#{茶男與藍牌}

Chef: WARN: HTTP Request Returned 401 Unauthorized: Failed to authenticate as mhasan. Synchronize the clock on your host.

茶男 — Fri, 11 May 2012 13:04:51 +0000

ntpdate pool.ntp.org

Add script to startup

茶男 — Wed, 09 May 2012 02:59:18 +0000

update-rc.d SCRIPT_NAME defaults

Understanding delete

茶男 — Tue, 03 Apr 2012 22:40:49 +0000

from http://perfectionkills.com/understanding-delete/

A couple of weeks ago, I had a chance to glance through Stoyan Stefanov’s Object-Oriented Javascript. The book had an exceptionally high rating on Amazon (12 reviews with 5 stars), so I was curious to see if it was something worth recommending. I started reading through chapter on functions, and really enjoyed the [...]

Rails 3: cache: [GET /] miss

茶男 — Wed, 07 Mar 2012 01:14:15 +0000

If you get this from your error log, there might be two things you might look into:

1. assets pipeline precompile

2. cache_store is not properly set up for the environment (like staging and production)

Rails 3.2 asset pipeline precompile needs a Javascript runtime.

茶男 — Wed, 07 Mar 2012 00:33:02 +0000

To precompile the asset pipeline, you need a Javascript runtime like node.js

Or you will see the error message when you run

rake assets:precompile Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.

Global functions can go into the /lib in Rails

茶男 — Thu, 01 Mar 2012 06:02:01 +0000

Write the code in /lib/global.rb

def hello; "world"; end

Autoload in /config/application.rb

config.autoload_paths += Dir["#{config.root}/lib/**.rb/"]

Why Web Browser DNS Caching Can Be A Bad Thing

茶男 — Tue, 28 Feb 2012 21:52:17 +0000

from http://dyn.com/web-browser-dns-caching-bad-thing/

The whole reason for caching DNS records is to reduce unnecessary DNS queries; many webservers don’t change their IP addresses all that often. Every DNS record that your operating system requests has what is called a “Time to Live” (TTL), which is a number (in seconds) that determines how long a particular DNS record [...]

Discover ActiveModel: Dirty Record

茶男 — Thu, 23 Feb 2012 05:14:44 +0000

How to find out the old value for an attribute in active model? How to find out whether the value has changed?

If you take a look at the module ActiveModel::Dirty, you will know.

Take a look at the following examples:

Reference: http://api.rubyonrails.org/classes/ActiveModel/Dirty.html

1 error(s) on assignment of multiparameter attributes

茶男 — Sat, 18 Feb 2012 22:16:44 +0000

from http://gabeodess.heroku.com/posts/14

I found myself wanting to set an attr_accessor to handle passing a date to my model in a form_for tag with the f.datetime_select helper. So this is what I had:

Model:

attr_accessor :my_time

View:

<%= f.datetime_select :my_time %>

Unfortunately when I submit my form I get this:

1 error(s) on assignment of multiparameter [...]

Gem::Package::FormatError: no metadata found in ???

茶男 — Thu, 16 Feb 2012 03:22:46 +0000

If you have ever run into this issue like:

Gem::Package::FormatError: no metadata found in /Users/username/.rvm/gems/ruby-1.8.7-p334@project/cache/cancan-1.5.1.gem An error occured while installing cancan (1.5.1), and Bundler cannot continue. Make sure that `gem install cancan -v '1.5.1'` succeeds before bundling.

Gem::Package::FormatError: corrupt gem (Gem::Package::TarInvalidError: tar is corrupt, name contains null byte) in /Users/username/.rvm/gems/ruby-1.8.7-p334@project/cache/warden-1.0.5.gem An error occured while [...]