[Twisted-web] Re: [Web-SIG] WSGI woes

[Alan Kennedy]

[Alan Kennedy]
> Though I suppose having the top 
> component pulling input from an iterator chain mirrors nicely the 
> situation where the server pulls output from an iterator chain.

Which also means that the top component must be prepared to receive "" 
from the component below it in the input chain.

Say for example that the headers for a new chunk body arrive on the 
client socket, but not a chunk-encoded body, yet.

The top iterator, e.g. the uploaded-file processor, pulls data from the 
component below it, which is say the dechunker. The dechunker will read 
the headers and get the relevant metadata for the chunk. But since there 
is no actual data available now, it must yield "" to the next component up.

I was wondering if we might need to mirror the pause/resume facility on 
the input stream. But it's not a required, because the application is 
getting a callback directly from the server when there is data 
available. It's just that the data on socket that gave rise to the 
notification may not translate to actual data for the called application.

Regards,

Alan.