What is Aident LocalLink?

Aident LocalLink makes local hardware and file resources (printers, drives, custom peripherals) available inside Microsoft Dynamics 365 Business Central on-premises.

How does it work?

Part	Runs on	Purpose
Aident LocalLink Agent	Windows host next to the NAV/BC Service Tier	Windows service that exposes one REST endpoint group per installed plug-in.
Aident LocalLink Connector (BC App)	Business Central tenant	AL extension that authenticates with the Agent and calls its APIs via HTTP/HTTPS.

Everything stays on-premises: network calls never leave your LAN / VPN.

Architecture at a glance

%% System Architecture – Aident LocalLink
graph TD
    %% ====== BC layer ======
    subgraph BC["Business Central (onprem)"]
        BCConnector["Aident LocalLink Connector<br/>(AL extension)"]
    end

    %% ====== Customer environment ======
    subgraph OnPrem["Customer on-prem server / workstation"]
        NavST["BC Service Tier"]
        LocalLink["Aident LocalLink<br/>(Windows service)"]

        %% Visual hint that LocalLink is installed side-by-side with the NST
        LocalLink -. co-located .- NavST

        %% ----- Plugin zone -----
        subgraph Plugins["Plug-in DLLs (extensible)"]
            FilePlugin["File API plug-in<br/>file.dll"]
            PrinterPlugin["Printer API plug-in<br/>printer.dll"]
            FuturePlugin["Future plug-in(s)<br/>*.dll"]
        end

        %% Endpoints exposed per plug-in
        LocalLink -->|REST endpoint&nbsp;/file| FilePlugin
        LocalLink -->|REST endpoint&nbsp;/printer| PrinterPlugin
        LocalLink -->|REST endpoint&nbsp;/&lt;plugin&gt;| FuturePlugin
    end

    %% Cross-boundary call from BC to on-prem service
    BCConnector -->|HTTPS / JSON| LocalLink 

Key Features

• File storage operations - list drives/directories/files, upload/download, copy, move, create, delete.
• Printer operations - enumerate printers, fetch capabilities, submit print jobs.
• Health check - /api/ping for monitoring tools.
• Plug-in loader - drop additional *.dll files to expose brand-new REST groups automatically.
• Zero cloud egress - all data stays within your network

Security & Deployment Notes

• Authentication - Basic Auth over TLS; credentials live only in BC’s encrypted storage and on the Agent host.
• Network scope - Default URL https://localhost:5000; restrict inbound firewall rules as needed.
• Upgrades - Run choco upgrade LocalLinkAgent; settings and logs are preserved.
• Observability - Structured JSON logs ship to Windows Event Log and any syslog/ELK target you configure.

All logs are written to Event Viewer ➜ Applications and Services Logs ➜ LocalLink.

API Catalog (quick reference)

Group	Endpoint(s)	Summary
System	GET /api/ping	Liveness probe
Storage	listDrives, listDirectories, listFiles, directoryExists, fileExists, getFile, copyFile, moveFile, createDirectory, deleteDirectory, createFile, deleteFile	Local file system
Printer	GET /api/Printer, GET /api/Printer/{name}, POST /api/Printer/{name}/jobs	Printer inventory & jobs
Future plug-ins	/api/{PluginName}/*	Added automatically when a new DLL is dropped

API specification

Next step

Install and configure the LocalLink Agent and connect it to your Business Central.