Proxy: support for connection upgrade (101 Switching Protocols).

This allows to proxy WebSockets by using configuration like this:

    location /chat/ {
        proxy_pass http://backend;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection "upgrade";
    }

Connection upgrade is allowed as long as it was requested by a client
via the Upgrade request header.

2 files changed, 9 insertions, 0 deletions

diff --git a/src/http/modules/ngx_http_chunked_filter_module.c b/src/http/modules/ngx_http_chunked_filter_module.c
index 94313a8f6..a7dc5bf4d 100644
--- a/src/http/modules/ngx_http_chunked_filter_module.c
+++ b/src/http/modules/ngx_http_chunked_filter_module.c
@@ -62,6 +62,7 @@ ngx_http_chunked_header_filter(ngx_http_request_t *r)
 
     if (r->headers_out.status == NGX_HTTP_NOT_MODIFIED
         || r->headers_out.status == NGX_HTTP_NO_CONTENT
+        || r->headers_out.status < NGX_HTTP_OK
         || r != r->main
         || (r->method & NGX_HTTP_HEAD))
     {
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index ce47a9e34..a623adc34 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -1474,6 +1474,14 @@ ngx_http_proxy_process_header(ngx_http_request_t *r)
                 u->keepalive = !u->headers_in.connection_close;
             }
 
+            if (u->headers_in.status_n == NGX_HTTP_SWITCHING_PROTOCOLS) {
+                u->keepalive = 0;
+
+                if (r->headers_in.upgrade) {
+                    u->upgrade = 1;
+                }
+            }
+
             return NGX_OK;
         }