如何使用Node.js将base64编码图像(字符串)直接上传到Google Cloud Storage存储桶？

Question

目前,我正在使用@ google-cloud/storage NPM软件包将文件直接上传到Google云端存储分区.这需要一些技巧,因为我只有图像的base64编码字符串.我必须:

• 解码字符串
• 将其另存为文件
• 将文件路径发送到以下脚本以上传到Google云端存储
• 删除本地文件

我想避免将文件存储在文件系统中,因为我使用的是Google App Engine,如果删除操作因任何原因无效,我不想重载文件系统/留下垃圾文件.这就是我的上传脚本现在的样子:

// Convert the base64 string back to an image to upload into the Google Cloud Storage bucket
var base64Img = require('base64-img');
var filePath = base64Img.imgSync(req.body.base64Image, 'user-uploads', 'image-name');

// Instantiate the GCP Storage instance
var gcs = require('@google-cloud/storage')(),
    bucket = gcs.bucket('google-cloud-storage-bucket-name');

// Upload the image to the bucket
bucket.upload(__dirname.slice(0, -15) + filePath, {
    destination: 'profile-images/576dba00c1346abe12fb502a-original.jpg',
    public: true,
    validation: 'md5'
}, function(error, file) {

    if (error) {
        sails.log.error(error);
    }

    return res.ok('Image uploaded');
});

无论如何直接上传图像的base64编码字符串而不是必须将其转换为文件,然后使用路径上传？

Answer 1

该解决方案,我相信,是使用file.createWriteStream该功能的bucket.upload功能在谷歌云节点SDK包.

我对溪流的经验很少,所以如果不能正常工作,请尽量忍受.

首先,我们需要获取base64数据并将其放入流中.为此,我们将包括stream库,从base64数据创建缓冲区,并将缓冲区添加到流的末尾.

var stream = require('stream');
var bufferStream = new stream.PassThrough();
bufferStream.end(Buffer.from(req.body.base64Image, 'base64'));

有关解码base64和创建流的更多信息.

然后我们将流传输到由file.createWriteStream函数创建的写入流中.

var gcs = require('@google-cloud/storage')({
  projectId: 'grape-spaceship-123',
  keyFilename: '/path/to/keyfile.json'
});

//Define bucket.
var myBucket = gcs.bucket('my-bucket');
//Define file & file name.
var file = myBucket.file('my-file.jpg');
//Pipe the 'bufferStream' into a 'file.createWriteStream' method.
bufferStream.pipe(file.createWriteStream({
    metadata: {
      contentType: 'image/jpeg',
      metadata: {
        custom: 'metadata'
      }
    },
    public: true,
    validation: "md5"
  }))
  .on('error', function(err) {})
  .on('finish', function() {
    // The file upload is complete.
  });

信息file.createWriteStream,文档文档,bucket.upload以及bucket.uploadNode SDK中的方法代码.

因此,上述代码的工作方式是定义要放入文件的存储桶,然后定义文件和文件名.我们不在此处设置上传选项.然后,bufferStream我们将刚刚创建的变量传递给file.createWriteStream我们之前讨论过的方法.在这些选项中,我们定义了您要实现的元数据和其他选项.直接查看Github上的Node代码以了解它们如何分解bucket.upload函数非常有帮助,并建议您也这样做.最后,我们会在上传完成和错误发布时附加一些事件.

Answer 2

发布我的答案版本以响应@krlozadan的上述要求:

// Convert the base64 string back to an image to upload into the Google Cloud Storage bucket
var mimeTypes = require('mimetypes');

var image = req.body.profile.image,
    mimeType = image.match(/data:([a-zA-Z0-9]+\/[a-zA-Z0-9-.+]+).*,.*/)[1],
    fileName = req.profile.id + '-original.' + mimeTypes.detectExtension(mimeType),
    base64EncodedImageString = image.replace(/^data:image\/\w+;base64,/, ''),
    imageBuffer = new Buffer(base64EncodedImageString, 'base64');

// Instantiate the GCP Storage instance
var gcs = require('@google-cloud/storage')(),
    bucket = gcs.bucket('my-bucket');

// Upload the image to the bucket
var file = bucket.file('profile-images/' + fileName);

file.save(imageBuffer, {
    metadata: { contentType: mimeType },
    public: true,
    validation: 'md5'
}, function(error) {

    if (error) {
        return res.serverError('Unable to upload the image.');
    }

    return res.ok('Uploaded');
});

这对我来说很好.忽略前几行中的一些额外逻辑,因为它们只与我正在构建的应用程序相关.

Answer 3

如果要将字符串另存为 Google Cloud Storage 中的文件，可以使用以下file.save方法轻松完成：

const {Storage} = require('@google-cloud/storage');
const storage = new Storage();
const myBucket = storage.bucket('my-bucket');

const file = myBucket.file('my-file.txt');
const contents = 'This is the contents of the file.';

file.save(contents).then(() => console.log('done'));

Answer 4

:) 什么问题！！已经尝试过并遇到问题图像已上传到 firebase 存储但没有下载，只是加载器正在四处移动......花了时间之后......通过下载成功将图像上传到 firebase 存储......有访问令牌中的问题...

check the screenshot

如果您检查右侧底部的文件位置部分，则有一个选项“创建访问令牌”，如果您在那里手动创建访问令牌，则不会显示任何“访问令牌”，然后刷新页面图像将显示...所以现在的问题是如何通过代码创建它......

只需使用下面的代码来创建访问令牌

const uuidv4 = require('uuid/v4');
const uuid = uuidv4();
metadata: { firebaseStorageDownloadTokens: uuid }

下面给出了用于将图像上传到 firebase 存储上的存储图像的完整代码

const functions = require('firebase-functions')
var firebase = require('firebase');
var express = require('express');
var bodyParser = require("body-parser");

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

    const os = require('os')
    const path = require('path')
    const cors = require('cors')({ origin: true })
    const Busboy = require('busboy')
    const fs = require('fs')
    var admin = require("firebase-admin");


    var serviceAccount = {
        "type": "service_account",
        "project_id": "xxxxxx",
        "private_key_id": "xxxxxx",
        "private_key": "-----BEGIN PRIVATE KEY-----\jr5x+4AvctKLonBafg\nElTg3Cj7pAEbUfIO9I44zZ8=\n-----END PRIVATE KEY-----\n",
        "client_email": "xxxx@xxxx.iam.gserviceaccount.com",
        "client_id": "xxxxxxxx",
        "auth_uri": "https://accounts.google.com/o/oauth2/auth",
        "token_uri": "https://oauth2.googleapis.com/token",
        "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
        "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/firebase-adminsdk-5rmdm%40xxxxx.iam.gserviceaccount.com"
      }

    admin.initializeApp({
        credential: admin.credential.cert(serviceAccount),
        storageBucket: "xxxxx-xxxx" // use your storage bucket name
    });


    const app = express();
    app.use(bodyParser.urlencoded({ extended: false }));
    app.use(bodyParser.json());
app.post('/uploadFile', (req, response) => {
    response.set('Access-Control-Allow-Origin', '*');
    const busboy = new Busboy({ headers: req.headers })
    let uploadData = null
    busboy.on('file', (fieldname, file, filename, encoding, mimetype) => {
        const filepath = path.join(os.tmpdir(), filename)
        uploadData = { file: filepath, type: mimetype }
        console.log("-------------->>",filepath)
        file.pipe(fs.createWriteStream(filepath))
      })

      busboy.on('finish', () => {
        const bucket = admin.storage().bucket();
        bucket.upload(uploadData.file, {
            uploadType: 'media',
            metadata: {
              metadata: { firebaseStorageDownloadTokens: uuid,
                contentType: uploadData.type,
              },
            },
          })

          .catch(err => {
            res.status(500).json({
              error: err,
            })
          })
      })
      busboy.end(req.rawBody)
   });




exports.widgets = functions.https.onRequest(app);

Answer 5

您必须将 base64 转换为图像缓冲区，然后按如下方式上传，您需要提供image_data_from_html变量作为从 HTML 事件中提取的数据。

const base64Text = image_data_from_html.split(';base64,').pop();
const imageBuffer = Buffer.from(base64Text, 'base64');
const contentType = data.image_data.split(';base64,')[0].split(':')[1];
const fileName = 'myimage.png';
const imageUrl = 'https://storage.googleapis.com/bucket-url/some_path/' + fileName;

await admin.storage().bucket().file('some_path/' + fileName).save(imageBuffer, {
    public: true,
    gzip: true,
    metadata: {
        contentType,
        cacheControl: 'public, max-age=31536000',
    }
});

console.log(imageUrl);