如何判断哪些错误状态代码将从Rails异常中呈现？

Question

有没有办法告诉rail生产中针对特定错误代码（例如ActionController::ParameterMissing）呈现的错误代码？

Answer 1

Rails source code定义了这种映射：

  "ActionController::RoutingError"               => :not_found,
  "AbstractController::ActionNotFound"           => :not_found,
  "ActionController::MethodNotAllowed"           => :method_not_allowed,
  "ActionController::UnknownHttpMethod"          => :method_not_allowed,
  "ActionController::NotImplemented"             => :not_implemented,
  "ActionController::UnknownFormat"              => :not_acceptable,
  "ActionController::InvalidAuthenticityToken"   => :unprocessable_entity,
  "ActionController::InvalidCrossOriginRequest"  => :unprocessable_entity,
  "ActionDispatch::Http::Parameters::ParseError" => :bad_request,
  "ActionController::BadRequest"                 => :bad_request,
  "ActionController::ParameterMissing"           => :bad_request,
  "Rack::QueryParser::ParameterTypeError"        => :bad_request,
  "Rack::QueryParser::InvalidParameterError"     => :bad_request