btrc-hub/backend/app/controllers/wiki_proxy_controller.rb

require 'net/http'
require 'uri'


class WikiProxyController < ApplicationController
  def edit
    tag = params[:tag]
    uri = "http://localhost:4567/gollum/edit/#{ URI.encode_www_form_component(tag) }"
    begin
      res = fetch_with_redirect(uri)
      render html: res.body.html_safe, content_type: res.content_type
    rescue => e
      render plain: "Wiki システムとの通信に失敗しました：#{ e.message }", status: 502
    end
  end

  private

  def fetch_with_redirect uri_str, limit = 5
    raise 'Too many redirects' if limit == 0

    uri = URI.parse(uri_str)
    res = Net::HTTP.get_response(uri)
    if res.is_a? Net::HTTPRedirection
      location = res['location']
      fetch_with_redirect(location, limit - 1)
    else
      res
    end
  end
end