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January 11, 2010
0 thanks

Includes all ancestors

May be helpful to know that this returns true if B is any ancestor of A, not just a direct one. As an example:

class Foo; end
class Bar < Foo; end
class Baz < Bar; end

Foo > Bar #=> true
Foo > Baz #=> true
January 11, 2010
0 thanks

Includes descendants

May be helpful to know that this returns true if A is any descendant of B, not just a direct one. As an example:

class Foo; end
class Bar < Foo; end
class Baz < Bar; end

Bar <= Foo #=> true
Baz <= Foo #=> true
January 11, 2010
0 thanks

Includes descendants

May be helpful to know that this returns true if A is any descendant of B, not just a direct one. As an example:

class Foo; end
class Bar < Foo; end
class Baz < Bar; end

Bar < Foo #=> true
Baz < Foo #=> true

If you want direct descendance try Class#superclass:

Bar.superclass == Foo #=> true
Baz.superclass == Foo #=> false
January 8, 2010
1 thank

Status Codes

Full detail: http://en.wikipedia.org/wiki/List_of_HTTP_status_codes

  • 100 - Continue

  • 101 - Switching Protocols

  • 200 - OK

  • 201 - Created

  • 202 - Accepted

  • 203 - Non-Authoritative Information

  • 204 - No Content

  • 205 - Reset Content

  • 206 - Partial Content

  • 300 - Multiple Choices

  • 301 - Moved Permanently

  • 302 - Found

  • 303 - See Other

  • 304 - Not Modified

  • 305 - Use Proxy

  • 306 - No Longer Used

  • 307 - Temporary Redirect

  • 400 - Bad Request

  • 401 - Not Authorised

  • 402 - Payment Required

  • 403 - Forbidden

  • 404 - Not Found

  • 405 - Method Not Allowed

  • 406 - Not Acceptable

  • 407 - Proxy Authentication Required

  • 408 - Request Timeout

  • 409 - Conflict

  • 410 - Gone

  • 411 - Length Required

  • 412 - Precondition Failed

  • 413 - Request Entity Too Large

  • 414 - Request URI Too Long

  • 415 - Unsupported Media Type

  • 416 - Requested Range Not Satisfiable

  • 417 - Expectation Failed

  • 500 - Internal Server Error

  • 501 - Not Implemented

  • 502 - Bad Gateway

  • 503 - Service Unavailable

  • 504 - Gateway Timeout

  • 505 - HTTP Version Not Supported

January 6, 2010
6 thanks

Doesn't return nil if the object you try from isn't nil.

Note that this doesn’t prevent a NoMethodError if you attempt to call a method that doesn’t exist on a valid object.

a = Article.new

a.try(:author) #=> #<Author ...>

nil.try(:doesnt_exist) #=> nil

a.try(:doesnt_exist) #=> NoMethodError: undefined method `doesnt_exist' for #<Article:0x106c7d5d8>

This is on Ruby 1.8.7 patchlevel 174

January 6, 2010
1 thank

Alternative:

without using at

[:a, :b, :c].try(:[], 1)
December 31, 2009
2 thanks

Replacing with "\" and match — a simple solution

A somewhat different approach to the same problem:

v.gsub(/(?=\W)/, '\\') #=> Foo\ Bar\!

But from what you are trying to achieve I suspect you might be interested in Regexp.escape method :)

December 28, 2009
4 thanks

Attribute names are Strings, not Symbols

Another possible gotcha – the returned hash keys are of type String, not Symbol:

user.attributes["login"] # => "joe"
user.attributes[:login] # => nil
December 23, 2009 - (<= v2.3.2)
0 thanks

Compare dates

You can check a date resides between two dates.

Date.today.between?(Date.yesterday, Date.tomorrow)

will return true

Date.yesterday.between?(Date.today, Date.tomorrow)

will return false

December 21, 2009
0 thanks

expire_page outside controller and sweepers

If you want to expire cached pages from scripts or console just use class-method expire_page. But don’t forget about difference between instance and class method. In class-method you pass page url, not a hash of action/controller:

ActionController::Base.expire_page your_page_url
December 21, 2009 - (>= v2.0.0)
0 thanks

Expire cache from console or whatever...

I know only one possible method:

ApplicationController.new.expire_fragment(:your_fragment)

December 18, 2009
4 thanks

Version Ranges

To specify a version range, use array syntax like this:

config.gem 'paperclip', :version => ['>= 2.3.1.1', '< 3.0']

The example will, of course, match any version 2.3.1.1 or newer up until (not including) 3.0 or later.

December 16, 2009
0 thanks

path

send_file always uses the absolute path /www/somewebsite/public/downloads/file

December 13, 2009
1 thank

yijisoo

create generates the object and saves. new only generates the object.

e.g.

o = Object.new(:foo => 'bar')
o.save

is the same as

o = Object.create(:foo => 'bar')
December 13, 2009
0 thanks

What's difference between create and new?

What’s difference between create and new?

December 3, 2009
2 thanks

Replacing with "\" and match

If you’re trying to place a “" in front of your matches, you’ll quickly see that it is a pain in the ass to add the quoting in the replacement string.

Here’s an example:

v = "Foo Bar!"  # Target: Foo\ Bar\!
# Resulting strings will not be quoted to decrease
# the amount of backslashes. Compare \\! to "\\\\!"

v.gsub(/\W/, '\0') #=> Foo Bar!

# \\ escapes to a literal \, which next to the 0 becomes \0
v.gsub(/\W/, '\\0') #=> Foo Bar!

# \\\0, means "\ \0", or "escaped \0"
v.gsub(/\W/, '\\\0') #=> Foo\0Bar\0

# Same mechanism as before. \\ → \
v.gsub(/\W/, '\\\\0') #=> Foo\0Bar\0

# Finally! We have now an escaped \ before \0 and
# we get the results we want.
v.gsub(/\W/, '\\\\\0') #=> Foo\ Bar\!

# It's very tempting to just write it like this now, right?
v.gsub(/\W/) { |m| "\\#{m}" } #=> Foo\ Bar\!
# It might not be shorter, but anyone can understand it.

Surely, there must be an easier way to do this. I haven’t found it, though. Hopefully, this makes it easier for you to understand why it behaves the way it does. :-)

December 3, 2009 - (v1_8_6_287 - v1_8_7_72)
0 thanks

Testing Regular Expressions?

Writing regular expressions is never easy. You may use http://rubular.com to test and optimize your regular expressions.

December 3, 2009 - (>= v2.2.1)
1 thank

Capturing blocks after >2.2

After 2.2, you can omit the do …end block and simply use the &block variable directly:

concat(content_tag(:div, :class => "wrapped_content") do
  capture(&block)
end, block.binding)

becomes simply:

concat(content_tag(:div, capture(&block), :class => "wrapped_content"))
December 2, 2009
2 thanks

IE GOTCHA - multiple javascript_include_tags with cache => true

If you have multiple lines of javascript_include_tag ‘jsfile’, :cache => true, IE does not load them all (though it seems Firefox and Safari do). And the error won’t show up until you’re in production (since that’s only when caching kicks in.)

You should include them all on one line:

javascript_include_tag 'file1.js', 'file2.js', 'file3.js', :cache => 'myfiles'
November 30, 2009
2 thanks

Clearing out previous values from content_for

By default, content_for :thing appends whatever you put in your block to the previous value of :thing. In some cases, you’d like to clear out :thing rather than append to it.

I just posted a way to do this on my blog: http://stevechanin.blogspot.com/2009/11/clearing-out-content-in-contentfor.html

I add a new method set_content_for that works just like content_for, but clears out :thing first. It doesn’t touch how content_for works, so it shouldn’t cause any problems anywhere else in your app.

November 30, 2009
0 thanks

You can specify the format as well

You can also specify the format (in case you need to redirect a request coming in one format to another format):

redirect_to :action => 'show', :format => 'html'
November 26, 2009
0 thanks

How to check if a Yield has content?

How do I do this without actually calling the yield?

- if yield :footer
  = yield :footer
- else
  = render "layouts/footer_big"

(Note: HAML Syntax) Thanks.

November 26, 2009
0 thanks

How to use with HAML

Are you using HAML and try to do the block-thing (do…)? Please note that the whole block has to be in a single line. More: http://groups.google.com/group/haml/browse_thread/thread/52e62ef501c504a3

November 26, 2009
0 thanks

Streaming Does Not Work with Mongrel

If you are trying to stream output via render :text => Proc and Mongrel, be sure to note that this does NOT work. Mongrel returns a StringIO, which by nature buffers everything.

Unsure of how to actually stream output with Rails in a consistent fashion.

November 23, 2009
3 thanks

Make directory if not exists

If the directory already exists, mkdir raises exception. To prevent this:

Dir.mkdir(dir) unless File.exists?(dir)
November 22, 2009
0 thanks

assert_response(:success) checks if the status code is in the range 200-299

success? in ActionController::TestResponseBehavior is defined as:

def success?
  (200..299).include?(response_code)
end
November 18, 2009
0 thanks

Be careful with float ranges

Pay close attention to the fact that the object passed to :in must be enumerable.

If you want to validate a ranking, the following won’t work:

validates_inclusion_of :rating, :in => (0.0..10.0)

Instead, you’ll want to use validates_numericality_of like this:

validates_numericality_of :rating, :greater_than_or_equal_to => 0.0, :less_than_or_equal_to => 10.0
November 18, 2009 - (>= v1_8_6_287)
4 thanks

Example

code:

class Klass
  def set(string)
    var_name = "@#{string}"  # the '@' is required
    self.instance_variable_set(var_name, 'bar')
  end
  def puts_foo
    puts @foo
  end
end
k = Klass.new
k.puts_foo  # nil
k.set('foo')
k.puts_foo  # 'bar'
November 18, 2009
0 thanks

More Docs and Explanation

You probably want to look at the class level docs

http://apidock.com/rails/ActiveRecord/NestedAttributes/ClassMethods

(cut and paste, apidocks can’t render the above for some reason)

November 16, 2009
2 thanks