Added support for specifying delimiter while exporting query results as CSV (#653)

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/Contracts/SaveResultsRequest.cs

@@ -77,6 +77,11 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts
         /// Include headers of columns in CSV
         /// </summary>
         public bool IncludeHeaders { get; set; }
+
+        /// <summary>
+        /// Delimeter for separating data items in CSV
+        /// </summary>
+        public string Delimiter { get; set; }
     }
 
     /// <summary>

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/DataStorage/SaveAsCsvFileStreamWriter.cs

@@ -48,13 +48,20 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.DataStorage
         /// </param>
         public override void WriteRow(IList<DbCellValue> row, IList<DbColumnWrapper> columns)
         {
+            string delimiter = ",";
+            if(!string.IsNullOrEmpty(saveParams.Delimiter))
+            {
+                delimiter = saveParams.Delimiter;
+            }            
+
             // Write out the header if we haven't already and the user chose to have it
             if (saveParams.IncludeHeaders && !headerWritten)
             {
                 // Build the string
                 var selectedColumns = columns.Skip(ColumnStartIndex ?? 0).Take(ColumnCount ?? columns.Count)
                     .Select(c => EncodeCsvField(c.ColumnName) ?? string.Empty);
-                string headerLine = string.Join(",", selectedColumns);
+                
+                string headerLine = string.Join(delimiter, selectedColumns);
 
                 // Encode it and write it out
                 byte[] headerBytes = Encoding.UTF8.GetBytes(headerLine + Environment.NewLine);
@@ -67,7 +74,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.DataStorage
             var selectedCells = row.Skip(ColumnStartIndex ?? 0)
                 .Take(ColumnCount ?? columns.Count)
                 .Select(c => EncodeCsvField(c.DisplayValue));
-            string rowLine = string.Join(",", selectedCells);
+            string rowLine = string.Join(delimiter, selectedCells);
 
             // Encode it and write it out
             byte[] rowBytes = Encoding.UTF8.GetBytes(rowLine + Environment.NewLine);

test/Microsoft.SqlTools.ServiceLayer.UnitTests/QueryExecution/DataStorage/SaveAsCsvFileStreamWriterTests.cs

@@ -212,5 +212,54 @@ namespace Microsoft.SqlTools.ServiceLayer.UnitTests.QueryExecution.DataStorage
                 Assert.Equal(data[i].DisplayValue, dataValues[i - 1]);
             }
         }
+
+        [Fact]
+        public void WriteRowWithCustomDelimeters()
+        {
+            // Setup:
+            // ... Create a request params that has custom delimeter say pipe("|") then this delimeter should be used
+            // ... Create a set of data to write
+            // ... Create a memory location to store the data
+            var requestParams = new SaveResultsAsCsvRequestParams
+            {
+                Delimiter = "|",
+                IncludeHeaders = true
+            };
+            List<DbCellValue> data = new List<DbCellValue>
+            {
+                new DbCellValue { DisplayValue = "item1" },
+                new DbCellValue { DisplayValue = "item2" }
+            };
+            List<DbColumnWrapper> columns = new List<DbColumnWrapper>
+            {
+                new DbColumnWrapper(new TestDbColumn("column1")),
+                new DbColumnWrapper(new TestDbColumn("column2"))
+            };
+            byte[] output = new byte[8192];
+
+            // If: I write a row
+            SaveAsCsvFileStreamWriter writer = new SaveAsCsvFileStreamWriter(new MemoryStream(output), requestParams);
+            using (writer)
+            {
+                writer.WriteRow(data, columns);
+            }
+
+            // Then:
+            // ... It should have written two lines
+            string outputString = Encoding.UTF8.GetString(output).TrimEnd('\0', '\r', '\n');
+            string[] lines = outputString.Split(new[] { Environment.NewLine }, StringSplitOptions.None);
+            Assert.Equal(2, lines.Length);
+
+            // ... It should have written a header line with two, pipe("|") separated names
+            string[] headerValues = lines[0].Split('|');
+            Assert.Equal(2, headerValues.Length);
+            for (int i = 0; i < columns.Count; i++)
+            {
+                Assert.Equal(columns[i].ColumnName, headerValues[i]);
+            }
+
+            // Note: No need to check values, it is done as part of the previous tests
+        }
+
     }
 }