无法从Firebase的getDownloadURL获取URL

如何解决无法从Firebase的getDownloadURL获取URL

我正在使用Firebase存储将图像存储到其中，图像很容易上传到存储中，但是当我尝试获取图像形式Promise的url时，它不返回url。

  const imageSaveHandler = (e) => {
    e.preventDefault();
    const uploadTask = storage.ref(`images/${image.name}`).put(image);
    uploadTask.on(
      "state_changed",(error) => {
        console.log(error);
      },() => {
        return storage
          .ref(`images/${image.name}`)
          .getDownloadURL()
          .then((url) => {console.log(url)})
          .catch((err) => console.log(err));
      }
    );
  };

解决方法

根据https://firebase.google.com/docs/storage/web/upload-files的示例，看来uploadTask.on的第三个参数当前具有的处理程序应改为第四个参数：

var uploadTask = storageRef.child('images/rivers.jpg').put(file);

// Register three observers:
// 1. 'state_changed' observer,called any time the state changes
// 2. Error observer,called on failure
// 3. Completion observer,called on successful completion
uploadTask.on('state_changed',function(snapshot){
  // Observe state change events such as progress,pause,and resume
  // Get task progress,including the number of bytes uploaded and the total number of bytes to be uploaded
  var progress = (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
  console.log('Upload is ' + progress + '% done');
  switch (snapshot.state) {
    case firebase.storage.TaskState.PAUSED: // or 'paused'
      console.log('Upload is paused');
      break;
    case firebase.storage.TaskState.RUNNING: // or 'running'
      console.log('Upload is running');
      break;
  }
},function(error) {
  // Handle unsuccessful uploads
},function() {
  // Handle successful uploads on complete
  // For instance,get the download URL: https://firebasestorage.googleapis.com/...
  uploadTask.snapshot.ref.getDownloadURL().then(function(downloadURL) {
    console.log('File available at',downloadURL);
  });
});