25 Ruby programming details

25 Ruby programming details

This article mainly introduces 25 programming details (tips and practical code segments) of Ruby. This article provides the subject and corresponding code. For more information, see

1. try will never throw an exception and return nil if there is no

The Code is as follows:

Province_id = Province. find_by_name (prov). try (: id)

2. The find (: first,: condotions) method does not speak

The Code is as follows:

Mobile_info = MobileInfo. find (: first,: conditions => ["mobile_num =? ", Mobile_num.to_ I])

3. find (: all,: select,: conditions)

The Code is as follows:

Support_amount_a = ProvinceMerchantChangeValue. find (: all,: select => "DISTINCT change_value_id ",

: Conditions => ["status = 1 and merchant_id =? And province_id =? And channel_id in (select id from channels where status = 1 )",

Merchant_id, province_id]). map {| cv. change_value_id}. compact

Support_amount_s = ChangeValue. find (: all,: select => "price",: conditions => ["id in (?) ", Support_amount_a]) \

. Map {| cv. try (: price). to_ I}. compact

4. the post request can be executed in shell.

The Code is as follows:

Curl-d "channel = CITIC differential payment & action_type = entertainment festival-mobile phone recharge & user_indicate = 13911731997 & original_amount = 10000" http://xx.xxx.xxx: 3000/search. json

5. Ruby pure data structure (Struct and OpenStruct)

Let's talk about the differences between them:

Fields must be explicitly declared at the beginning of Struct. OpenStruct users can add attributes at any time as their names

Struct performance is good; and OpenStruct almost, the specific performance gap can be seen here: http://stackoverflow.com/questions/1177594/ruby-struct-vs-openstruct

Struct is built into the Ruby interpreter and implemented in C; OpenStruct is the Ruby standard library and Ruby implementation

Different APIs: Struct API and OpenStruct

6. MIme: Type. register

The Code is as follows:

Mime: Type. register "application/json",: ejson

Config/initializers/mime_types.rb

7. config/initializers/secure_problem_solved.rb

The Code is as follows:

ActiveSupport: CoreExtensions: Hash: Conversions: XML_PARSING.delete ('symbol ')

ActiveSupport: CoreExtensions: Hash: Conversions: XML_PARSING.delete ('yaml ')

8. config/initializers/new_rails_default.rb

The Code is as follows:

If defined? (ActiveRecord)

# Include Active Record class name as root for JSON serialized output.

ActiveRecord: Base. include_root_in_json = true

# Store the full class name (including module namespace) in STI type column.

ActiveRecord: Base. store_full_sti_class = true

End

ActionController: Routing. generate_best_match = false

# Use ISO 8601 format for JSON serialized times and dates.

ActiveSupport. use_standard_json_time_format = true

# Don't escape HTML entities in JSON, leave that for the # json_escape helper.

# If you're including raw json in an HTML page.

ActiveSupport. escape_html_entities_in_json = false

9. MemCacheStore Cache

The Code is as follows:

@ _ Cache = ActiveSupport: Cache: MemCacheStore. new (

CONFIG ['host'], {: namespace => "# {CONFIG ['namespace'] }:#{@ name }"}

)

Localhost: callback_lock

@ _ Cache. write (pay_channel.channel_id, 'true ')

V = @ _ cache. read (pay_channel.channel_id)

If v. nil? | V! = 'True'

Return false

Else

Return true

End

End

10. Joint Index

The Code is as follows:

Gem 'composite _ primary_keys ', '6. 123'

Https://github.com/momoplan

0. Hash assert_valid_keys White List

11. puma-C puma_service_qa.rb

12. pow

13. Time

The Code is as follows:

Start_time = start_time.to_s.to_datetime.at_beginning_of_day

End_time = end_time.to_s.to_datetime.end_of_day

14. merchant. instance_of? MplusMerchant

The Code is as follows:

M_order [: merchant_id] = (merchant. instance_of? MplusMerchant )? Merchant. id: merchant

15. will_paginate rails

After installation, modify the config/environment. rb file.

Add at the end of the file:

The Code is as follows:

Require 'will _ paginate'

Modify the index method in the controller file:

# @ Products = Product. find (: all)

@ Products = Product. paginate: page => params [: page],

: Per_page => 2

. Pagination

= Will_paginate @ mplus_orders,: class => 'digg _ pagination'

It is better to have an include

16. # Excel Generator

The Code is as follows:

Gem 'readsheet ',' ~> 0.7.3'

PROVINCE = % w {Anhui Beijing Fujian Gansu Guangdong Guangxi Guizhou Hainan Hebei Henan Heilongjiang Hubei

Hunan Jilin Jiangsu Jiangxi Liaoning Inner Mongolia Ningxia Qinghai Shandong Shanxi Shaanxi Shanghai

Sichuan, Tianjin, Tibet, Xinjiang, Yunnan, Zhejiang, Chongqing}

MONTH = 1. upto (12). to_a

Def self. total_to_xls (year = '201312', opts = {})

Book = Spreadsheet: Workbook. new

Sheet1 = book. create_worksheet

Months = MONTH

Months = opts [: month]. to_s.split (/,/) if opts [: month]

Fixed_row = months. collect {| m. to_s + 'month'}. insert (0 ,'')

Sheet1.row (0). concat (fixed_row)

Row1 = ['']

(Months. size-1). times {row1 <['users', 'amount', 'order singles']}

Sheet1.row (1). concat (row1.flatten !)

Row = 2

Sheet1.row (row). insert (0, 'China ')

Months. each_with_index do | m, I |

Sheet1.row (row). insert (I * 3 + 1, self. monthly_users_count (m ))

Sheet1.row (row). insert (I * 3 + 2, self. monthly_amount (m ))

Sheet1.row (row). insert (I * 3 + 3, self. monthly_orders_count (m ))

End

PROVINCE. each do | province |

Row + = 1

Sheet1.row (row). insert (0, province)

Months. each_with_index do | m, I |

Sheet1.row (row). insert (I * 3 + 1, self. monthly_users_count_by_province (m, province ))

Sheet1.row (row). insert (I * 3 + 2, self. monthly_amount_by_province (m, province ))

Sheet1.row (row). insert (I * 3 + 3, self. monthly_orders_count_by_province (m, province ))

End

End

Path = "tmp/phone_recharge.xls"

Book. write path

Path

End

17. inject ({})

The Code is as follows:

Selected_conditions = base_conditions.inject ({}) do | hash, data |

Hash [data. first] = data. last unless data. last. blank?

Hash

End

18. time_str.instance_of?

The Code is as follows:

Return time_str if time_str.instance_of? Time

19. Person. instance_eval

The Code is as follows:

Person. instance_eval do

Def species

"Homo Sapien"

End

End

20. class_eval

The Code is as follows:

Class Foo

End

Metaclass = (class <Foo; self; end)

Metaclass. class_eval do

Def species

"Homo Sapien"

End

End

End

21. respond_to? In Ruby? And send usage

Http://galeki.is-programmer.com/posts/183.html

Because the obj object cannot respond to the talk message, if respond_to? This method can be used to determine whether an object can respond to a given message.

The Code is as follows:

Obj = Object. new

If obj. respond_to? ("Talk ")

Obj. talk

Else

Puts "Sorry, object can't talk! "

End

Request = gets. chomp

If book. respond_to? (Request)

Puts book. send (request)

Else

Puts "Input error"

End

22. method_missing, a Ruby programmer's dream lover

The Code is as follows:

Def method_missing (method, * args)

If method. to_s = ~ /(. *) _ With_cent $/

Attr_name = $1

If self. respond_to? (Attr_name)

'%. 2f' % (self. send (attr_name). to_f/100.00)

Else

Super

End

End

End

23. chomp

The chomp method removes the delimiters at the end of a string, for example, \ n, \ r, etc.... while the default delimiters of gets are \ n.

24. hash. each_pair {| k, v |}& send ()

The Code is as follows:

If bank_order.present?

Data_hash.each_pair {| k, v | bank_order.send ("# {k} =", v )}

Else

Bank_order = BankOrder. new data_hash

End

25. config. middleware can be viewed through rake-T. In config/-Remove unnecessary middleware

26.1.day.ago.strftime ('% Y % m % D ')