DirectoryScanReceiver/README.md

DirectoryScanReceiver

DirectoryScanReceiver is a small TCP server that receives file data over a simple delimiter-based protocol and writes files into an output directory.

It is the receiver counterpart to DirectoryScanSender, and both projects can work together out of the box with the current default settings.

Companion Project

• Sender counterpart: DirectoryScanSender
• Shared default TCP port: 7156

Shared Protocol

Both projects use the same message format:

<path>|<length>|<content>\r\n\r\n

• path: file path string sent by the sender
• length: declared payload length
• content: payload content

Multiple messages can be sent over the same TCP connection, each terminated by \r\n\r\n.

Features

• Listens for TCP connections on port 7156
• Accepts multiple file messages over a connection
• Writes files to an output directory next to the executable
• Creates subdirectories when needed
• Skips existing files (no overwrite)
• Prevents writing outside the output directory

Runtime Behavior

• The server waits for incoming TCP connections.
• Each valid message is parsed and written as one file.
• Empty or invalid messages are ignored.
• The output directory is cleared once when the application starts.

Console output includes connection events, received payload sizes, and written file paths.

Requirements

• .NET SDK with support for net10.0

Build and Run

From the repository root:

dotnet build
dotnet run --project DirectoryScanReceiver

The server prints messages such as:

• Started Server!
• Waiting for data!

Test Message Example

Using nc (netcat):

printf 'hello.txt|5|hello\r\n\r\n' | nc 127.0.0.1 7156

This writes hello.txt into the receiver's output directory.

Subdirectories are also supported:

printf 'subdir/note.txt|11|hello world\r\n\r\n' | nc 127.0.0.1 7156

Notes

• The protocol is simple and delimiter-based.
• The receiver is intended to be used with DirectoryScanSender or another sender that follows the same message format.
• The current defaults match the local DirectoryScanSender project (localhost:7156).
• The service uses plain TCP and does not include authentication or encryption.

License and Disclaimer

This project may be used, copied, modified, and shared freely.

It is provided as is, without warranty of any kind. The author is not liable for any damages or losses resulting from its use.