用Firebase 3上传Base64图像

Question

是否可以将base64图像上传到Firebase？

我试过这样的代码：

                    var storageRef = firebase.storage().ref();
                console.log(storageRef);                                        
                var file = "data:image/jpeg;base64,BASE64.....";

                var uploadTask = storageRef.child('avatars/'+user.providerData[0].uid+'/photo-'+$scope.number+'.jpg').put(file);
                uploadTask.on('state_changed', function(snapshot){
                }, function(error) {
                  console.log('error');
                }, function() {
                  console.log('success');
                  var downloadURL = uploadTask.snapshot.downloadURL;
                });

但我有个错误：

{code: "storage/invalid-argument", message: "Firebase Storage: Invalid argument in `put` at index 0: Expected Blob or File.", serverResponse: null, name: "FirebaseError"}

Answer 1

可以将base64传递给返回blob的函数，如下所示：

base64toBlob(base64Data, contentType) {
        contentType = contentType || '';
        var sliceSize = 1024;
        var byteCharacters = atob(base64Data);
        var bytesLength = byteCharacters.length;
        var slicesCount = Math.ceil(bytesLength / sliceSize);
        var byteArrays = new Array(slicesCount);

        for (var sliceIndex = 0; sliceIndex < slicesCount; ++sliceIndex) {
            var begin = sliceIndex * sliceSize;
            var end = Math.min(begin + sliceSize, bytesLength);

            var bytes = new Array(end - begin);
            for (var offset = begin, i = 0 ; offset < end; ++i, ++offset) {
                bytes[i] = byteCharacters[offset].charCodeAt(0);
            }
            byteArrays[sliceIndex] = new Uint8Array(bytes);
        }
        return new Blob(byteArrays, { type: contentType });
    }

Answer 2

您只需要使用putString函数，而不需要将BASE64转换为blob。

firebase.storage().ref('/your/path/here').child('file_name')
.putString(your_base64_image, ‘base64’, {contentType:’image/jpg’});

确保将元数据{contentType:’image/jpg’}作为(第三个参数(可选))传递给函数putString，以便以图像格式检索数据。

或者简单地说：

uploadTask = firebase.storage().ref('/your/path/here').child('file_name').putString(image, 'base64', {contentType:'image/jpg'});
uploadTask.on(firebase.storage.TaskEvent.STATE_CHANGED, // or 'state_changed'
  function(snapshot) {
    // 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) {
    console.log(error);
}, function() {
  // Upload completed successfully, now we can get the download URL
  var downloadURL = uploadTask.snapshot.downloadURL;
});

然后，您可以使用downloadURL保存到firebase.database()和/或将其作为src保存到<img>标记。

Answer 3

Firebase采用JS 文件或水滴类型，而不是字符串。您可以将base64编码的数据存储在文件中，然后上传，不过我建议将它们转换为“真实的”文件(根据jpg或png的判断，它看起来像一张照片)，这样您就可以拥有内容类型，让浏览器对其进行处理，并获得压缩等好处。