def _check_frames(frames):
if not inspect.isgenerator(frames):
raise Exception("Invalid frames: not a generator")
# ensure the frames are in a valid format; valid formats are
# - <data> -- will be assumed to be plain text
# - (<mime_type>, <data>)
# - (<mime_type>, <data>, <metadata>)
for (n, frame) in enumerate(frames):
if frame is None:
yield None
elif not utils.is_iterable(frame):
# default content type is plain text
yield (MIME_TYPE.TEXT.value, unicode(frame), None)
else:
try:
assert utils.is_iterable(frame), "Not an iterable"
frame = list(frame)
frame_length = len(frame)
if frame_length == 2:
(mime_type_, content_), metadata_ = frame, None
elif frame_length == 3:
(mime_type_, content_, metadata_) = frame
else:
raise Exception("Unexpected tuple length: %d" % frame_length)
yield (_validate_mime_type(mime_type_), content_, metadata_)
except Exception as e:
raise Exception("Invalid frame #%d: %s" % (n + 1, e))
def register_renderer(renderer, mime_type):
global _renderers
if not utils.is_callable(renderer):
raise ValueError("Invalid renderer: not a function")
if not utils.is_iterable(mime_type):
mime_types = (mime_type,)
else:
mime_types = mime_type
for mime_type in mime_types:
mime_type = _validate_mime_type(mime_type)
_renderers.insert(0, (renderer, mime_type))
_logger.debug("added renderer for %s: %s" % (mime_type, renderer))
