Class: RelaxDB::Paginator

Inherits:
Object
  • Object
show all
Defined in:
lib/relaxdb/paginator.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(paginate_params, page_params) ⇒ Paginator

Returns a new instance of Paginator.



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# File 'lib/relaxdb/paginator.rb', line 7

def initialize(paginate_params, page_params)
  @paginate_params = paginate_params
  @orig_paginate_params = @paginate_params.clone
  
  @page_params = page_params.is_a?(String) ? JSON.parse(page_params).to_mash : page_params
  # Where the magic happens - the original params are updated with the page specific params
  @paginate_params.update(@page_params)
end

Instance Attribute Details

#paginate_params ⇒ Object (readonly)

Returns the value of attribute paginate_params.



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# File 'lib/relaxdb/paginator.rb', line 5

def paginate_params
  @paginate_params
end

Instance Method Details

#add_next_and_prev(docs, view_name, view_keys) ⇒ Object

view_keys are used to determine the params for the prev and next links. If a view_key is a symbol the key value will be the result of invoking the method named by the symbol on the first / last element in the result set. If a view_key is not a symbol, its value will be used directly.



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# File 'lib/relaxdb/paginator.rb', line 40

def add_next_and_prev(docs, view_name, view_keys)
  unless docs.empty?
    no_docs = docs.size
    offset = docs.offset
    orig_offset = orig_offset(view_name)
    total_doc_count = total_doc_count(view_name)      
  
    next_exists = !@paginate_params.order_inverted? ? (offset - orig_offset + no_docs < total_doc_count) : true
    next_params = next_exists ? create_next(docs.last, view_keys) : false

    prev_exists = @paginate_params.order_inverted? ? (offset - orig_offset + no_docs < total_doc_count) : 
      (offset - orig_offset == 0 ? false : true)
    prev_params = prev_exists ? create_prev(docs.first, view_keys) : false
  else
    next_exists = prev_exists = false
  end
  
  add_next_and_prev_meths docs, next_params, prev_params      
end

#add_next_and_prev_meths(docs, next_params, prev_params) ⇒ Object 



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# File 'lib/relaxdb/paginator.rb', line 94

def add_next_and_prev_meths docs, next_params, prev_params
  docs.meta_class.instance_eval do        
    define_method(:next_params) { next_params }
    define_method(:next_query) { next_params ? "page_params=#{::CGI::escape(next_params.to_json)}" : false }
  
    define_method(:prev_params) { prev_params }
    define_method(:prev_query) { prev_params ? "page_params=#{::CGI::escape(prev_params.to_json)}" : false }
  end      
end

#add_q_next_and_prev(docs, view_name, view_keys) ⇒ Object 



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# File 'lib/relaxdb/paginator.rb', line 16

def add_q_next_and_prev docs, view_name, view_keys    
  if docs.empty?        
    next_exists = prev_exists = false
  else
    next_exists = docs.size >= @paginate_params.limit
    next_params = next_exists ? create_next(docs.last, view_keys) : false
  
    prev_exists = !@page_params.empty?
    prev_params = prev_exists ? create_prev(docs.first, view_keys) : false        
  end
        
  add_next_and_prev_meths docs, next_params, prev_params
end

#create_next(doc, view_keys) ⇒ Object 



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# File 'lib/relaxdb/paginator.rb', line 60

def create_next(doc, view_keys)
  next_key = view_keys_to_vals doc, view_keys
  next_key = next_key.length == 1 ? next_key[0] : next_key
  next_key_docid = doc._id
  { :startkey => next_key, :startkey_docid => next_key_docid, :descending => @orig_paginate_params.descending }
end

#create_prev(doc, view_keys) ⇒ Object 



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# File 'lib/relaxdb/paginator.rb', line 67

def create_prev(doc, view_keys)
  prev_key = view_keys_to_vals doc, view_keys
  prev_key = prev_key.length == 1 ? prev_key[0] : prev_key
  prev_key_docid = doc._id
  prev_params = { :startkey => prev_key, :startkey_docid => prev_key_docid, :descending => !@orig_paginate_params.descending }
end

#orig_offset(view_name) ⇒ Object 



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# File 'lib/relaxdb/paginator.rb', line 83

def orig_offset(view_name)
  if @paginate_params.order_inverted?
    params = {:startkey => @orig_paginate_params.endkey, :descending => !@orig_paginate_params.descending}
  else
    params = {:startkey => @orig_paginate_params.startkey, :descending => @orig_paginate_params.descending}
  end
  params[:limit] = 1
        
  RelaxDB.rf_view(view_name, params).offset
end

#total_doc_count(view_name) ⇒ Object 



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# File 'lib/relaxdb/paginator.rb', line 30

def total_doc_count(view_name)
  RelaxDB.view view_name, :startkey => @orig_paginate_params.startkey, :endkey => @orig_paginate_params.endkey,
    :descending => @orig_paginate_params.descending, :reduce => true
end

#view_keys_to_vals(doc, view_keys) ⇒ Object 



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# File 'lib/relaxdb/paginator.rb', line 74

def view_keys_to_vals doc, view_keys
  view_keys.map do |k|
    if k.is_a?(Symbol) then doc.send(k)
    elsif k.is_a?(Proc) then k.call(doc)
    else k
    end
  end
end