Feature/save results as csv (#33)

* Code changes to save results as csv

*  changes to save resultset as csv

* removed csvHelper

* Retrieve right resultSet after batch execution]

* code clean up

* encode column names and use string.Join

* code review changes - property fix and rowBuilder removal

* changes to fix execution tests

* Code clean up

* Code clean up

* Test save as CSV

* Fix tests for Mac/Linux

* Add doc comment

* Add doc comments

* Delete file if exception occurs

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

@@ -0,0 +1,70 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+
+using System;
+using Microsoft.SqlTools.ServiceLayer.Hosting.Protocol.Contracts;
+
+namespace Microsoft.SqlTools.ServiceLayer.QueryExecution.Contracts
+{
+    /// <summary>
+    /// Parameters for the save results request
+    /// </summary>
+    public class SaveResultsRequestParams
+    {
+        /// <summary>
+        /// The path of the file to save results in
+        /// </summary>
+        public string FilePath { get; set; }
+
+        /// <summary>
+        /// The encoding of the file to save results in
+        /// </summary>
+        public string FileEncoding { get; set; }
+
+        /// <summary>
+        /// Include headers of columns in CSV
+        /// </summary>
+        public bool IncludeHeaders { get; set; }
+
+        /// <summary>
+        /// Index of the batch to get the results from
+        /// </summary>
+        public int BatchIndex { get; set; }
+
+        /// <summary>
+        /// Index of the result set to get the results from
+        /// </summary>
+        public int ResultSetIndex { get; set; }
+
+        /// <summary>
+        /// CSV - Write values in quotes 
+        /// </summary>
+        public Boolean ValueInQuotes { get; set; }
+
+        /// <summary>
+        /// URI for the editor that called save results
+        /// </summary>
+        public string OwnerUri { get; set; }
+    }
+
+    /// <summary>
+    /// Parameters for the save results result
+    /// </summary>
+    public class SaveResultRequestResult
+    {
+        /// <summary>
+        /// Error messages for saving to file. 
+        /// </summary>
+        public string Messages { get; set; }
+    }
+
+    public class SaveResultsAsCsvRequest
+    {
+        public static readonly
+            RequestType<SaveResultsRequestParams, SaveResultRequestResult> Type =
+            RequestType<SaveResultsRequestParams, SaveResultRequestResult>.Create("query/save");
+    }
+
+}

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/QueryExecutionService.cs

@@ -2,9 +2,10 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 //
-
 using System;
 using System.Collections.Concurrent;
+using System.IO;
+using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.SqlTools.ServiceLayer.Connection;
 using Microsoft.SqlTools.ServiceLayer.Hosting;
@@ -98,6 +99,7 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
             serviceHost.SetRequestHandler(QueryExecuteSubsetRequest.Type, HandleResultSubsetRequest);
             serviceHost.SetRequestHandler(QueryDisposeRequest.Type, HandleDisposeRequest);
             serviceHost.SetRequestHandler(QueryCancelRequest.Type, HandleCancelRequest);
+            serviceHost.SetRequestHandler(SaveResultsAsCsvRequest.Type, HandleSaveResultsAsCsvRequest);
 
             // Register handler for shutdown event
             serviceHost.RegisterShutdownTask((shutdownParams, requestContext) =>
@@ -256,6 +258,58 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
             }
         }
 
+        /// <summary>
+        /// Process request to save a resultSet to a file in CSV format
+        /// </summary>
+        public async Task HandleSaveResultsAsCsvRequest( SaveResultsRequestParams saveParams,
+            RequestContext<SaveResultRequestResult> requestContext)
+        {
+            // retrieve query for OwnerUri
+            Query result;
+            if (!ActiveQueries.TryGetValue(saveParams.OwnerUri, out result))
+            {
+                await requestContext.SendResult(new SaveResultRequestResult
+                {
+                    Messages = "Failed to save results, ID not found."
+                });
+                return;
+            }
+            try
+            {
+                using (StreamWriter csvFile = new StreamWriter(File.OpenWrite(saveParams.FilePath)))
+                {
+                    // get the requested resultSet from query
+                    Batch selectedBatch = result.Batches[saveParams.BatchIndex];
+                    ResultSet selectedResultSet = (selectedBatch.ResultSets.ToList())[saveParams.ResultSetIndex];
+                    if ( saveParams.IncludeHeaders) 
+                    {
+                        // write column names to csv
+                        await csvFile.WriteLineAsync( string.Join( ",", selectedResultSet.Columns.Select( column => SaveResults.EncodeCsvField(column.ColumnName) ?? string.Empty)));
+                    }
+
+                    // write rows to csv
+                    foreach( var row in selectedResultSet.Rows)
+                    {
+                        await csvFile.WriteLineAsync(string.Join( ",", row.Select( field => SaveResults.EncodeCsvField( (field != null) ? field.ToString(): string.Empty))));
+                    }
+                }
+            }
+            catch(Exception ex)
+            {
+                // Delete file when exception occurs
+                if(File.Exists(saveParams.FilePath))
+                {
+                    File.Delete(saveParams.FilePath);
+                }
+                await requestContext.SendError(ex.Message);
+                return;
+            }
+            await requestContext.SendResult(new SaveResultRequestResult
+            {
+                Messages = "Success"
+            });
+            return;
+        }
         #endregion
 
         #region Private Helpers

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/ResultSet.cs

@@ -111,6 +111,14 @@ namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
         /// </summary>
         public long RowCount { get; private set; }
 
+        /// <summary>
+        /// The rows of this result set
+        /// </summary>
+        public IEnumerable<object[]> Rows
+        {
+            get { return FileOffsets.Select(offset => fileStreamReader.ReadRow(offset, Columns)); }
+        }
+
         #endregion
 
         #region Public Methods

src/Microsoft.SqlTools.ServiceLayer/QueryExecution/SaveResults.cs

@@ -0,0 +1,84 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+//
+using System;
+using System.Text;
+
+namespace Microsoft.SqlTools.ServiceLayer.QueryExecution
+{
+    internal class SaveResults{
+
+        /// Method ported from SSMS
+
+        /// <summary>
+        /// Encodes a single field for inserting into a CSV record. The following rules are applied:
+        /// <list type="bullet">
+        /// <item><description>All double quotes (") are replaced with a pair of consecutive double quotes</description></item>
+        /// </list>
+        /// The entire field is also surrounded by a pair of double quotes if any of the following conditions are met:
+        /// <list type="bullet">
+        /// <item><description>The field begins or ends with a space</description></item>
+        /// <item><description>The field begins or ends with a tab</description></item>
+        /// <item><description>The field contains the ListSeparator string</description></item>
+        /// <item><description>The field contains the '\n' character</description></item>
+        /// <item><description>The field contains the '\r' character</description></item>
+        /// <item><description>The field contains the '"' character</description></item>
+        /// </list>
+        /// </summary>
+        /// <param name="field">The field to encode</param>
+        /// <returns>The CSV encoded version of the original field</returns>
+        internal static String EncodeCsvField(String field)
+        {
+            StringBuilder sbField = new StringBuilder(field);
+            
+            //Whether this field has special characters which require it to be embedded in quotes
+            bool embedInQuotes = false;
+
+            //Check for leading/trailing spaces
+            if (sbField.Length > 0 &&
+                (sbField[0] == ' ' ||
+                sbField[0] == '\t' ||
+                sbField[sbField.Length - 1] == ' ' ||
+                sbField[sbField.Length - 1] == '\t'))
+            {
+                embedInQuotes = true;
+            }
+            else
+            {   //List separator being in the field will require quotes
+                if (field.Contains(","))
+                {
+                    embedInQuotes = true;
+                }
+                else
+                {
+                    for (int i = 0; i < sbField.Length; ++i)
+                    {
+                        //Check whether this character is a special character
+                        if (sbField[i] == '\r' ||
+                            sbField[i] == '\n' ||
+                            sbField[i] == '"')
+                        { //If even one character requires embedding the whole field will
+                            //be embedded in quotes so we can just break out now
+                            embedInQuotes = true;
+                            break;
+                        }
+                    }
+                }
+            }
+            
+            //Replace all quotes in the original field with double quotes
+            sbField.Replace("\"", "\"\"");
+
+            String ret = sbField.ToString();
+          
+            if (embedInQuotes)
+            {
+                ret = "\"" + ret + "\"";
+            }
+
+            return ret;
+        }
+    }
+
+}