let Hyperscript.Node be used for an HTTP.Response

[clarkevans]

It'd be great if Hyperscript could work out-of-the-box with HTTP.jl and this does not appear to be the case.

julia> using HTTP
julia> using Hyperscript
julia> @tags html body
julia> HTTP.Response(200, html(body("Hello")))
ERROR: MethodError: no method matching length(::Hyperscript.Node{Hyperscript.HTMLSVG})
Closest candidates are:
  length(::Cmd) at process.jl:639
  length(::Base.Iterators.Flatten{Tuple{}}) at iterators.jl:1061
  length(::BitSet) at bitset.jl:365
  ...
Stacktrace:
 [1] _array_for(::Type{Pair{SubString{String},SubString{String}}}, ::Hyperscript.Node{Hyperscript.HTMLSVG}, ::Base.HasLength) at ./array.jl:677
 [2] mkheaders(::Hyperscript.Node{Hyperscript.HTMLSVG}) at /home/cce/.julia/packages/HTTP/IAI92/src/Messages.jl:205
 [3] HTTP.Messages.Response(::Int64, ::Hyperscript.Node{Hyperscript.HTMLSVG}; body::Array{UInt8,1}, request::Nothing) at /home/cce/.julia/packages/HTTP/IAI92/src/Messages.jl:114
 [4] HTTP.Messages.Response(::Int64, ::Hyperscript.Node{Hyperscript.HTMLSVG}) at /home/cce/.julia/packages/HTTP/IAI92/src/Messages.jl:111
 [5] top-level scope at REPL[11]:1

[SimonDanisch]

I think this is more an issue for HTTP.jl... If that would fall back to show(io, MIME"text/html"(), x), this would already work nicely!

[clarkevans]

I like your suggestion, but why should HTTP.jl assume MIME"text/html"? Most output these days from web-servers are JSON. For its fallback, perhaps HTTP.jl should attempt to convert(::Vector{UInt8}, ... ).

HTTP.jl is trying to ducktype its response as a vector of characters, does it make sense to support iteration protocol?

Alternatively, I'm curious if HTML{String} being in the default Julia installation could be leveraged. We could ask HTTP.jl to support HTML{...} setting the Content-Type to reflect a MIME type of "text/html" and then rendering content as you suggest. I'm not sure how this could work though; how would Hyperscript.Node signal that it's a HTML data type?

It's not out-of-the-box, but this works...

using HTTP
using Hyperscript
import HTTP: Response

Response(status::Int, node::Hyperscript.Node) = Response(status,
  [SubString("Content-Type") => SubString("text/html; charset=utf-8")];
  body=HTTP.bytes(string(node)))
Response(node::Hyperscript.Node) = Response(200, node)

[SimonDanisch]

Maybe it should just have Response types, that determine the mime like:

HTMLResponse, JSONResponse

[clarkevans]

Anyway, I agree this is an issue for HTTP.jl. In fact the 2nd argument in the fallback isn't even content, it's a set of headers. I think that API could use some improvement since that was not obvious to me. Perhaps a traits like interface, e.g. Tables.istable() might be useful in this regard.