From 8ddd61b34d52ad2fbb253c5bc2a38f58a509a678 Mon Sep 17 00:00:00 2001
From: Adam Dubiel <adam.dubiel@allegrogroup.com>
Date: Mon, 27 Oct 2014 13:27:07 +0100
Subject: [PATCH] Validate negative sampling

---
 lib/helpers.js        | 13 +++++++++++--
 test/helpers_tests.js |  1 +
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/helpers.js b/lib/helpers.js
index 98c6225..52ba3a3 100644
--- a/lib/helpers.js
+++ b/lib/helpers.js
@@ -11,6 +11,15 @@ function isNumber(str) {
     return Boolean(str && !isNaN(str));
 }
 
+function isValidSampleRate(str) {
+    var validSampleRate = false;
+    if(str.length > 1 && str[0] === '@') {
+        var numberStr = str.substring(1);
+        validSampleRate = isNumber(numberStr) && numberStr[0] != '-';
+    }
+    return validSampleRate;
+}
+
 function is_valid_packet(fields) {
 
     // test for existing metrics type
@@ -19,8 +28,8 @@ function is_valid_packet(fields) {
     }
 
     // filter out malformed sample rates
-    if (fields[2] !== undefined) {
-        if (fields[2].length <= 1 || fields[2][0] != '@' || !isNumber(fields[2].substring(1))) {
+    if(fields[2] !== undefined) {
+        if(!isValidSampleRate(fields[2])) {
             return false;
         }
     }
diff --git a/test/helpers_tests.js b/test/helpers_tests.js
index d10da0b..cb76984 100644
--- a/test/helpers_tests.js
+++ b/test/helpers_tests.js
@@ -112,6 +112,7 @@ module.exports = {
     test.equals(helpers.is_valid_packet(['345345', 'ms', '@.']), false);
     test.equals(helpers.is_valid_packet(['345345', 'ms', '@.1.']), false);
     test.equals(helpers.is_valid_packet(['345345', 'ms', '@.1.2.3']), false);
+    test.equals(helpers.is_valid_packet(['345345', 'ms', '@-1.0']), false);
     test.done();
   },