nginx · arut · Jun 19, 2025 · Jun 18, 2025 · Nov 15, 2024
diff --git a/src/http/modules/ngx_http_grpc_module.c b/src/http/modules/ngx_http_grpc_module.c
@@ -1869,7 +1869,8 @@ ngx_http_grpc_process_header(ngx_http_request_t *r)
                         return NGX_HTTP_UPSTREAM_INVALID_HEADER;
                     }
 
-                    if (status < NGX_HTTP_OK) {
+                    if (status < NGX_HTTP_OK && status != NGX_HTTP_EARLY_HINTS)
+                    {
                         ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                                       "upstream sent unexpected :status \"%V\"",
                                       status_line);
@@ -1902,6 +1903,10 @@ ngx_http_grpc_process_header(ngx_http_request_t *r)
                 h->lowcase_key = h->key.data;
                 h->hash = ngx_hash_key(h->key.data, h->key.len);
 
+                if (u->headers_in.status_n == NGX_HTTP_EARLY_HINTS) {
+                    continue;
+                }
+
                 hh = ngx_hash_find(&umcf->headers_in_hash, h->hash,
                                    h->lowcase_key, h->key.len);
 
@@ -4413,6 +4418,7 @@ ngx_http_grpc_create_loc_conf(ngx_conf_t *cf)
     conf->upstream.pass_request_body = 1;
    conf->upstream.force_ranges = 0;
     conf->upstream.pass_trailers = 1;
+    conf->upstream.pass_early_hints = 1;
     conf->upstream.preserve_output = 1;
 
     conf->headers_source = NGX_CONF_UNSET_PTR;

diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
@@ -1888,6 +1888,13 @@ ngx_http_proxy_process_status_line(ngx_http_request_t *r)
                    u->headers_in.status_n, &u->headers_in.status_line);
 
     if (ctx->status.http_version < NGX_HTTP_VERSION_11) {
+
+        if (ctx->status.code == NGX_HTTP_EARLY_HINTS) {
+            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
+                          "upstream sent HTTP/1.0 response with early hints");
+            return NGX_HTTP_UPSTREAM_INVALID_HEADER;
+        }
+
         u->headers_in.connection_close = 1;
     }
 
@@ -1949,6 +1956,14 @@ ngx_http_proxy_process_header(ngx_http_request_t *r)
                 ngx_strlow(h->lowcase_key, h->key.data, h->key.len);
             }
 
+            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                           "http proxy header: \"%V: %V\"",
+                           &h->key, &h->value);
+
+            if (r->upstream->headers_in.status_n == NGX_HTTP_EARLY_HINTS) {
+                continue;
+            }
+
             hh = ngx_hash_find(&umcf->headers_in_hash, h->hash,
                                h->lowcase_key, h->key.len);
 
@@ -1960,10 +1975,6 @@ ngx_http_proxy_process_header(ngx_http_request_t *r)
                 }
             }
 
-            ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
-                           "http proxy header: \"%V: %V\"",
-                           &h->key, &h->value);
-
             continue;
         }
 
@@ -1974,6 +1985,10 @@ ngx_http_proxy_process_header(ngx_http_request_t *r)
             ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                            "http proxy header done");
 
+            if (r->upstream->headers_in.status_n == NGX_HTTP_EARLY_HINTS) {
+                return NGX_OK;
+            }
+
             /*
              * if no "Server" and "Date" in header line,
              * then add the special empty headers
@@ -3628,10 +3643,10 @@ ngx_http_proxy_create_loc_conf(ngx_conf_t *cf)
     conf->ssl_conf_commands = NGX_CONF_UNSET_PTR;
 #endif
 
-    /* "proxy_cyclic_temp_file" is disabled */
+    /* the hardcoded values */
     conf->upstream.cyclic_temp_file = 0;
-
     conf->upstream.change_buffering = 1;
+    conf->upstream.pass_early_hints = 1;
 
     conf->headers_source = NGX_CONF_UNSET_PTR;
 

diff --git a/src/http/ngx_http.c b/src/http/ngx_http.c
@@ -72,6 +72,7 @@ ngx_uint_t   ngx_http_max_module;
 
 
 ngx_http_output_header_filter_pt  ngx_http_top_header_filter;
+ngx_http_output_header_filter_pt  ngx_http_top_early_hints_filter;
 ngx_http_output_body_filter_pt    ngx_http_top_body_filter;
 ngx_http_request_body_filter_pt   ngx_http_top_request_body_filter;
 

diff --git a/src/http/ngx_http.h b/src/http/ngx_http.h
@@ -152,6 +152,7 @@ ngx_int_t ngx_http_read_client_request_body(ngx_http_request_t *r,
 ngx_int_t ngx_http_read_unbuffered_request_body(ngx_http_request_t *r);
 
 ngx_int_t ngx_http_send_header(ngx_http_request_t *r);
+ngx_int_t ngx_http_send_early_hints(ngx_http_request_t *r);
 ngx_int_t ngx_http_special_response_handler(ngx_http_request_t *r,
     ngx_int_t error);
 ngx_int_t ngx_http_filter_finalize_request(ngx_http_request_t *r,
@@ -191,6 +192,7 @@ extern ngx_str_t  ngx_http_html_default_types[];
 
 
 extern ngx_http_output_header_filter_pt  ngx_http_top_header_filter;
+extern ngx_http_output_header_filter_pt  ngx_http_top_early_hints_filter;
 extern ngx_http_output_body_filter_pt    ngx_http_top_body_filter;
 extern ngx_http_request_body_filter_pt   ngx_http_top_request_body_filter;
 

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
@@ -670,6 +670,13 @@ static ngx_command_t  ngx_http_core_commands[] = {
       offsetof(ngx_http_core_loc_conf_t, etag),
       NULL },
 
+    { ngx_string("early_hints"),
+      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_1MORE,
+      ngx_http_set_predicate_slot,
+      NGX_HTTP_LOC_CONF_OFFSET,
+      offsetof(ngx_http_core_loc_conf_t, early_hints),
+      NULL },
+
     { ngx_string("error_page"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
                         |NGX_CONF_2MORE,
@@ -1857,6 +1864,37 @@ ngx_http_send_header(ngx_http_request_t *r)
 }
 
 
+ngx_int_t
+ngx_http_send_early_hints(ngx_http_request_t *r)
+{
+    ngx_int_t                  rc;
+    ngx_http_core_loc_conf_t  *clcf;
+
+    if (r->post_action) {
+        return NGX_OK;
+    }
+
+    if (r->header_sent) {
+        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                      "header already sent");
+ 
9E88
       return NGX_ERROR;
+    }
+
+    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+    rc = ngx_http_test_predicates(r, clcf->early_hints);
+
+    if (rc != NGX_DECLINED) {
+        return rc;
+    }
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "http send early hints \"%V?%V\"", &r->uri, &r->args);
+
+    return ngx_http_top_early_hints_filter(r);
+}
+
+
 ngx_int_t
 ngx_http_output_filter(ngx_http_request_t *r, ngx_chain_t *in)
 {
@@ -3637,6 +3675,7 @@ ngx_http_core_create_loc_conf(ngx_conf_t *cf)
     clcf->chunked_transfer_encoding = NGX_CONF_UNSET;
     clcf->etag = NGX_CONF_UNSET;
     clcf->server_tokens = NGX_CONF_UNSET_UINT;
+    clcf->early_hints = NGX_CONF_UNSET_PTR;
     clcf->types_hash_max_size = NGX_CONF_UNSET_UINT;
     clcf->types_hash_bucket_size = NGX_CONF_UNSET_UINT;
 
@@ -3917,6 +3956,8 @@ ngx_http_core_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_conf_merge_uint_value(conf->server_tokens, prev->server_tokens,
                               NGX_HTTP_SERVER_TOKENS_ON);
 
+    ngx_conf_merge_ptr_value(conf->early_hints, prev->early_hints, NULL);
+
     ngx_conf_merge_ptr_value(conf->open_file_cache,
                               prev->open_file_cache, NULL);
 

diff --git a/src/http/ngx_http_core_module.h b/src/http/ngx_http_core_module.h
@@ -430,6 +430,8 @@ struct ngx_http_core_loc_conf_s {
     ngx_http_complex_value_t  *disable_symlinks_from;
 #endif
 
+    ngx_array_t  *early_hints;             /* early_hints */
+
     ngx_array_t  *error_pages;             /* error_page */
 
     ngx_path_t   *client_body_temp_path;   /* client_body_temp_path */

diff --git a/src/http/ngx_http_header_filter_module.c b/src/http/ngx_http_header_filter_module.c
@@ -13,6 +13,7 @@
 
 static ngx_int_t ngx_http_header_filter_init(ngx_conf_t *cf);
 static ngx_int_t ngx_http_header_filter(ngx_http_request_t *r);
+static ngx_int_t ngx_http_early_hints_filter(ngx_http_request_t *r);
 
 
 static ngx_http_module_t  ngx_http_header_filter_module_ctx = {
@@ -50,6 +51,9 @@ static u_char ngx_http_server_string[] = "Server: nginx" CRLF;
 static u_char ngx_http_server_full_string[] = "Server: " NGINX_VER CRLF;
 static u_char ngx_http_server_build_string[] = "Server: " NGINX_VER_BUILD CRLF;
 
+static ngx_str_t ngx_http_early_hints_status_line =
+    ngx_string("HTTP/1.1 103 Early Hints" CRLF);
+
 
 static ngx_str_t ngx_http_status_lines[] = {
 
@@ -625,10 +629,113 @@ ngx_http_header_filter(ngx_http_request_t *r)
 }
 
 
+static ngx_int_t
+ngx_http_early_hints_filter(ngx_http_request_t *r)
+{
+    size_t            len;
+    ngx_buf_t        *b;
+    ngx_uint_t        i;
+    ngx_chain_t       out;
+    ngx_list_part_t  *part;
+    ngx_table_elt_t  *header;
+
+    if (r != r->main) {
+        return NGX_OK;
+    }
+
+    if (r->http_version < NGX_HTTP_VERSION_11) {
+        return NGX_OK;
+    }
+
+    len = 0;
+
+    part = &r->headers_out.headers.part;
+    header = part->elts;
+
+    for (i = 0; /* void */; i++) {
+
+        if (i >= part->nelts) {
+            if (part->next == NULL) {
+                break;
+            }
+
+            part = part->next;
+            header = part->elts;
+            i = 0;
+        }
+
+        if (header[i].hash == 0) {
+            continue;
+        }
+
+        len += header[i].key.len + sizeof(": ") - 1 + header[i].value.len
+               + sizeof(CRLF) - 1;
+    }
+
+    if (len == 0) {
+        return NGX_OK;
+    }
+
+    len += ngx_http_early_hints_status_line.len
+           /* the end of the early hints */
+           + sizeof(CRLF) - 1;
+
+    b = ngx_create_temp_buf(r->pool, len);
+    if (b == NULL) {
+        return NGX_ERROR;
+    }
+
+    b->last = ngx_copy(b->last, ngx_http_early_hints_status_line.data,
+                       ngx_http_early_hints_status_line.len);
+
+    part = &r->headers_out.headers.part;
+    header = part->elts;
+
+    for (i = 0; /* void */; i++) {
+
+        if (i >= part->nelts) {
+            if (part->next == NULL) {
+                break;
+            }
+
+            part = part->next;
+            header = part->elts;
+            i = 0;
+        }
+
+        if (header[i].hash == 0) {
+            continue;
+        }
+
+        b->last = ngx_copy(b->last, header[i].key.data, header[i].key.len);
+        *b->last++ = ':'; *b->last++ = ' ';
+
+        b->last = ngx_copy(b->last, header[i].value.data, header[i].value.len);
+        *b->last++ = CR; *b->last++ = LF;
+    }
+
+    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                   "%*s", (size_t) (b->last - b->pos), b->pos);
+
+    /* the end of HTTP early hints */
+    *b->last++ = CR; *b->last++ = LF;
+
+    r->header_size = b->last - b->pos;
+
+    b->flush = 1;
+
+    out.buf = b;
+    out.next = NULL;
+
+    return ngx_http_write_filter(r, &out);
+}
+
+
 static ngx_int_t
 ngx_http_header_filter_init(ngx_conf_t *cf)
 {
     ngx_http_top_header_filter = ngx_http_header_filter;
+    ngx_http_top_early_hints_filter = ngx_http_early_hints_filter;
 
     return NGX_OK;
 }
diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
@@ -74,6 +74,7 @@
 #define NGX_HTTP_CONTINUE                  100
 #define NGX_HTTP_SWITCHING_PROTOCOLS       101
 #define NGX_HTTP_PROCESSING                102
+#define NGX_HTTP_EARLY_HINTS               103
 
 #define NGX_HTTP_OK                        200
 #define NGX_HTTP_CREATED                   201