sanm1992 (sanm)

Wiki 访问不了了

sanm1992 — Mon, 23 Dec 2019 10:43:29 +0800

Wiki 访问不了了啊

关于 rails 查询：

sanm1992 — Sat, 08 Sep 2018 12:03:32 +0800

我在 model 中写了两个 scope

scope :next,     -> (this_id){where("id > ?", this_id).order(id: :asc).first}
scope :previous, -> (this_id){where("id < ?", this_id).order(id: :desc).first}

controller

@next        = Article.enabled.tec_articles.next(params['id'])
@previous    = Article.enabled.tec_articles.previous(params['id'])

当 next 或者 previous 查不到数据的时候，后台日志：

Article Load (3.4ms)  SELECT  `articles`.* FROM `articles` WHERE `articles`.`enabled` = TRUE AND `articles`.`category` = 'tec' AND `articles`.`id` = 5 LIMIT 1
  Article Load (3.4ms)  SELECT  `articles`.* FROM `articles` WHERE `articles`.`enabled` = TRUE AND `articles`.`category` = 'tec' AND (id > '5') ORDER BY `articles`.`id` ASC LIMIT 1
  Article Load (3.5ms)  SELECT  `articles`.* FROM `articles` WHERE `articles`.`enabled` = TRUE AND `articles`.`category` = 'tec' AND (id < '5') ORDER BY `articles`.`id` DESC LIMIT 1
#<Article id: 5, tag: "rails", title: "路由拆分", content: "* 当项目路由越来越多，routes文件会变得拥挤，难以管理，这时候就需要我们对路由文件进行拆分\r\n...", reading_time: 0, category: "tec", attachment: nil, enabled: true, created_at: "2018-09-06 09:34:59", updated_at: "2018-09-06 09:38:37">
#<Article id: 4, tag: "rails", title: "rails中的ActiveSupport::Concern", content: "#### ActiveSupport::Concern的作用以及由来\r\n在rails项目中，如果mo...", reading_time: 0, category: "tec", attachment: nil, enabled: true, created_at: "2018-09-05 10:04:43", updated_at: "2018-09-06 09:51:28">


  Article Load (3.5ms)  SELECT  `articles`.* FROM `articles` WHERE `articles`.`enabled` = TRUE AND `articles`.`category` = 'tec' LIMIT 11
#<ActiveRecord::Relation [#<Article id: 4, tag: "rails", title: "rails中的ActiveSupport::Concern", content: "#### ActiveSupport::Concern的作用以及由来\r\n在rails项目中，
如果mo...", reading_time: 0, category: "tec", attachment: nil, enabled: true, created_at: "2018-09-05 10:04:43", updated_at: "2018-09-06 09:51:28">, #<Article id: 5, tag: 
"rails", title: "路由拆分", content: "* 当项目路由越来越多，routes文件会变得拥挤，难以管理，这时候就需要我们对路由文件进行拆分\r\n...", reading_time: 0, category: 
"tec", attachment: nil, enabled: true, created_at: "2018-09-06 09:34:59", updated_at: "2018-09-06 09:38:37">]>

从日志来看，当查不到数据的时候就为自动去去除了相关查询条件返回结果，这是什么机制啊？其实我本意是想让它返回 nil 的

系统使用 Devise 做的登录，有个需求 [同一帐号被另一台机器登录，本机器被强制退出登录]，求大神指点一下

sanm1992 — Tue, 04 Sep 2018 14:24:47 +0800

公司系统用 devise 做的登录，有个需求【同一帐号被另一台机器登录，本机器被强制退出登录】，也就是一个账号只能登录同时登录一台电脑，本来觉着很简单，但自己鼓捣了半天也没什么好的方法，希望有经验的打大神指点一下

rails 项目执行 rake db:migrate 时候遇到如下错误，希望大神帮忙看看

sanm1992 — Sun, 19 Aug 2018 23:40:10 +0800

如题：rails 项目执行 rake db:migrate 时候遇到如下错误

/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-mysql2-adapter-0.0.3/lib/active_record/connection_adapters/mysql2_adapter.rb:606: warning: constant ::Fixnum is deprecated
rake aborted!
ArgumentError: wrong number of arguments (given 4, expected 1)
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:1066:in `type_to_sql'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-mysql2-adapter-0.0.3/lib/active_record/connection_adapters/mysql2_adapter.rb:520:in `type_to_sql'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_creation.rb:19:in `type_to_sql'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_creation.rb:34:in `visit_ColumnDefinition'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_creation.rb:16:in `accept'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_creation.rb:47:in `block in visit_TableDefinition'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_creation.rb:47:in `map'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_creation.rb:47:in `visit_TableDefinition'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_creation.rb:16:in `accept'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/connection_adapters/abstract/schema_statements.rb:311:in `create_table'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-mysql2-adapter-0.0.3/lib/active_record/connection_adapters/mysql2_adapter.rb:439:in `create_table'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/schema_migration.rb:29:in `create_table'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/migration.rb:1187:in `initialize'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/migration.rb:1036:in `new'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/migration.rb:1036:in `up'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/migration.rb:1011:in `migrate'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/tasks/database_tasks.rb:172:in `migrate'
/usr/local/rvm/gems/ruby-2.4.0/gems/activerecord-5.2.1/lib/active_record/railties/databases.rake:60:in `block (2 levels) in <main>'
/usr/local/rvm/gems/ruby-2.4.0/gems/rake-12.3.1/exe/rake:27:in `<top (required)>'
/usr/local/rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `eval'
/usr/local/rvm/gems/ruby-2.4.0/bin/ruby_executable_hooks:15:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

ruby -v 2.4.0 rails -v 5.2.1

database.ym 配置是这样的

# SQLite version 3.x
#   gem install sqlite3
#
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
#
default: &default
  adapter: mysql2
  encoding: utf8
  pool: 5
  host: 39.108.184.220
  port: 3306
  username: username
  password: password

development:
  <<: *default
  database: sanm_dev

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: sanm_test

production:
  <<: *default
  database: sanm_pro

gemfile 中相关是这样的

gem 'mysql2', '~>0.3.6'
gem 'activerecord-mysql2-adapter'

不是很明白发什么了什么，并且要怎么解决，希望大神们帮忙看看，指点一下

现在公司有个需求，要求点击网站 a 的订单按钮跳转到网站 b 的订单列表，用户信息是同一个，要求跳转同时自动登录网站 b,求大神指点

sanm1992 — Thu, 26 Jul 2018 19:18:48 +0800

现在公司有个需求，要求点击网站 a 的订单按钮跳转到网站 b 的订单列表，用户信息是同一个，要求跳转同时自动登录网站 b，求大神指点

rails 中怎么更具不同的 layout 加载不同的样式？

sanm1992 — Wed, 23 May 2018 19:41:39 +0800

最近些修改自己博客练习项目，然后看到了比较好的布局模版，重新写了 layout，但是之前写好的有些标签的样式会产生影响，求大神教怎么根据不同的 layout 引用不同的样式文件？

最近在看《元编程》，基本看来一遍，但是我依然对 ‘元编程’ 的含义很困惑，希望大神能给些帮助

sanm1992 — Thu, 31 Aug 2017 23:46:10 +0800

毕业就开始 ruby 编程的我，到现在一年多了，之前基本都沉浸在 crud 业务代码，满足于完成 story。最近想提高一下自己，于是开始看《元编程》，但是看了一段时间，发现我依然不理解什么叫‘元编程’，希望老司机给予指点，或者给予一些学习 ruby 的建议。

安装了 Rails 5.1.1 和 Ruby 2.4.0p0,然后又安装了 Ruby 2.1.10，并切换成默认版本，之后 rails -v 找不到 rails 版本了，这是什么问题？

sanm1992 — Thu, 13 Jul 2017 21:51:36 +0800

[新人求助] 我本来安装了 Rails 5.1.1 和 ruby 2.4.0p0，然后又安装了 ruby2.1.10，并切换成默认版本，之后 rails -v 找不到 rails 版本了，这是什么问题？