Handle undefined tags

lib/loggly/client.js

@@ -172,9 +172,12 @@ Loggly.prototype.log = function (msg, tags, callback) {
     : this.tags;
 
   //
-  // Optionally send `X-LOGGLY-TAG` if we have them
+  // Optionally send `X-LOGGLY-TAG` if we have them.
+  // Set the 'X-LOGGLY-TAG' only when we have actually some tag value.
+  // The library receives "400 Bad Request" in response when the
+  // value of 'X-LOGGLY-TAG' is empty string in request header.
   //
-  if (tags) {
+  if (tags && tags.length) {
     // Decide whether to add tags as http headers or add them to the URI.
     if (this.useTagHeader) {
       logOptions.headers['X-LOGGLY-TAG'] = tags.join(',');
@@ -227,7 +230,7 @@ Loggly.prototype.tagFilter = function (tags) {
     //
     // Remark: length may need to use Buffer.byteLength?
     //
-    return isSolid.test(tag) && tag.length <= 64;
+    return tag && isSolid.test(tag) && tag.length <= 64;
   });
 };
 

lib/loggly/common.js

@@ -147,7 +147,7 @@ common.loggly = function () {
     }
   }
   var requestOptions = {
-    uri: isBulk ? uri + '/tag/' + headers['X-LOGGLY-TAG'] : uri,
+    uri: (isBulk && headers['X-LOGGLY-TAG']) ? uri + '/tag/' + headers['X-LOGGLY-TAG'] : uri,
     method: method,
     headers: isBulk ? {} : headers || {},             // Set headers empty for bulk
     proxy: proxy