STREAM_PORT = 'stream'
MULTISTREAM_PORT = 'multistream'
DOCUMENT_PORT = 'document'
GRID_PORT = 'grid'

STREAM_COLLECTION_PORT = 'stream[]'
DOCUMENT_COLLECTION_PORT = 'document[]'
GRID_COLLECTION_PORT = 'grid[]'

INPUT_PORT = 'input'
OUTPUT_PORT = 'output'
