gistfile1.txt

irb(main):015:0> cat = Puppet::Resource::Catalog.convert_from(:pson, File.read('mycat.json'))
=> #<Puppet::Resource::Catalog:0x007fdd3b9a2f70 @in_to={}, @out_from={}, @upstream_from={}, @downstream_from={}, @name="foo", @catalog_uuid="626a8af6-2d1a-4357-b38d-6da2d74a3ea6", @classes=[], @resource_table={}, @resources=[], @relationship_graph=nil, @host_config=true, @environment_instance=<Puppet::Node::Environment::Remote:70294082229380 @name="none" @manifest="no_manifest" @modulepath="" >, @environment="none", @code_id=nil, @aliases={}, @tags=#<Puppet::Util::TagSet: {}>>
...
irb(main):017:0> cat.render(:pson)
=> "{\"tags\":[],\"name\":\"foo\",\"version\":null,\"code_id\":null,\"catalog_uuid\":\"626a8af6-2d1a-4357-b38d-6da2d74a3ea6\",\"environment\":\"none\",\"resources\":[],\"edges\":[],\"classes\":[]}"
irb(main):018:0> cat.name
=> "foo"