FEATURE: add custom postprocessing function for the ADQL translation

[kimakan]

Sometimes it is useful to alter the ADQL translation from the queryparser to make use of the archive specific features, i.e., using pos column for the cone search for a performance boost. For this, one can add a dummy postprocessor function right after the standard translation by the queryparser. This function can be overloaded by the daiquiri app. There is no solution for the implementation yet.

The translation of the ADQL query happens here

daiquiri/daiquiri/query/process.py

Lines 123 to 138 in 33094c5

	def translate_query(query_language, query):
	# get the adapter
	adapter = DatabaseAdapter()
	# translate adql -> mysql string
	if query_language == 'adql-2.0':
	try:
	translator = cache.get_or_set('translator', ADQLQueryTranslator(), 3600)
	translator.set_query(query)
	if adapter.database_config['ENGINE'] == 'django.db.backends.mysql':
	return translator.to_mysql()
	elif adapter.database_config['ENGINE'] == 'django.db.backends.postgresql':
	return translator.to_postgresql()
	else:
	raise Exception('Unknown database engine')