如何限制ASP.NET WebAPI中的最大并发连接数/请求/会话数

Question

I'm looking for a mechanism to limit the number of concurrent connections to a service exposed using ASP.NET WebAPI.

Why? Because this service is performing operations that are expensive on the hardware resources and I would like to prevent degradation under stress.

More info:

• I don't know how many requests will be issued per period of time.
• This service runs in its own IIS application pool and limiting the maximum connections on the parent site in IIS is not an option.
• I found this suite, but the supported algorithms do not include the one that I'm interested in.

I'm looking for something out of the box (something as straightforward as an IIS config setting) but I could not find exactly what I need.

Any clues?

Thanks!

Answer 1

Scaling your service would probably be a better idea than limiting the number of requests. You could send the heavy processing to some background jobs and keep your API servicing requests.

But assuming the above cannot be done, you will need to use one of the throttling package available or write your own if none meets your requirements.

I suggest starting with the ThrottlingHandler from WebApiContrib You might be able to meet your needs by properly implementing the GetUserIdentifier method.

If not, you will need to implement your own MessageHandler and the handler mentioned would be a good starting point.