Hi Everyone,
I just need some further help clarifying a custom rake task I’m building
and the logistics of how it should be working.
I’ve created a custom rake task in libs/tasks called scraper.rake which
so far just contains the following:
desc “This task will parse data from ncaa.org and upload the data to our
db”
task :scraper => :environment do
code goes here for scraping
end
This rake task will be parsing data from ncaa.org and placing it into my
DB for further processing. The .rb file I created has the following:
===============================
#== Scraper Version 1.0
#Created By: Elricstorm
_Special thanks to Soledad Penades for his initial parse idea which I
worked with to create the Scraper program.
His article is located at
http://www.iterasi.net/openviewer.aspx?sqrlitid=wd5wiad-hkgk93aw8zidbw_
require ‘hpricot’
require ‘open-uri’
This class is used to parse and collect data out of an html element
class Scraper
attr_accessor :url, :element_type, :clsname, :childsearch, :doc,
:numrows
Define what the url is, what element type and class name we want to
parse and open the url.
def initialize(url, element_type, clsname, childsearch)
@url = url
@element_type = element_type
@clsname = clsname
@childsearch = childsearch
@doc = Hpricot(open(url))
@numrows = numrows
end
Scrape data based on the type of element, its class name, and define
the child element that contains our data
def scrape_data
@rows = []
(doc/"#{@element_type}.#{@clsname}#{@childsearch}").each do |row|
cells = []
(row/"td").each do |cell|
if (cell/" span.s").length > 0
values = (cell/"span.s").inner_html.split('<br
/>‘).collect{ |str|
pair = str.strip.split(’=').collect{|val| val.strip}
Hash[pair[0], pair[1]]
}
if(values.length==1)
cells << cell.inner_text.strip
else
cells << values.strip
end
elsif
cells << cell.inner_text.strip
end
end
@rows << cells
end
@rows.shift # Shifting removes the row containing the <th> table
header elements.
@rows.delete([]) # Remove any empty rows in our array of arrays.
@numrows = @rows.length
end
def clean_celldata
@rows[@numrows-1][0] = 120
end
Print a joined list by row to see our results
def print_values
puts “Number of rows = #{numrows}.”
for i in 0…@numrows-1
puts @rows[i].join(', ')
end
end
end
In our search we are supplying the website url to parse, the type of
element (ex: table), the class name of that element
and the child element that contains the data we wish to retrieve.
offensive_rushing =
Scraper.new(‘http://web1.ncaa.org/mfb/natlRank.jsp?year=2008&rpt=IA_teamrush&site=org’,
‘table’, ‘statstable’, ‘//tr’)
offensive_rushing.scrape_data
offensive_rushing.clean_celldata
offensive_rushing.print_values
================================
If you tested that out, you will see a print out of 120 rows of data…
What I want to do is to utilize the .rb file I created with my rake
task. However, I’m not sure how to incorporate that into rails. Once I
get past this hurdle it should help with future issues.
So, here are my list of questions in order of what I am curious to
know…
-
Where do custom .rb files go inside of my rails project? (for
instance I understand the MVC but with a rake task - in my brain it’s
outside of the project and I’m not sure how it is supposed to
communicate with controllers or pull/associate variables from those
areas. -
With my custom .rb I’m also requiring ‘hpricot’. Is there anything
special I need to do with a .rake file to make sure that it knows to
pull this gem? And, if I export to my real site, how do I ensure that
hpricot is loaded there too? In otherwords, what expectations should I
be relying on? -
When I run a rake task and need to communicate with my database (for
uploading purposes) is there an easy way to do this? Can I utilize
.rake with my DB inside of my rails environment? Or, are rake tasks
completely seperate and distinct and need to be considered outside of
scope? -
Can anyone provide me a summarized step by step (nothing too fancy
or that takes up too much of your own time) with how “you” would
accomplish this kind of rake task given a similar .rb and .rake file?
What generalized steps would you take? Create a class? (if so, where
would you place it) How would you communicate with the DB within rails?
etc.
I know these are a lot of questions but I figure even if one or two of
them get answered, I’m happy. You don’t have to feel that you can’t
reply if you don’t have the answers to all of them. Any answers that
can be touched upon would be greatly appreciated.
I am a newbie and learning rails (but many books do not talk about these
particulars). So, I’m relying on others that have patience and
understanding to help enlighten me so that one day I too, can help
others that need similar help.
Thanks.