Module: CouchRest::Mixins::Views::ClassMethods

Defined in:
lib/couchrest/mixins/views.rb

Instance Method Summary collapse

Instance Method Details

#all_design_doc_versions ⇒ Object 



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# File 'lib/couchrest/mixins/views.rb', line 107

def all_design_doc_versions
  database.documents :startkey => "_design/#{self.to_s}-", 
    :endkey => "_design/#{self.to_s}-\u9999"
end

#cleanup_design_docs! ⇒ Object

Deletes any non-current design docs that were created by this class. Running this when you’re deployed version of your application is steadily and consistently using the latest code, is the way to clear out old design docs. Running it to early could mean that live code has to regenerate potentially large indexes.



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# File 'lib/couchrest/mixins/views.rb', line 117

def cleanup_design_docs!
  ddocs = all_design_doc_versions
  ddocs["rows"].each do |row|
    if (row['id'] != design_doc_id)
      database.delete_doc({
        "_id" => row['id'],
        "_rev" => row['value']['rev']
      })
    end
  end
end

#has_view?(view) ⇒ Boolean

returns stored defaults if the there is a view named this in the design doc

Returns:

  • (Boolean) 


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# File 'lib/couchrest/mixins/views.rb', line 92

def has_view?(view)
  view = view.to_s
  design_doc && design_doc['views'] && design_doc['views'][view]
end

#view(name, query = {}, &block) ⇒ Object

Dispatches to any named view.



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# File 'lib/couchrest/mixins/views.rb', line 98

def view(name, query={}, &block)
  unless design_doc_fresh
    refresh_design_doc
  end
  query[:raw] = true if query[:reduce]        
  raw = query.delete(:raw)
  fetch_view_with_docs(name, query, raw, &block)
end

#view_by(*keys) ⇒ Object

Define a CouchDB view. The name of the view will be the concatenation of by and the keys joined by and

Example views:

class Post
  # view with default options
  # query with Post.by_date
  view_by :date, :descending => true

  # view with compound sort-keys
  # query with Post.by_user_id_and_date
  view_by :user_id, :date

  # view with custom map/reduce functions
  # query with Post.by_tags :reduce => true
  view_by :tags,                                                
    :map =>                                                     
      "function(doc) {                                          
        if (doc['couchrest-type'] == 'Post' && doc.tags) {                   
          doc.tags.forEach(function(tag){                       
            emit(doc.tag, 1);                                   
          });                                                   
        }                                                       
      }",                                                       
    :reduce =>                                                  
      "function(keys, values, rereduce) {                       
        return sum(values);                                     
      }"                                                        
end

view_by :date will create a view defined by this Javascript function:

function(doc) {
  if (doc['couchrest-type'] == 'Post' && doc.date) {
    emit(doc.date, null);
  }
}

It can be queried by calling Post.by_date which accepts all valid options for CouchRest::Database#view. In addition, calling with the :raw => true option will return the view rows themselves. By default Post.by_date will return the documents included in the generated view.

CouchRest::Database#view options can be applied at view definition time as defaults, and they will be curried and used at view query time. Or they can be overridden at query time.

Custom views can be queried with :reduce => true to return reduce results. The default for custom views is to query with :reduce => false.

Views are generated (on a per-model basis) lazily on first-access. This means that if you are deploying changes to a view, the views for that model won’t be available until generation is complete. This can take some time with large databases. Strategies are in the works.

To understand the capabilities of this view system more compeletly, it is recommended that you read the RSpec file at spec/core/model_spec.rb.



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# File 'lib/couchrest/mixins/views.rb', line 77

def view_by(*keys)
  self.design_doc ||= Design.new(default_design_doc)
  opts = keys.pop if keys.last.is_a?(Hash)
  opts ||= {}
  ducktype = opts.delete(:ducktype)
  unless ducktype || opts[:map]
    opts[:guards] ||= []
    opts[:guards].push "(doc['couchrest-type'] == '#{self.to_s}')"
  end
  keys.push opts
  self.design_doc.view_by(*keys)
  self.design_doc_fresh = false
end