We have been interacting with Autodesk's Design Automation API and Model Derivative API, but there are a lot of bells and whistles we don't need for our business requirements (we only require 3 pieces of information from 2D dwg and dxf files).
So we thought we'd just develop our own API that can process DWG and DXF files (hopefully more file types) and get the desired outputs we want using a script that can be triggered by the API.
As a web developer I don't know exactly how the workflow would look, but I know that we want to build something similar to Autodesk's API that can run custom scripts on an AutoCAD file.
The API would need to be able to handle 100 files a day being processed, and also needs to have a Node.js interface. We obviously need a commercial license for autoCAD software (I'm assuming AutoCAD is a term that refers to general processing of dwg-like files).
Question: What is the best commercial license where we can use it however much we want, and pay a fixed fee instead of monthly? Is there only repeat-charge licenses available?
The easiest way would be to write a C# plugin with the AutoCAD API to load, read to get data into a JSON format, save/close the drawing.
I'd embed a simple server into the plugin that takes CRUD requests to do this work. You can have say an Nginx main server running on port 80 (standard port) that routes requests to your node web app and also to your AutoCAD server via different ports depending on the routes. Apache can do this too but I find Nginx easier personally. the node and CAD servers can then talk to each other as well either directly by port number or via the main server (probably best).
Regardless of what CAD platform you use this would be the best setup pretty much, you 'could' just use the server embedded in the CAD app but for security and reliability I'd route it through Apache/Nginx.
hth
P.S.
You could write a plugin to distribute to the CAD users that supply the drawing that mines out the data then sends it to your web app for processing but then you have many app's to maintain and distribute rather than only one plugin for the server app.