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diff src/http/ngx_http_request_body.c @ 7914:9cf043a5d9ca

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Request body: reading body buffering in filters. If a filter wants to buffer the request body during reading (for example, to check an external scanner), it can now do so. To make it possible, the code now checks rb->last_saved (introduced in the previous change) along with rb->rest == 0. Since in HTTP/2 this requires flow control to avoid overflowing the request body buffer, so filters which need buffering have to set the rb->filter_need_buffering flag on the first filter call. (Note that each filter is expected to call the next filter, so all filters will be able set the flag if needed.)
author Maxim Dounin <mdounin@mdounin.ru>
date Sun, 29 Aug 2021 22:22:02 +0300
parents 185c86b830ef
children 97cf8284fd19 fac88e160653
line wrap: on
line diff
--- a/src/http/ngx_http_request_body.c
+++ b/src/http/ngx_http_request_body.c
@@ -69,6 +69,8 @@ ngx_http_read_client_request_body(ngx_ht
      *     rb->busy = NULL;
      *     rb->chunked = NULL;
      *     rb->received = 0;
+     *     rb->filter_need_buffering = 0;
+     *     rb->last_sent = 0;
      *     rb->last_saved = 0;
      */
 
@@ -147,7 +149,7 @@ ngx_http_read_client_request_body(ngx_ht
         }
     }
 
-    if (rb->rest == 0) {
+    if (rb->rest == 0 && rb->last_saved) {
         /* the whole request body was pre-read */
         r->request_body_no_buffering = 0;
         post_handler(r);
@@ -175,6 +177,10 @@ ngx_http_read_client_request_body(ngx_ht
             size += preread;
         }
 
+        if (size == 0) {
+            size++;
+        }
+
     } else {
         size = clcf->client_body_buffer_size;
     }
@@ -273,6 +279,7 @@ ngx_http_do_read_client_request_body(ngx
     size_t                     size;
     ssize_t                    n;
     ngx_int_t                  rc;
+    ngx_uint_t                 flush;
     ngx_chain_t                out;
     ngx_connection_t          *c;
     ngx_http_request_body_t   *rb;
@@ -280,12 +287,17 @@ ngx_http_do_read_client_request_body(ngx
 
     c = r->connection;
     rb = r->request_body;
+    flush = 1;
 
     ngx_log_debug0(NGX_LOG_DEBUG_HTTP, c->log, 0,
                    "http read client request body");
 
     for ( ;; ) {
         for ( ;; ) {
+            if (rb->rest == 0) {
+                break;
+            }
+
             if (rb->buf->last == rb->buf->end) {
 
                 /* update chains */
@@ -309,12 +321,25 @@ ngx_http_do_read_client_request_body(ngx
                         return NGX_AGAIN;
                     }
 
+                    if (rb->filter_need_buffering) {
+                        clcf = ngx_http_get_module_loc_conf(r,
+                                                         ngx_http_core_module);
+                        ngx_add_timer(c->read, clcf->client_body_timeout);
+
+                        if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
+                            return NGX_HTTP_INTERNAL_SERVER_ERROR;
+                        }
+
+                        return NGX_AGAIN;
+                    }
+
                     ngx_log_error(NGX_LOG_ALERT, c->log, 0,
                                   "busy buffers after request body flush");
 
                     return NGX_HTTP_INTERNAL_SERVER_ERROR;
                 }
 
+                flush = 0;
                 rb->buf->pos = rb->buf->start;
                 rb->buf->last = rb->buf->start;
             }
@@ -326,6 +351,10 @@ ngx_http_do_read_client_request_body(ngx
                 size = (size_t) rest;
             }
 
+            if (size == 0) {
+                break;
+            }
+
             n = c->recv(c, rb->buf->last, size);
 
             ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
@@ -350,6 +379,7 @@ ngx_http_do_read_client_request_body(ngx
 
             /* pass buffer to request body filter chain */
 
+            flush = 0;
             out.buf = rb->buf;
             out.next = NULL;
 
@@ -371,11 +401,19 @@ ngx_http_do_read_client_request_body(ngx
         ngx_log_debug1(NGX_LOG_DEBUG_HTTP, c->log, 0,
                        "http client request body rest %O", rb->rest);
 
-        if (rb->rest == 0) {
+        if (flush) {
+            rc = ngx_http_request_body_filter(r, NULL);
+
+            if (rc != NGX_OK) {
+                return rc;
+            }
+        }
+
+        if (rb->rest == 0 && rb->last_saved) {
             break;
         }
 
-        if (!c->read->ready) {
+        if (!c->read->ready || rb->rest == 0) {
 
             clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
             ngx_add_timer(c->read, clcf->client_body_timeout);
@@ -1280,7 +1318,9 @@ ngx_http_request_body_save_filter(ngx_ht
         return NGX_OK;
     }
 
-    /* rb->rest == 0 */
+    if (!rb->last_saved) {
+        return NGX_OK;
+    }
 
     if (rb->temp_file || r->request_body_in_file_only) {