ruby benchmark

Benchmarking Makes it Better
<br />require 'benchmark'<br /><br />#The bm method provides basic interface to the benchmark method. It takes an optional label_width argument. Each method tested can have a label specified.<br /><br />n = 5_000_000<br />Benchmark.bm(15) do |x|<br /> x.report("for loop:") { for i in 1..n; a = "1"; end }<br /> x.report("times:") { n.times do ; a = "1"; end }<br /> x.report("upto:") { 1.upto(n) do ; a = "1"; end }<br />end<br /><br /><br /># Model<br />Project.benchmark("Creating project") do<br /> project = Project.create("name" => "stuff")<br /> project.create_manager("name" => "David")<br /> project.milestones << Milestone.find(:all)<br />end<br /><br /># Controller<br />def process_projects<br /> self.class.benchmark("Processing projects") do<br /> Project.process(params[:project_ids])<br /> Project.update_cached_projects<br /> end<br />end<br /><br /># View<br /><% benchmark("Showing projects partial") do %><br /> <%= render :partial => @projects %><br /><% end %><br />

X-Sendfile

mod_xsendfile
Reference : Advanced Rails p121

The X-Sendfile protocol is a very simple standard, first introduced in the Lighttpd
web server, which directs the web server to send a file from the filesystem to the client
rather than a response generated by the application server.

X-Sendfile uses the X-Sendfile HTTPheader pointing to the server’s path to the file
to send, in conjunction with the other standard HTTPheaders. A typical response
using X-Sendfile would look something like this:
X-Sendfile: /home/rails/sample_application/private/secret_codes_69843.zip<br />Content-Type: application/octet-stream<br />Content-Disposition: attachment; file="secret_codes.zip"<br />Content-Length: 654685<br />Assuming the web server is properly

From Rails, you can set the response headers by modifying the response.headers
hash:<br />response.headers['X-Sendfile'] = file_path<br />response.headers['Content-Type'] = 'application/octet-stream'<br />response.headers['Content-Disposition'] = "attachment; file=\"#{file_name}\""<br />response.headers['Content-Length'] = File.size(file_path)

delegate

Rails delegate method

<br />class User < ActiveRecord::Base <br /> belongs_to :customer <br />end <br /><br />class Customer < ActiveRecord::Base <br /> has_one :user <br /> delegate :name, :name=, :email, :email=, :to => :user <br />end<br />
那個 :to => :user 其實是由customer object 再去找 user 的 instance method
所以其實可以在 overwirte 掉做其他的處理

Metric Fu

Metric Fu railscast
ASCIIcast Metric Fu
About metric_fu 1.1.4
flog_file error
test_helper error

apache 設定

一些apache 設定 Etags and expire gzip compression
Speed up your Apache/Passenger Rails app in 2min
<br /><[ifmodule mod_expires.c]><br /> <[FilesMatch "\.(ico|pdf|flv|jpg|jpeg|png|gif|js|css|swf)?d{10}"]><br /> ExpiresActive on<br /> ExpiresDefault "access plus 1 year"<br /> <[/filesmatch]><br /><[/ifmodule]><br /> <br />FileETag MTime Size<br /> <br /><[VirtualHost *:8888]><br /> ServerAdmin lake@here.com<br /> ServerName lake.com<br /> DocumentRoot /home/lake/deploy/current/public<br /> <br /> # gzip html, css and js<br /> AddOutputFilterByType DEFLATE text/html text/css application/x-javascript application/javascript<br /> <br /> RewriteEngine On<br /> <br /> RewriteCond %{HTTP_HOST} algostars\.com\.tw [NC]<br /> RewriteRule ^/(.*) http://www.algostars.com/$1 [L,R]<br /> <br /><[/VirtualHost]><br />

capistrano, fast_remote_cache

fast_remote_cache

37signals 用hard link 取代 copy 的方式

因為有需要一直用新的branch 更新, cache_copy 有需要一直變換其svn repository

所以需要overwrite 一下 fast_remote_cache 的一些 methods
#lib/capistrano/recipes/deploy/strategy<br />/fast_remote_cache.rb<br /><br /> def deploy!<br /> prepare!<br /> copy_repository_cache<br /> end<br /><br /> def prepare!<br /> switch_repository_cache<br /> update_repository_cache<br /> end<br /><br /> private<br /><br /> def switch_repository_cache<br /> logger.trace "switching the cached checkout on all servers"<br /> command = "if [ -d #{repository_cache} ]; then " +<br /> "#{source.switch(repository, repository_cache)}; " +<br /> "fi"<br /> scm_run(command)<br /> end<br /><br />require 'capistrano/recipes/deploy/scm/subversion'<br />class Capistrano::Deploy::SCM::Subversion<br /> def switch(url,destination)<br /> logger.trace "switch #{destination} to #{url}"<br /> scm :switch, arguments, verbose, authentication, url, destination<br /> end<br />end<br /><br />

ssh 免打密碼自動登入 memo

from here
在 自己電腦 Client 端
<br />[root@ ~]# ssh-keygen -t dsa<br />Generating public/private dsa key pair.<br />Enter file in which to save the key (/root/.ssh/id_dsa): <br />Enter passphrase (empty for no passphrase):<br />Enter same passphrase again:<br />Your identification has been saved in /root/.ssh/id_dsa.<br />Your public key has been saved in /root/.ssh/id_dsa.pub.<br />The key fingerprint is:<br />ad:85:bddb5:ddr:a544c:fc:ef:57:dd:4b:ef:a9:8a:db root@~<br /><br />[root@ ~]# cd /root/.ssh/id_dsa<br />id_dsa id_dsa.pub <br />[root@ ~]# scp /root/.ssh/id_dsa.pub root@192.168.188.199:/root/.ssh/ <br />

server 端<br />cd .ssh<br />cat ./id_rsa.pub >> authorized_keys<br />