Module: CouchRest::Model::Views::ClassMethods
- Defined in:
- lib/couchrest/model/views.rb
Instance Method Summary collapse
-
#first_from_view(name, *args) ⇒ Object
Find the first entry in the view.
-
#has_view?(view) ⇒ Boolean
returns stored defaults if there is a view named this in the design doc.
-
#view(name, query = {}, &block) ⇒ Object
Dispatches to any named view.
-
#view_by(*keys) ⇒ Object
Define a CouchDB view.
Instance Method Details
#first_from_view(name, *args) ⇒ Object
Find the first entry in the view. If the second parameter is a string it will be used as the key for the request, for example:
Course.first_from_view('by_teacher', 'Fred')
More advanced requests can be performed by providing a hash:
Course.first_from_view('by_teacher', :startkey => 'bbb', :endkey => 'eee')
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# File 'lib/couchrest/model/views.rb', line 112 def first_from_view(name, *args) query = {:limit => 1} case args.first when String, Array query.update(args[1]) unless args[1].nil? query[:key] = args.first when Hash query.update(args.first) end view(name, query).first end |
#has_view?(view) ⇒ Boolean
returns stored defaults if there is a view named this in the design doc
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# File 'lib/couchrest/model/views.rb', line 88 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/model/views.rb', line 94 def view(name, query={}, &block) query = query.dup # Modifications made on copy! db = query.delete(:database) || database refresh_design_doc(db) query[:raw] = true if query[:reduce] raw = query.delete(:raw) fetch_view_with_docs(db, 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['model'] == '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['model'] == '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.
Calling with :database => [instance of CouchRest::Database] will send the query to a specific database, otherwise it will go to the model’s default database (use_database)
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 completely, it is recommended that you read the RSpec file at spec/couchrest/more/extended_doc_spec.rb
.
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# File 'lib/couchrest/model/views.rb', line 74 def view_by(*keys) opts = keys.pop if keys.last.is_a?(Hash) opts ||= {} ducktype = opts.delete(:ducktype) unless ducktype || opts[:map] opts[:guards] ||= [] opts[:guards].push "(doc['#{model_type_key}'] == '#{self.to_s}')" end keys.push opts design_doc.view_by(*keys) req_design_doc_refresh end |