节点JS/Firebase Admin SDK/Firebase Storage-上载到Firebase Storage的base64映像未生成预览

Question

我正在尝试将从angular frontend接收的base64映像保存到firebase存储目录中。但由于某些原因，保存在firebase文件夹中的图像未生成预览。此外，在尝试检索图像文件时，我无法获取该文件的签名URL。

我正在使用Firebase admin-sdk生成桶引用-'storageRef'。

节点后端接收到的图像数据似乎很好，我使用在线base64解码器测试了相同的数据，并正确地重新生成原始图像。有人能告诉我这里出了什么问题吗？

exports.createContent = async(req, res, next) => {

  // Add a new document with a generated id.
  const writer = await db.collection('feeds').doc(req.body.language).collection(req.body.type).add({
  author: req.body.author,
  cat: req.body.cat,
  content: req.body.content,
  createdAt: admin.firestore.Timestamp.fromDate(new Date(req.body.createdAt)),
  excerpt: req.body.excerpt,
  lastEdit: admin.firestore.Timestamp.fromDate(new Date(req.body.lastEdit)),
  media: req.body.media,
  os_android: req.body.os_android === 'true' ? true : false,
  os_ios: req.body.os_ios === 'true' ? true : false,
  region: req.body.region,
  status: req.body.status,
  title: req.body.title,
  type: req.body.type
}).then((docRef) => {

  let bufferStream = new stream.PassThrough();
  base64EncodedImageString = req.body.imageSrc.replace(/^data:image\/\w+;base64,/, '');
  bufferStream.end(Buffer.from(base64EncodedImageString, 'base64'));

  var file = storageRef.file('thumbnail/' + req.body.type + '/' + docRef.id + '.png');
  //Pipe the 'bufferStream' into a 'file.createWriteStream' method.
  bufferStream.pipe(file.createWriteStream({
      metadata: {
        contentType: 'image/png',
        metadata: {
          custom: 'metadata'
        }
      },
      public: true,
      validation: "md5"
    }))
    .on('error', function(err) {
      console.log(err);
    })
    .on('finish', function() {
      res.json({
        message: "Feeds Added Successfully",
        feeds: docRef.id
      });
    });
})

};

Answer 1

问题是，我在NodeJS中使用Firebase管理员SDK，我试图在代码中公开该文件，违反存储桶的访问规则。因此，我将公共访问密钥转换为false，并在上传时为该文件生成访问令牌。我在下面包含了我的工作代码。

var stream = require('stream');
const uuidv4 = require('uuid/v4');

const uuid = uuidv4();
let bufferStream = new stream.PassThrough();
var base64EncodedImageString = req.body.imageSrc.replace(/^data:image\/\w+;base64,/, '');
bufferStream.end(new Buffer.from(base64EncodedImageString, 'base64'));
    
var file = storageRef.file('thumbnail/' + req.body.type + '/' + docRef.id + '.png');
//Pipe the 'bufferStream' into a 'file.createWriteStream' method.
        bufferStream.pipe(file.createWriteStream({
          metadata: {
            contentType: 'image/png',
            metadata :{
              firebaseStorageDownloadTokens: uuid
           }
          },
          public: false,
          validation: 'md5'
        }))
        .on('error', function(err) {
          console.log(err);
        })
        .on('finish', function() {
          res.json({
            message: "Feeds Added Successfully",
            feeds: docRef.id
          });
        });