feat(auth): implement user authentication system

backend/node_modules/formidable/src/PersistentFile.js

@@ -0,0 +1,87 @@
+/* eslint-disable no-underscore-dangle */
+
+'use strict';
+
+const fs = require('fs');
+const crypto = require('crypto');
+const { EventEmitter } = require('events');
+
+class PersistentFile extends EventEmitter {
+  constructor({ filepath, newFilename, originalFilename, mimetype, hashAlgorithm }) {
+    super();
+
+    this.lastModifiedDate = null;
+    Object.assign(this, { filepath, newFilename, originalFilename, mimetype, hashAlgorithm });
+
+    this.size = 0;
+    this._writeStream = null;
+
+    if (typeof this.hashAlgorithm === 'string') {
+      this.hash = crypto.createHash(this.hashAlgorithm);
+    } else {
+      this.hash = null;
+    }
+  }
+
+  open() {
+    this._writeStream = new fs.WriteStream(this.filepath);
+    this._writeStream.on('error', (err) => {
+      this.emit('error', err);
+    });
+  }
+
+  toJSON() {
+    const json = {
+      size: this.size,
+      filepath: this.filepath,
+      newFilename: this.newFilename,
+      mimetype: this.mimetype,
+      mtime: this.lastModifiedDate,
+      length: this.length,
+      originalFilename: this.originalFilename,
+    };
+    if (this.hash && this.hash !== '') {
+      json.hash = this.hash;
+    }
+    return json;
+  }
+
+  toString() {
+    return `PersistentFile: ${this.newFilename}, Original: ${this.originalFilename}, Path: ${this.filepath}`;
+  }
+
+  write(buffer, cb) {
+    if (this.hash) {
+      this.hash.update(buffer);
+    }
+
+    if (this._writeStream.closed) {
+      cb();
+      return;
+    }
+
+    this._writeStream.write(buffer, () => {
+      this.lastModifiedDate = new Date();
+      this.size += buffer.length;
+      this.emit('progress', this.size);
+      cb();
+    });
+  }
+
+  end(cb) {
+    if (this.hash) {
+      this.hash = this.hash.digest('hex');
+    }
+    this._writeStream.end(() => {
+      this.emit('end');
+      cb();
+    });
+  }
+
+  destroy() {
+    this._writeStream.destroy();
+    fs.unlink(this.filepath, () => {});
+  }
+}
+
+module.exports = PersistentFile;