Fetching now working via DelayedJob

app/controllers/book_controller.rb

@@ -21,7 +21,11 @@ def view
       @bookseer = BookseerInfo::link(@bookinfo)
     end
 
-    @stores = Rails.cache.fetch("prices:#{@isbn}", :expires_in => 1.day) { Bookprice::prices(@isbn) }
+    @prices = Bookprice.new(:isbn => @isbn)
+    @stores = Rails.cache.read(@prices.cache_key)
+    if @stores.nil?
+      Delayed::Job.enqueue(@prices)
+    end
     @not_available = Bookprice::NOT_AVAILABLE
 
     respond_with(@stores) do |format|

app/models/bookprice.rb

@@ -6,6 +6,27 @@ class Bookprice
 
   NOT_AVAILABLE = 999_999
 
+  attr_accessor :isbn
+
+  def initialize(given_isbn)
+    self.isbn = self.class.check_isbn(given_isbn)
+  end
+
+  # For usage with DelayedJob : Bookprice.new(:isbn => "9789380032825").perform
+  def perform
+    prices = self.class.prices(self.isbn)
+    Rails.cache.write(self.cache_key, prices)
+    prices
+  end
+
+  def cache_key
+    "prices:#{self.isbn}"
+  end
+
+  def number_of_stores
+    self.class.searches.size
+  end
+
   class << self
 
     def find_price_at_end(text)
@@ -33,16 +54,22 @@ def is_isbn(text)
     def searches
       # e.g. ["search_a1books", "search_infibeam", "search_rediff"]
       functions = self.methods.select { |name| name =~ /^search_(\w+)$/ }.sort
-      # e.g. [["a1books", search_a1books], ["infibeam", search_infibeam], ["rediff", search_rediff]]
+      # e.g. [[:a1books, search_a1books], [:infibeam, search_infibeam], [:rediff, search_rediff]]
       functions.collect { |fname| [ fname.split("_")[1].to_sym, self.method(fname) ] }
     end
 
     def names
       self.searches.map { |name, search| name.to_s }.sort.map(&:to_sym)
     end
 
+    def check_isbn(isbn)
+      isbn = isbn[:isbn] if isbn.is_a?(Hash)
+      raise ArgumentError, "Invalid ISBN: #{isbn}" unless !isbn.nil? && isbn.is_a?(String) && is_isbn(isbn)
+      isbn
+    end
+
     def prices(isbn)
-      raise "Invalid ISBN : #{isbn}" unless is_isbn(isbn)
+      isbn = check_isbn(isbn)
       self.searches.map { |name, search| [name, search.call(isbn)] }.sort_by { |p| p[1][:price] }
     end
 

app/views/book/view.html.erb

@@ -29,26 +29,37 @@
   <% end %>
 <% end %>
 
-<h2>Where to Buy</h2>
-<div class="stores">
-  <p>(Sorted by price)</p>
-  <table>
-    <% @stores.each do |store, data| %>
-      <tr>
-        <td>
-          <a href="<%= data[:url] %>"><%= store %></a>
-        </td>
-        <td>
-          <% unless data[:price] == @not_available %>
-            <span style="font-family:rupee">R</span> <%= data[:price] %>
-          <% else %>
-            not available
-          <% end %>
-        </td>
-      </tr>
-    <% end %>
-  </table>
-</div>
+<% unless @stores.nil? %>
+  <h2>Where to Buy</h2>
+  <div class="stores">
+    <p>(Sorted by price)</p>
+    <table>
+      <% @stores.each do |store, data| %>
+        <tr>
+          <td>
+            <a rel="nofollow" href="<%= data[:url] %>"><%= store %></a>
+          </td>
+          <td>
+            <% unless data[:price] == @not_available %>
+              <span style="font-family:rupee">R</span> <%= data[:price] %>
+            <% else %>
+              not available
+            <% end %>
+          </td>
+        </tr>
+      <% end %>
+    </table>
+  </div>
+<% else %>
+  <p>
+  <em>Fetching prices from <%= @prices.number_of_stores %> online stores... please be patient!</em> (This page will be automatically refreshed, please do NOT manually refresh)
+  </p>
+  <% content_for :js do %>
+    $( function() {
+      setTimeout("location.reload(true)", 60 * 1000);
+    });
+  <% end %>
+<% end %>
 
 <h2>Reviews</h2>
 <div class="goodreads">
@@ -57,5 +68,5 @@
 
 <h2>What to read next?</h2>
 <% unless @bookseer.nil? %>
-  <a href="<%= @bookseer %>">Consult the Bookseer</a>
+  <a rel="nofollow" href="<%= @bookseer %>">Consult the Bookseer</a>
 <% end %>

script/delayed_job

@@ -0,0 +1,5 @@
+#!/usr/bin/env ruby
+
+require File.expand_path(File.join(File.dirname(__FILE__), '..', 'config', 'environment'))
+require 'delayed/command'
+Delayed::Command.new(ARGV).daemonize