Allow insertion of custom filters

[duvy]

With the current interface, there is a filter chain of optional built-in filters, that we can append to with custom filters. But we cannot add insert custom filters at specific points in the chain. For example, we may want to add Jetty's QOS Filter fairly high up in the chain.

It would be good to have an option of inserting filters at specific points in the foundations's filter chain before starting the server (maybe using enums like BEFORE_AVAILABILITY_FILTER).

Alternatively, there could be an option to define the complete chain beforehand, picking which of the foundation built-in filters to use, and ordering them as desired together with the custom filters. Then the assembled chain can be used when starting the server. This solution seems more robust, but allows for misuse by not ordering the foundation filters properly.

[yairogen]

In your mind would exposing the filter list in a configuration set resolve your issue? You would then be able to inherit a default set, but you can override the chain partially or fully.

[duvy]

Sounds good. Can you show an example of what you have in mind?

[yairogen]

Something of this sort:
.filter.1.name
.filter.1.path
.filter.1.className

className is optional as if you reference in the "name" a Foundation known filter (e.g. "FlowContextFilter") we will know the class-name internally. If you want to add a custom filter you can use both name and class name and the index in this array will represent the location in the filter chain.

Would that work?

Naturally will be build the current hard-coded list into the default configuration for transparency.