Question

all, i need to do this as the following

require 'sinatra'
require 'app_env'

get '/home' do
  'home page'
end

get '/about' do
  'about page'
end

get '/docs' do
  'docs page'
end

I not sure which route will be the root route, maybe the home, about, or docs page. So, i have to set the root page in a file app_env.rb with a line like this route_map '/home' => '/' .
Now, how do i write the method/function route_map

or anything else to implement my requirement for mapping the route dynamically.

EDIT : MY ANSWER

HOMEPAGE = '/home_page'
get '/' do
    status, headers, body = call! env.merge("PATH_INFO" => HOMEPAGE)
end

Answer 1

If you are looking to reroute requests for ‘/’ to ‘/home’ then all that you need to do is:

get '/'
  redirect '/home'
end

If you do not want to redirect you could do this:

get '/foo' do
    status, headers, body = call env.merge("PATH_INFO" => '/bar')
    [status, headers, body.map(&:upcase)]
end

get '/bar' do
    "bar"
end

See this for details.