Merge pull request #396 from JocaPC/master

Added POST with retry login in SqlClr asembly

Author: jovanpop-msft

samples/features/sql-clr/Curl/Curl.cs

@@ -2,6 +2,7 @@
 using System;
 using System.Data.SqlTypes;
 using System.Net;
+using System.Threading;
 
 /// <summary>
 /// Provides CURL-like functionalities in T-SQL code.
@@ -13,29 +14,19 @@ public partial class Curl
     public static SqlChars Get(SqlChars H, SqlChars url)
     {
         var client = new WebClient();
-        if (!H.IsNull)
-        {
-            var header = H.ToSqlString().Value;
-            if (!string.IsNullOrWhiteSpace(header))
-                client.Headers.Add(header);
-        }
+        AddHeader(H, client);
         return new SqlChars(
                 client.DownloadString(
                     Uri.EscapeUriString(url.ToSqlString().Value)
-                    ).ToCharArray());   
+                    ).ToCharArray());
     }
 
     [SqlProcedure]
     public static void Post(SqlChars H, SqlChars d, SqlChars url)
     {
         var client = new WebClient();
-        if (!H.IsNull)
-        {
-            var header = H.ToSqlString().Value;
-            if (!string.IsNullOrWhiteSpace(header))
-                client.Headers.Add(header);
-        }
-        if(d.IsNull)
+        AddHeader(H, client);
+        if (d.IsNull)
             throw new ArgumentException("You must specify data that will be sent to the endpoint", "@d");
         var response =
                 client.UploadString(
@@ -44,4 +35,47 @@ public static void Post(SqlChars H, SqlChars d, SqlChars url)
                     );
         SqlContext.Pipe.Send(response);
     }
+
+    [SqlProcedure]
+    public static void PostWithRetry(SqlChars H, SqlChars d, SqlChars url)
+    {
+        var client = new WebClient();
+        AddHeader(H, client);
+        if (d.IsNull)
+            throw new ArgumentException("You must specify data that will be sent to the endpoint", "@d");
+        int i = RETRY_COUNT;
+        string response = "";
+        do try
+            {
+                response =
+                        client.UploadString(
+                            Uri.EscapeUriString(url.ToSqlString().Value),
+                            d.ToSqlString().Value
+                            );
+                i = -1;
+                break;
+            }
+            catch (Exception ex)
+            {
+                SqlContext.Pipe.Send("Error:\t" + ex.Message + ". Waiting " + DELAY_ON_ERROR + "ms.");
+                i--;
+                Thread.Sleep(DELAY_ON_ERROR);
+            }
+        while (i > 0);
+        if(i==-1)
+            SqlContext.Pipe.Send("Request is executed." + response);
+    }
+
+    static readonly int RETRY_COUNT = 3;
+    static readonly int DELAY_ON_ERROR = 50;
+
+    private static void AddHeader(SqlChars H, WebClient client)
+    {
+        if (!H.IsNull)
+        {
+            var header = H.ToSqlString().Value;
+            if (!string.IsNullOrWhiteSpace(header))
+                client.Headers.Add(header);
+        }
+    }
 };