+static inline void web_client_send_http_header(struct web_client *w) {
+ if(unlikely(w->response.code != 200))
+ buffer_no_cacheable(w->response.data);
+
+ // set a proper expiration date, if not already set
+ if(unlikely(!w->response.data->expires)) {
+ if(w->response.data->options & WB_CONTENT_NO_CACHEABLE)
+ w->response.data->expires = w->tv_ready.tv_sec + rrd_update_every;
+ else
+ w->response.data->expires = w->tv_ready.tv_sec + 86400;
+ }
+
+ // prepare the HTTP response header
+ debug(D_WEB_CLIENT, "%llu: Generating HTTP header with response %d.", w->id, w->response.code);
+
+ const char *content_type_string = web_content_type_to_string(w->response.data->contenttype);
+ const char *code_msg = web_response_code_to_string(w->response.code);
+
+ // prepare the last modified and expiration dates
+ char date[32], edate[32];
+ {
+ struct tm tmbuf, *tm;
+
+ tm = gmtime_r(&w->response.data->date, &tmbuf);
+ strftime(date, sizeof(date), "%a, %d %b %Y %H:%M:%S %Z", tm);
+
+ tm = gmtime_r(&w->response.data->expires, &tmbuf);
+ strftime(edate, sizeof(edate), "%a, %d %b %Y %H:%M:%S %Z", tm);
+ }
+
+ buffer_sprintf(w->response.header_output,
+ "HTTP/1.1 %d %s\r\n"
+ "Connection: %s\r\n"
+ "Server: NetData Embedded HTTP Server\r\n"
+ "Access-Control-Allow-Origin: %s\r\n"
+ "Access-Control-Allow-Credentials: true\r\n"
+ "Content-Type: %s\r\n"
+ "Date: %s\r\n"
+ , w->response.code, code_msg
+ , w->keepalive?"keep-alive":"close"
+ , w->origin
+ , content_type_string
+ , date
+ );
+
+ if(unlikely(web_x_frame_options))
+ buffer_sprintf(w->response.header_output, "X-Frame-Options: %s\r\n", web_x_frame_options);
+
+ if(w->cookie1[0] || w->cookie2[0]) {
+ if(w->cookie1[0]) {
+ buffer_sprintf(w->response.header_output,
+ "Set-Cookie: %s\r\n",
+ w->cookie1);
+ }
+
+ if(w->cookie2[0]) {
+ buffer_sprintf(w->response.header_output,
+ "Set-Cookie: %s\r\n",
+ w->cookie2);
+ }
+
+ if(respect_web_browser_do_not_track_policy)
+ buffer_sprintf(w->response.header_output,
+ "Tk: T;cookies\r\n");
+ }
+ else {
+ if(respect_web_browser_do_not_track_policy) {
+ if(w->tracking_required)
+ buffer_sprintf(w->response.header_output,
+ "Tk: T;cookies\r\n");
+ else
+ buffer_sprintf(w->response.header_output,
+ "Tk: N\r\n");
+ }
+ }
+
+ if(w->mode == WEB_CLIENT_MODE_OPTIONS) {
+ buffer_strcat(w->response.header_output,
+ "Access-Control-Allow-Methods: GET, OPTIONS\r\n"
+ "Access-Control-Allow-Headers: accept, x-requested-with, origin, content-type, cookie, pragma, cache-control\r\n"
+ "Access-Control-Max-Age: 1209600\r\n" // 86400 * 14
+ );
+ }
+ else {
+ buffer_sprintf(w->response.header_output,
+ "Cache-Control: %s\r\n"
+ "Expires: %s\r\n",
+ (w->response.data->options & WB_CONTENT_NO_CACHEABLE)?"no-cache":"public",
+ edate);
+ }
+
+ // copy a possibly available custom header
+ if(unlikely(buffer_strlen(w->response.header)))
+ buffer_strcat(w->response.header_output, buffer_tostring(w->response.header));
+
+ // headers related to the transfer method
+ if(likely(w->response.zoutput)) {
+ buffer_strcat(w->response.header_output,
+ "Content-Encoding: gzip\r\n"
+ "Transfer-Encoding: chunked\r\n"
+ );
+ }
+ else {
+ if(likely((w->response.data->len || w->response.rlen))) {
+ // we know the content length, put it
+ buffer_sprintf(w->response.header_output, "Content-Length: %zu\r\n", w->response.data->len? w->response.data->len: w->response.rlen);
+ }
+ else {
+ // we don't know the content length, disable keep-alive
+ w->keepalive = 0;
+ }
+ }
+
+ // end of HTTP header
+ buffer_strcat(w->response.header_output, "\r\n");
+
+ // sent the HTTP header
+ debug(D_WEB_DATA, "%llu: Sending response HTTP header of size %zu: '%s'"
+ , w->id
+ , buffer_strlen(w->response.header_output)
+ , buffer_tostring(w->response.header_output)
+ );
+
+ web_client_crock_socket(w);
+
+ ssize_t bytes = send(w->ofd, buffer_tostring(w->response.header_output), buffer_strlen(w->response.header_output), 0);
+ if(bytes != (ssize_t) buffer_strlen(w->response.header_output)) {
+ if(bytes > 0)
+ w->stats_sent_bytes += bytes;
+
+ debug(D_WEB_CLIENT, "%llu: HTTP Header failed to be sent (I sent %zu bytes but the system sent %zd bytes). Closing web client."
+ , w->id
+ , buffer_strlen(w->response.header_output)
+ , bytes);
+
+ WEB_CLIENT_IS_DEAD(w);
+ return;
+ }
+ else
+ w->stats_sent_bytes += bytes;
+}
+