Ruby on Rails problems & solutions - Dec 6, 2010


December 8, 2010

Git delete last commit.  Enough said.

http://nakkaya.com/2009/09/24/git-delete-last-commit/

Getting Roo working under Rails 3

Something of a challenge, actually.  The gem doesn’t list it’s dependencies properly, so we have to “guess”.  This got me started:

http://www.eggheadcafe.com/software/aspnet/35719402/using-roo-to-avoid-need-f…

From the comments, use rubyzip2, instead of  febeling-rubyzip. Bundler should pick up the rest of the gems not identified by this post. <Grumble, growl, SNAP>

Using Roo

http://rubyonwindows.blogspot.com/2008/01/parsing-spreadsheets-with-roo-gem.html

No, no, never mind.  Don’t use Roo

2 minutes?!?! just to open the file?!?!? I can use rubyzip2 and nokogiri to

  1. Open the xlsm file (zipped archive)

  2. Pull out the xl/worksheet.xml file

  3. Search for the definitions for the 3 values I want to read

  4. Parse out the sheet locations for those defined values

  5. Open those sheets and read the required values

Ok, so you need to learn the Zip::ZipFileSystem API (actually, very simple).  And then you need to use Nokogiri, and some selectors (if XPath doesn’t turn your crank, then use the CSS selector).  Considerably less than 2 minutes, and I don’t have to bundle Spreadsheet gem, which has one of the stupidest licenses on earth.

require ‘zip/zipfilesystem’

require ‘nokogiri’ zip = Zip::ZipFile.open(“some_excel_file.xlsm”)

workbook = Nokogiri::XML(zip.read(‘xl/workbook.xml’))

location = workbook.css(‘definedNames definedName[@name = “intLPGTotal”]’).last.child.content

I think you can see where I am going here.  Roo is undoubtly a great tool, but in my case, it was a sledgehammer, and I needed tweezers.

(Apologies.  This was a grumpy sort of day)


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