params["id"] instead of params[:id]
2012-03-03 15:30:13 +0800 由 tonytonyjan
在 Ruby on Rails 節點 中發起
最後由 匿名 於回應
, 296次閱讀
在寫 rails 時，在 controller 中用到 params 這個 hash 是很常見的，但我突然想知道為什麼 params[:id] 和 params["id"] 都可以 access 同一份資料，於是展開了 trace code 奇幻之旅。
我臨時寫了一個程式，trace params[:id]，再 trace params["id"]，並用等於符號分隔，看他們之間的不同：
set_trace_func proc { |event, file, line, id, binding, classname|
printf "%8s %s:%-2d %10s %8s\n", event, file, line, id, classname
}
params[:id]
set_trace_func nil
puts "====================="
set_trace_func proc { |event, file, line, id, binding, classname|
printf "%8s %s:%-2d %10s %8s\n", event, file, line, id, classname
}
params["id"]
set_trace_func nil
我本來以為使用 Symbol 替代 String 是比較快的，想不到 rails 下當我們呼叫 params[:key_name] 時，會徒增許多 call stack，事實就是，rails 還得幫我們把 Symbol 轉成 String。
c-return D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:61 set_trace_func Kernel
line D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:62 UpdatePlayerInfo ApiController
call C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_controller/metal.rb:143 params ActionController::Metal
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_controller/metal.rb:144 params ActionController::Metal
call C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_dispatch/http/parameters.rb:8 parameters ActionDispatch::Http::Parameters
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_dispatch/http/parameters.rb:9 parameters ActionDispatch::Http::Parameters
return C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_dispatch/http/parameters.rb:14 parameters ActionDispatch::Http::Parameters
return C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_controller/metal.rb:145 params ActionController::Metal
c-call D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:62 [] Hash
call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:32 default ActiveSupport::HashWithIndifferentAccess
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 default ActiveSupport::HashWithIndifferentAccess
c-call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 is_a? Kernel
c-return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 is_a? Kernel
c-call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 to_s Symbol
c-return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 to_s Symbol
call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:88 key? ActiveSupport::HashWithIndifferentAccess
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:89 key? ActiveSupport::HashWithIndifferentAccess
call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:152 convert_key ActiveSupport::HashWithIndifferentAccess
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:153 convert_key ActiveSupport::HashWithIndifferentAccess
c-call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:153 kind_of? Kernel
c-return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:153 kind_of? Kernel
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:153 convert_key ActiveSupport::HashWithIndifferentAccess
return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:154 convert_key ActiveSupport::HashWithIndifferentAccess
c-call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:89 key? Hash
c-return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:89 key? Hash
return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:90 key? ActiveSupport::HashWithIndifferentAccess
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:36 default ActiveSupport::HashWithIndifferentAccess
c-call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:36 default Hash
c-return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:36 default Hash
return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:38 default ActiveSupport::HashWithIndifferentAccess
c-return D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:62 [] Hash
line D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:63 UpdatePlayerInfo ApiController
c-call D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:63 set_trace_func Kernel
=====================
c-return D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:67 set_trace_func Kernel
line D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:68 UpdatePlayerInfo ApiController
call C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_controller/metal.rb:143 params ActionController::Metal
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_controller/metal.rb:144 params ActionController::Metal
return C:/Ruby193/lib/ruby/gems/1.9.1/gems/actionpack-3.2.2/lib/action_controller/metal.rb:145 params ActionController::Metal
c-call D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:68 [] Hash
call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:32 default ActiveSupport::HashWithIndifferentAccess
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 default ActiveSupport::HashWithIndifferentAccess
c-call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 is_a? Kernel
c-return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:33 is_a? Kernel
line C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:36 default ActiveSupport::HashWithIndifferentAccess
c-call C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:36 default Hash
c-return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:36 default Hash
return C:/Ruby193/lib/ruby/gems/1.9.1/gems/activesupport-3.2.2/lib/active_support/hash_with_indifferent_access.rb:38 default ActiveSupport::HashWithIndifferentAccess
c-return D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:68 [] Hash
line D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:69 UpdatePlayerInfo ApiController
c-call D:/TonySpace/workspace/monster-fighter/app/controllers/api_controller.rb:69 set_trace_func Kernel
另外我想請教前輩們，你們在 trace code 有什麼樣的技巧呢？我最常用的是 grep、find 和上述的 set_trace_func。
暫無回應。