diff --git a/src/api/common/add-file-to-drive.ts b/src/api/common/add-file-to-drive.ts
deleted file mode 100644
index 6bf5fcbc0..000000000
--- a/src/api/common/add-file-to-drive.ts
+++ /dev/null
@@ -1,306 +0,0 @@
-import { Buffer } from 'buffer';
-import * as fs from 'fs';
-import * as tmp from 'tmp';
-import * as stream from 'stream';
-
-import * as mongodb from 'mongodb';
-import * as crypto from 'crypto';
-import * as _gm from 'gm';
-import * as debug from 'debug';
-import fileType = require('file-type');
-import prominence = require('prominence');
-
-import DriveFile, { getGridFSBucket } from '../models/drive-file';
-import DriveFolder from '../models/drive-folder';
-import { pack } from '../models/drive-file';
-import event, { publishDriveStream } from '../event';
-import config from '../../conf';
-
-const gm = _gm.subClass({
-	imageMagick: true
-});
-
-const log = debug('misskey:register-drive-file');
-
-const tmpFile = (): Promise<string> => new Promise((resolve, reject) => {
-	tmp.file((e, path) => {
-		if (e) return reject(e);
-		resolve(path);
-	});
-});
-
-const addToGridFS = (name: string, readable: stream.Readable, type: string, metadata: any): Promise<any> =>
-	getGridFSBucket()
-		.then(bucket => new Promise((resolve, reject) => {
-			const writeStream = bucket.openUploadStream(name, { contentType: type, metadata });
-			writeStream.once('finish', (doc) => { resolve(doc); });
-			writeStream.on('error', reject);
-			readable.pipe(writeStream);
-		}));
-
-const addFile = async (
-	user: any,
-	path: string,
-	name: string = null,
-	comment: string = null,
-	folderId: mongodb.ObjectID = null,
-	force: boolean = false
-) => {
-	log(`registering ${name} (user: ${user.username}, path: ${path})`);
-
-	// Calculate hash, get content type and get file size
-	const [hash, [mime, ext], size] = await Promise.all([
-		// hash
-		((): Promise<string> => new Promise((res, rej) => {
-			const readable = fs.createReadStream(path);
-			const hash = crypto.createHash('md5');
-			const chunks = [];
-			readable
-				.on('error', rej)
-				.pipe(hash)
-				.on('error', rej)
-				.on('data', (chunk) => chunks.push(chunk))
-				.on('end', () => {
-					const buffer = Buffer.concat(chunks);
-					res(buffer.toString('hex'));
-				});
-		}))(),
-		// mime
-		((): Promise<[string, string | null]> => new Promise((res, rej) => {
-			const readable = fs.createReadStream(path);
-			readable
-				.on('error', rej)
-				.once('data', (buffer: Buffer) => {
-					readable.destroy();
-					const type = fileType(buffer);
-					if (type) {
-						return res([type.mime, type.ext]);
-					} else {
-						// 種類が同定できなかったら application/octet-stream にする
-						return res(['application/octet-stream', null]);
-					}
-				});
-		}))(),
-		// size
-		((): Promise<number> => new Promise((res, rej) => {
-			fs.stat(path, (err, stats) => {
-				if (err) return rej(err);
-				res(stats.size);
-			});
-		}))()
-	]);
-
-	log(`hash: ${hash}, mime: ${mime}, ext: ${ext}, size: ${size}`);
-
-	// detect name
-	const detectedName: string = name || (ext ? `untitled.${ext}` : 'untitled');
-
-	if (!force) {
-		// Check if there is a file with the same hash
-		const much = await DriveFile.findOne({
-			md5: hash,
-			'metadata.userId': user._id
-		});
-
-		if (much !== null) {
-			log('file with same hash is found');
-			return much;
-		} else {
-			log('file with same hash is not found');
-		}
-	}
-
-	const [wh, avgColor, folder] = await Promise.all([
-		// Width and height (when image)
-		(async () => {
-			// 画像かどうか
-			if (!/^image\/.*$/.test(mime)) {
-				return null;
-			}
-
-			const imageType = mime.split('/')[1];
-
-			// 画像でもPNGかJPEGかGIFでないならスキップ
-			if (imageType != 'png' && imageType != 'jpeg' && imageType != 'gif') {
-				return null;
-			}
-
-			log('calculate image width and height...');
-
-			// Calculate width and height
-			const g = gm(fs.createReadStream(path), name);
-			const size = await prominence(g).size();
-
-			log(`image width and height is calculated: ${size.width}, ${size.height}`);
-
-			return [size.width, size.height];
-		})(),
-		// average color (when image)
-		(async () => {
-			// 画像かどうか
-			if (!/^image\/.*$/.test(mime)) {
-				return null;
-			}
-
-			const imageType = mime.split('/')[1];
-
-			// 画像でもPNGかJPEGでないならスキップ
-			if (imageType != 'png' && imageType != 'jpeg') {
-				return null;
-			}
-
-			log('calculate average color...');
-
-			const buffer = await prominence(gm(fs.createReadStream(path), name)
-				.setFormat('ppm')
-				.resize(1, 1)) // 1pxのサイズに縮小して平均色を取得するというハック
-				.toBuffer();
-
-			const r = buffer.readUInt8(buffer.length - 3);
-			const g = buffer.readUInt8(buffer.length - 2);
-			const b = buffer.readUInt8(buffer.length - 1);
-
-			log(`average color is calculated: ${r}, ${g}, ${b}`);
-
-			return [r, g, b];
-		})(),
-		// folder
-		(async () => {
-			if (!folderId) {
-				return null;
-			}
-			const driveFolder = await DriveFolder.findOne({
-				_id: folderId,
-				userId: user._id
-			});
-			if (!driveFolder) {
-				throw 'folder-not-found';
-			}
-			return driveFolder;
-		})(),
-		// usage checker
-		(async () => {
-			// Calculate drive usage
-			const usage = await DriveFile
-				.aggregate([{
-					$match: { 'metadata.userId': user._id }
-				}, {
-					$project: {
-						length: true
-					}
-				}, {
-					$group: {
-						_id: null,
-						usage: { $sum: '$length' }
-					}
-				}])
-				.then((aggregates: any[]) => {
-					if (aggregates.length > 0) {
-						return aggregates[0].usage;
-					}
-					return 0;
-				});
-
-			log(`drive usage is ${usage}`);
-
-			// If usage limit exceeded
-			if (usage + size > user.driveCapacity) {
-				throw 'no-free-space';
-			}
-		})()
-	]);
-
-	const readable = fs.createReadStream(path);
-
-	const properties = {};
-
-	if (wh) {
-		properties['width'] = wh[0];
-		properties['height'] = wh[1];
-	}
-
-	if (avgColor) {
-		properties['avgColor'] = avgColor;
-	}
-
-	return addToGridFS(detectedName, readable, mime, {
-		userId: user._id,
-		folderId: folder !== null ? folder._id : null,
-		comment: comment,
-		properties: properties
-	});
-};
-
-/**
- * Add file to drive
- *
- * @param user User who wish to add file
- * @param file File path or readableStream
- * @param comment Comment
- * @param type File type
- * @param folderId Folder ID
- * @param force If set to true, forcibly upload the file even if there is a file with the same hash.
- * @return Object that represents added file
- */
-export default (user: any, file: string | stream.Readable, ...args) => new Promise<any>((resolve, reject) => {
-	// Get file path
-	new Promise((res: (v: [string, boolean]) => void, rej) => {
-		if (typeof file === 'string') {
-			res([file, false]);
-			return;
-		}
-		if (typeof file === 'object' && typeof file.read === 'function') {
-			tmpFile()
-				.then(path => {
-					const readable: stream.Readable = file;
-					const writable = fs.createWriteStream(path);
-					readable
-						.on('error', rej)
-						.on('end', () => {
-							res([path, true]);
-						})
-						.pipe(writable)
-						.on('error', rej);
-				})
-				.catch(rej);
-		}
-		rej(new Error('un-compatible file.'));
-	})
-	.then(([path, shouldCleanup]): Promise<any> => new Promise((res, rej) => {
-		addFile(user, path, ...args)
-			.then(file => {
-				res(file);
-				if (shouldCleanup) {
-					fs.unlink(path, (e) => {
-						if (e) log(e.stack);
-					});
-				}
-			})
-			.catch(rej);
-	}))
-	.then(file => {
-		log(`drive file has been created ${file._id}`);
-		resolve(file);
-
-		pack(file).then(serializedFile => {
-			// Publish drive_file_created event
-			event(user._id, 'drive_file_created', serializedFile);
-			publishDriveStream(user._id, 'file_created', serializedFile);
-
-			// Register to search database
-			if (config.elasticsearch.enable) {
-				const es = require('../../db/elasticsearch');
-				es.index({
-					index: 'misskey',
-					type: 'drive_file',
-					id: file._id.toString(),
-					body: {
-						name: file.name,
-						userId: user._id.toString()
-					}
-				});
-			}
-		});
-	})
-	.catch(reject);
-});