Question

所以我一直在尝试制作一些仅将项目上载到firebase的东西。..我无法真正解释该项目，但是我想做的是：

上传文件时获取firebase下载URL。
将其保存在firebase实时数据库中。

我为此编写的代码是

    let downloadURL;
    var filename = filenamechosen;
    var storageRef = firebase.storage().ref('/dav' + 'projects' + '/' + filename);
    var uploadTask = storageRef.put(selectedFile);

    uploadTask.on("state_changed", function(snapshot){

    }, function(error){

    }, function(){
        console.log(uploadTask.snapshot.ref.getDownloadURL());
    });
    };

function uploadOne(){
    let projectinf = document.getElementById("projectinfo").value;
    let name = document.getElementById("studentname").value;
    let cls = document.getElementById("cls").value;
    let email = document.getElementById("email").value;
    let projectlnk = downloadURL;
    let marks = document.getElementById("marks").value;
    let submitfrm = document.getElementById("submitfrm");
    let studentObj = {
        class: cls,
        email: email, 
        projectinfo: projectinf,
        projectlink: projectlnk,
        marks: "lol",
    }
    firebase.database().ref('/schools/dav/').child(`${name}`).set(studentObj).then().catch();
    console.log("done");
}

要获取下载网址，我得到了这样的答复

jt {a: 0, i: undefined, c: jt, b: null, f: null, …}
a: 2
b: null
c: null
f: null
g: false
h: false
i: "https://firebasestorage.googleapis.com/v0/b/workspace-c7042.appspot.com/o/davproject.... //Continues

我不知道在获取下载网址后如何将其存储在Firebase实时数据库中。

<form action="uploadOne()">
<!--Some inputs as defined in the uploadOne function.-->
<button type="submit">SUBMIT</button>
</form>

这几乎是我正在使用的所有表格。

Answer 1

getDownloadURL()方法是异步，并返回一个Promise，该URL可以使用downloadURL进行解析。

因此，您需要按照以下步骤做一些事情，使用then()方法来等待Promise解决：

  uploadTask.snapshot.ref.getDownloadURL().then(function(downloadURL) {
    console.log('File available at', downloadURL);
  });

您的代码中如何链接两个不同的部分（哪个调用哪个以及如何选择文件）尚不清楚，但是下面显示了一种可能性：

let downloadURL;
var filename = filenamechosen;
var storageRef = firebase.storage().ref('/dav' + 'projects' + '/' + filename);
var uploadTask = storageRef.put(selectedFile);

uploadTask.on("state_changed",
null,  /// <- See https://firebase.google.com/docs/reference/js/firebase.storage.UploadTask#on
null,
function(){
   // Upload completed successfully, now we can get the download URL
    uploadTask.snapshot.ref.getDownloadURL()
    .then(function(downloadURL) {
        console.log('File available at', downloadURL);
        uploadOne(downloadURL);  // <- We call the uploadOne function passing the downloadURL as parameter
    });
});


function uploadOne(downloadURL){
    let projectinf = document.getElementById("projectinfo").value;
    let name = document.getElementById("studentname").value;
    let cls = document.getElementById("cls").value;
    let email = document.getElementById("email").value;
    let projectlnk = downloadURL;
    let marks = document.getElementById("marks").value;
    let submitfrm = document.getElementById("submitfrm");
    let studentObj = {
        class: cls,
        email: email, 
        projectinfo: projectinf,
        projectlink: projectlnk,
        marks: "lol",
    }
    firebase.database().ref('/schools/dav/').child(`${name}`).set(studentObj)
    .then(function() {
        console.log("done");
      })
      .catch(function(error) {
        console.log(error);
      });
}

这样，uploadTask触发了对数据库的写入。您可以根据需要进行调整，但是在任何情况下，您只能在实现Promise时调用的回调函数中获得downloadURL的值。

Firebase-获取下载URL（Firebase存储）并将其保存在Firebase实时数据库中

1 个答案: