caddyhttp: Add map handler

[sarge]

Simple map implementation. #2824

Open to suggestions around hybrid implementations or other data types.

Maps are resolved during request pipeline at the point in the pipeline, I did consider deferring evaluation to the point of substitution.

[edit]
A recurring idea I have for this feature is to make it more caddy-like, somehow taking the idea of matchers. It does make it more verbose specifying a matcher for each case.

map [dest_var] {
   [matcher] [value]
   ...
}

map $is_an_image {
   path /img/* true
   path /images/* true
   path_regexp *.[jpg|bmp] true
   default false
}

[mholt]

Thanks Sarge! Excited to take a look at this more. However, the major features tree for 2.0 is closed now so the earliest we'd see a module like this is in 2.1.

[francislavoie]

@sarge think you could rebase? 🙂

[mholt]

FYI, I am still thinking about this one.

[mholt]

Thanks for this @sarge -- I'm still trying to design final upgrades for v2.1 but I think there's a place for a map directive (and handler) like this. These comments are my first pass, there will likely be more.

[sarge]

@mholt I think I have addressed the first round of feedback. Thanks for that.

[mholt]

Thanks for the revisions! We're getting there :)

[mholt]

Let's give this a spin in the 2.2 dev tree, then. Thanks for working on this, @sarge!