应,只是检查了 datapresent 是否为真,所以在 function 之前使用异步定义并在 ref.once(value) 之前等待,我的问题是解决。 下面的工作代码:
const signInBtn = document.getElementById('signinbtn');
const signOutBtn = document.getElementById('signoutbtn');
const userDetails = document.getElementById('username');
var database = firebase.database();
const auth = firebase.auth();
const provider = new firebase.auth.GoogleAuthProvider();
signInBtn.onclick = () => auth.signInWithPopup(provider);
signOutBtn.onclick = () => auth.signOut();
async function checkdata(user){
let ref = firebase.database().ref("users");
let snapshot = await ref.once('value');
if (!snapshot.hasChild(user.uid)){
console.log(user)
writeUserData(user.uid,user.displayName,user.email,user.photoURL)
console.log("write done")
}
else{
console.log("did not write")
}
}
function writeUserData(userId, name, email, imageUrl) {
firebase.database().ref('users/' + userId).set({
username: name,
email: email,
profile_picture: imageUrl,
cropdata: []
});
}
function toggle(className, displayState) {
var elements = document.getElementsByClassName(className)
for (var i = 0; i < elements.length; i++) {
elements[i].style.display = displayState;
}
}
auth.onAuthStateChanged(function (user) {
if (user) {
// signed in
toggle('userishere', 'block');
toggle('usernothere', 'none');
//userDetails.innerHTML = `<h3>Hello ${user.displayName}!</h3> <p>User ID: ${user.uid}</p>`;
userDetails.innerHTML = `Hello ${user.displayName}!`
console.log(user)
checkdata(user)
}
else {
toggle('userishere', 'none');
toggle('usernothere', 'block');
userDetails.innerHTML = '';
}
})
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