[dev] synchronous write

[Igor Sysoev]

On Mon, Oct 22, 2007 at 01:11:21PM +0200, Manlio Perillo wrote:

> Igor Sysoev ha scritto:
> >[...]
> >>>No, this completely kill the idea of nginx - a worker will be blocked.
> >>>
> >>Unfortunately this is required by the WSGI spec, and some "legacy" WSGI 
> >>applications will block the worker, anyway.
> >>
> >>I have implemented an alternative version that uses a buffer, but I 
> >>would like to know if using this "hack" is "safe", that is if Nginx will 
> >>send the correct data to the client and if after setting again the 
> >>socket to nonblocking mode, Nginx will work as usual.
> >
> >Yes, it will work. However, you should use the following cycle:
> >
> >    ngx_blocking(self->r->connection->fd);
> >
> >    do {
> >        rc = ngx_http_output_filter(self->r, &out);
> >    } while (rc == NGX_AGAIN);
> >
> >    ngx_nonblocking(self->r->connection->fd);
> >
> 
> That's unexpected, I have assumed that with socket in blocking mode 
> ngx_http_output_filter never returns NGX_AGAIN.

No, write() to a socket in blocking mode may send less bytes than you ask.


-- 
Igor Sysoev
http://sysoev.ru/en/