When a Supplier<Flux<Foo>> is composed with a Function<Foo,Bar>
the resulting handler (supplier) should have Flux as its output
wrapper still (the most general output wrapper type in the chain).
A Spring Boot 2.0 app should behave the same as a Spering Boot 1.5
app with this change. The key thing was to change the return type
of the FunctionController and move the computation of single
valuedness for the output there (instead of trying to do it in the
return value handler, which isn't used in Spring 5).
The web module doesn't really need to depend on tomcat and all of
the Spring Boot web stack, but users need a way to grab that stuff
quickly if they want it (hence the new starter).
Also removed all spring-boot-starter dependencies from core and
context modules.
User can extend SpringBootApiGatewayRequestHandler instead of the
generic SpringBootRequestHandler. It ties the code to AWS and the
API Gateway, but at least it supports the incoming data fully.
Fixes gh-111, closes gh-136
They all work except the AWS one, where the shadow plugin seems to
prang the thin launcher one. Removing the thin plugin gets us
something that works.
Fixes gh-105
The compiled functions implement that interface which means you can inspect
the signature of the method that created them and discover its
generic types.
These can be used to more reliably discover whether the user
has declared a function with flux types or "bare" POJOs. They
then pave the way to supporting single valued types in a special
way.
Also consolidate and simplify the logic in FunctionInspector
So that single Strings can be POSTed without JSON conversion.
There's still some work to do to support single POJOs in JSON, and
to reach parity with the WebFlux reactive type handlers, but it's
now closer to what we had before we moved the String conversion
out of the function layer.
There is one behaviour change (you have to POST an array to a function
endpoint if you are sending a body), and also a message converter that
needed to be removed so that arrays are not toStringed in the response
body.
