Example of how to save files in a db and gcs

gcs-api-example.ts

import { GetSignedUrlConfig, Storage, File, Bucket } from '@google-cloud/storage';

const storage = new Storage({
  keyFilename: './config/creds.json',
});

type UploadedFile = {
  url: string;
  bucketId: string;
  bucketName: string;
  bucketPath: string;
  fileName: string;
};

const uploadFileToBucket = (
  bucket: Bucket,
  file: Express.Multer.File,
  path: string = 'default-path'
) =>
  new Promise<UploadedFile>((resolve, reject) => {
    const { originalname, buffer } = file;

    const blob: File = bucket.file(path);
    const blobStream = blob.createWriteStream({
      resumable: false,
    });
    blobStream
      .on('finish', () => {
        const url = `https://storage.googleapis.com/${bucket.name}/${blob.name}`;
        const bucketId = bucket.id;
        const bucketName = bucket.name;
        const bucketPath = blob.name;
        resolve({ url, bucketId, bucketName, bucketPath, fileName: originalname });
      })
      .on('error', (err) => {
        reject(`Unable to upload file, something went wrong: ${err}`);
      })
      .end(buffer);
  });

// Upload file api endpoint
(async () => {
  // the request comes in with file
  let file: Express.Multer.File;

  // somehow we get the organization id and/or user id from the request
  const userId = 'some-user-id';
  const organizationId = 'some-organization-id';

  // save a file to gcs
  const bucket = storage.bucket('my-bucket');
  const path = `${organizationId}/${userId}`;
  const { url, bucketId, bucketName, bucketPath, fileName } = await uploadFileToBucket(
    bucket,
    file,
    path
  );

  const savedFileInfo = {
    organizationId,
    userId,
    url,
    bucketId,
    bucketName,
    bucketPath,
    fileName,
  };

  // save the GCS file info to db
  // return db.collection.save('uploaded-files', savedFileInfo)
})();

// List files owned by organization api endpoint
(async () => {
  // somehow we get the organization id
  const organizationId = 'some-organization-id';

  // get all files from db
  // const files = await db.collection.find('uploaded-files', { organizationId });

  // return files
})();

// Download file api endpoint
(async () => {
  // somehow we get the organization id from request
  const organizationId = 'some-organization-id';
  // somehow we get file id from request
  const fileId = 'some-file-id';

  // get file from db
  // const file = await db.collection.findOne('uploaded-files', { organizationId, fileId });

  // dummy file "from db" for example to work...
  const file = { bucketName: 'my-bucket', bucketPath: 'some-path' };

  // get signed url
  const bucket = storage.bucket(file.bucketName);
  const fileToDownload = bucket.file(file.bucketPath);
  const config: GetSignedUrlConfig = {
    action: 'read',
    expires: Date.now() + 1000 * 60 * 60, // 1 hour
  };
  const [url] = await fileToDownload.getSignedUrl(config);

  // we return the url to the client for them to click and download
  return url;
})();