[英]How to get DownloadURL from Firebase Storage
我正在存儲Firebase上工作,我試圖獲取URL並將其設置為變量,但不幸的是我無法執行此操作,我的代碼有問題。 有人可以幫我嗎?
這是錯誤:
firebase.js:1未捕獲(承諾)錯誤:Reference.push失敗:第一個參數包含未定義的屬性'PostUsers.ImageURL.i'
這是代碼:
console.log('Nice, The file has been successfully uploaded to the Firebase storage!');
var DownloadURL = uploadTask.snapshot.downloadURL;
var Url_File = uploadTask.snapshot.ref.getDownloadURL().then(function (URL) {
return URL;
});
alert(Url_File);
uploadTask.snapshot.ref.getDownloadURL().then(function (downloadURL) {
console.log('File available at', downloadURL);
//Url_File = downloadURL;
});
//getting the publication time
var dayObj = new Date();
var day = dayObj.getDate();
var monthNames = ["January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
];
var month = monthNames[dayObj.getMonth()]
var year = dayObj.getFullYear();
var hour = dayObj.getHours();
var minutes = dayObj.getMinutes();
var seconds = dayObj.getSeconds();
var GlobalUserName = <%=Session["UserId"] %>;
firebase.database().ref('PostUsers/').push({
ImageURL: Url_File,
userAuthor: GlobalUserName,
day: day,
month: month,
year: year,
hour: hour,
minutes: minutes,
seconds: seconds
});
//console.log('the download Url of your file is: '+ downloadURL);
console.log('User post successfully added to realtime data bases');
});
我已經嘗試了許多不同的方法,但是它們都無法正常工作。
提前致謝。
在這段代碼中:
var Url_File = uploadTask.snapshot.ref.getDownloadURL().then(function (URL) {
return URL;
});
下載URL在名為URL
的變量的promise回調中。 它不在Url_File
。 Url_File
將包含then()
返回的promise。
您需要將使用下載URL的代碼放在第一次可用的promise回調中。 您現在擁有的方式是,在URL可用之前,正在執行使用下載URL的代碼。
下載URL僅在從getDownloadURL()
獲得的then
回調中可用。 您不能在此之外訪問它。
因此,解決辦法是將需要下載的URL 步入回調的所有代碼:
uploadTask.snapshot.ref.getDownloadURL().then(function (URL) {
//getting the publication time
var dayObj = new Date();
var day = dayObj.getDate();
var monthNames = ["January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
];
var month = monthNames[dayObj.getMonth()]
var year = dayObj.getFullYear();
var hour = dayObj.getHours();
var minutes = dayObj.getMinutes();
var seconds = dayObj.getSeconds();
var GlobalUserName = <%=Session["UserId"] %>;
firebase.database().ref('PostUsers/').push({
ImageURL: URL,
userAuthor: GlobalUserName,
day: day,
month: month,
year: year,
hour: hour,
minutes: minutes,
seconds: seconds
});
console.log('User post successfully added to realtime database');
});
在處理現代Web API時,這是一種非常常見的模式:它們都是異步的,因此您的代碼必須對此進行處理。
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