Uploader Class Explanation

The Uploader class is a JavaScript implementation designed to handle file uploads within a Node.js environment. It is equipped to manage uploads from multiple clients simultaneously by leveraging unique file identifiers and organizing files into user- and project-specific directories. Below is a detailed explanation of its components and functionality.

Class Structure

- Constructor: Initializes the this.uploads object to track the status of ongoing uploads.

- safeFileName (Static Method): Sanitizes the original file name to prevent directory traversal or invalid characters, returning a filename based on the uniqueFileId.

- uploadStatus: Checks if the file already exists in the specified userID and projectID directory and creates the directory if necessary. If the file exists, it verifies if the uploaded size matches the expected size.

- uploadFiles: Handles the file upload process, including validating headers, determining the byte range for partial uploads, and appending data to the target file. It supports uploading from the beginning or resuming part-way through a file.

- uploadComplete: Finalizes the upload process by generating a URL for the uploaded file. It's intended for post-upload processing, such as moving the file or updating a database.

- initializeUpload: Prepares for an upload by initializing tracking for the uploaded file's size. This method is essential for tracking progress but is not utilized in the provided code.

- extractHeaders: Extracts necessary information from the request headers, including uniqueFileId, fileSize, userID, projectID, and contentRange.

- parseContentRange: Parses the Content-Range header to determine the current upload chunk's start and end bytes, crucial for handling partial uploads.

Handling Multiple Client Uploads

The class manages uploads from multiple clients by using unique file identifiers and organizing files into specific directories based on the user and project.

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- Utilizes uniqueFileId for each file, allowing the server to differentiate between files, even with identical names, and manage simultaneous uploads effectively.

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- Creates separate directories for each user and project (uploads/${userID}/${projectID}/), preventing file conflicts and organizing uploads efficiently.

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- Supports partial uploads through Content-Range handling, enabling clients to resume interrupted uploads without starting from scratch.

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- Although not explicitly implementing concurrency controls, the class benefits from Node.js's non-blocking I/O model, efficiently handling concurrent upload streams.

Summary

The Uploader class provides a robust solution for managing file uploads in web applications, supporting features like resuming uploads, handling files from multiple clients, and organizing files in a structured manner. It leverages Node.js's asynchronous capabilities to efficiently process simultaneous upload requests.

Installation

Install the module using npm:

``sh
npm install --save node-file-uploader
`

Usage

`sh
const fs = require("fs");
const cors = require("cors");
const express = require("express");
const Uploader = require("node-file-uploader");
const app = express();
`

Initialize the Express app and Uploader instance:

`sh
const uploaderInstance = new Uploader();
`

Define Express routes to handle file upload actions:

`sh
const minioClientSettings = {
endPoint: "your minio end point",
port: port,
useSSL: true|false,
accessKey: "accessKey",
secretKey: "secretKey",
bucket: "bucket",
};

app.get("/upload/status", (req, res) => {
uploaderInstance.uploadStatus(req, res);
});

app.post("/upload/files", (req, res) => {
uploaderInstance.uploadFiles(req, res, minioClientSettings);

});

app.post("/upload/complete", (req, res) => {
uploaderInstance.uploadComplete(req, res, minioClientSettings);
});
``