Archive for category Ruby
ruby method before filters
rails 里面有alias_method_chain实现了方法的前置过滤
这里的是用alias_method实现的
class MethodFilter
def self.before_filter(method)
puts "add before filter here"
method = method.to_s
eval_string = "
alias_method :old_#{method}, :#{method}
def #{method}(*args)
puts 'call'
old_#{method}(*args)
puts 'after'
end
"
class_eval(eval_string)
end
end
class Demo < MethodFilter
def hello
puts "hello"
end
before_filter(:hello)
end
Demo.new.hello
def self.before_filter(method)
puts "add before filter here"
method = method.to_s
eval_string = "
alias_method :old_#{method}, :#{method}
def #{method}(*args)
puts 'call'
old_#{method}(*args)
puts 'after'
end
"
class_eval(eval_string)
end
end
class Demo < MethodFilter
def hello
puts "hello"
end
before_filter(:hello)
end
Demo.new.hello
rvm使用(原)
ruby version manager(RVM)
一.安装，网上常用的方法有两种
第一种方法(需要安装git)
mkdir -p ~/.rvm/src/rvm/
cd ~/.rvm/src
git clone http://github.com/wayneeseguin/rvm.git
cd rvm
./install
cd ~/.rvm/src
git clone http://github.com/wayneeseguin/rvm.git
cd rvm
./install
第二种方法
$ bash < <( curl http://rvm.beginrescueend.com/releases/rvm-install-head )
官方这两种方法都给了，还是第二种方法简单给力
使用方法,更新自己的bash session,也就是~/.bashrc(这个要看用的是哪个类型的shell，如果是zsh,那么就是zshrc)
添加一行[[ -s "$HOME/.rvm/scripts/rvm" ]] && . “$HOME/.rvm/scripts/rvm” 然后source一下.bashrc就OK了
二.使用rvm
1.装两种ruby的版本
rvm install 1.9.1
rvm install 1.8.7
安装ruby的企业版本
rvm install ree-1.8.7-2010.02
2.更换ruby版本
rvm 1.8.7 –default,就是将ruby 1.8.7换成默认的版本
3.更新ruby版本
rvm upgrade 1.9.1 如果你的1.9.1安装的是一个非release版本的ruby,那么rvm将会为你安装一个release版本
三.管理gems 和bundle
http://marcgrabanski.com/articles/gem-management-with-rvm-and-bundler
1.rvm exec
rvm 1.8.7 exec gem install rails # 只在1.8.7下面安装rails
rvm 1.8.7 exec gem uninstall rails # 卸载1.8.7下面的rails
rvm 1.8.7 1.9.1 gem install rails # 两个版本下面都安装rails
rvm exec gem install rails # 多个版本都安装rails
rvm ruby demo.rb # 用所有的ruby版本执行demo.rb
rvm 1.8.7 ruby demo.rb # 用所有的ruby版本执行demo.rb
rvm 1.8.7 exec gem uninstall rails # 卸载1.8.7下面的rails
rvm 1.8.7 1.9.1 gem install rails # 两个版本下面都安装rails
rvm exec gem install rails # 多个版本都安装rails
rvm ruby demo.rb # 用所有的ruby版本执行demo.rb
rvm 1.8.7 ruby demo.rb # 用所有的ruby版本执行demo.rb
2.rvm rake
rvm 1.8.7 1.9.1 rake db:migrate # 使用两个ruby版本运行
rvm 1.8.7 rake db:migrate # 使用一个ruby版本运行
rvm 1.8.7 rake db:migrate # 使用一个ruby版本运行
3.使用命名的gem版本
rvm gemset create demo # 创建一个叫做demo的gem版本，然后使用它
rvm gemset use demo # 使用创建的gem环境
rvm gemset use demo # 使用创建的gem环境
可以看到这里下安装了哪些gems
neo@ubuntu:~/.rvm/help$ gem list
*** LOCAL GEMS ***
rake (0.8.7)
rails关键字过滤
Posted by Neo in Ruby, Ruby On Rails on 2010/10/26
从前了解关键字过滤以为就是普通正则表达式的循环，原来关键词的过滤也是有算法的！！！
下面是一个简单的实现的dfa词法树，写给一个论坛板块做关键词过滤的，随着关键词的递增，耗时与正则表达式比起来要节约很多
class WordReplacement < ActiveRecord::Base
def self.replacement_hash
Hash[*all.collect{|re| [re.regex_str,re.replacement] }.flatten]
end
def self.filter_word_tree(object = nil)
word_tree = Array.new(256)
word_tree << 0
object = replacement_hash if object.nil?
object.each do |word,replace|
temp = word_tree
bytes = word.bytes.to_a
len = bytes.size
bytes.each_with_index do |asicc_code,arr_index|
if arr_index < len - 1
if temp[asicc_code].nil?
node = [Array.new(256),0]
temp[asicc_code] = node
elsif temp[asicc_code] == 1
node = [Array.new(256),1]
temp[asicc_code] = node
else
end
temp = temp[asicc_code][0]
else
temp[asicc_code] = 1
end # end if
end # end bytes
end # end word
[word_tree,0]
end
def self.handle_word(do_words,replace = true,word_tree = nil,word_hash = nil)
word_tree = filter_word_tree if word_tree.nil?
word_hash = replacement_hash if word_hash.nil?
temp = word_tree
nodeTree = word_tree
words = []
word = []
to_replace= []
a = 0
while a < do_words.size
index = do_words[a]
temp = temp[0][index]
if temp.nil?
temp = nodeTree
a = a - word.size
word = []
to_replace = []
elsif temp == 1 or temp[1] == 1
word << index
to_replace << a
words << word
if replace
replace_word = word_hash[asicc_code_to_s(word)]
do_words[(a-to_replace.size + 1),to_replace.size] = replace_word
a = (a - to_replace.size + 1) + (replace_word.size - 1)
else
a = a - word.size + 1
end
word = []
to_replace = []
temp = nodeTree
else
word << index
to_replace << a
end
a += 1
end
return do_words if replace
words.collect{|e| e.collect{|ch|ch.chr}.join }
end
protected
def self.asicc_code_to_s(words)
words.collect{|e| e.chr }.join
end
end
def self.replacement_hash
Hash[*all.collect{|re| [re.regex_str,re.replacement] }.flatten]
end
def self.filter_word_tree(object = nil)
word_tree = Array.new(256)
word_tree << 0
object = replacement_hash if object.nil?
object.each do |word,replace|
temp = word_tree
bytes = word.bytes.to_a
len = bytes.size
bytes.each_with_index do |asicc_code,arr_index|
if arr_index < len - 1
if temp[asicc_code].nil?
node = [Array.new(256),0]
temp[asicc_code] = node
elsif temp[asicc_code] == 1
node = [Array.new(256),1]
temp[asicc_code] = node
else
end
temp = temp[asicc_code][0]
else
temp[asicc_code] = 1
end # end if
end # end bytes
end # end word
[word_tree,0]
end
def self.handle_word(do_words,replace = true,word_tree = nil,word_hash = nil)
word_tree = filter_word_tree if word_tree.nil?
word_hash = replacement_hash if word_hash.nil?
temp = word_tree
nodeTree = word_tree
words = []
word = []
to_replace= []
a = 0
while a < do_words.size
index = do_words[a]
temp = temp[0][index]
if temp.nil?
temp = nodeTree
a = a - word.size
word = []
to_replace = []
elsif temp == 1 or temp[1] == 1
word << index
to_replace << a
words << word
if replace
replace_word = word_hash[asicc_code_to_s(word)]
do_words[(a-to_replace.size + 1),to_replace.size] = replace_word
a = (a - to_replace.size + 1) + (replace_word.size - 1)
else
a = a - word.size + 1
end
word = []
to_replace = []
temp = nodeTree
else
word << index
to_replace << a
end
a += 1
end
return do_words if replace
words.collect{|e| e.collect{|ch|ch.chr}.join }
end
protected
def self.asicc_code_to_s(words)
words.collect{|e| e.chr }.join
end
end
ruby observer模式
ruby的观察者模式范例
require 'observer'
class User
include Observable
attr_accessor :username
attr_accessor :password
def initialize(username,password)
@username = username
@password = password
end
def change_username
changed
@username = "find_by_username"
notify_observers
end
end
class Foo
def update()
p "attribute has update"
end
end
#试着改变username属性
user = User.new("neo","123")
user.add_observer(Foo.new)
user.change_username
class User
include Observable
attr_accessor :username
attr_accessor :password
def initialize(username,password)
@username = username
@password = password
end
def change_username
changed
@username = "find_by_username"
notify_observers
end
end
class Foo
def update()
p "attribute has update"
end
end
#试着改变username属性
user = User.new("neo","123")
user.add_observer(Foo.new)
user.change_username
ruby diff工具
基于ruby_lcs简单的文件版本比较(假装支持HTML);
ruby_lcs不支持中文,需要重写String类的size方法,需要修改Diff::LCS.traverse_sequences
默认都中文会变成乱码类似”\232\234\232″，而string的[]会将它分成”\232″、”\234″、”\232
require 'jcode'
class String
def size
self.jsize
end
end
class NeoDiff
$KCODE = "u"
attr_accessor :output
attr_accessor :last_call
def initialize(output)
@output = output
@last_call = nil
end
def change(event)
if @last_call.nil?
@output << "<span class='change'>#{event.old_element}"
elsif @last_call == "change"
@output << event.old_element
else
@output << "</span><span class='change'>#{event.old_element}"
end
@last_call = "change"
end
def match(event)
if @last_call.nil?
@output << "<span class='match'>#{event.old_element}"
elsif @last_call == "match"
@output << event.old_element
else
@output << "</span><span class='match'>#{event.old_element}"
end
@last_call = "match"
end
def discard_a(event)
if @last_call.nil?
@output << "<span class='only_a'>#{event.old_element}"
elsif @last_call == "discard_a"
@output << event.old_element
else
@output << "</span><span class='only_a'>#{event.old_element}"
end
@last_call = "discard_a"
end
def discard_b(event)
if @last_call.nil?
@output << "<span class='only_b'>#{event.new_element}"
elsif @last_call == "discard_b"
@output << event.new_element
else
@output << "</span><span class='only_b'>#{event.new_element}"
end
@last_call = "discard_b"
end
end
class String
def size
self.jsize
end
end
class NeoDiff
$KCODE = "u"
attr_accessor :output
attr_accessor :last_call
def initialize(output)
@output = output
@last_call = nil
end
def change(event)
if @last_call.nil?
@output << "<span class='change'>#{event.old_element}"
elsif @last_call == "change"
@output << event.old_element
else
@output << "</span><span class='change'>#{event.old_element}"
end
@last_call = "change"
end
def match(event)
if @last_call.nil?
@output << "<span class='match'>#{event.old_element}"
elsif @last_call == "match"
@output << event.old_element
else
@output << "</span><span class='match'>#{event.old_element}"
end
@last_call = "match"
end
def discard_a(event)
if @last_call.nil?
@output << "<span class='only_a'>#{event.old_element}"
elsif @last_call == "discard_a"
@output << event.old_element
else
@output << "</span><span class='only_a'>#{event.old_element}"
end
@last_call = "discard_a"
end
def discard_b(event)
if @last_call.nil?
@output << "<span class='only_b'>#{event.new_element}"
elsif @last_call == "discard_b"
@output << event.new_element
else
@output << "</span><span class='only_b'>#{event.new_element}"
end
@last_call = "discard_b"
end
end
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