如何根据同一模型的属性之间的条件保存属性？除非属性的状态仍为真，否则我无法更新记录。
我之前检查过这个帖子：Rails. Update model attributes on save
这是我正在运行的代码：
class Ip < ActiveRecord::Base
has_paper_trail
has_and_belongs_to_many :users
validates_uniqueness_of :ip_address, :hostname
before_save :set_availability
extend Enumerize
enumerize :status, in: [:available, :allocated, :pending, :blocked], default: :available
def ip_address_name
self.ip_address
end
def set_availability
self.is_available = false unless self.status.available?
end
end
基本上我有一个＆＃34; Ips＆＃34;我想跟踪它，并且＆＃34; is_available＆＃34;布尔告诉我ip的状态是否可用（应该根据＆＃34; status＆＃34;字段自动设置）。
所以问题是，例如，
我访问模型，编辑记录，更改：状态从：可用到：已分配，然后点击＆＃34;保存＆＃34;，它回滚，引发我＆＃34; Ip未能更新＆＃34 34;，并且在服务器上交易是＆＃34; 已完成406不可接受＆＃34;
这是日志：
=============== Phusion Passenger Standalone web server started ===============
PID file: /home/user/IP_Manager/tmp/pids/passenger.3000.pid
Log file: /home/user/IP_Manager/log/passenger.3000.log
Environment: development
Accessible via: http://0.0.0.0:3000/
You can stop Phusion Passenger Standalone by pressing Ctrl-C.
Problems? Check https://www.phusionpassenger.com/library/admin/standalone/troubleshooting/
===============================================================================
App 31353 stdout:
App 31368 stdout:
Started HEAD "/" for 127.0.0.1 at 2015-08-04 09:41:07 -0300
ActiveRecord::SchemaMigration Load (0.2ms) SELECT "schema_migrations".* FROM "schema_migrations"
Processing by HomeController#index as HTML
Redirected to http://0.0.0.0/users/sign_in
Completed 302 Found in 10ms (ActiveRecord: 0.0ms)
Started GET "/admin/ip/2/edit" for 127.0.0.1 at 2015-08-04 09:41:14 -0300
Processing by RailsAdmin::MainController#edit as HTML
Parameters: {"model_name"=>"ip", "id"=>"2"}
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT 1 [["id", 1]]
Ip Load (0.1ms) SELECT "ips".* FROM "ips" WHERE "ips"."id" = ? ORDER BY "ips"."id" ASC LIMIT 1 [["id", 2]]
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_boolean.html.haml (2.4ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_field.html.haml (1.2ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_field.html.haml (0.2ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_enumeration.html.haml (2.7ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_text.html.haml (1.0ms)
User Load (0.2ms) SELECT "users".* FROM "users" INNER JOIN "ips_users" ON "users"."id" = "ips_users"."user_id" WHERE "ips_users"."ip_id" = ? [["ip_id", 2]]
(0.1ms) SELECT COUNT(*) FROM "users"
User Load (0.1ms) SELECT "users".* FROM "users" ORDER BY users.id desc
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_filtering_multiselect.html.haml (27.7ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_submit_buttons.html.haml (2.8ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/edit.html.haml within layouts/rails_admin/application (64.5ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/_secondary_navigation.html.haml (3.7ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/_navigation.html.haml (6.6ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/_sidebar_navigation.html.haml (4.1ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/pjax.html.haml (7.3ms)
Completed 200 OK in 611ms (Views: 484.5ms | ActiveRecord: 1.6ms)
Started PUT "/admin/ip/2/edit" for 127.0.0.1 at 2015-08-04 09:41:20 -0300
Processing by RailsAdmin::MainController#edit as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"OI5LqfNXeYLQm1wGglmnPvkrTL3sHTYsiE/uJGp7Uxuserk7ee8b8ozIXclBkUtYYcoIeKCjcNnyZ00siruQjEZQ==", "ip"=>{"is_available"=>"1", "ip_address"=>"192.168.0.2", "hostname"=>"localhost2", "status"=>"allocated", "details"=>"", "user_ids"=>["", "", "1"]}, "return_to"=>"", "_save"=>"", "model_name"=>"ip", "id"=>"2"}
User Load (0.1ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? ORDER BY "users"."id" ASC LIMIT 1 [["id", 1]]
Ip Load (0.1ms) SELECT "ips".* FROM "ips" WHERE "ips"."id" = ? ORDER BY "ips"."id" ASC LIMIT 1 [["id", 2]]
User Load (0.2ms) SELECT "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1 [["id", 1]]
User Load (0.1ms) SELECT "users".* FROM "users" INNER JOIN "ips_users" ON "users"."id" = "ips_users"."user_id" WHERE "ips_users"."ip_id" = ? [["ip_id", 2]]
(1.1ms) begin transaction
Ip Exists (0.2ms) SELECT 1 AS one FROM "ips" WHERE ("ips"."ip_address" = '192.168.0.2' AND "ips"."id" != 2) LIMIT 1
Ip Exists (0.2ms) SELECT 1 AS one FROM "ips" WHERE ("ips"."hostname" = 'localhost2' AND "ips"."id" != 2) LIMIT 1
(0.1ms) rollback transaction
PaperTrail::Version Load (0.3ms) SELECT "versions".* FROM "versions" WHERE "versions"."item_id" = ? AND "versions"."item_type" = ? ORDER BY "versions"."created_at" ASC, "versions"."id" ASC [["item_id", 2], ["item_type", "Ip"]]
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_boolean.html.haml (0.4ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_field.html.haml (0.4ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_field.html.haml (0.3ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_enumeration.html.haml (1.1ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_text.html.haml (0.5ms)
User Load (0.2ms) SELECT "users".* FROM "users" ORDER BY users.id desc
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_form_filtering_multiselect.html.haml (5.0ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/_submit_buttons.html.haml (1.5ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/rails_admin/main/edit.html.haml within layouts/rails_admin/application (25.7ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/_secondary_navigation.html.haml (1.9ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/_navigation.html.haml (3.6ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/_sidebar_navigation.html.haml (2.6ms)
Rendered /home/user/.rvm/gems/ruby-2.2.1/gems/rails_admin-0.6.8/app/views/layouts/rails_admin/pjax.html.haml (6.1ms)
Completed 406 Not Acceptable in 267ms (Views: 223.5ms | ActiveRecord: 2.9ms)
这是我的Gemfile（除了默认宝石之外只有额外的宝石）：
# Administration Panel Gems
gem 'rails_admin' # Rails Administration Panel Gem
gem 'rails_admin_history_rollback' # Enables users to visualise and revert history
gem 'rails_admin_import', "~> 1.0.0" # Enables importation
gem 'devise' # Authentication Gem
gem 'cancancan' # Authorization Gem
gem 'paper_trail', '~> 4.0.0.rc' # Auditing Gem (History)
gem 'enumerize' # Gem for enumerizing attributes
# Server gem
gem 'passenger'
感谢您的时间！
答案 0 :(得分：4)
不确定是否是导致问题的原因，但可能是。如果以before_save执行的任何方法返回false，则整个事务将中止。
你的方法：
def set_availability
self.is_available = false unless self.status.available?
end
将返回false或nil。第一种情况将取消交易。将此方法更改为：
def set_availability
self.is_available = false unless self.status.available?
true
end
答案 1 :(得分：1)
由于您在set_availability中设置了false值，因此从回调中返回false值并回滚。返回false的before *回调将回滚模型上的所有更新。
来自Rails文档http://guides.rubyonrails.org/active_record_callbacks.html
6停止执行
当您开始为模型注册新的回调时，它们将是 排队等待执行。此队列将包含您的所有模型 验证，已注册的回调和数据库操作 被执行。
整个回调链包含在一个事务中。如果有的话 回调方法返回完全错误或引发异常， 执行链停止并发出ROLLBACK;回调后 只能通过提出例外来实现这一点。
这样的事情可能有用。
def set_availability
self.is_available = false unless self.status.available?
true
end