Transport controller and file model (#42)

* Transport controller and file model

* Use randomBytes intead of pseudoRandomBytes

* Cover all lines with tests

* Update code style

* Update code style

* View for image block

* Fix serving static files

* Mkdir -p for uploads dirs

* Add default secret param

* Add image Tool

* Update src/utils/objects.js

Co-Authored-By: talyguryn <vitalik7tv@yandex.ru>

* Use vars for image tool colors

* Revert var

* Remove --color-gray-border var

* Update src/controllers/transport.js

Co-Authored-By: talyguryn <vitalik7tv@yandex.ru>

* Add mp4 support for Image Tool

src/controllers/transport.js

@@ -0,0 +1,119 @@
+const fileType = require('file-type');
+const fetch = require('node-fetch');
+const fs = require('fs');
+const nodePath = require('path');
+
+const Model = require('../models/file');
+const { random16 } = require('../utils/crypto');
+const { deepMerge } = require('../utils/objects');
+const config = require('../../config');
+
+/**
+ * @class Transport
+ * @classdesc Transport controller
+ *
+ * Allows to save files from client or fetch them by URL
+ */
+class Transport {
+  /**
+   * Saves file passed from client
+   * @param {object} multerData - file data from multer
+   * @param {string} multerData.originalname - original name of the file
+   * @param {string} multerData.filename - name of the uploaded file
+   * @param {string} multerData.path - path to the uploaded file
+   * @param {number} multerData.size - size of the uploaded file
+   * @param {string} multerData.mimetype - MIME type of the uploaded file
+   *
+   * @param {object} map - object that represents how should fields of File object should be mapped to response
+   * @return {Promise<FileData>}
+   */
+  static async save(multerData, map) {
+    const { originalname: name, path, filename, size, mimetype } = multerData;
+
+    const file = new Model({ name, filename, path, size, mimetype });
+
+    await file.save();
+
+    let response = file.data;
+
+    if (map) {
+      response = Transport.composeResponse(file, map);
+    }
+
+    return response;
+  }
+
+  /**
+   * Fetches file by passed URL
+   * @param {string} url - URL of the file
+   * @param {object} map - object that represents how should fields of File object should be mapped to response
+   * @return {Promise<FileData>}
+   */
+  static async fetch(url, map) {
+    const fetchedFile = await fetch(url);
+    const buffer = await fetchedFile.buffer();
+    const filename = await random16();
+
+    const type = fileType(buffer);
+    const ext = type ? type.ext : nodePath.extname(url).slice(1);
+
+    fs.writeFileSync(`${config.uploads}/${filename}.${ext}`, buffer);
+
+    const file = new Model({
+      name: url,
+      filename: `${filename}.${ext}`,
+      path: `${config.uploads}/${filename}.${ext}`,
+      size: buffer.length,
+      mimetype: type ? type.mime : fetchedFile.headers.get('content-type')
+    });
+
+    await file.save();
+
+    let response = file.data;
+
+    if (map) {
+      response = Transport.composeResponse(file, map);
+    }
+
+    return response;
+  }
+
+  /**
+   * Map fields of File object to response by provided map object
+   *
+   * @param {File} file
+   * @param {object} map - object that represents how should fields of File object should be mapped to response
+   *
+   */
+  static composeResponse(file, map) {
+    const response = {};
+    const { data } = file;
+
+    Object.entries(map).forEach(([name, path]) => {
+      const fields = path.split(':');
+
+      if (fields.length > 1) {
+        let object = {};
+        let result = object;
+
+        fields.forEach((field, i) => {
+          if (i === fields.length - 1) {
+            object[field] = data[name];
+            return;
+          }
+
+          object[field] = {};
+          object = object[field];
+        });
+
+        deepMerge(response, result);
+      } else {
+        response[fields[0]] = data[name];
+      }
+    });
+
+    return response;
+  }
+}
+
+module.exports = Transport;