mod_proxy_fcgi: Add the support for mod_proxy's

flushpackets and flushwait params

This change was requested on the development mailing
list in order to fill another gap between mod_fcgi
and mod_proxy_fcgi, namely the -flush funtionality.

The more evolved core trunk code would not need this
feature becuse of the non-blocking writes, but it
is be needed in 2.4.x.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1802040 13f79535-47bb-0310-9956-ffa450edef68

CHANGES

@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) mod_proxy_fcgi: Add the support for mod_proxy's flushpackets and flushwait
+     parameters. [Luca Toscano, Ruediger Pluem, Yann Ylavic]
+
   *) mod_proxy_wstunnel: Fix detection of unresponded request which could have
      led to spurious HTTP 502 error messages sent on upgrade connections.
      PR 61283.  [Yann Ylavic]

docs/manual/mod/mod_proxy.xml

@@ -1089,7 +1089,7 @@ ProxyPass "/example" "http://backend.example.com" max=20 ttl=120 retry=300
         only when needed; 'on' means after each chunk is sent; and
         'auto' means poll/wait for a period of time and flush if
         no input has been received for 'flushwait' milliseconds.
-        Currently, this is in effect only for AJP.
+        Currently, this is in effect only for mod_proxy_ajp and mod_proxy_fcgi.
     </td></tr>
     <tr><td>flushwait</td>
         <td>10</td>

modules/proxy/mod_proxy_fcgi.c

@@ -532,6 +532,8 @@ static apr_status_t dispatch(proxy_conn_rec *conn, proxy_dir_conf *conf,
     ap_fcgi_header header;
     unsigned char farray[AP_FCGI_HEADER_LEN];
     apr_pollfd_t pfd;
+    apr_pollfd_t *flushpoll;
+    apr_int32_t flushpoll_fd;
     int header_state = HDR_STATE_READING_HEADERS;
     char stack_iobuf[AP_IOBUFSIZE];
     apr_size_t iobuf_size = AP_IOBUFSIZE;
@@ -548,6 +550,13 @@ static apr_status_t dispatch(proxy_conn_rec *conn, proxy_dir_conf *conf,
     pfd.p = r->pool;
     pfd.reqevents = APR_POLLIN | APR_POLLOUT;
 
+    if (conn->worker->s->flush_packets == flush_auto) {
+        flushpoll = apr_pcalloc(r->pool, sizeof(apr_pollfd_t));
+        flushpoll->reqevents = APR_POLLIN;
+        flushpoll->desc_type = APR_POLL_SOCKET;
+        flushpoll->desc.s = conn->sock;
+    }
+
     ib = apr_brigade_create(r->pool, c->bucket_alloc);
     ob = apr_brigade_create(r->pool, c->bucket_alloc);
 
@@ -876,6 +885,19 @@ recv_again:
                     break;
                 }
             }
+
+            if ((conn->worker->s->flush_packets == flush_on) ||
+                ((conn->worker->s->flush_packets == flush_auto) && 
+                 (apr_poll(flushpoll, 1, &flushpoll_fd,
+                           conn->worker->s->flush_wait) == APR_TIMEUP))) {
+                apr_bucket* flush_b = apr_bucket_flush_create(r->connection->bucket_alloc);
+                APR_BRIGADE_INSERT_TAIL(ob, flush_b);
+                rv = ap_pass_brigade(r->output_filters, ob);
+                if (rv != APR_SUCCESS) {
+                    *err = "passing headers brigade to output filters";
+                    break;
+                }
+            }
         }
     }