Merge pull request #191 from Hedlund01/issue_177a

ID Collison between Generated and Vanity URLS
microsoft · Dec 29, 2020 · 120f2e9 · 120f2e9
2 parents 1c9a43c + 4ff397d
commit 120f2e9
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diff --git a/src/shortenerTools/Domain/StorageTableHelper.cs b/src/shortenerTools/Domain/StorageTableHelper.cs
@@ -1,4 +1,6 @@
 using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 using Microsoft.Azure.Cosmos.Table;
 
@@ -85,6 +87,32 @@ public async Task<List<ClickStatsEntity>> GetAllStatsByVanity(string vanity)
             return lstShortUrl;
         }
 
+        /// <summary>
+        /// Returns the ShortUrlEntity of the <paramref name="vanity"/>
+        /// </summary>
+        /// <param name="vanity"></param>
+        /// <returns>ShortUrlEntity</returns>
+        public async Task<ShortUrlEntity> GetShortUrlEntityByVanity(string vanity)
+        {
+            var tblUrls = GetUrlsTable();
+            TableContinuationToken token = null;
+            ShortUrlEntity shortUrlEntity = null;
+            do
+            {
+                TableQuery<ShortUrlEntity> query = new TableQuery<ShortUrlEntity>().Where(
+                    filter: TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.Equal, vanity));
+                var queryResult = await tblUrls.ExecuteQuerySegmentedAsync(query, token);
+                shortUrlEntity = queryResult.Results.FirstOrDefault();
+            } while (token != null);
+
+            return shortUrlEntity;
+        }
+
+        public async Task<bool> IfShortUrlEntityExistByVanity(string vanity)
+        {
+            ShortUrlEntity shortUrlEntity = await GetShortUrlEntityByVanity(vanity);
+            return (shortUrlEntity != null);
+        }
 
         public async Task<bool> IfShortUrlEntityExist(ShortUrlEntity row)
         {

diff --git a/src/shortenerTools/Domain/Utility.cs b/src/shortenerTools/Domain/Utility.cs
@@ -21,6 +21,9 @@ public static async Task<string> GetValidEndUrl(string vanity, StorageTableHelpe
             {
                 var newKey = await stgHelper.GetNextTableId();
                 string getCode() => Encode(newKey);
+                if (await stgHelper.IfShortUrlEntityExistByVanity(getCode()))
+                    return await GetValidEndUrl(vanity, stgHelper);
+
                 return string.Join(string.Empty, getCode());
             }
             else