FileTransfer Tool

A robust, production-ready console application for secure and efficient file transfer with parallel block processing, integrity verification, and automatic retry mechanisms.

Overview

The FileTransfer Tool is designed to transfer files reliably from a source location to a destination location with built-in error handling, data integrity verification, and parallel processing capabilities. The tool divides files into manageable 1MB blocks and processes them concurrently using a configurable number of threads, ensuring fast and resilient transfers even for large files.

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Key Functionalities

1. Parallel Block Transfer

• Files are automatically divided into 1MB blocks for efficient processing
• Supports configurable thread concurrency (1-32 threads) for parallel block transfer
• Uses semaphore-based concurrency control to prevent resource exhaustion
• Default: 2 threads

2. Data Integrity Verification

• Dual-hash verification approach:
  • MD5 hashing for individual blocks (fast, per-block verification)
  • SHA256 hashing for complete file verification (cryptographic security)
• Each transferred block is read back and compared with source using hash matching
• Final full-file hash comparison ensures end-to-end integrity

3. Automatic Retry Logic

• Up to 3 automatic retries for failed blocks (configurable)
• Exponential backoff: retry delay increases with each attempt (100ms × retry count)
• Hash mismatch detection and reporting for diagnostics
• Automatic cancellation of remaining operations on permanent failure

4. Flexible Path Resolution

• Intelligent destination path handling:
  • Accepts existing directories, file paths, or drive roots
  • Auto-creates parent directories if needed
  • Validates and creates destination file with proper permissions
• Supports both absolute and relative paths

5. Progress Reporting

• Real-time transfer progress with block-level tracking
• Displays successful/failed block counts
• Shows transfer duration and performance metrics
• Console-based color-coded status messages

6. Transfer Summary & Verification Report

• Detailed transfer summary with success/failure statistics
• Per-block checksums displayed in hexadecimal format
• Offset and hash information for each block
• Overall transfer status indication (✓ SUCCESS / ✗ FAILED)

7. Multi-Transfer Sessions

• Users can perform multiple sequential transfers in a single session
• Interactive prompts for retry, path re-entry, or application exit
• Graceful error handling with clear messaging

8. Cancellation Support

• Full support for CancellationToken propagation
• Graceful shutdown of ongoing transfers
• Cleanup of partial results on cancellation

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Technologies & Architecture

Technology Stack

• Language: C# 12.0
• Framework: .NET 8
• Architecture Pattern: Clean Architecture with Dependency Injection
• Concurrency Model: Async/Await with Task Parallel Library (TPL)
• Hashing Algorithms: MD5, SHA256 (.NET built-in cryptography)