FileLoaderService

FileLoaderService is a C# API that allows reading files from multiple sources such as Local, HTTP/HTTPS, FTP/SFTP, and Email (IMAP/POP3).
It is designed for integrations and automated file ingestion workflows, and it is fully Dockerized for quick deployment.

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📂 Supported Sources

• Local — Direct access to the file system.
• HTTP/HTTPS — Download from URLs.
• FTP/SFTP — With authentication.
• Email — IMAP/POP3 for reading attachments.

Its main purpose is to unify access to files distributed across different sources, simplifying integration into systems and automated processes.

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🚀 Features

• Modular and extensible architecture.
• JSON responses with Base64 content or binary download.
• Standardized HTTP error handling.
• Easily extendable to more sources (Google Drive, Azure Blob Storage, Amazon S3, etc.).
• Docker-ready — Runs instantly in containerized environments.

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🏛 Architectures and Design Patterns Used

This project follows professional development principles and patterns to ensure maintainability, scalability, and ease of extension:

Architecture

• N-Layer Architecture (Presentation → Application → Domain → Infrastructure).
• Clear separation of responsibilities.
• Ready to evolve into Clean Architecture if needed.

Design Patterns

• Strategy — To handle different file sources using specific classes that implement the same interface (IFileLoader).
• Factory Method — To create the correct file loader instance based on the source type.
• Dependency Injection — Configured with Microsoft.Extensions.DependencyInjection for low coupling.
• Adapter — To unify external libraries like MailKit under a common interface.
• Template Method — To define reusable base flows while allowing customization for each loader type.

Principles and Best Practices

• SOLID
• DRY (Don't Repeat Yourself)
• KISS (Keep It Simple, Stupid)
• YAGNI (You Aren’t Gonna Need It)
• Use of DTOs for data transfer.
• Code documented and following .NET Coding Standards conventions.

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🐳 Running with Docker

Build the image

docker build -t fileloaderservice .

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📦 Requirements

• .NET 6 or later
• NuGet package MailKit (for IMAP/POP3 support)

📌 Usage Examples

Local GET http://localhost:5000/api/files/localfile?path=C:\Temp\test.txt

HTTP GET http://localhost:5000/api/files/httpfile?path=https://example.com/file.txt

FTP GET http://localhost:5000/api/files/ftpfile?user=username&password=secret&path=ftp://example.com/file.txt

Email (IMAP) GET http://localhost:5000/api/files/emailfile?host=imap.example.com&port=993&username=user@example.com&pass

Install MailKit:

dotnet add package MailKit