document filter syntax

src/Core/Models/SyncConfiguration.cs

@@ -32,8 +32,38 @@ namespace Bit.Core.Models
             }
         }
 
+        /* 
+         * Depending on what server type you are using, filters are be one of the following:
+         * 
+         * 1. ActiveDirectory or Other
+         *    - LDAP query/filter syntax
+         *    - Read more at: http://bit.ly/2qyLpzW
+         *    - ex. "(&(givenName=John)(|(l=Dallas)(l=Austin)))"
+         *    
+         * 2. AzureActiveDirectory
+         *    - OData syntax for a Microsoft Graph query parameter '$filter'
+         *    - Read more at http://bit.ly/2q3FOOD
+         *    - ex. "startswith(displayName,'J')"
+         *    
+         * 3. GSuite
+         *    - Group Filter
+         *      - Custom filtering syntax that allows you to exclude or include a comma separated list of group names.
+         *      - ex. "include:Group A,Sales People,My Other Group"
+         *         or "exclude:Group C,Developers,Some Other Group"
+         *    - User Filter
+         *      - Custom filtering syntax that allows you to exclude or include a comma separated list of group names.
+         *      - Allows you to concatenate a GSuite Admin API user search query to the end of the filter after delimiting
+         *        the include/exclude filter with a pipe (|).
+         *      - Read more at http://bit.ly/2rlTskX
+         *      - ex. 
+         *         or "include:joe@company.com,bill@company.com,tom@company.com"
+         *         or "exclude:john@company.com,bill@company.com|orgName=Engineering orgTitle:Manager"
+         *         or "|orgName=Engineering orgTitle:Manager"
+         */
+
         public string GroupFilter { get; set; }
         public string UserFilter { get; set; }
+
         public bool SyncGroups { get; set; } = true;
         public bool SyncUsers { get; set; } = true;
         public int IntervalMinutes { get; set; } = 5;

src/Core/Services/GSuiteDirectoryService.cs

@@ -233,7 +233,7 @@ namespace Bit.Core.Services
             }
 
             var mainParts = filter.Split('|');
-            if(mainParts.Count() < 2)
+            if(mainParts.Count() < 2 || string.IsNullOrWhiteSpace(mainParts[1]))
             {
                 return null;
             }
@@ -249,7 +249,7 @@ namespace Bit.Core.Services
             }
 
             var mainParts = filter.Split('|');
-            if(mainParts.Count() < 1)
+            if(mainParts.Count() < 1 || string.IsNullOrWhiteSpace(mainParts[0]))
             {
                 return null;
             }