Properly handle keep-alive connections

HTTP/1.1 connections are keep-alive by default,
HTTP/1.0 are KA only if explicitly requested.

PUBLISHED_FROM=cb2070c2d4e4be6beeab4ae5914b8a01b04bc0cb

examples/restful_server/restful_server.c

@@ -35,7 +35,7 @@ static void ev_handler(struct mg_connection *nc, int ev, void *ev_data) {
       } else if (mg_vcmp(&hm->uri, "/printcontent") == 0) {
         char buf[100] = {0};
         memcpy(buf, hm->body.p,
-               sizeof(buf) - 1 < hm->body.len? sizeof(buf) - 1 : hm->body.len);
+               sizeof(buf) - 1 < hm->body.len ? sizeof(buf) - 1 : hm->body.len);
         printf("%s\n", buf);
       } else {
         mg_serve_http(nc, hm, s_http_server_opts); /* Serve static content */
@@ -57,6 +57,12 @@ int main(int argc, char *argv[]) {
 
   mg_mgr_init(&mgr, NULL);
 
+  /* Use current binary directory as document root */
+  if (argc > 0 && ((cp = strrchr(argv[0], DIRSEP)) != NULL)) {
+    *cp = '\0';
+    s_http_server_opts.document_root = argv[0];
+  }
+
   /* Process command line options to customize HTTP server */
   for (i = 1; i < argc; i++) {
     if (strcmp(argv[i], "-D") == 0 && i + 1 < argc) {
@@ -110,17 +116,10 @@ int main(int argc, char *argv[]) {
 #endif
 
   mg_set_protocol_http_websocket(nc);
-  s_http_server_opts.document_root = ".";
   s_http_server_opts.enable_directory_listing = "yes";
 
-  /* Use current binary directory as document root */
+  printf("Starting RESTful server on port %s, serving %s\n", s_http_port,
-  if (argc > 0 && ((cp = strrchr(argv[0], '/')) != NULL ||
+         s_http_server_opts.document_root);
-      (cp = strrchr(argv[0], '/')) != NULL)) {
-    *cp = '\0';
-    s_http_server_opts.document_root = argv[0];
-  }
-
-  printf("Starting RESTful server on port %s\n", s_http_port);
   for (;;) {
     mg_mgr_poll(&mgr, 1000);
   }

mongoose.c

@@ -4130,6 +4130,7 @@ struct mg_http_proto_data_file {
   FILE *fp;      /* Opened file. */
   int64_t cl;    /* Content-Length. How many bytes to send. */
   int64_t sent;  /* How many bytes have been already sent. */
+  int keepalive; /* Keep connection open after sending. */
   enum mg_http_proto_data_type type;
 };
 
@@ -4812,10 +4813,8 @@ static void mg_http_transfer_file_data(struct mg_connection *nc) {
       mg_send(nc, buf, n);
       pd->file.sent += n;
     } else {
+      if (!pd->file.keepalive) nc->flags |= MG_F_SEND_AND_CLOSE;
       mg_http_free_proto_data_file(&pd->file);
-#ifdef MG_DISABLE_HTTP_KEEP_ALIVE
-      nc->flags |= MG_F_SEND_AND_CLOSE;
-#endif
     }
   } else if (pd->file.type == DATA_PUT) {
     struct mbuf *io = &nc->recv_mbuf;
@@ -4827,10 +4826,8 @@ static void mg_http_transfer_file_data(struct mg_connection *nc) {
       pd->file.sent += n;
     }
     if (n == 0 || pd->file.sent >= pd->file.cl) {
+      if (!pd->file.keepalive) nc->flags |= MG_F_SEND_AND_CLOSE;
       mg_http_free_proto_data_file(&pd->file);
-#ifdef MG_DISABLE_HTTP_KEEP_ALIVE
-      nc->flags |= MG_F_SEND_AND_CLOSE;
-#endif
     }
   }
 #ifndef MG_DISABLE_CGI
@@ -5946,6 +5943,17 @@ static void mg_http_send_file2(struct mg_connection *nc, const char *path,
       }
     }
 
+#ifndef MG_DISABLE_HTTP_KEEP_ALIVE
+    {
+      struct mg_str *conn_hdr = mg_get_http_header(hm, "Connection");
+      if (conn_hdr != NULL) {
+        pd->file.keepalive = (mg_vcasecmp(conn_hdr, "keep-alive") == 0);
+      } else {
+        pd->file.keepalive = (mg_vcmp(&hm->proto, "HTTP/1.1") == 0);
+      }
+    }
+#endif
+
     mg_http_construct_etag(etag, sizeof(etag), st);
     mg_gmt_time_string(current_time, sizeof(current_time), &t);
     mg_gmt_time_string(last_modified, sizeof(last_modified), &st->st_mtime);
@@ -5963,14 +5971,13 @@ static void mg_http_send_file2(struct mg_connection *nc, const char *path,
               "Last-Modified: %s\r\n"
               "Accept-Ranges: bytes\r\n"
               "Content-Type: %.*s\r\n"
-#ifdef MG_DISABLE_HTTP_KEEP_ALIVE
+              "Connection: %s\r\n"
-              "Connection: close\r\n"
-#endif
               "Content-Length: %" SIZE_T_FMT
               "\r\n"
               "%sEtag: %s\r\n\r\n",
               current_time, last_modified, (int) mime_type.len, mime_type.p,
-              (size_t) cl, range, etag);
+              (pd->file.keepalive ? "keep-alive" : "close"), (size_t) cl, range,
+              etag);
 
     pd->file.cl = cl;
     pd->file.type = DATA_FILE;