ruby 和 rails 调试方法

console

命令行输入 irb

rails console

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bundle exec rails console
或者
bundle exec rails dbconsole

不打印返回值：在命令后面加上分号和0：“; 0”

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your-command; 0

meta information

  • self # 当前对象，打印出类名
  • class 类型
  • included_modules 所有包含的Module

  • ancestors 祖先（继承自）

  • 类名.constants
  • methods 所有方法
  • instance_methods 实例方法
    • instance_methods(false) 不要包含继承来的方法

  • instance_variables # 打印出当前实例的所有变量

  • 例子
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# 查找类是否包含方法
ActiveRecord.methods.each {|m| p m if m.to_s.include?('version')}
ActiveRecord::Base.instance_methods.each {|m| p m if m.to_s.include?('version')}

# 查找数组的方法是否包含，re开头的
[].methods.grep /^re/ # => [:reverse_each, :reverse, ..., :replace, ...]

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# 查找方法是继承自哪里
puts Car.ancestors.inspect

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Issue.ancestors.each { |a| p a if a.instance_methods.include?(:your-wanna-method) }
String.ancestors.grep(Class)
object.method(:your-method)
object.method(:your-method).source_location

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some-class.methods    # 打印出对应类的方法

logger

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logger.debug "Person attributes hash: #{@person.attributes.inspect}"
logger.info "Processing the request..."
logger.fatal "Terminating application, raised unrecoverable error!!!"

字符编码

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String#force_encoding("utf-8")    # 强制编码 UTF-8
String#encode("utf-8")            # 当前编码转换为 UTF-8
String#unpack("C*")               # 将字符串转换为 无符号整数数组
String#unpack("C*").map {|b| b.to_s(16)} # 展示为十六进制
Array.pack("C*")                  # 将无符号整数数组 转换为 字符串

rails

进入rails 执行环境，测试语句

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rails console

查看 route

命令行列出所有可用routes

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bundle exec rake routes

# 某个controller 的 routes
CONTROLLER=users bundle exec rake routes

开发模式直接网页查看 routes

http://localhost:3000/rails/info/routes

app.entities_path 打印 route path

在 controller 中调试

参考： http://guides.rubyonrails.org/debugging_rails_applications.html

调试 Activie Record 使用 explain ， 能打印出SQL

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User.where(:id => 1).joins(:posts).explain
User.where(:id => 1).includes(:posts).explain

获取 header，request.env

request.env[‘HTTP_ACCEPT_LANGUAGE’] # 获取 Accept-Language

View 里面打印调试

debug

<%= debug @post %>

inspect

<%= [1, 2, 3, 4, 5].inspect %>

Logger

The available log levels are: :debug, :info, :warn, :error, and :fatal,
corresponding to the log level numbers from 0 up to 4 respectively.

The default Rails log level is info in production mode and debug in development and test mode.

如何配置

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config.log_level = :warn # In any environment initializer, or
Rails.logger.level = 0 # at any time

写日志

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logger.debug "Person attributes hash: #{@person.attributes.inspect}"
logger.info "Processing the request..."
logger.fatal "Terminating application, raised unrecoverable error!!!"