ASP.net Core pipeline

The pipeline takes an input, an http request

• It passes it through to the Kestrel server

• Then the request goes through middleware for processing

• Then it comes back out to the website for consumption

The middleware can do these things when it receives a request

• Do some code

  • What's an example?

• Decide to terminate

  • If this happens, then the request is passed back through to the last middleware

• Decide to pass the request on to the next middleware

  • It can pass along a context to the next middleware as well

  • After passing the request on, it can also execute some more code

    • What's an example of this?

    • Is this so that when the request passes back through, it can pick up this code?

• Each middleware is oblivious of the rest of the pipeline

Order matters

• These are individual units that you line up in order

• Order really matters, because the request is passed through and updated in that order

• Exception handling should be one of the first request delegates in the pipeline, so that it can handle any exceptions that occur along the rest of the pipeline

Types of middleware / request delegates

• Map, run, use

• Run is a terminal middleware. It does not pass the request on to the next delegate

• Use: has the concept of passing the request to the next delegate

Terminology

• Request delegate: this is the middleware block

• Terminal middleware

• Request processing pipeline

Things I researched to get this understanding

• Frank Liu's youtube channel

• Microsoft