一、Ruby语言本身
- String 对象的is_digit?
通过scan方法实现：3.0.1 :039 > '0108551'.scan(/\D/).empty? => true 3.0.1 :040 > '0108551a'.scan(/\D/).empty? => false 3.0.1 :041 >
- require、load和include。
require：形式为require 'active_support/concern'。 请求一个模块，需要不带扩展名的文件名，程序中多次requrie这个模块不会多次装载，ruby会使用内存中的缓存；
load：形式为require 'active_support/concern.rb'。请求装载一个模块，需要带扩展名，每次执行到load，不管以前是否装载过，ruby都会再次读取此模块；
include：形式为：include ActiveSupport::Concern。mixin一个模块，使用的是模块的名称而不是文件名，其实和前两个没啥关系，很多时候需要一起使用；
- 查看一个类的方法。
methods、public_methods、private_methods、instance_methods、public_instance_methodsirb(main):025:0> Test2.instance_methods => [:m1, :to_json, :blank?, :as_json, :acts_like?, :deep_dup, :present?, :duplicable?, :with_options, :html_safe?, :in?, :presence_in, :dclone, :`, :to_yaml, :to_param, :to_query, :instance_values,
:instance_variable_names, :presence, :pretty_print_cycle, :pretty_print_inspect, :pretty_print, :pretty_print_instance_variables, :require_dependency, :unloadable, :require_or_load,
:load_dependency, :try, :try!, :instance_variable_defined?, :remove_instance_variable, :instance_of?, :kind_of?, :is_a?, :tap, :instance_variable_get, :instance_variables, :instance_variable_set,
:protected_methods, :private_methods, :public_send, :method, :public_method, :singleton_method, :class_eval, :pretty_inspect, :define_singleton_method, :extend, :suppress_warnings, :to_enum,
:enum_for, :<=>, :===, :=~, :!~, :eql?, :respond_to?, :gem, :freeze, :inspect, :object_id, :send, :to_s, :display, :class, :nil?, :hash, :dup, :singleton_class, :clone, :then, :itself,
:yield_self, :untaint, :taint, :tainted?, :trust, :untrust, :untrusted?, :singleton_methods, :frozen?, :methods, :public_methods, :equal?, :!, :==, :instance_exec, :!=, :instance_eval,
:__id__, :__send__]# 为了便于查看，可以排一下序 irb(main):034:0> Test2.instance_methods.sort => [:!, :!=, :!~, :<=>, :==, :===, :=~, :__id__, :__send__, :`, :acts_like?, :as_json, :blank?, :class, :class_eval, :clone, :dclone, :deep_dup, :define_singleton_method, :display, :dup,
:duplicable?, :enum_for, :eql?, :equal?, :extend, :freeze, :frozen?, :gem, :hash, :html_safe?, :in?, :inspect, :instance_eval, :instance_exec, :instance_of?, :instance_values,
:instance_variable_defined?, :instance_variable_get, :instance_variable_names, :instance_variable_set, :instance_variables, :is_a?, :itself, :kind_of?, :load_dependency, :m1, :method,
:methods, :nil?, :object_id, :presence, :presence_in, :present?, :pretty_inspect, :pretty_print, :pretty_print_cycle, :pretty_print_inspect, :pretty_print_instance_variables, :private_methods,
:protected_methods, :public_method, :public_methods, :public_send, :remove_instance_variable, :require_dependency, :require_or_load, :respond_to?, :send, :singleton_class, :singleton_method,
:singleton_methods, :suppress_warnings, :taint, :tainted?, :tap, :then, :to_enum, :to_json, :to_param, :to_query, :to_s, :to_yaml, :trust, :try, :try!, :unloadable, :untaint, :untrust,
:untrusted?, :with_options, :yield_self] irb(main):035:0> - YAML.load 替代JSON.parse
ruby虽然内置了JSON，但是由于限制太严格（比如，不能有结尾逗号：{"a":1,"b":2,} ), 那是相当地不太好用，这里推荐使用YAML.load替代，那个谁用谁知道。
- URI.url_encode没有了，但是我们还有 ERB::Util.url_encode
- 如果项目的安全性没那么重要，我建议还是把config/master.key加入源码控制吧
- Time.now.to_i 返回自1970-01-01 0:00:00以来的秒数（UTC）, Time.at(刚才那个数) 转回时间， Time.at(0)就是1970-01-01 0:00:00
- 在ApplicationController中添加
before_action ->{ActiveStorage::Current.host = request.base_url}
这样对于ActiveStorage的附件，就可以用.url来获取其访问地址了（console中不行，但是可以手工设置一下ActiveStorage::Current.host ='http://localhost:3000'） - 'ActiveViewUtils'.tableize => "active_view_utils"
- "active_view_utils".camelize => 'ActiveViewUtils'
二、UI视图(ActionView)相关
- AJAX访问（非get方法）错误引发错误“ActionController::InvalidAuthenticityToken (ActionController::InvalidAuthenticityToken)” ， 在controller中添加下面命令，跳过校验
skip_before_action :verify_authenticity_token
如果不想跳过，则需要在ajax参数中添加这个key
var pn=$('meta[name="csrf-param"').attr('content'),pv=$('meta[name="csrf-token"').attr('content'); if(data instanceof FormData){ data.append(pn,pv);
}else{ data[pn] = pv; }
三、ActiveRecord
- 事务操作Transaction，使用ActiveRecord::Base.transaction开始事务，注意的是，内部数据库操作需要使用出错时引发例外的方法（多数以！结尾），这样才能触发事务回滚操作
ActiveRecord::Base.transaction do item.save! data.save! end
- Migration的迁移和回滚操作View Code
# 执行所有未执行的migration [ruby@dev project1]$ rails db:migrate # 查看数据库中migration的当前状态 [ruby@dev project1]$ rails db:migrate:status warning ../package.json: No license field database: db/development.sqlite3 Status Migration ID Migration Name -------------------------------------------------- up 20201124051602 Create active storage tablesactive storage up 20201124065250 Create scores up 20201124073822 Create score items # 回滚一个migration，注意表中数据需要自行保存 [ruby@dev project1]$ rails db:rollback [ruby@pms rparanking]$ rails db:rollback warning ../package.json: No license field == 20201124073822 CreateScoreItems: reverting ================================= -- remove_index(:score_items, {:name=>"index_score_items_uniqueness"}) -> 0.0032s -- remove_index(:score_items, {:column=>:scorer}) -> 0.0032s -- drop_table(:score_items) -> 0.0038s == 20201124073822 CreateScoreItems: reverted (0.0135s) ======================== [ruby@pms rparanking]$ rails db:migrate:status warning ../package.json: No license field database: db/development.sqlite3 Status Migration ID Migration Name -------------------------------------------------- up 20201124051602 Create active storage tablesactive storage up 20201124065250 Create scores down 20201124073822 Create score items [ruby@dev project1]$ rails db:rollback warning ../package.json: No license field == 20201124065250 CreateScores: reverting ===================================== -- remove_index(:scores, {:column=>:score_times}) -> 0.0055s -- remove_index(:scores, {:column=>:score}) -> 0.0031s -- remove_index(:scores, {:column=>:pinyin}) -> 0.0030s -- remove_index(:scores, {:column=>:name}) -> 0.0035s -- remove_index(:scores, {:column=>:ename}) -> 0.0020s -- drop_table(:scores) -> 0.0014s == 20201124065250 CreateScores: reverted (0.0215s) ============================ [ruby@dev project1]$ rails db:migrate:status warning ../package.json: No license field database: db/development.sqlite3 Status Migration ID Migration Name -------------------------------------------------- up 20201124051602 Create active storage tablesactive storage down 20201124065250 Create scores down 20201124073822 Create score items # 执行db:migrate 回复所有migration状态为up # 回滚指定的migration，通过VERSION指定，所谓版本就是db/migrate/下面migration文件名最开始的那一串数字 [ruby@dev project1]$ rails db:migrate:down VERSION=20201124065250 # 执行特定的migration，通过VERSION指定，所谓版本就是db/migrate/下面migration文件名最开始的那一串数字 [ruby@dev project1]$ rails db:migrate:up VERSION=20201124065250