Memoize function "get_matched_rule"

matcher.lua

local function memoize(fn)
  local t = {}
  return function(m,h,p,r)
    local x, y
    local key = j({m,h,p,tostring(r)}, string.char(28))
    if t[key] then
      x, y = t[key][1], t[key][2]
    else
      x, y = fn(m,h,p,r)
      t[key] = {x,y}
    end
    return x, y
  end
end

function M.get_matched_rule(method, hostname, path, rules)
  local req = ("%s %s%s"):format(method, hostname, path)

  for i=1, #rules do
    local rule = rules[i]

    -- pattern has the public host and pattern so public_host can be nil
    local rule_host_pattern = ("^%s %s%s"):format(rule.method, (rule.public_host or ''), rule.pattern)

    if req:match(rule_host_pattern) then
      local match = req:match(rule_host_pattern)
      local extra_path = req:sub(#match + 1)
      return rule, extra_path
    end
  end
end

M.get_matched_rule = memoize(M.get_matched_rule)