Reitit default middleware

[ikitommi]

new module metosin/reitit-middleware with common / handy ring-middleware, aiming to be on par with compojure-api.

Review the decisions:

exception-middleware

• in compojure-api, the middleware took options map with just :handlers key. As there are no other top-level keys, the handlers-map is the only arg taken. I think this is better this way. There is also new :reitit.ring.middleware.exception/wrap key which can be used for example to log all errors - like ring middleware, but for exception handlers, takes 3 args instead of the normal 2 (handler being the first one). With the old options-syntax, this could be the other top-level key in options besides the :handlers, but a special key gives better ergonomics I think.

multipart-middleware

• ok'ish, before the arrival of Support for OpenAPI3 #84

muuntaja

• the middleware do not take any options, but they read the :muuntaja key from route data. If that is not set, nothing happens (without any warning!)
  • => one needs to set both the middleware and the muuntaja instance to get it working. We could set the muuntaja instance to default one if it's not set, but that would mean it's always enabled for all paths. Currently meta-merge doesn't support removing keys easily - if we inlined meta-merge, we could use the default muuntaja instance if that is not explicitly set (the common case) and people could set it to nil for certain routes which don't require the functionality.
    => I think the explicit :muuntaja key is good.

naming

• module: reitit-middleware or reitit-ring-middleware or something different?
• ns'es: reitit.ring.middleware.exception or just reitit.middleware.exception?

[ikitommi]

reviewed by @jarppe