Should Oxygen.jl add support for templating?

[ndortega]

In a recent PR, it was suggested to add built-in support for Mustache.jl and OteraEngine.jl templating. I liked the idea and wanted to see what kind of interface I could come up with. Below I go more into how they're used, but I want to know if people think this belongs in this package. This package was marketed as a "light-weight" alternative and I'd like to hear the community feedback on whether this belongs in the project or not.

# Mustache.jl Support
function mustache(template::String; kwargs...)
function mustache(tokens::Mustache.MustacheTokens; kwargs...)
function mustache(file::IO; mime_type=nothing, kwargs...)

# OteraEngine.jl Support
function otera(file::IO; mime_type=nothing, kwargs...)
function otera(template::String; kwargs...)

What do these templating helpers do?

• Wraps the content inside an HTTP.Response object
• They return a helper function to render the loaded template with data. Returning a render function optionally allows us to load templates only once to reduce overhead
• They automatically determine the mime type of the templated content ( can template different types of files html, xml, etx...)

What would this look like in practice?

using Oxygen

# define our template
mustache_template_str = """
  Hello {{name}}
  You have just won {{value}} dollars!
"""

# load the template and provide a helper function to create the HTML Response
# (the name of this variable doesn't matter)
render = mustache(mustache_template_str)

# render this template with our data and return an HTML.Response 
@get "/mustache/string" function()
  data = Dict("name" => "Chris", "value" => 10000)
  return render(data)
end

Here's how you could load a template from a file:

using Oxygen

# load the template once (assume this is similar to the template defined above)
render = mustache("./congratulations.html")

# render the loaded template with dynamic data
@get "/mustache/file/{name}/{value}" function(req, name::String, value::Float64)
  data = Dict("name" => name, "value" => value)
  return render(data)
end

For those who want to checkout the implementation, here's the source code for these proposed changes:
https://github.com/ndortega/Oxygen.jl/blob/feature/templating-support/src/templating.jl#L33