add function is_blank() to see if var is either null, '', or whitespace

Author: davidpanderson

html/inc/db.inc

@@ -168,10 +168,10 @@ function db_init_aux($try_replica=false) {
             if ($x) $db_name = $x;
         }
     }
-    if (!$host) {
+    if (is_blank($host)) {
         $host = parse_config($config, "<db_host>");
     }
-    if (!$host) {
+    if (is_blank($host)) {
         $host = "localhost";
     }
     if (1) {

html/inc/util_basic.inc

@@ -242,6 +242,13 @@ function time_diff($x, $res=3) {
     return $s;
 }
 
+// is the arg either null, '', or whitespace?
+// Note: if ($x) will be false if $x is '0'.
+// We don't want to treat '0' as blank.
+//
+function is_blank($x) {
+    return $x === null || trim($x) === '';
+}
 
 // security vulnerabilities and user-supplied strings:
 // sources:

html/inc/util_ops.inc

@@ -103,7 +103,7 @@ function db_init_cli() {
     $config = get_config();
     $db_name = parse_config($config, "<db_name>");
     $host = parse_config($config, "<db_host>");
-    if (!$host) {
+    if (is_blank($host)) {
         $host = "localhost";
     }
     $in = fopen("php://stdin","r");

html/user/pm.php

@@ -199,7 +199,7 @@ function do_send_team($logged_in_user) {
         error_page("no team admin");
     }
 
-    if (!$subject || !$content) {
+    if (is_blank($subject) || is_blank($content)) {
         pm_team_form(
             $logged_in_user, $teamid,
             tra("You need to fill all fields to send a private message")
@@ -235,7 +235,7 @@ function do_send($logged_in_user) {
         pm_form_page($replyto, $userid);
         return;
     }
-    if (!$to || !$subject || !$content ) {
+    if (is_blank($to) || is_blank($subject) || is_blank($content)) {
         pm_form_page(
             $replyto, $userid,
             tra("You need to fill all fields to send a private message")