152 lines
6.1 KiB
Ruby
152 lines
6.1 KiB
Ruby
module CouchRest
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module Model
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module Views
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extend ActiveSupport::Concern
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module ClassMethods
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# Define a CouchDB view. The name of the view will be the concatenation
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# of <tt>by</tt> and the keys joined by <tt>_and_</tt>
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#
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# ==== Example views:
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#
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# class Post
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# # view with default options
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# # query with Post.by_date
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# view_by :date, :descending => true
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#
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# # view with compound sort-keys
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# # query with Post.by_user_id_and_date
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# view_by :user_id, :date
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#
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# # view with custom map/reduce functions
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# # query with Post.by_tags :reduce => true
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# view_by :tags,
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# :map =>
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# "function(doc) {
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# if (doc['model'] == 'Post' && doc.tags) {
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# doc.tags.forEach(function(tag){
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# emit(doc.tag, 1);
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# });
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# }
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# }",
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# :reduce =>
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# "function(keys, values, rereduce) {
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# return sum(values);
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# }"
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# end
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#
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# <tt>view_by :date</tt> will create a view defined by this Javascript
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# function:
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#
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# function(doc) {
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# if (doc['model'] == 'Post' && doc.date) {
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# emit(doc.date, null);
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# }
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# }
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#
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# It can be queried by calling <tt>Post.by_date</tt> which accepts all
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# valid options for CouchRest::Database#view. In addition, calling with
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# the <tt>:raw => true</tt> option will return the view rows
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# themselves. By default <tt>Post.by_date</tt> will return the
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# documents included in the generated view.
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#
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# Calling with :database => [instance of CouchRest::Database] will
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# send the query to a specific database, otherwise it will go to
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# the model's default database (use_database)
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#
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# CouchRest::Database#view options can be applied at view definition
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# time as defaults, and they will be curried and used at view query
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# time. Or they can be overridden at query time.
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#
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# Custom views can be queried with <tt>:reduce => true</tt> to return
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# reduce results. The default for custom views is to query with
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# <tt>:reduce => false</tt>.
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#
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# Views are generated (on a per-model basis) lazily on first-access.
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# This means that if you are deploying changes to a view, the views for
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# that model won't be available until generation is complete. This can
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# take some time with large databases. Strategies are in the works.
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#
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# To understand the capabilities of this view system more completely,
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# it is recommended that you read the RSpec file at
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# <tt>spec/couchrest/more/extended_doc_spec.rb</tt>.
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def view_by(*keys)
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return unless auto_update_design_doc
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opts = keys.pop if keys.last.is_a?(Hash)
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opts ||= {}
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ducktype = opts.delete(:ducktype)
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unless ducktype || opts[:map]
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opts[:guards] ||= []
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opts[:guards].push "(doc['#{model_type_key}'] == '#{self.to_s}')"
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end
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keys.push opts
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design_doc.view_by(*keys)
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end
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# returns stored defaults if there is a view named this in the design doc
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def has_view?(name)
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design_doc && design_doc.has_view?(name)
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end
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# Check if the view can be reduced by checking to see if it has a
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# reduce function.
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def can_reduce_view?(name)
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design_doc && design_doc.can_reduce_view?(name)
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end
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# Dispatches to any named view.
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def view(name, query={}, &block)
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query = query.dup # Modifications made on copy!
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db = query.delete(:database) || database
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query[:raw] = true if query[:reduce]
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raw = query.delete(:raw)
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save_design_doc(db)
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fetch_view_with_docs(db, name, query, raw, &block)
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end
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# Find the first entry in the view. If the second parameter is a string
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# it will be used as the key for the request, for example:
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#
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# Course.first_from_view('by_teacher', 'Fred')
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#
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# More advanced requests can be performed by providing a hash:
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#
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# Course.first_from_view('by_teacher', :startkey => 'bbb', :endkey => 'eee')
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#
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def first_from_view(name, *args)
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query = {:limit => 1}
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case args.first
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when String, Array
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query.update(args[1]) unless args[1].nil?
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query[:key] = args.first
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when Hash
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query.update(args.first)
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end
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view(name, query).first
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end
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private
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def fetch_view_with_docs(db, name, opts, raw=false, &block)
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if raw || (opts.has_key?(:include_docs) && opts[:include_docs] == false)
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fetch_view(db, name, opts, &block)
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else
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opts = opts.merge(:include_docs => true)
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view = fetch_view db, name, opts, &block
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view['rows'].collect{|r| build_from_database(r['doc'])} if view['rows']
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end
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end
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def fetch_view(db, view_name, opts, &block)
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raise "A view needs a database to operate on (specify :database option, or use_database in the #{self.class} class)" unless db
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design_doc.view_on(db, view_name, opts, &block)
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end
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end # module ClassMethods
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end
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end
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end
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