quick-start-write.js

const os = require('os');
const path = require('path');
const ulid = require('ulid').ulid;
const BlobStore = require('scalable-blob-store');
const data = 'The quick brown fox jumps over the lazy dog.';
const line = '='.repeat(80);

const options = {
  blobStoreRoot: os.tmpdir() + '/blobs', // TODO: Change this!
  idFunction: ulid,
  dirDepth: 3,
  dirWidth: 1000,
};

// Creating the blobStore Object
const blobStore = new BlobStore(options);

// Calling the quick start async function
quickStartWrite(data);

async function quickStartWrite(writeData) {
  console.log(line);
  console.log('Quick Start Write Example');
  console.log(line);

  console.log('Saving data using blobStore.write:');
  const firstBlobPath = await blobStore.write(writeData);
  console.log('First file is located in the following blobPath:');
  console.log(firstBlobPath);
  console.log('First file full path is:');
  console.log(path.join(options.blobStoreRoot, firstBlobPath));

  // firstBlobPath is not a full file system path
  // The full path will be the blobStoreRoot + blobPath
  // firstBlobPath: /01CTZBM6BA090XZNRCWBXFA25R/01CTZBM6BBXXTNWM7YZBMFBC3W/01CTZBM6BBD3F8KZQ14Q79ZNKM/01CTZBM6BCEMJ4FXVZKHQ3FAJZ/01CTZBM6BD74MC5HVQ39PFGP0J

  // Opening a readStream from the file system for an example to write with
  const fs = require('fs');
  const fullFilePath = path.join(options.blobStoreRoot, firstBlobPath);
  const fsReadStream = await fs.createReadStream(fullFilePath);

  // Writing data using writeStream
  const result = await blobStore.createWriteStream();

  console.log('Following is the object returned from blobStore.createWriteStream:');
  console.dir(result, { depth: 0 });
  // Logs the result object which contains the blobPath and writeStream.
  // Use the writeStream to save your blob.
  // Store the blobPath in your database.
  //
  // result object will be similar to this:
  // {
  //   blobPath: "/01CTZBM6BA090XZNRCWBXFA25R/01CTZBM6BBXXTNWM7YZBMFBC3W/01CTZBM6BBD3F8KZQ14Q79ZNKM/01CTZBM6BCEMJ4FXVZKHQ3FAJZ/01CTZBM6BM53X3XBW7TJR2RBFQ",
  //   writeStream: [WriteStream]
  // }

  await new Promise((resolve, reject) => {
    result.writeStream.on('finish', resolve);
    result.writeStream.on('error', reject);
    fsReadStream.pipe(result.writeStream);
  });

  console.log('As you can see it contains the writeStream and the blobPath.');
  console.log('Save the blobPath for the file into your database:');
  console.log(result.blobPath);

  console.log('We can append data to an existing blob using blobStore.append:');
  await blobStore.append(result.blobPath, ' - New content...');
  const content = await blobStore.read(result.blobPath);
  console.log(content);

  console.log('We can copy a blob to a new blobPath:');
  const newCopyBlobPath = await blobStore.copy(result.blobPath);
  console.log('Here is the blobPath for the new copy:');
  console.log(newCopyBlobPath);
  console.log('And here is the content of the new file:');
  const newCopyContent = await blobStore.read(newCopyBlobPath);
  console.log(newCopyContent);

  console.log(line);
}