Hi all,

Finally, I do not use subrequest, I write the following code, inspired from
upstream module.
I call ngx_http_upstream_send_another_request from process_header. It's
working fine.

Feel free to comment my code, if you think I can have problem, memory
allocation, segfault or others.

Regards,

Bertrand


static void
ngx_http_upstream_send_another_request_dummy_handler(ngx_http_request_t *r,
ngx_http_upstream_t *u)
{
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http upstream send another request dummy handler");
}

static ngx_int_t
ngx_http_upstream_send_another_request(ngx_http_request_t *r,
ngx_http_upstream_t *u);

static void
ngx_http_upstream_send_another_request_handler(ngx_http_request_t *r,
ngx_http_upstream_t *u)
{
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http upstream send another request handler");

ngx_http_upstream_send_another_request(r, u);
}

static ngx_int_t
ngx_http_upstream_send_another_request(ngx_http_request_t *r,
ngx_http_upstream_t *u)
{
ngx_int_t rc;
ngx_connection_t *c;

c = u->peer.connection;

ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
"http upstream send another request");
//
// if (!u->request_sent && ngx_http_upstream_test_connect(c) != NGX_OK)
{
// ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_ERROR);
// return;
// }

c->log->action = "sending request to upstream";

rc = ngx_output_chain(&u->output, u->request_sent ? NULL :
u->request_bufs);

u->request_sent = 1;

if (rc == NGX_ERROR) {
return rc;
}

if (c->write->timer_set) {
ngx_del_timer(c->write);
}

if (rc == NGX_AGAIN) {
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
"ngx_output_chain return NGX_AGAIN");

u->write_event_handler =
ngx_http_upstream_send_another_request_handler;

ngx_add_timer(c->write, u->conf->send_timeout);

if (ngx_handle_write_event(c->write, u->conf->send_lowat) !=
NGX_OK) {
return NGX_ERROR;
}

return NGX_AGAIN;
}

/* rc == NGX_OK */

if (c->tcp_nopush == NGX_TCP_NOPUSH_SET) {
if (ngx_tcp_push(c->fd) == NGX_ERROR) {
ngx_log_error(NGX_LOG_CRIT, c->log, ngx_socket_errno,
ngx_tcp_push_n " failed");
return NGX_ERROR;
}

c->tcp_nopush = NGX_TCP_NOPUSH_UNSET;
}

ngx_add_timer(c->read, u->conf->read_timeout);

// #if 1
// if (c->read->ready) {
//
// /* post aio operation */
//
// /*
// * TODO comment
// * although we can post aio operation just in the end
// * of ngx_http_upstream_connect() CHECK IT !!!
// * it's better to do here because we postpone header buffer
allocation
// */
//
// return u->process_header(r);
// }
// #endif

u->write_event_handler =
ngx_http_upstream_send_another_request_dummy_handler;

if (ngx_handle_write_event(c->write, 0) != NGX_OK) {
return NGX_ERROR;
}

return NGX_AGAIN;
}

On Tue, Jan 17, 2012 at 04:14, bigplum <nginx-forum@nginx.us> wrote:

> Hi,
>
> This demo maybe helpful.
> https://github.com/bigplum/nginx-http-nphase-module
>
> Posted at Nginx Forum:
> http://forum.nginx.org/read.php?2,221329,221339#msg-221339
>
> _______________________________________________
> nginx mailing list
> nginx@nginx.org
> http://mailman.nginx.org/mailman/listinfo/nginx
>
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