Class: Amazon::Hacks::Link

Inherits:
Object
  • Object
show all
Includes:
Countries
Defined in:
lib/amazon-hacks.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Countries

#country_host, #country_imgcode, #country_imghost

Constructor Details

#initialize(url = nil, country = nil, asin = nil) ⇒ Link

Returns a new instance of Link.



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# File 'lib/amazon-hacks.rb', line 59

def initialize(url=nil, country=nil, asin=nil)
  if url.nil?
    @url = @country = @asin = nil
  else
    @url = URI.parse(url)
    @country = country ? country : Amazon::Hacks::Link.extract_country(url)
    @asin = asin ? asin : Amazon::Hacks::Link.extract_asin(url)
  end
end

Instance Attribute Details

#asin ⇒ Object (readonly)

Returns the value of attribute asin.



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# File 'lib/amazon-hacks.rb', line 57

def asin
  @asin
end

#country ⇒ Object (readonly)

Returns the value of attribute country.



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# File 'lib/amazon-hacks.rb', line 57

def country
  @country
end

Class Method Details

.extract_asin(url) ⇒ Object

Extracts the Amazon Standard Identification Number (ASIN) from a string url. Each product on an Amazon store has a unique ASIN used to identify it. As Amazon’s help documents describe it:

“For books, the ASIN is the same as the ISBN number, but for all other products a new ASIN is created when the item is uploaded to our catalog”

ASIN values are specific to the store they’re applied to and can not be used against another store nor are they guaranteed to be globally unique. Put another way, the ASIN for the US edition of a book will not return the UK edition when used with the UK store and might return nothing or something completely different. Also, ASINs are alphanumeric strings, not numbers.

Amazon has used several different major URL formats interchangeably and this function extracts the ASIN from the following URL paths:

/o/asin/<ASIN VALUE>

/exec/obidos/ASIN/<ASIN VALUE>

/exec/obidos/tg/detail/-/<ASIN VALUE>

/long-title-goes-here/dp/<ASIN VALUE>

This is only an informally gathered list. If you find a case where extract_asin fails, please send me the URL. If the ASIN is not matched, returns nil



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# File 'lib/amazon-hacks.rb', line 127

def Link.extract_asin(url)  
  u = URI.parse(url)
  asin = nil

  asin_regexps = [ /^\/o\/asin\/([^\/]+)/, 
    /^\/exec\/obidos\/ASIN\/([^\/]+)/, 
    /^\/exec\/obidos\/tg\/detail\/-\/([^\/]+)/, 
    /^\/[^\/]+\/dp\/([^\/]+)/ 
  ]
  
  asin_regexps.each do |re|
    md = re.match(u.path)
    if md
    then
      asin = md[1]
      break
    end
  end
  
  asin
end

.extract_country(url) ⇒ Object

This method analyzes the url string and returns a symbol representing the country (eg, :us). If the host is not recognized, returns nil



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# File 'lib/amazon-hacks.rb', line 152

def Link.extract_country(url)
  u = URI.parse(url)
  c = COUNTRIES.find { |key, value| value.host == u.host }
  c[0] unless c.nil? #.country unless c.nil? 
end

Instance Method Details

#associate_url(assoc_id) ⇒ Object

Returns a normalized URL for the product with an Amazon Associate ID appended to it.



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# File 'lib/amazon-hacks.rb', line 161

def associate_url(assoc_id)
 normalize + "/#{assoc_id}"
end

#normalize ⇒ Object

Returns a normalized form of the Link’s URL. This is the shortest valid URL that links to the product on Amazon

For example, the normalized form of a URL like:

www.amazon.com/Refactoring-Improving-Design-Existing-Code/dp/0201485672/sr=8-1/qid=1165273301/ref=pd_bbs_sr_1/002-2410048-1716806?ie=UTF8&s=books

would be:

www.amazon.com/o/asin/0201485672

Since it removes the session and other variables from the URL, normalization is very useful for comparing two Amazon links directly. The Link== method does NOT normalize, but you might want to consider that if you need it.



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# File 'lib/amazon-hacks.rb', line 94

def normalize
  "http://#{country_host}/o/asin/#{asin}"
end

#normalize! ⇒ Object

Like #normalize, but changes the internal url



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# File 'lib/amazon-hacks.rb', line 167

def normalize!
  u = normalize
  @url = URI.parse(u)
  self
end

#url ⇒ Object Also known as: to_s

Returns the saved URL



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# File 'lib/amazon-hacks.rb', line 175

def url
  @url.to_s
end

#url=(url) ⇒ Object

Sets the internal url of the link to be url. Also parses the values of the asin and country from the URL



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# File 'lib/amazon-hacks.rb', line 72

def url=(url)
  @url = URI.parse(url)
  @country = Amazon::Hacks::Link.extract_country(url)
  @asin = Amazon::Hacks::Link.extract_asin(url)
end