Nginx_push_stream module and X-Accel-Redirect, nginx sub-request issue?

dubstep · June 21, 2011, 3:49am

Hi

I’m trying to use the nginx push stream module here:

The general flow is that the client connects to https://server/events/,
which internally does some auth checks on the connection, and then does
X-Accel-Redirect to to https://server/sub?id=*channelname* to connect
the push channel to the user.

Unfortunately nginx closes the connection after 5 seconds. I asked the
module author about this, and he mentioned that he had already seen the
issue, but it’s related to an internal nginx code design with sub
requests which he talks about here:

https://groups.google.com/group/nginxpushstream/msg/577fe1ffe636da75

Not being an expert on the code, I’m not sure where the issue is, but
was hoping to connect people so it can be resolved

Rob
Rob M.
[email protected]

Robert_Mueller · July 3, 2011, 11:56pm

Hello!

On Tue, Jun 21, 2011 at 11:48:59AM +1000, Robert Mueller wrote:

Unfortunately nginx closes the connection after 5 seconds. I asked the
module author about this, and he mentioned that he had already seen the
issue, but it’s related to an internal nginx code design with sub
requests which he talks about here:

https://groups.google.com/group/nginxpushstream/msg/577fe1ffe636da75

Not being an expert on the code, I’m not sure where the issue is, but
was hoping to connect people so it can be resolved

(in case it’s still intresting)

This looks like the problem in push stream module from here. It
incorrectly set r->discard_body by hand[1] instead of using
ngx_http_discard_request_body() function, and this causes
lingering to be activated and close connection as long as there
are no data from client within lingering_timeout (5s by default).

[1]

github.com

wandenberg/nginx-push-stream-module/blob/master/src/ngx_http_push_stream_module_subscriber.c#L145


      
                  requested_channel = ngx_queue_data(q, ngx_http_push_stream_requested_channel_t, queue);
          
          
        if (ngx_http_push_stream_subscriber_assign_channel(mcf, cf, r, requested_channel, if_modified_since, tag, last_event_id, worker_subscriber, ctx->temp_pool) != NGX_OK) {
                      return NGX_HTTP_INTERNAL_SERVER_ERROR;
                  }
              }
          
          
    if (ctx->temp_pool != NULL) {
                  ngx_destroy_pool(ctx->temp_pool);
                  ctx->temp_pool = NULL;
              }
              return NGX_DONE;
          }
          
          
static ngx_int_t
          ngx_http_push_stream_subscriber_polling_handler(ngx_http_request_t *r, ngx_http_push_stream_requested_channel_t *requested_channels, time_t if_modified_since, ngx_int_t tag, ngx_str_t *last_event_id, ngx_flag_t longpolling, ngx_pool_t *temp_pool)
          {
              ngx_http_push_stream_main_conf_t               *mcf = ngx_http_get_module_main_conf(r, ngx_http_push_stream_module);
              ngx_http_push_stream_loc_conf_t                *cf = ngx_http_get_module_loc_conf(r, ngx_http_push_stream_module);
              ngx_slab_pool_t                                *shpool = mcf->shpool;
              ngx_http_push_stream_module_ctx_t              *ctx = ngx_http_get_module_ctx(r, ngx_http_push_stream_module);

Maxim D.