Class: XapianDb::Resultset

Inherits:
Array
  • Object
show all
Includes:
Utilities
Defined in:
lib/xapian_db/resultset.rb

Overview

The resultset encapsulates a Xapian::Query object and allows paged access to the found documents. The resultset is compatible with will_paginate and kaminari.

Examples:

Process the first page of a resultsest

resultset.paginate(:page => 1, :per_page => 10).each do |doc|
  # do something with the xapian document
end

Use the resultset and will_paginate in a view

<%= will_paginate resultset %>

Use the resultset and kaminari in a view

<%= paginate resultset %>

Author:

  • Gernot Kogler

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Utilities

#assert_valid_keys, #camelize, #constantize

Constructor Details

#initialize(enquiry, options = {}) ⇒ Resultset

Constructor

Parameters:

Options Hash (options):

  • :db_size (Integer) —

    The current size (nr of docs) of the database

  • :limit (Integer) —

    The maximum number of documents to retrieve

  • :offset (Integer) —

    The index of the first result to retrieve

  • :page (Integer) — default: 1 —

    The page number to retrieve

  • :per_page (Integer) — default: 10 —

    How many docs per page? Ignored if a limit option is given

  • :spelling_suggestion (String) — default: nil —

    The spelling corrected query (if a language is configured)



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# File 'lib/xapian_db/resultset.rb', line 53

def initialize(enquiry, options={})

  return build_empty_resultset if enquiry.nil?
  params               = options.dup
  db_size              = params.delete :db_size
  @spelling_suggestion = params.delete :spelling_suggestion
  limit                = params.delete :limit
  offset               = params.delete :offset
  page                 = params.delete :page
  per_page             = params.delete :per_page
  raise ArgumentError.new "unsupported options for resultset: #{params}" if params.size > 0
  raise ArgumentError.new "db_size option is required" unless db_size

  unless (page.nil? && per_page.nil?) || (limit.nil? && offset.nil?)
    raise ArgumentError.new "Impossible combination of parameters. Either pass page and/or per_page, or limit and/or offset."
  end

  calculated_page = offset.nil? || limit.nil? ? nil : (offset.to_f / limit.to_f) + 1

  limit    = limit.nil? ? db_size : limit.to_i
  per_page = per_page.nil? ? limit.to_i : per_page.to_i
  page     = page.nil? ? (calculated_page.nil? ? 1 : calculated_page) : page.to_i
  offset   = offset.nil? ? (page - 1) * per_page : offset.to_i
  count    = per_page < limit ? per_page : limit

  return build_empty_resultset if (page - 1) * per_page > db_size
  result_window = enquiry.mset(offset, count)
  @hits = result_window.matches_estimated
  return build_empty_resultset if @hits == 0

  self.replace result_window.matches.map{|match| decorate(match).document}
  @total_pages  = (@hits / per_page.to_f).ceil
  @current_page = (page == page.to_i) ? page.to_i : page
  @limit_value  = per_page
end

Instance Attribute Details

#current_page ⇒ Integer (readonly)

The current page

Returns:

  • (Integer) 


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# File 'lib/xapian_db/resultset.rb', line 34

def current_page
  @current_page
end

#hits ⇒ Integer (readonly) Also known as: total_count, total_entries

The number of hits

Returns:

  • (Integer) 


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# File 'lib/xapian_db/resultset.rb', line 23

def hits
  @hits
end

#limit_value ⇒ Object (readonly)

The number of records per page



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# File 'lib/xapian_db/resultset.rb', line 41

def limit_value
  @limit_value
end

#spelling_suggestion ⇒ String

The spelling corrected query (if a language is configured)

Returns:

  • (String) 


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# File 'lib/xapian_db/resultset.rb', line 38

def spelling_suggestion
  @spelling_suggestion
end

#total_pages ⇒ Integer (readonly) Also known as: num_pages

The number of pages

Returns:

  • (Integer) 


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# File 'lib/xapian_db/resultset.rb', line 29

def total_pages
  @total_pages
end

Instance Method Details

#build_empty_resultset ⇒ Object

Build an empty resultset



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# File 'lib/xapian_db/resultset.rb', line 102

def build_empty_resultset
  @hits         = 0
  @total_pages  = 0
  @current_page = 0
  @limit_value  = 0
  self
end

#decorate(match) ⇒ Xapian::Match

Decorate a Xapian match with field accessors for each configured attribute

Parameters:

  • a (Xapian::Match) —

    match

Returns:

  • (Xapian::Match) —

    the decorated match



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# File 'lib/xapian_db/resultset.rb', line 113

def decorate(match)
  klass_name = match.document.values[0].value
  blueprint  = XapianDb::DocumentBlueprint.blueprint_for klass_name
  match.document.extend blueprint.accessors_module
  match.document.instance_variable_set :@score, match.percent
  match
end

#next_page ⇒ Integer

The next page number

Returns:

  • (Integer) —

    The number of the next page or nil, if we are at the last page



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# File 'lib/xapian_db/resultset.rb', line 97

def next_page
  @current_page < @total_pages ? (@current_page + 1): nil
end

#previous_page ⇒ Integer

The previous page number

Returns:

  • (Integer) —

    The number of the previous page or nil, if we are at page 1



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# File 'lib/xapian_db/resultset.rb', line 91

def previous_page
  @current_page > 1 ? (@current_page - 1) : nil
end