migration - add GridFS migration

tools/migration/use-gridfs.js

@@ -0,0 +1,49 @@
+// for Node.js interpret
+
+const { default: db } = require('../../built/db/mongodb')
+const { default: DriveFile, getGridFSBucket } = require('../../built/api/models/drive-file')
+const { Duplex } = require('stream')
+
+const writeToGridFS = (bucket, buffer, ...rest) => new Promise((resolve, reject) => {
+	const writeStream = bucket.openUploadStreamWithId(...rest)
+	
+	const dataStream = new Duplex()
+	dataStream.push(buffer)
+	dataStream.push(null)
+
+	writeStream.once('finish', resolve)
+	writeStream.on('error', reject)
+
+	dataStream.pipe(writeStream)
+})
+
+const migrateToGridFS = async (doc) => {
+	const id = doc._id
+	const buffer = doc.data.buffer
+	const created_at = doc.created_at
+
+	delete doc._id
+	delete doc.created_at
+	delete doc.datasize
+	delete doc.hash
+	delete doc.data
+
+	const bucket = await getGridFSBucket()
+	const added = await writeToGridFS(bucket, buffer, id, `${id}/${doc.name}`, { metadata: doc })
+
+	const result = await DriveFile.update(id, {
+		$set: {
+			uploadDate: created_at
+		}
+	})
+
+	return added && result.ok === 1
+}
+
+const main = async () => {
+	const docs = await db.get('drive_files').find()
+	const all = await Promise.all(docs.map(migrateToGridFS))
+	return all
+}
+
+main().then(console.dir).catch(console.error)