[Psilidae]

Before I read this article (having just seen the title) I assumed this was going to be covering a reverse proxy system, and started pondering how I would implement something like this myself. A very basic approach probably would be simpler than middleware, but the question I got stuck on was whether or not a reverse proxy would need to be "smart" about the content it was limiting. That is, would it need to be programmed to parse requests and understand what the intention and purpose was of each request?

For example, limiting traffic by IP address via reverse proxy is simple, but it seems like it would be more difficult to limit by request priority.

I was surprised when the article revealed it was middleware, and suddenly that made a lot more sense and seemed easier because it no-longer requires duplicating application logic to understand the content of requests. Middleware definitely seems like the better approach to me after these considerations.

What kinds of methods would one use to solve the problem of needing to parse and understand incoming requests using the reverse proxy method?

[b-ryan]

From the bit I know, I think there are at least some options available. For example, in nginx I believe you can use the "map" module to mix and match different components of the request into your limiting.

From what I saw, HAProxy appears to be even more powerful. Its ACL concepts are completely able to create rules based on headers, IPs in the request, etc. and you can compose them into larger ACLs.

With the example of request priority, if you can determine the priority by it's URL or a header, let's say, you can achieve this with nginx. But if you need to look the user up in a DB and see how much they're paying you, you obviously have to do it in the application.