Evernote Openbook: Code http://www.evernote.com/pub/cdunn/code Notes from cdunn's Evernote Openbook: Code Tue, 14 Jul 2009 18:08:39 GMT can't activate rails (<= 1.2.6, runtime), already activated rails-2.3.2 http://www.evernote.com/pub/cdunn/code#5247c060-fff4-47cc-aeb5-8f43544a1608 rake aborted!
can't activate rails (<= 1.2.6, runtime), already activated rails-2.3.2
/Library/Ruby/Site/1.8/rubygems.rb:149:in `activate'
/Library/Ruby/Site/1.8/rubygems.rb:49:in `gem'
/Users/cdunn/Projects/elc/profiles/vendor/gems/mbbx6spp-twitter4r-0.3.1/lib/twitter/ext/stdlib.rb:45:in `gem_present?'
/Users/cdunn/Projects/elc/profiles/vendor/gems/mbbx6spp-twitter4r-0.3.1/lib/twitter/rails.rb:4

FIX:
sudo mv /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/specifications/rails-1.2.6.gemspec ~/Desktop/rails-1.2.6.gemspec.bak
]]> Tue, 14 Jul 2009 18:08:39 GMT http://www.evernote.com/pub/cdunn/code#5247c060-fff4-47cc-aeb5-8f43544a1608 How to Freeze Gems with Rails >= 2.1 http://www.evernote.com/pub/cdunn/code#37087acf-df98-4337-96c5-4cc3bfc8c9e1

I spent a couple of minutes trying to figure out how to ‘freeze’ gems with a recent Rails app (2.2.2) I’m developing. A bunch of git repositories have this vendor/gems folder a bit like in Merb, so I was pretty sure something had changed in Rails itself. I finally found this screencast. I’m sharing it again as I spent a bit of time already myself.

Turns out it’s pretty well integrated. First edit your environment.rb to specify which gem you want to register as a dependency:

Rails::Initializer.run do |config| # ... # Specify gems that this application depends on. # They can then be installed with "rake gems:install" on new installations. # You have to specify the :lib option for libraries, where the Gem name (sqlite3-ruby) differs from the file itself (sqlite3) config.gem "fastercsv", :version => '1.4.0' # ... end

If you want to freeze the registered gems automatically under vendor/gems, just do:

rake gems:unpack

There is also the possibility to install them on any machine using this:

rake gems:install

Generally, I prefer to keep things in my repository, as I don’t want my deployment to fail because of network or routing issues.

]]> Wed, 22 Apr 2009 21:17:35 GMT http://www.evernote.com/pub/cdunn/code#37087acf-df98-4337-96c5-4cc3bfc8c9e1 Daniel Morrison - A prettier truncate helper http://www.evernote.com/pub/cdunn/code#b6ca0d02-a5ea-4362-9b87-79b21e472153 # Awesome truncate # First regex truncates to the length, plus the rest of that word, if any. # Second regex removes any trailing whitespace or punctuation (except ;). # Unlike the regular truncate method, this avoids the problem with cutting # in the middle of an entity ex.: truncate("this &amp; that",9) => "this &am..." # though it will not be the exact length. def awesome_truncate(text, length = 30, truncate_string = "...") return if text.nil? l = length - truncate_string.chars.length text.chars.length > length ? text[/\A.{#{l}}\w*\;?/m][/.*[\w\;]/m] + truncate_string : text end ]]> Fri, 17 Apr 2009 19:34:27 GMT http://www.evernote.com/pub/cdunn/code#b6ca0d02-a5ea-4362-9b87-79b21e472153 Big Spaceship Labs » Ensnaring mouseEnabled http://www.evernote.com/pub/cdunn/code#aab9e7b3-3e7a-491b-9f81-b6660f6d4f6a Ensnaring mouseEnabled

A lot of what we do here at the Spaceship involves complex SWFs loaded in and layered on top of other SWFs. We wind up with a lot of buttons nested underneath of movieclips nested inside of SWFs.

When we got to handling mouse interaction in AS2, this was fine so long as a button wasn’t layered on top of another button. But in AS3 it’s a different ball of wax — each DisplayObject has a mouseEnabled property, which is set to true by default. mouseEnabled means that the DisplayObject in question *can* react to mouse events.

This can be lead to some tricky and irritating issues. Hit the jump for specifically what is happening and how to fix it.


The rule of thumb is more or less this:

When a mouse event happens, the DisplayObject underneath the mouse at the highest depth with mouseEnabled set to true will fire a MouseEvent, which will relay to it’s parent, and it will go all the way down to the stage.

Consider this: MovieClip A is on the topmost layer. MovieClip B has a MouseEvent.CLICK listener. MovieClip A overlaps MovieClip B.

Any time a user clicks on MovieClip A it will hear the MouseEvent and sending it down the chain… MovieClip B would never hear it. This effectively creates the “I’m listening for the mouse but nothing happens for no reason” bug. By setting MovieClip A to mouseEnabled=false, all is well. Note that if MovieClip A had anything nested inside of it, they too would have to be disabled. You can do this either with mouseEnabled=false on each of them painstakingly or by setting MovieClip A’s mouseChildren=false.

So okay! We know what the problem is… a MovieClip can block the mouse from another movieclip. But most of what we’re building in Flash is far more complex than one MovieClip on top of another… is there an easy way to find the culprit of mouse blocking? Indeed there is! Sort of. Just drop this code on your main timeline (or your root class, if you prefer):


stage.addEventListener(MouseEvent.CLICK,_checkMouseEventTrail,false,0,true);
function _checkMouseEventTrail($e:MouseEven...

]]> Wed, 15 Apr 2009 16:25:37 GMT http://www.evernote.com/pub/cdunn/code#aab9e7b3-3e7a-491b-9f81-b6660f6d4f6a Stored Procedures and Rails - Part 1 « class Nasir < Jamal http://www.evernote.com/pub/cdunn/code#13321fd6-8155-4c63-a3cd-78e3b0261dfc Stored Procedures and Rails - Part 13 12 2007


There is no documentation in Rails about how to use stored procedures or atleast it is difficult to find where to look at. And according to DHH stored procedures is not the Rails Way to do things. DHH mentioned in his post

I want a single layer of cleverness: My domain model. Object-orientation is all about encapsulating clever. Letting it sieve half ways through to the database is a terrible violation of those fine intentions. And I want no part of it.

I somewhat agree to what DHH has to say. And that’s all fine but what if we don’t have any other option apart from using stored procedure and our stored procedure has some complex logic which we don’t want to put in our Ruby code then here is a little hack to it

ActiveRecord::Base.connection.execute("execute procedure_name")

But the above line will not return anything it will only execute your procedure, considering everything went OK.

Moreover, it’s not DRY if everytime you have to write that line of code just to call a procedure.

Here is a better way to do it:

1) Create a class and let’s call it

Class CallStoredProcedures your methods here ....... end

2) Create a class method within it

def self.fetch_db_records(proc_name_with_parameters) ActiveRecord::Base.connection.execute(proc_name_with_parameters) end

Then simply call it as

CallStoredProcedures.fetch_db_records("exec procedure_name 'args1', 'args2', 'and so on' ")

Now you might say, that this will only execute a procedure (as I mentioned above) what if I want to return records or values from stored procedures. Then I will prefer class methods and this is how I would do it,

class CallStoredProcedures < ActiveRecord::Base def self.fetch_db_records(proc_name_with_parameters) connection.select_all(proc_name_with_parameters) end def self.insert_update_delete_calculate(proc_name_with_parameters) connection.execute(proc_name_with_parameters) end def self.fetch_val_from_sp(proc_name_with_parameters) connection.select_value(proc_name_with_param...
]]> Fri, 10 Apr 2009 19:19:11 GMT http://www.evernote.com/pub/cdunn/code#13321fd6-8155-4c63-a3cd-78e3b0261dfc Goondocks > Zip Code Radius Search using MySQL http://www.evernote.com/pub/cdunn/code#3dd5df0f-3329-4107-b5d3-030151c61a0a I had a project that required me to get a list of zip codes within a certain distance from a given zip code. Here is a web-based tool that does what I'm describing.

I found a great post on how to do this using ColdFusion . I converted the SQL found on this page to work with MySQL and have posted it on this page.

First, you are going to need to get a database that maps zip codes to longitude & latitude. I personally purchased this data for $5 from the following web site: http://www.teamredline.com/zc/

Update: Heyrog posted on StumbleUpon that you can get the zip code database for free from: http://www.populardata.com/downloads.html

Next, you need to create a MySQL function to calculate distances between two longitudes and latitudes:

DELIMITER $$    DROP   FUNCTION  IF EXISTS `GetDistance`$$     CREATE   FUNCTION  `GetDistance`(    lat1  numeric (9,6),    lon1  numeric (9,6),    lat2  numeric (9,6),    lon2  numeric (9,6)   )  RETURNS   decimal (10,5)   BEGIN     DECLARE  x  decimal (20,10);     DECLARE  pi  decimal (21,20);     SET  pi = 3.14159265358979323846;     SET  x = sin( lat1 * pi/180 ) * sin( lat2 * pi/180  ) + cos(    lat1 *pi/180 ) * cos( lat2 * pi/180 ) * cos(  abs ( (lon2 * pi/180) -    (lon1 *pi/180) ) );     SET  x = atan( ( sqrt( 1- power( x, 2 ) ) ) / x );     RETURN  ( 1.852 * 60.0 * ((x/pi)*180) ) / 1.609344;   END $$     DELIMITER ; 

You will now need to create a MySQL stored procedure that accepts a zip code and a radius and returns a list of zip codes that fall within the given radius:

DELIMITER $$    DROP   PROCEDURE  IF EXISTS `GetNearbyZipCodes`$$     CREATE   PROCEDURE  `GetNearbyZipCodes`(       zipbase  varchar (6),       range  numeric (15)   )   BEGIN   DECLARE  lat1  decimal (5,2);   DECLARE  long1  decimal (5,2);   DECLARE  rangeFactor  decimal (7,6);   SET  rangeFactor = 0.014457;   SELECT  latitude,longitude  into  lat1,long1  FROM  tbl_zipcodes  WHERE  zipcode = zipbase;   SELECT  B.zipcode   FROM  tbl_zipcodes  AS  B    WHERE      B.latitude  BETWEEN  lat1-(range*rangeFactor)  AND  la...
]]> Thu, 09 Apr 2009 16:34:24 GMT http://www.evernote.com/pub/cdunn/code#3dd5df0f-3329-4107-b5d3-030151c61a0a Rmagick Autorotation via EXIF http://www.evernote.com/pub/cdunn/code#3e4cf4e4-df90-4634-87e8-fbe9b918ff57

append to config/environment.rb):

require 'RMagick' unless defined?(Magick)
Magick::Image.class_eval do
class << self
def read_with_auto_upright(*args, &block)
self.read_without_auto_upright(*args, &block).collect do |img|
begin
# if there's nothing to rotate, auto_orient! will return nil
img.auto_orient! || img
rescue NotImplementedError
# Older versions of ImageMagick has no auto_orient!
case img.get_exif_by_entry("Orientation") && img["EXIF:Orientation"]
# img["EXIF:Orientation"] might not be ready until get_exif_by_entry() is called
when "6"
# Magick::RightTopOrientation
img.rotate!(90)
img["EXIF:Orientation"] = "1"
when "3"
# Magick::BottomRightOrientation
img.rotate!(180)
img["EXIF:Orientation"] = "1"
when "8"
# Magick::LeftBottomOrientation
img.rotate!(270)
img["EXIF:Orientation"] = "1"
end
img
end
end
end

# wrap around RMagick::Image#read method so that
# any images loaded in memory are already upright
alias :read_without_auto_upright :read
alias :read :read_with_auto_upright
# note: not using alias_method_chain so that this
# snippet can be used outside of Rails
end
end

  ImageScience users, if you trust my C++ code, just place this patched image_science.rb in your vendor/ directory. Otherwise you can apply this patch manually:

--- lib/image_science.rb 2007-10-16 12:11:08.000000000 +0800
+++ lib/image_science.rb.new 2007-10-16 12:11:01.000000000 +0800
@@ -150,6 +150,21 @@
VALUE result = Qnil;
int flags = fif == FIF_JPEG ? JPEG_ACCURATE : 0;
if (bitmap = FreeImage_Load(fif, input, flags)) {
+ FITAG *tagValue = NULL;
+ FreeImage_GetMetadata(FIMD_EXIF_MAIN, bitmap, "Orientation", &tagValue);
+ switch (tagValue == NULL ? 0 : *((short *) FreeImage_GetTagValue(tagValue))) {
+ case</... ]]> Tue, 07 Apr 2009 18:31:17 GMT http://www.evernote.com/pub/cdunn/code#3e4cf4e4-df90-4634-87e8-fbe9b918ff57 Ruby on Rails 2.3 Release Notes http://www.evernote.com/pub/cdunn/code#5fdde28c-8308-458d-8f31-cdd251fdf753
Ruby on Rails 2.3 Release Notes

Rails 2.3 delivers a variety of new and improved features, including pervasive Rack integration, refreshed support for Rails Engines, nested transactions for Active Record, dynamic and default scopes, unified rendering, more efficient routing, application templates, and quiet backtraces. This list covers the major upgrades, but doesn’t include every little bug fix and change. If you want to see everything, check out the list of commits in the main Rails repository on GitHub or review the CHANGELOG files for the individual Rails components.

]]> Sun, 05 Apr 2009 18:34:16 GMT http://www.evernote.com/pub/cdunn/code#5fdde28c-8308-458d-8f31-cdd251fdf753 selfcontained » Blog Archive » Subscribing to an image loaded event http://www.evernote.com/pub/cdunn/code#0512b88f-fd00-42fd-8ed7-221089ce39cc Subscribing to an image loaded event

I recently was working on something where I needed to swap the src of an image, but then perform some specific javascript AFTER the new image was loaded, namely resize the dimensions a little. This may seem pretty simple, but took me a little research, along with trial and error to get a working solution, so hopefully it helps someone else. I often use jQuery on my smaller projects, so I’ll show how I accomplished this with that toolkit.

  1. First, I would need to listen to the load event of the image I was replacing the src of.
  2. Next, in order to trigger the handler, we need to actually change the src of the image
$('#my-image').load(function() { //Logic for w/e here, resizing, etc. }).attr('src', myNewImageSrc);

The code itself is really simple, but it took me a few to realize that jQuery solved the problem by simply letting us listen to the load event of the image, and count on it being fired when the src changes, and finishes loading.

]]> Fri, 03 Apr 2009 20:22:00 GMT http://www.evernote.com/pub/cdunn/code#0512b88f-fd00-42fd-8ed7-221089ce39cc Alchemy:Documentation:Getting Started - Adobe Labs http://www.evernote.com/pub/cdunn/code#07b57033-8ffe-4f3e-a46e-fd89785ac651

Alchemy:Documentation:Getting Started From Adobe Labs

This article will walk through the steps of getting the Alchemy tool-chain setup, show how to compile C / C++ code into a SWC, and then use that SWC within a simple ActionScript example.

Alchemy (formerly referred to as FLACC) is a project from Adobe that allows users to compile C/C++ code that is targeted to run on the open source ActionScript virtual machine (AVM2). The C/C++ code is compiled to AS3 as a SWF or SWC that runs on Flash Player 10 or AIR 1.5. Alchemy is primarily intended to be used with C/C++ libraries that have few OS dependencies. The generated content is within the security constraints of the AVM2, and cannot bypass Flash Player security protections.

Table of contents [showhide] Macintosh

This section will show how to setup and use Alchemy on Mac OS X, although the general steps are also applicable on both Windows and Linux.

Requirements
  • Alchemy Toolkit Package for your operating system
  • XCode 2.4+
  • Flex 3.2 SDK
  • Flex Builder or Flex SDK setup to target compilation for Flash Player 10
Steps

Step 1 Download the Flex 3.2 SDK and make sure that the $FLEX_HOME/bin directory ...

]]> Tue, 31 Mar 2009 15:57:38 GMT http://www.evernote.com/pub/cdunn/code#07b57033-8ffe-4f3e-a46e-fd89785ac651 osx fzip http://www.evernote.com/pub/cdunn/code#40ea4256-2bdb-4c51-8c78-b9cddba32126 1. Setup: For the sake of this example, put a copy of the python fixer tool (included in FZip under tools) on your Desktop, along with a folder of files you want to zip up. Open Terminal. I’m not a command line guy myself so maybe there are better ways to do the next steps but they worked for me. (Terminal is in Applications/Utilities). Type in the word zip and hit return, this shows the list of options for zipping files. Finally, download and install Python, it’s a simple, normal installation with no catches.

2. In Terminal, navigate to your desktop, like: cd /Users/moses/Desktop

3. Create the zip directory, using this syntax but replace the names with whatever you want to call the zip and whatever the folder of files to zip is actually called: zip newZipFile.zip folderOfFiles/*

(For a plain folder of files this is fine. There’s also an option -j that lets you exclude folders, and some other options for including subfolders recursively. FZip doesn’t mind folders, foldernames are readable in your code via a file’s filename property.)

4. Check your Desktop to see if the zip is there, and try unzipping it to see if the files are in it. Last, apply the adler checksum fix which we copied to the desktop in step1, using the actual name of your zipfile of course: python fzip-prepare.py newZipFile.zip

(You may see a warning about a deprecated something or other when you run the fix, which is okay.)

Hope that helps someone out. ]]> Tue, 31 Mar 2009 05:02:19 GMT http://www.evernote.com/pub/cdunn/code#40ea4256-2bdb-4c51-8c78-b9cddba32126 Ruby/zlib version 0.3.0 http://www.evernote.com/pub/cdunn/code#866036a1-dac8-4c7c-953e-157bf60a772c Ruby/zlib version 0.3.0

The extension library to use zlib from Ruby. Ruby/zlib also provides the features for accessing gzipped files.

You can modify or redistribute Ruby/zlib in the same manner of Ruby interpreter.

Zlib

Zlib is the module which provides the other features in zlib C library. See zlib.h for function details.

Module Functions: version

Returns the string which represents the version of zlib library.

adler32([string, [adler]])

Calculates Alder-32 checksum for string, and returns updated value of alder. If string is omitted, it returns the CRC initial value. If alder is omitted, it assumes that the initial value is given to alder.

crc32([string, [crc]])

Calculates CRC checksum for string, and returns updated value of crc. If string is omitted, it returns the CRC initial value. If crc is omitted, it assumes that the initial value is given to crc.

crc_table

Returns the table for calculating CRC checksum.

Exceptions:

The following exceptions are defined in Zlib module. These exceptions are raised when zlib library functions returns with an error status.

  • Zlib::ErrorZlib::StreamEndZlib::NeedDictZlib::DataErrorZlib::StreamErrorZlib::MemErrorZlib::BufErrorZlib::VersionError
Zlib::ZStream

The abstruct class for the stream which handles the compressed data. The operations are defined in the subclasses, Deflate for compression, and Inflate for decompression.

SuperClass:

Object

Methods: total_in

Returns the total bytes of the input data to the stream.

total_out

Returns the total bytes of the output data from the stream.

data_type

Guesses the type of the data which have been inputed into the stream. The returned value is Zlib::ZStream::BINARY, Zlib::ZStream::ASCII, or Zlib::ZStream::UNKNOWN.

adler

Returns the alder-32 checksum. See zlib.h for details.

closeend

Closes the stream. All operations on the closed stream will raise an exception.

closed?

Returns true if the stream closed.

reset

Resets and initializes the stream. All buffered data in the stream are discarded. ...

]]> Wed, 25 Mar 2009 23:13:06 GMT http://www.evernote.com/pub/cdunn/code#866036a1-dac8-4c7c-953e-157bf60a772c Jacob Repp » Blog Archive » Build Huffman Compression in Ruby http://www.evernote.com/pub/cdunn/code#7bf8a56a-630c-432a-869f-54cabafa8d34
Jacob ReppGame programming, music and life

Many wonderful things can be done with binary trees. One brilliant usage of the binary tree was proposed by David Huffman in 1951 at MIT which has since become the foundation for much of the compression technology available today. Huffman discovered a simple way to generate a provable minimal binary encoding given a set of input symbols. It’s a deep subject, and one which I’d eventually like to spend more time getting into. For now I’ll walk through how this simple idea can be used to implement some decent compression using pure Ruby.

First of all you have your basic binary tree representation. I previously showed a simple binary tree example that demonstrates how binary trees are easily manipulated in ruby. Every binary tree node holds a value and links off to a right and left nodes that may also hold values. A leaf node is a node with dead links (left and right are both set to nil).

In the Huffman tree the leaves contain a single symbol while interior nodes summarize their sub-tree. I have simplified the idea so that all nodes wrap what is called an association list (assoc list). This is an old lisp idiom of a list containing name value pairs in the form ((name value) (name value)). To find a value in an association list you just walk the list looking at the first element of each sub-list. A reverse association list (rassoc list) takes the same form as an assoc list with the name and value pair swapped. For very small sets of data the performance of assoc lists is better than deeper structures such as a hash or tree. Ruby provides a few array APIs to deal with assoc and rassoc lists. I always store a rassoc list with the (occurance count, symbol) in a leaf and a sum of all contained lists in interior nodes. None of this information is important in understanding how Huffman encoding works but I use this concept below so I thought I should at least call it out.

class Node # binar...
]]> Wed, 25 Mar 2009 23:12:42 GMT http://www.evernote.com/pub/cdunn/code#7bf8a56a-630c-432a-869f-54cabafa8d34 proxy_next_upstream -- nginx http://www.evernote.com/pub/cdunn/code#ed33b4fd-ee27-474a-974e-320732501b68 proxy_next_upstream

syntax: proxy_next_upstream [error|timeout|invalid_header|http_500|http_502|http_503|http_504|http_404|off]

default: proxy_next_upstream error timeout

context: http, server, location

Directive determines, in what cases the request will be transmitted to the next server:

* error — an error has occurred while connecting to the server, sending a request to it, or reading its response;
* timeout — occurred timeout during the connection with the server, transfer the requst or while reading response from the server;
* invalid_header — server returned a empty or incorrect answer;
* http_500 — server returned answer with code 500
* http_502 — server returned answer with code 502
* http_503 — server returned answer with code 503
* http_504 — server returned answer with code 504
* http_404 — server returned answer with code 404
* off — it forbids the request transfer to the next server

Transferring the request to the next server is only possible when nothing has been transferred to the client -- that is, if an error or timeout arises in the middle of the transfer of the request, then it is not possible to retry the current request on a different server. ]]> Mon, 16 Mar 2009 16:17:43 GMT http://www.evernote.com/pub/cdunn/code#ed33b4fd-ee27-474a-974e-320732501b68 sql between days http://www.evernote.com/pub/cdunn/code#3220bb74-1d31-425d-bbf7-c5131f49389f Posted by Isaac Shepard on October 11 2003 2:53pm [Delete] [Edit]

If you're looking for generic SQL queries that will allow you to get the days, months, and years between any two given dates, you might consider using these. You just need to substitute date1 and date2 with your date expressions.

NOTE: Some of these formulas are complex because they account for all cases where date1 < date2, date1 = date2, and date1 > date2. Additionally, these formulas can be used in very generic queries where aliases and temporary variables are not allowed.


Number of days between date1 and date2:


TO_DAYS(date2) - TO_DAYS(date1)


Number of months between date1 and date2:


IF((((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) > 0, (((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) - (MID(date2, 9, 2) < MID(date1, 9, 2)), IF((((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) < 0, (((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1))) + (MID(date1, 9, 2) < MID(date2, 9, 2)), (((YEAR(date2) - 1) * 12 + MONTH(date2)) - ((YEAR(date1) - 1) * 12 + MONTH(date1)))))


Number of years between date1 and date2:


IF((YEAR(date2) - YEAR(date1)) > 0, (YEAR(date2) - YEAR(date1)) - (MID(date2, 6, 5) < MID(date1, 6, 5)), IF((YEAR(date2) - YEAR(date1)) < 0, (YEAR(date2) - YEAR(date1)) + (MID(date1, 6, 5) < MID(date2, 6, 5)), (YEAR(date2) - YEAR(date1))))


Now for some comments about these.


1. These results return integer number of years, months, and days. They are "floored." Thus, 1.4 days would display as 1 day, and 13.9 years would display as 13 years. Likewise, -1.4 years would display as -1 year, and -13.9 months would display as -13 months.


2. Note that I use boolean expressions in many cases. Because boolean expressions evaluate to 0 or 1, I can use them to subtract or add 1 from the total based on a condition.


For example, to calculate the number of years between to dates, first simply subtract the years. The problem is that doi... ]]> Sat, 14 Mar 2009 22:13:11 GMT http://www.evernote.com/pub/cdunn/code#3220bb74-1d31-425d-bbf7-c5131f49389f Untitled Clipped Note http://www.evernote.com/pub/cdunn/code#b9437b1e-9063-4737-b0c0-5123743b1c78
CASE
WHEN modified_date between date_sub(now(), INTERVAL 60 minute) and now() THEN concat(minute(TIMEDIFF(now(), modified_date)), ' minutes ago')
WHEN datediff(now(), modified_date) = 1 THEN 'Yesterday'
WHEN modified_date between date_sub(now(), INTERVAL 24 hour) and now() THEN concat(hour(TIMEDIFF(NOW(), modified_date)), ' hours ago')
ELSE date_format(modified_date, '%a, %m/%d/%y')
END ]]> Sat, 14 Mar 2009 21:42:00 GMT http://www.evernote.com/pub/cdunn/code#b9437b1e-9063-4737-b0c0-5123743b1c78 rotate logs http://www.evernote.com/pub/cdunn/code#cadd05bb-ff13-4e26-afd3-9f2695f5dea3 config.logger = Logger.new("#{RAILS_ROOT}/log/#{ENV['RAILS_ENV']}.log", 50, 1048576) ]]> Sat, 14 Mar 2009 16:43:41 GMT http://www.evernote.com/pub/cdunn/code#cadd05bb-ff13-4e26-afd3-9f2695f5dea3 Date / Rational / Fixnum#gcd hack increased app performance by 15% http://www.evernote.com/pub/cdunn/code#23d6ab78-739a-412d-815d-23d6bfc59c6f Ruby: Date / Rational / Fixnum#gcd hack increased app performance by 15%
Kurt on Wed, 2007-03-28 22:23.
rails | ruby

Ruby Date uses Rational heavily, which calls Integer#gcd for every new Rational. The Integer#gcd method is generic to handle Bignums, but performs terribly for Fixnum#gcd(Fixnum), which is probably the most often case.

This RubyInline hack saved 15% execution time in a large Rails application:

require 'inline'

class Fixnum
inline do | builder |
builder.c_raw '
static
VALUE
gcd(int argc, VALUE *argv, VALUE self) {
if ( argc != 1 ) {
rb_raise(rb_eArgError, "wrong number of arguments (%d for %d)",
argc, 1);
}
/* Handle Fixnum#gcd(Fixnum) case directly. */
if ( FIXNUM_P(argv[0]) ) {
/* fprintf(stderr, "Using Fixnum#gcd(Fixnum)\n"); */
long a = FIX2LONG(self);
long b = FIX2LONG(argv[0]);
long min = a < 0 ? - a : a;
long max = b < 0 ? - b : b;
while ( min > 0 ) {
int tmp = min;
min = max % min;
max = tmp;
}
return LONG2FIX(max);
} else {
/* fprintf(stderr, "Using super#gcd\n"); */
return rb_call_super(1, argv);
}
}
'
end
end

Update:

Sorry for the late reply. If the code above does not work via cut-and-paste, download it from here.

This will be released soon as a gem dynamic library called speedfreaks,
with other performance-enhancing snippets.

Thanks for the feedback! ]]> Thu, 12 Mar 2009 07:05:18 GMT http://www.evernote.com/pub/cdunn/code#23d6ab78-739a-412d-815d-23d6bfc59c6f Use helpers in controllers or models http://www.evernote.com/pub/cdunn/code#454e0a5d-0d06-4819-8d86-0e0ede502e38
Use helpers in controllers or models

Published in: Ruby

URL: http://snippets.dzone.com/posts/show/1799

This is an easy to use any helpers that rails provides in any other place besides views and view helpers
Embed | Plain TextExpand

Copy this code and paste it in your HTML

1.
# create a new file inside lib/ and call it helpers.rb
2.
# paste the following:
3.

4.
def help
5.
Helper.instance
6.
end
7.

8.
class Helper
9.
include Singleton
10.
# look inside ActionView::Helpers to include any other helpers that you might need
11.
include ActionView::Helpers::DateHelper
12.
include ActionView::Helpers::TextHelper
13.
end
14.

15.
# then in any model or controller:
16.
require 'lib/helpers'
17.

18.
# to use:
19.
# help.name_of_helper
20.
# EX: help.pluralize 10, "person"

]]> Wed, 11 Mar 2009 16:13:01 GMT http://www.evernote.com/pub/cdunn/code#454e0a5d-0d06-4819-8d86-0e0ede502e38 HOWTO: Fix Aspect ratio of Divx,etc for DVD with ffmpeg http://www.evernote.com/pub/cdunn/code#b5e4a478-f484-4ec7-992c-8e90d21a11fa HOWTO: Fix Aspect ratio of Divx,etc for DVD with ffmpeg
I have created a simple bash script to calculate the aspect ratio when using ffmpeg for DivX->DVD-Video ready mpeg. So when watching the finished DVD on a stand alone DVDplayer, the image should not be squashed or squeezed.

Burning DVD Videos is described elsewhere.

The script calculates the correct amount of (top and bottom) padding required to maintain the AVi,etc Display Aspect Ratio. I exclusively use PAL so the resulting ratio will be 720X576. For NTSC (not tested) changing the variable dh=480 "should" work.

For details on the how the calculation is made go here

Copy the script to whatever name your want, chmod u+x script_name, to make it executable

First
Get the Display Aspect Ratio of the AVI,etc video file from the file properties, if for example AVI is 592x320,
usage: script_name 592 320
Some input error checking is included as well.
OUTPUT will be
#put the folowing into ffmpeg options assuming its a PAL dvd you want:
-target pal-dvd -s 720x554 -padtop 10 -padbottom 12

copy the above flags to the ffmpeg command line options, I would also use the flag -aspect 16:9 to be safe.
e.g.
ffmpeg -i <input_file.avi> -target pal-dvd -s 720x554 -padtop 10 -padbottom 12 -aspect 16:9 <output.mpg>

Code:

#!/bin/bash
#
# A script to correct the resolution of an AVI file and
# make a DVD without any stretching or squashing
#
if [ "$1" == help ]
then
echo "When encoding to a 16:9
Aspect MPEG (*see note below*)
Source Aspect NTSC/PAL CVD NTSC/PAL SVCD NTSC/PAL DVD
1.33 1.33 Not Applicable: See above table for 1.33 resolutions

1.78 *352x480 / *352x576 *480x480 / *480x576 352x480 / 352x576 704x480 / 704x576 720x480 / 720x576

1.85 *352x460 / *352x552 *480x460 / *480x552 352x460 / 352x552 704x460 / 704x552 720x460 / 720x552

2.20 *352x388 / *352x432 *480x388 / *480x464 352x388 / 352x464 704x388 / 704x464 720x388 / 720x464

2.35 *352x360 / *352x432 *480x360 / *480x432 352x360 / 352x432 704x360 / 704x432 720x360 / 720x432
See http://www.transcoding.org... ]]> Wed, 11 Mar 2009 06:08:39 GMT http://www.evernote.com/pub/cdunn/code#b5e4a478-f484-4ec7-992c-8e90d21a11fa HOWTO: Compiling the latest FFmpeg & x264 on CentOS 4 http://www.evernote.com/pub/cdunn/code#5395eb65-c557-4bef-9d87-d90b52d8c14d HOWTO: Compiling the latest FFmpeg & x264 on CentOS 4
Intoduction

FFmpeg is a superb video processing tool used to encode and transcode video files. In this particular project I needed to build “youtube” style video upload which would transcode into FLV, specifically catering for video files from the Nokia N95.

I spent quite a long time messing about with the stock version of ffmpeg on CentOS 4/Ubuntu trying to make it work, but it turned out not to be new enough/have all the right support compiled in.

This howto was written because I couldn’t find anything that fitted the bill for CentOS/RHEL (And being a Ubuntu man, found it a pain to get it compiled and working under CentOS). It’s based on the excellent tutorial by FakeOutdoorsman over on the Ubuntu forums. So big thanks to them.

These instructions have been tested on a fresh minimal install of CentOS 4.6 running in a VirtualBox VM.
Preparation

1. Ensure that you have the rpmforge repo’s added to yum. See here for instructions.
2. Update the install

yum update

3. (If you are not installing onto a fresh minimal install) Remove ffmpeg, x264 and faad2 to avoid confusion.

yum remove ffmpeg x264 faad2 faad2-devel

4. Install the necessary build tools

yum install gcc gcc-c++ automake autoconf libtool yasm git subversion

5. Install the necessary libraries

yum install zlib-devel libmad-devel libvorbis-devel libtheora-devel lame-devel faac-devel a52dec-devel xvidcore-devel freetype-devel

Compile supporting libraries

1. Compile & Install faad2 (for some reason I couldn’t get it to compile against the standard rpm version)

cd ~
wget http://downloads.sourceforge.net/faac/faad2-2.6.1.tar.gz
tar xzvf faad2-2.6.1.tar.gz
cd faad2
autoreconf -vif
./configure
make
make install

2. Compile & Install GPAC

cd ~
wget http://downloads.sourceforge.net/gpac/gpac-0.4.4.tar.gz
tar -xzvf gpac-0.4.4.tar.gz
cd gpac
./configure
make
make install
make install-lib

Note: if the compile... ]]> Wed, 11 Mar 2009 03:01:17 GMT http://www.evernote.com/pub/cdunn/code#5395eb65-c557-4bef-9d87-d90b52d8c14d error while loading shared libraries: libavdevice.so.52: cannot open shared object file: No such file or directory http://www.evernote.com/pub/cdunn/code#996d297e-a8cd-493b-be96-29e0c2026cf1 error while loading shared libraries: libavdevice.so.52: cannot open shared object file: No such file or directory

error while loading shared libraries: libavdevice.so.52: cannot open shared object file: No such file or directory

right, this error usually comes when ldconfig does not know where to search for the libraries, so, in order to help it out, on my fedora/centos systems, i did the following:

cd /etc/ld.so.conf.d

add another file: custom-libs.conf

inside, put :

/usr/local/lib

save,

then do ldconfig, et voila. ]]> Wed, 11 Mar 2009 02:59:28 GMT http://www.evernote.com/pub/cdunn/code#996d297e-a8cd-493b-be96-29e0c2026cf1 Building Ffmpeg from source -- partial working http://www.evernote.com/pub/cdunn/code#3384f052-90e5-4ec8-8d8a-b10b58ca5c04 Building Ffmpeg from source
Sooo...you've noticed that lovely rpm build of ffmpeg you've got doesn't include some key pieces, like h264 or aac encoding.

Here are some instructions on building ffmpeg from source. I used latest from subversion (on Sep 8, 06) and built on Fedora Core 5.

[1] Get ffmpeg source from svn:

svn checkout svn://svn.mplayerhq.hu/ffmpeg/trunk ffmpeg


[2a] Install faad
yum install faad2
yum install faad2-devel

[2b] Install faac and faac-devel rpms (yum may not help here)
try here: http://dries.ulyssis.org/rpm/packages

[3] Install lame
yum install lame
yum install lame-devel

[4] Install xvid
yum install libxvid
yum install xvidcore
yum install xvidcore-devel

[5] Install dc1394
yum install libdc1394
yum install libdc1394-devel

[5.5] Install vorbis
yum install libvorbis
yum install libvorbis-devel

[6] Build and install gpac multimedia library (needed by x264)
http://gpac.sourceforge.net/
download source,
configure --use-ffmpeg=no
make lib
make install-lib

[7] Build and install x264
svn co svn://svn.videolan.org/x264/trunk x264
./configure --enable-mp4-output --enable-shared
make
make install
cp /usr/local/lib/libx264.* /usr/lib

[8] Build ffmpeg
./configure --prefix=/usr --libdir=/usr/lib --mandir=/usr/share/man --enable-mp3lame --enable-faac
--enable-libogg --enable-vorbis --enable-faad --enable-xvid --enable-x264 --enable-a52
--enable-a52bin --enable-pp --enable-shared --enable-pthreads --enable-dc1394 --enable-gpl
--disable-strip
--extra-cflags="-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m32 -march=i386 -mtune=generic -fasynchronous-unwind-tables"

make
make install ]]> Wed, 11 Mar 2009 02:36:24 GMT http://www.evernote.com/pub/cdunn/code#3384f052-90e5-4ec8-8d8a-b10b58ca5c04 ffmpeg x264 http://www.evernote.com/pub/cdunn/code#7e9e5ed7-8f38-497f-8ede-f5bff6df9331
sudo port install x264
sudo port install ffmpeg +lame +libogg +vorbis +faac +faad +xvid +x264 +a52
sudo port install AtomicParsley

ffmpeg -i wolverine-tlra_h720p.mov -f mp4 -acodec libfaac -ab 128k -ac 1 -vcodec libx264 -b 768k -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -flags2 +mixed_refs -me umh -subq 5 -trellis 1 -refs 5 -coder 0 -me_range 16 -g 250 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -maxrate 768k -bufsize 2M -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 13 -s 320x240 -y test.m4v

ffmpeg -i wolverine-tlra_h720p.mov -f mp4 -acodec libfaac -ab 128k -ac 1 -vcodec libx264 -b 768k -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -flags2 +mixed_refs -me umh -subq 5 -trellis 1 -refs 5 -coder 0 -me_range 16 -g 250 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -maxrate 768k -bufsize 2M -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 13 -s 704x400 -y test.m4v

ffmpeg -i wolverine-tlra_h720p.mov -acodec libfaac -ab 128k -ar 44100 -s 704x400 -r 20 -vcodec libx264 -b 256000 -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -me_method umh -subq 5 -trellis 1 -refs 2 -bf 1 -coder 1 -me_range 16 -g 300 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -bt 256000 -maxrate 4M -bufsize 4M -rc_eq 'blurCplx^(1-qComp)' -qcomp 0.6 -qmin 10 -qmax 51 -qdiff 4 -level 21 test.mp4

ffmpeg -y -i wolverine-tlra_h720p.mov -acodec libfaac -ar 44100 -ab 96k -vcodec libx264 -level 41 -crf 20 -bufsize 20000k -maxrate 25000k -g 250 -r 20 -s 1280x544 -coder 1 -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -me_method umh -subq 7 -me_range 16 -keyint_min 25 -sc_threshold 40 -i_qfactor 0.71 -rc_eq 'blurCplx^(1-qComp)' -bf 16 -b_strategy 1 -bidir_refine 1 -refs 6 -deblockalpha 0 -deblockbeta 0 output.mp4

ffmpeg -i wolverine-tlra_h720p.mov -an -pass 1 -vcodec libx264 -b 768k -flags +loop -cmp +chroma -partitions +parti4x4+partp8x8+partb8x8 -me_method dia -subq 1 -trellis 0 -refs 1 -bf 16 -b_strategy 1 -coder 1 -me_range 16 -g 250 -keyint...
]]> Wed, 11 Mar 2009 01:52:20 GMT http://www.evernote.com/pub/cdunn/code#7e9e5ed7-8f38-497f-8ede-f5bff6df9331 Untitled Clipped Note http://www.evernote.com/pub/cdunn/code#44a0400b-08be-494c-810f-a137c69c3376 yum install faac faac-devel faad2 faad2-devel a52dec a52dec-devel lame lame-devel libdca libdca-devel x264 x264-devel libogg libogg-devel libvorbis libvorbis-devel libtheora libtheora-devel xvidcore xvidcore-devel ]]> Wed, 11 Mar 2009 01:20:29 GMT http://www.evernote.com/pub/cdunn/code#44a0400b-08be-494c-810f-a137c69c3376