URL rewrite at the agent web server to support multiple dashboard versions (#15247)

* new routing for web requests

* renamed and better error control

* add missing return statements

* do not serve files when no file extension is given

* restore the api of the functions; use internal web_client flags to keep state; support redirects to fix directories

* add window.location.hash to url redirect

* do not redirect when sending to specific dashboard version and there are data after the version

* uniform function to append slash to URL

* remove obsolete proxy https flag

2 files changed, 8 insertions, 10 deletions

diff --git a/libnetdata/buffer/buffer.h b/libnetdata/buffer/buffer.h
index 0021c38ff6..5aaa26a079 100644
--- a/libnetdata/buffer/buffer.h
+++ b/libnetdata/buffer/buffer.h
@@ -242,19 +242,16 @@ static inline void buffer_strncat(BUFFER *wb, const char *txt, size_t len) {
     if(unlikely(!txt || !*txt)) return;
 
     const char *t = txt;
-    while(*t) {
-        buffer_need_bytes(wb, len);
-        char *s = &wb->buffer[wb->len];
-        char *d = s;
-        const char *e = &wb->buffer[wb->len + len];
+    buffer_need_bytes(wb, len + 1);
+    char *s = &wb->buffer[wb->len];
+    char *d = s;
+    const char *e = &wb->buffer[wb->len + len];
 
-        while(*t && d < e)
-            *d++ = *t++;
+    while(*t && d < e)
+        *d++ = *t++;
 
-        wb->len += d - s;
-    }
+    wb->len += d - s;
 
-    buffer_need_bytes(wb, 1);
     wb->buffer[wb->len] = '\0';
 
     buffer_overflow_check(wb);
diff --git a/libnetdata/http/http_defs.h b/libnetdata/http/http_defs.h
index 774ea0b71d..906e3bdfb2 100644
--- a/libnetdata/http/http_defs.h
+++ b/libnetdata/http/http_defs.h
@@ -10,6 +10,7 @@
 #define HTTP_RESP_MOVED_PERM 301
 #define HTTP_RESP_REDIR_TEMP 307
 #define HTTP_RESP_REDIR_PERM 308
+#define HTTP_RESP_HTTPS_UPGRADE 399
 
 // HTTP_CODES 4XX Client Errors
 #define HTTP_RESP_BAD_REQUEST 400