in my resource's "render" method, I'm doing some things that require a fairly long time to accomplish, so each time through a loop, I want to render some intermediate results to the brower. Kinda like this: class myResource(resource.Resource): isLeaf = True def render(self, request): # Now I build up a string to render to the browser html = make_body() # And now I want to go into a loop for item in items: result = compute_some_item(item) # I just do something that returns some result request.write(result) # then send it to the browser return(server.NOT_DONE_YET) # Do I return now? If so, will I re-enter my "render" method again request.finish() # Now, do I just return the html I generated earlier return(html) what happens when I return with server.NOT_DONE_YET? will I get called again so I can do the request.write(something)? What is the sequence? According to the documentation, I quote: (from render.py) def render(self, request): """Render a given resource. This must be implemented in all subclasses of Resource. The return value of this method will be the rendered page, unless the return value is twisted.web.server.NOT_DONE_YET, in which case it is this class's responsibility to write the results to request.write(data), then call request.finish(). """ According to this, I return server.NOT_DONE_YET... but then it goes on to say it's my classes responsibility to write the results to request.write(data), to write the results, but how do i do that, because if i return server.NOT_DONE_YET then I've exited, and have no opportunity to call request.write(something). So when do I call it? Do I call it BEFORE I return? If so, then why doesn't the bloody document say that? And, in the using Web document, it says.... A Resource object may do various things to produce output which will be sent back to the browser: * Return a string * Call request.write("stuff") as many times as desired, then call request.finish() and return server.NOT_DONE_YET (This is deceptive, since you are in fact done with the request, but is the correct way to do this) * Request a Deferred, return server.NOT_DONE_YET, and call request.write("stuff") and request.finish() later, in a callback on the Deferred. This seems a little more reasonable, and my question, according to this is.... do I do it in this order? 1) call request.write(html) # from above Then for each interation of some loop: 1) call request.write(stuff) a bunch of times, which for each iteration of a loop, may take up to a minute. 2) call request.finish() 3) return server.NOT_DONE_YET Is this the right order for doing this? Should I try to use a Deferred? I have no clue how to do that, there appears to be a severe lack of examples similar to what I want to do. Lets say I want to defer ONE interation of a loop... Lets call this function... def do_iteration(item): # do the interation So, would I construct my loop like this: # In the render method. for item in items: # process some item # Then do something to add this deferred, which I still don't know how to do. # something like this? reactor.callLater(something, do_iteration) # But since I'm in the "render" method, how do I get a reference to "reactor"? # And what it the meaning of "something" in the first argument of "callLater"? John