ruby on rails 代码技巧

git仓库输出

git archive --format=tar --prefix=actasfavor/ HEAD | (cd /home/holin/work/ && tar xf -)

输出到/home/holin/work/actasfavor/目录下

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Posted by holin At May 16, 2008 16:42

加载plugins中的controller和model

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# Include hook code here require 'act_as_favor' #make plugin controller, model, helper available to app config.load_paths += %W(#{ActAsFavor::PLUGIN_CONTROLLER_PATH} #{ActAsFavor::PLUGIN_HELPER_PATH} #{ActAsFavor::PLUGIN_MODELS_PATH}) Rails::Initializer.run(:set_load_path, config) # require the controller require 'favors_controller' # require models require 'favor'

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Posted by holin At May 15, 2008 15:36

使用最频繁的前5个命令

history | awk {'print $2'} | sort | uniq -c | sort -k1 -rn| head -n5

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Posted by holin At May 15, 2008 10:40

按数组元素的某属性排序

@users.sort!{|a, b| a.last <=> b.last }

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Posted by holin At May 11, 2008 14:35

按日期备份数据库

mysqldump db_name -uroot > "/root/db_backup/kaoshi_web_`date +"%Y-%m-%d"`.sql"

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Posted by holin At May 08, 2008 12:05

用memcached手动cache数据

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sql = "SELECT * FROM blogs LIMIT 100" Blog.class k = MD5.new(sql) @blogs = Cache.get k if @blogs.blank? @blogs = Blog.find_by_sql(sql) Cache.put k, @blogs, 60*30 #expire after 30min end

memcache-client 1.5.0:

get(key, expiry = 0)

put(key, value, expiry = 0)

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Posted by devon At May 04, 2008 20:39

shuffle an array

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class Array def shuffle sort_by { rand } end def shuffle! self.replace shuffle end end

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Posted by holin At May 04, 2008 15:39

让所有的ajax请求都不render :layout

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def render(*args) args.first[:layout] = false if request.xhr? and args.first[:layout].nil? super end

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Posted by devon At May 03, 2008 10:53

Find with Hash

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Event.find( :all, :conditions => [ "title like :search or description like :search", {:search => "%Tiki%"}] )

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Posted by devon At May 03, 2008 10:49

执行sql语句脚本

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mysql -uroot -p123<<END use dbame; delete from results; delete from examings; quit END

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Posted by holin At May 01, 2008 12:14

SQL Transaction in Rails

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def fetch_value sql = ActiveRecord::Base.connection(); sql.execute "SET autocommit=0"; sql.begin_db_transaction id, value = sql.execute("SELECT id, value FROM sometable WHERE used=0 LIMIT 1 FOR UPDATE").fetch_row; sql.update "UPDATE sometable SET used=1 WHERE id=#{id}"; sql.commit_db_transaction value; end

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Posted by holin At April 30, 2008 09:37

显示 Flash 消息的动态效果

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<% if flash[:warning] or flash[:notice] %> <div id="notice" <% if flash[:warning] %>class="warning"<% end %>> <%= flash[:warning] || flash[:notice] %> </div> <script type="text/javascript"> setTimeout("new Effect.Fade('notice');", 15000) </script> <% end %>

15000 毫秒后自动 notice Div 自动消失。

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Posted by devon At April 29, 2008 13:02

删除环境中的常量

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Object.send(:remove_const, :A) >> Math => Math >> Object.send(:remove_const, :Math) => Math >> Math NameError: uninitialized constant Math

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Posted by devon At April 28, 2008 18:24

手动加上 authenticity_token

<div style="margin:0;padding:0"><input name="authenticity_token" type="hidden" value="<%= form_authenticity_token %>" /></div>

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Posted by devon At April 28, 2008 14:24

Rails group_by

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<% @articles.group_by(&:day).each do |day, articles| %> <div id='day' style="padding: 10px 0;"> <h2><%= day.to_date.strftime('%y年%m月%d日') %></h2> <%= render :partial => 'article', :collection => articles %> </div> <% end %>

articles 按天数分组

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Posted by devon At April 25, 2008 22:32

读写文件

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# Open and read from a text file # Note that since a block is given, file will # automatically be closed when the block terminates File.open('p014constructs.rb', 'r') do |f1| while line = f1.gets puts line end end # Create a new file and write to it File.open('test.rb', 'w') do |f2| # use "/n" for two lines of text f2.puts "Created by Satish/nThank God!" end

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Posted by holin At April 17, 2008 02:10

遍历目录

Dir.glob(File.join('app/controllers', "**", "*_controller.rb")) { |filename| puts filename }

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Posted by holin At April 16, 2008 15:28

字符串到 model

1 2	>> 'tag_course'.camelize.constantize.find(:first) => #<TagCourse id: 7, tag_id: 83, course_id: 2>

*camelize(lower_case_and_underscored_word, first_letter_in_uppercase = true)*

By default, camelize converts strings to UpperCamelCase. If the argument to camelize is set to ":lower" then camelize produces lowerCamelCase.

*constantize(camel_cased_word)*

Constantize tries to find a declared constant with the name specified in the string. It raises a NameError when the name is not in CamelCase or is not initialized.

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Posted by devon At April 07, 2008 17:32

调用Proc

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a = Proc.new { |i| puts i } a['haha'] a.call('hehe')

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Posted by holin At March 28, 2008 23:10

Rails中Host静态文件

1 2	config.action_controller.asset_host = "http://assets.example.com" config.action_controller.asset_host = "http://assets-%d.example.com"

The Rails image_path and similar helper methods will then use that host to reference files in the public directory.

The second line will distribute asset requests across assets-0.example.com,assets-1.example.com, assets-2.example.com, and assets-3.example.com.

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Posted by devon At March 26, 2008 18:18

打包gems到项目目录中

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$ mkdir vendor/gems $ cd vendor/gems $ gem unpack hpricot Unpacked gem: 'hpricot-0.4' config.load_paths += Dir["#{RAILS_ROOT}/vendor/gems/**"].map do |dir| File.directory?(lib = "#{dir}/lib") ? lib : dir end

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Posted by devon At March 26, 2008 18:12

在当前上下文中执行文件中的代码

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instance_eval(File.read('param.txt')) # such as @father = 'Father' instance_eval("puts @father") #Produces: #Father

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Posted by holin At March 20, 2008 01:13

将当前文件所在目录加入require路径

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$LOAD_PATH << File.expand_path(File.dirname(__FILE__)) # or $: << File.expand_path(File.dirname(__FILE__)) # this one puts current path before the other path. $:.unshift( File.expand_path(File.dirname(__FILE__)) )

*__ FILE __* 当前文件路径

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Posted by holin At March 19, 2008 01:40

多字段模糊搜索

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conditions = [] [:name, :school, :province, :city].each { |attr| conditions << Profile.send(:sanitize_sql, ["#{attr} LIKE ?", "%#{params[:q]}%"]) if params[:q] } conditions = conditions.any? ? conditions.collect { |c| "(#{c})" }.join(' OR ') : nil

在profile表里，按name, school, province, city模糊搜索

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Posted by devon At March 17, 2008 17:25

nginx 启动脚本

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#! /bin/sh # chkconfig: - 58 74 # description: nginx is the Nginx daemon. # Description: Startup script for nginx webserver on Debian. Place in /etc/init.d and # run 'sudo update-rc.d nginx defaults', or use the appropriate command on your # distro. # # Author: Ryan Norbauer # Modified: Geoffrey Grosenbach http://topfunky.com # Modified: David Krmpotic http://davidhq.com set -e PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin DESC="nginx daemon" NAME=nginx DAEMON=/usr/local/nginx/sbin/$NAME CONFIGFILE=/usr/local/nginx/conf/nginx.conf DAEMON=/usr/local/nginx/sbin/$NAME CONFIGFILE=/usr/local/nginx/conf/nginx.conf PIDFILE=/usr/local/nginx/logs/$NAME.pid SCRIPTNAME=/etc/init.d/$NAME # Gracefully exit if the package has been removed. test -x $DAEMON || exit 0 d_start() { $DAEMON -c $CONFIGFILE || echo -en "/n already running" } d_stop() { kill -QUIT `cat $PIDFILE` || echo -en "/n not running" } d_reload() { kill -HUP `cat $PIDFILE` || echo -en "/n can't reload" } case "$1" in start) echo -n "Starting $DESC: $NAME" d_start echo "." ;; stop) echo -n "Stopping $DESC: $NAME" d_stop echo "." ;; reload) echo -n "Reloading $DESC configuration..." d_reload echo "." ;; restart) echo -n "Restarting $DESC: $NAME" d_stop # One second might not be time enough for a daemon to stop, # if this happens, d_start will fail (and dpkg will break if # the package is being upgraded). Change the timeout if needed # be, or change d_stop to have start-stop-daemon use --retry. # Notice that using --retry slows down the shutdown process # somewhat. sleep 1 d_start echo "." ;; *) echo "Usage: $SCRIPTNAME {start|stop|restart|reload}" >&2 exit 3 ;; esac exit 0

将文件写入到 /etc/init.d/nginx
sudo chmod +x /etc/init.d/nginx

测试是否可正确运行
sudo /etc/init.d/nginx start

设置自动启动
sudo /sbin/chkconfig --level 345 nginx on

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Posted by devon At March 16, 2008 12:26

link_to_remote 取静态页面

1 2	<%= link_to_remote "update post", :update => 'post', :method => 'get', :url => '/post_1.html' %> <div id='post'></div>

将 url 改为静态面页的地址即可。

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Posted by devon At March 16, 2008 11:07

in_place_editor for rails2.0

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module InPlaceMacrosHelper # Makes an HTML element specified by the DOM ID +field_id+ become an in-place # editor of a property. # # A form is automatically created and displayed when the user clicks the element, # something like this: # <form id="myElement-in-place-edit-form" target="specified url"> # <input name="value" text="The content of myElement"/> # <input type="submit" value="ok"/> # <a onclick="javascript to cancel the editing">cancel</a> # </form> # # The form is serialized and sent to the server using an AJAX call, the action on # the server should process the value and return the updated value in the body of # the reponse. The element will automatically be updated with the changed value # (as returned from the server). # # Required +options+ are: # <tt>:url</tt>:: Specifies the url where the updated value should # be sent after the user presses "ok". # # Addtional +options+ are: # <tt>:rows</tt>:: Number of rows (more than 1 will use a TEXTAREA) # <tt>:cols</tt>:: Number of characters the text input should span (works for both INPUT and TEXTAREA) # <tt>:size</tt>:: Synonym for :cols when using a single line text input. # <tt>:cancel_text</tt>:: The text on the cancel link. (default: "cancel") # <tt>:save_text</tt>:: The text on the save link. (default: "ok") # <tt>:loading_text</tt>:: The text to display while the data is being loaded from the server (default: "Loading...") # <tt>:saving_text</tt>:: The text to display when submitting to the server (default: "Saving...") # <tt>:external_control</tt>:: The id of an external control used to enter edit mode. # <tt>:load_text_url</tt>:: URL where initial value of editor (content) is retrieved. # <tt>:options</tt>:: Pass through options to the AJAX call (see prototype's Ajax.Updater) # <tt>:with</tt>:: JavaScript snippet that should return what is to be sent # in the AJAX call, +form+ is an implicit parameter # <tt>:script</tt>:: Instructs the in-place editor to evaluate the remote JavaScript response (default: false) # <tt>:click_to_edit_text</tt>::The text shown during mouseover the editable text (default: "Click to edit") def in_place_editor(field_id, options = {}) function = "new Ajax.InPlaceEditor(" function << "'#{field_id}', " function << "'#{url_for(options[:url])}'" js_options = {} if protect_against_forgery? options[:with] ||= "Form.serialize(form)" options[:with] += " + '&authenticity_token=' + encodeURIComponent('#{form_authenticity_token}')" end js_options['cancelText'] = %('#{options[:cancel_text]}') if options[:cancel_text] js_options['okText'] = %('#{options[:save_text]}') if options[:save_text] js_options['loadingText'] = %('#{options[:loading_text]}') if options[:loading_text] js_options['savingText'] = %('#{options[:saving_text]}') if options[:saving_text] js_options['rows'] = options[:rows] if options[:rows] js_options['cols'] = options[:cols] if options[:cols] js_options['size'] = options[:size] if options[:size] js_options['externalControl'] = "'#{options[:external_control]}'" if options[:external_control] js_options['loadTextURL'] = "'#{url_for(options[:load_text_url])}'" if options[:load_text_url] js_options['ajaxOptions'] = options[:options] if options[:options] # js_options['evalScripts'] = options[:script] if options[:script] js_options['htmlResponse'] = !options[:script] if options[:script] js_options['callback'] = "function(form) { return #{options[:with]} }" if options[:with] js_options['clickToEditText'] = %('#{options[:click_to_edit_text]}') if options[:click_to_edit_text] js_options['textBetweenControls'] = %('#{options[:text_between_controls]}') if options[:text_between_controls] function << (', ' + options_for_javascript(js_options)) unless js_options.empty? function << ')' javascript_tag(function) end # Renders the value of the specified object and method with in-place editing capabilities. def in_place_editor_field(object, method, tag_options = {}, in_place_editor_options = {}) tag = ::ActionView::Helpers::InstanceTag.new(object, method, self) tag_options = {:tag => "span", :id => "#{object}_#{method}_#{tag.object.id}_in_place_editor", :class => "in_place_editor_field"}.merge!(tag_options) in_place_editor_options[:url] = in_place_editor_options[:url] || url_for({ :action => "set_#{object}_#{method}", :id => tag.object.id }) tag.to_content_tag(tag_options.delete(:tag), tag_options) + in_place_editor(tag_options[:id], in_place_editor_options) end end

解决在rails2.0以上版本使用in_place_editor时出现的 ActionController::InvalidAuthenticityToken 错误。

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Posted by devon At March 15, 2008 16:20

capture in view

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<% @greeting = capture do %> Welcome to my shiny new web page! The date and time is <%= Time.now %> <% end %> <html> <head><title><%= @greeting %></title></head> <body> <b><%= @greeting %></b> </body></html>

The capture method allows you to extract part of a template into a variable. You can then use this variable anywhere in your templates or layout.

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Posted by devon At March 13, 2008 14:06

在 before_filter 中使用不同的layout

before_filter Proc.new {|controller| layout 'iframe' unless controller.request.env["HTTP_REFERER"] =~ /localhost/ }

如果不是从localhost这个站点来访问的，则使用 iframe 的 layout

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Posted by devon At March 11, 2008 17:38

Rails中获取 HTTP_REFERER

request.env["HTTP_REFERER"]

可以取到的参数包括：

SERVER_NAME: localhost
PATH_INFO: /forum/forums
HTTP_USER_AGENT: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en) AppleWebKit/522.11 (KHTML, like Gecko) Version/3.0.2 Safari/522.12
HTTP_ACCEPT_ENCODING: gzip, deflate
SCRIPT_NAME: /
SERVER_PROTOCOL: HTTP/1.1
HTTP_HOST: localhost:3000
HTTP_CACHE_CONTROL: max-age=0
HTTP_ACCEPT_LANGUAGE: en
REMOTE_ADDR: 127.0.0.1
SERVER_SOFTWARE: Mongrel 1.1.3
REQUEST_PATH: /forum/forums
HTTP_REFERER: http://localhost:3000/
HTTP_COOKIE: _matchsession=BAh7BzoMY3NyZl9pZCIlNWJiNzg4NDUzOWQzNWFhZTQ4MGRkNTUwYzc0MDc5%250AZGYiCmZsYXNoSUM6J0FjdGlvbkNvbnRyb2xsZXI6OkZsYXNoOjpGbGFzaEhh%250Ac2h7AAY6CkB1c2VkewA%253D268e6091590591d959128f3b17b62ff46244a0a3; _slemail=temp%40email.com; _slhash=9dfd86431742273e3e96e06a1c20541d69f74dc9; _haha_session=BAh7BiIKZmxhc2hJQzonQWN0aW9uQ29udHJvbGxlcjo6Rmxhc2g6OkZsYXNo%250ASGFzaHsABjoKQHVzZWR7AA%253D%253D--96565e41694dc839bd244af40b5d5121a923c8e3
HTTP_VERSION: HTTP/1.1
REQUEST_URI: /forum/forums
SERVER_PORT: "3000"
GATEWAY_INTERFACE: CGI/1.2
HTTP_ACCEPT: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
HTTP_CONNECTION: keep-alive
REQUEST_METHOD: GET