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ruby on rails 代码技巧

摘要：git仓库输出gitarchive--format=tar--prefix=actasfavor/HEAD|(cd/home/holin/w...

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

Posted by holin At May 16, 2008 16:42

加载plugins中的controller和model

# 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'

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

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 }

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"

Posted by holin At May 08, 2008 12:05

用memcached手动cache数据

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)

Posted by devon At May 04, 2008 20:39

shuffle an array

class Array

def shuffle

sort_by { rand }

end

def shuffle!

self.replace shuffle

end

Posted by holin At May 04, 2008 15:39

让所有的ajax请求都不render :layout

def render(*args)

args.first[:layout] = false if request.xhr? and args.first[:layout].nil?

super

end

Posted by devon At May 03, 2008 10:53

Find with Hash

Event.find(

:all,

:conditions => [ "title like :search or description like :search",

{:search => "%Tiki%"}]

)

Posted by devon At May 03, 2008 10:49

执行sql语句脚本

mysql -uroot -p123<<END

use dbame;

delete from results;

delete from examings;

quit

END

Posted by holin At May 01, 2008 12:14

SQL Transaction in Rails

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

Posted by holin At April 30, 2008 09:37

显示 Flash 消息的动态效果

<% if flash[:warning] or flash[:notice] %>

<div id="notice" <% if flash[:warning] %>class="warning"<% end %>>

<%= flash[:warning] || flash[:notice] %>

</div>

setTimeout("new Effect.Fade('notice');", 15000)

</script>

<% end %>

15000 毫秒后自动 notice Div 自动消失。

Posted by devon At April 29, 2008 13:02

删除环境中的常量

Object.send(:remove_const, :A)

>> Math

=> Math

>> Object.send(:remove_const, :Math)

=> Math

>> Math

NameError: uninitialized constant Math

Posted by devon At April 28, 2008 18:24

手动加上 authenticity_token

Posted by devon At April 28, 2008 14:24

Rails group_by

<% @articles.group_by(&:day).each do |day, articles| %>

<%= render :partial => 'article', :collection => articles %>

</div>

<% end %>

articles 按天数分组

Posted by devon At April 25, 2008 22:32

读写文件

# 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

# 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 SatishnThank God!"

end

Posted by holin At April 17, 2008 02:10

遍历目录

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

Posted by holin At April 16, 2008 15:28

字符串到 model

>> '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.

Posted by devon At April 07, 2008 17:32

调用Proc

a = Proc.new { |i| puts i }

a['haha']

a.call('hehe')

Posted by holin At March 28, 2008 23:10

Rails中Host静态文件

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.

Posted by devon At March 26, 2008 18:18

打包gems到项目目录中

$ 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

Posted by devon At March 26, 2008 18:12

在当前上下文中执行文件中的代码

instance_eval(File.read('param.txt'))

# such as

@father = 'Father'

instance_eval("puts @father")

#Produces:

#Father

Posted by holin At March 20, 2008 01:13

将当前文件所在目录加入require路径

$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

Posted by holin At March 19, 2008 01:40

多字段模糊搜索

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

Posted by devon At March 17, 2008 17:25

nginx 启动脚本

#! /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

Posted by devon At March 16, 2008 12:26

link_to_remote 取静态页面

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

将 url 改为静态面页的地址即可。

Posted by devon At March 16, 2008 11:07

in_place_editor for rails2.0

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>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

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

Posted by devon At March 15, 2008 16:20

capture in view

<% @greeting = capture do %>

Welcome to my shiny new web page! The date and time is

<%= Time.now %>

<% end %>

<html>

<body>

</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.

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

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

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