从 Google Cloud 函数上传到 Firebase 存储

Question

我正在尝试创建一个 Firebase 函数，该函数允许我传入一组图像 URL 以创建蒙太奇，将文件上传到 Firebase 存储，然后返回生成的下载 URL。这将从我的应用程序中调用，因此我使用的是functions.https.onCall。

const functions = require("firebase-functions");
const admin = require('firebase-admin');
var gm = require('gm').subClass({imageMagick: true});
admin.initializeApp();


exports.createMontage = functions.https.onCall((data, context) => {
var storageRef = admin.storage().bucket( 'gs://xyz-zyx.appspot.com' );
var createdMontage = storageRef.file('createdMontage.jpg');
function generateMontage(list){
  let g = gm()
   list.forEach(function(p){
       g.montage(p);
   })
   g.geometry('+81+81')
   g.density(5000,5000)
   .write(createdMontage, function(err) {
       if(!err) console.log("Written montage image.");
   });
   return true
}

generateMontage(data)

return createdMontage.getDownloadURL();

});

函数 generateMontage() 在 NodeJs 上本地工作（具有本地写入目标）。

谢谢。

Answer 1

我认为您可以将来自 gm 模块的输出流通过管道传输到 firebase storage 对象写入流。

const functions = require("firebase-functions");
const admin = require('firebase-admin');
var gm = require('gm').subClass({imageMagick: true});
admin.initializeApp();

exports.createMontage = functions.https.onCall(async (data, context) => {
   var storage = admin.storage().bucket( 'gs://xyz-zyx.appspot.com' );
   
   var downloadURL = await new Promise((resolve, reject) => {
         let g = gm()
         list.forEach(function(p){
             g.montage(p);
         })
         g.geometry('+81+81')
         g.density(5000,5000)
          .stream((err, stdout, stderr) => {
              if (err) {
                  reject();
              }
              stdout.pipe(
                  storage.file('generatedMotent.png).createWriteStream({
                    metadata: {
                        contentType: 'image/png',
                    },
                })
              ).on('finish', () => {
                storage
                    .file('generatedMotent')
                    .getSignedUrl({
                        action: 'read',
                        expires: '03-09-2491', // Non expring public url
                    })
                    .then((url) => {
                        resolve(url);
                    });
              });
         })
   });

   return downloadURL;
});

仅供参考，Firebase Admin SDK 存储对象没有getDownloadURL() 功能。 您应该从存储对象生成不会过期的公共签名 URL。

此外，根据issue，一段时间后应该会引起另一个问题。 要解决此问题，您应该使用永久服务帐户初始化 Firebase 应用。

const admin = require('firebase-admin');
const serviceAccount = require('../your-service-account.json');

admin.initializeApp({
    credential: admin.credential.cert(serviceAccount),
    projectId: JSON.parse(process.env.FIREBASE_CONFIG).projectId,
    databaseURL: JSON.parse(process.env.FIREBASE_CONFIG).databaseURL,
    storageBucket: JSON.parse(process.env.FIREBASE_CONFIG).storageBucket,
});

Answer 2

查看文档中的这个示例：

https://cloud.google.com/storage/docs/uploading-objects#storage-upload-object-code-sample

2021-01-11 更新

这是一个工作示例。我正在使用常规的 Cloud Functions，它的局限性在于 srcObject、dstObject 和 bucketName 是常量，但它确实创建了蒙太奇，这是您的目标。

PROJECT=[[YOUR-PROJECT]]
BILLING=[[YOUR-BILLING]]
REGION=[[YOUR-REGION]]

FUNCTION=[[YOUR-FUNCTION]]

BUCKET=[[YOUR-BUCKET]]
OBJECT=[[YOUR-OBJECT]] # Path from ${BUCKET} root

gcloud projects create ${PROJECT}

gcloud beta billing projects link ${PROJECT} \
--billing-account=${BILLING}

gcloud services enable cloudfunctions.googleapis.com \
--project=${PROJECT}

gcloud services enable cloudbuild.googleapis.com \
--project=${PROJECT}

gcloud functions deploy ${FUNCTION} \
--memory=4gib \
--max-instances=1
--allow-unauthenticated \
--entry-point=montager \
--set-env-vars=BUCKET=${BUCKET},OBJECT=${OBJECT} \
--runtime=nodejs12 \
--trigger-http \
--project=${PROJECT} \
--region=${REGION}

ENDPOINT=$(\
  gcloud functions describe ${FUNCTION} \
  --project=${PROJECT} \
  --region=${REGION} \
  --format="value(httpsTrigger.url)")

curl \
--request GET \
${ENDPOINT}


`package.json`:
```JSON
{
  "name": "montage",
  "version": "0.0.1",
  "dependencies": {
    "@google-cloud/storage": "5.7.1",
    "gm": "^1.23.1"
  }
}

还有index.js:

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

const gm = require('gm').subClass({ imageMagick: true });

const bucketName = process.env["BUCKET"];
const srcObject = process.env["OBJECT"];
const dstObject = "montage.png";

// Creates 2x2 montage
const list = [
  `/tmp/${srcObject}`,
  `/tmp/${srcObject}`,
  `/tmp/${srcObject}`,
  `/tmp/${srcObject}`
];

const montager = async (req, res) => {
  // Download GCS `srcObject` to `/tmp`
  const f = await storage
    .bucket(bucketName)
    .file(srcObject)
    .download({
      destination: `/tmp/${srcObject}`
    });

  // Creating GCS write stream for montage
  const obj = await storage
    .bucket(bucketName)
    .file(dstObject)
    .createWriteStream();

  let g = gm();
  list.forEach(f => {
    g.montage(f);
  });

  console.log(`Returning`);
  g
    .geometry('+81+81')
    .density(5000, 5000)
    .stream()
    .pipe(obj)
    .on(`finish`, () => {
      console.log(`finish`);
      res.status(200).send(`ok`);
    })
    .on(`error`, (err) => {
      console.log(`error: ${err}`);
      res.status(500).send(`uhoh!`);
    });
}
exports.montager = montager;

Answer 3

我从未使用过'gm'，但根据它的npm page，它有一个toBuffer 功能。

所以也许这样的事情可以工作：

const functions = require('firebase-functions');
const admin = require('firebase-admin');
const gm = require('gm').subClass({ imageMagick: true });
admin.initializeApp();

exports.createMontage = functions.https.onCall((data, _context) => {
  const bucketName = 'xyz-zyx'; // not sure, I've always used the default bucket
  const bucket = admin.storage().bucket(bucketName);
  const storagePath = 'createdMontage.jpg';
  const fileRef = bucket.file(storagePath);
  const generateMontage = async (list) => {
    const g = gm();
    list.forEach(function (p) {
      g.montage(p);
    });
    g.geometry('+81+81');
    g.density(5000, 5000);
    return new Promise(resolve => {
      g.toBuffer('JPG', (_err, buffer) => {
        const saveTask = fileRef.save(buffer, { contentType: 'image/jpeg' });
        const baseStorageUrl = `https://firebasestorage.googleapis.com/v0/b/${bucket.name}/o/`;
        const encodedPath = encodeURIComponent(storagePath);
        const postfix = '?alt=media'; // see stackoverflow.com/a/58443247/6002078
        const publicUrl = baseStorageUrl + encodedPath + postfix;
        saveTask.then(() => resolve(publicUrl));
      });
    });
  };
  return generateMontage(data);
});

但它似乎可以更容易地完成。正如 Methkal Khalawi 所说：

这是full example on how to use ImageMagic with Functions。虽然他们用它来模糊图像，但想法是一样的。以及文档中的here is a tutorial。