Upstream: drop extra data sent by upstream.

Previous behaviour was to pass everything to the client, but this
seems to be suboptimal and causes issues (ticket #1695).  Fix is to
drop extra data instead, as it naturally happens in most clients.

This change covers generic buffered and unbuffered filters as used
in the scgi and uwsgi modules.  Appropriate input filter init
handlers are provided by the scgi and uwsgi modules to set corresponding
lengths.

Note that for responses to HEAD requests there is an exception:
we do allow any response length.  This is because responses to HEAD
requests might be actual full responses, and it is up to nginx
to remove the response body.  If caching is enabled, only full
responses matching the Content-Length header will be cached
(see b779728b180c).

1 files changed, 36 insertions, 0 deletions

diff --git a/src/http/modules/ngx_http_scgi_module.c b/src/http/modules/ngx_http_scgi_module.c
index 7216f781d..600999c88 100644
--- a/src/http/modules/ngx_http_scgi_module.c
+++ b/src/http/modules/ngx_http_scgi_module.c
@@ -49,6 +49,7 @@ static ngx_int_t ngx_http_scgi_create_request(ngx_http_request_t *r);
 static ngx_int_t ngx_http_scgi_reinit_request(ngx_http_request_t *r);
 static ngx_int_t ngx_http_scgi_process_status_line(ngx_http_request_t *r);
 static ngx_int_t ngx_http_scgi_process_header(ngx_http_request_t *r);
+static ngx_int_t ngx_http_scgi_input_filter_init(void *data);
 static void ngx_http_scgi_abort_request(ngx_http_request_t *r);
 static void ngx_http_scgi_finalize_request(ngx_http_request_t *r, ngx_int_t rc);
 
@@ -534,6 +535,10 @@ ngx_http_scgi_handler(ngx_http_request_t *r)
     u->pipe->input_filter = ngx_event_pipe_copy_input_filter;
     u->pipe->input_ctx = r;
 
+    u->input_filter_init = ngx_http_scgi_input_filter_init;
+    u->input_filter = ngx_http_upstream_non_buffered_filter;
+    u->input_filter_ctx = r;
+
     if (!scf->upstream.request_buffering
         && scf->upstream.pass_request_body
         && !r->headers_in.chunked)
@@ -1145,6 +1150,37 @@ ngx_http_scgi_process_header(ngx_http_request_t *r)
 }
 
 
+static ngx_int_t
+ngx_http_scgi_input_filter_init(void *data)
+{
+    ngx_http_request_t   *r = data;
+    ngx_http_upstream_t  *u;
+
+    u = r->upstream;
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http scgi filter init s:%ui l:%O",
+                   u->headers_in.status_n, u->headers_in.content_length_n);
+
+    if (u->headers_in.status_n == NGX_HTTP_NO_CONTENT
+        || u->headers_in.status_n == NGX_HTTP_NOT_MODIFIED)
+    {
+        u->pipe->length = 0;
+        u->length = 0;
+
+    } else if (r->method == NGX_HTTP_HEAD) {
+        u->pipe->length = -1;
+        u->length = -1;
+
+    } else {
+        u->pipe->length = u->headers_in.content_length_n;
+        u->length = u->headers_in.content_length_n;
+    }
+
+    return NGX_OK;
+}
+
+
 static void
 ngx_http_scgi_abort_request(ngx_http_request_t *r)
 {