Usually the response from a handler function is returned as a string, which means that the whole response has to be constructed in memory. If you want to return a very large file, however, this will consume a lot of memory.
Instead of returning a string, a handler can also return an instance of the quixote.http_response.Stream class, wrapping it around an iterable that returns chunks of the large object.
from quixote.http_response import Stream def generate_data (): "Generate a large amount of data" while (...): yield chunk def data_output (request): # Set the MIME type to whatever is suitable request.response_set_content_type('application/octet-stream') return Stream(generate_data())
For the common case of streaming output from a file, the quixote.util modules contains a FileStream class that takes a file object:
def large_file (request): filename = "/usr/share/qxapp/large-file.pdf' size = os.path.getsize(filename) request.response.set_content_type('application/pdf') input = open(filename, 'rb') return util.FileStream(input, size)
The size argument is optional and is used to set the Content-Length HTTP header; you should provide it whenever possible.
Note that not all Quixote server modules support streaming. Most notably, for Quixote <= 1.0b1 the quixote.server.twisted_http module simply converts the contents of the stream into an in-memory string. All Quixote 2 servers currently support streamed responses.
Also note that FileStream does not currently close the file after streaming is finished. Perhaps it should.