It is the gatekeeper of the application. It's the first response in the request/response chain. It takes information from a request, parses it and then executes to plan depending on the HTTP verb, which determines what the client gets back.
Either as instance variable or local variables within the verb block. If local variable, utilize :locals, paired with view erb file/variable.
Ex: Instance Variable
get '/' do @number = 8 erb :index end
Ex: Local variable get '/' do number = 8 erb(:index, :local => { :number => number, :count => 12 } ) end
<%= ruby_code%> in ERB file.
a hash called params
values assigned to the 'names' in the form/input tag are the keys to the params.
Looks good