-- root/api/hello.lua
local page = {}

function page:precheck(req, res)
    -- you can use res:checkXXX() to assert the conditions
    res:check400(req.query.name, "name parameter is required")
    res:check400(#req.query.name >= 3, "name should be longer than 3 characters")

    -- page:get() will not be called if we return false
    return res:isCheckPassed()
end

function page:get(req, res)
    return res:text("Hello, " .. req.query.name .. "!")
end

return page