fix: CSV extenstion uses invariant culture

Extensions/Csv/Cosmos.DataTransfer.CsvExtension/CsvFormatWriter.cs

@@ -22,7 +22,7 @@ public async Task FormatDataAsync(IAsyncEnumerable<IDataItem> dataItems, Stream
         settings.Validate();
 
         await using var textWriter = new StreamWriter(target, leaveOpen: true);
-        await using var writer = new CsvWriter(textWriter, new CsvConfiguration(CultureInfo.InvariantCulture)
+        await using var writer = new CsvWriter(textWriter, new CsvConfiguration(settings.GetCultureInfo())
         {
             Delimiter = settings.Delimiter,
             HasHeaderRecord = settings.IncludeHeader,
@@ -49,7 +49,7 @@ public async Task FormatDataAsync(IAsyncEnumerable<IDataItem> dataItems, Stream
 
             foreach (string field in item.GetFieldNames())
             {
-                writer.WriteField(item.GetValue(field)?.ToString());
+                writer.WriteField(item.GetValue(field));
             }
 
             firstRecord = false;

Extensions/Csv/Cosmos.DataTransfer.CsvExtension/Settings/CsvWriterSettings.cs

@@ -1,9 +1,19 @@
-using Cosmos.DataTransfer.Interfaces;
+using System.Globalization;
+using Cosmos.DataTransfer.Interfaces;
 
 namespace Cosmos.DataTransfer.CsvExtension.Settings;
 
 public class CsvWriterSettings : IDataExtensionSettings
 {
     public bool IncludeHeader { get; set; } = true;
     public string Delimiter { get; set; } = ",";
+    public string Culture { get; set; } = "InvariantCulture";
+    public CultureInfo GetCultureInfo() {
+        switch (this.Culture.ToLower())
+        {
+            case "invariantculture": return CultureInfo.InvariantCulture;
+            case "current": return CultureInfo.CurrentCulture;
+            default: return CultureInfo.GetCultureInfo(this.Culture);
+        }
+    }
 }

Extensions/Csv/README.md

@@ -24,6 +24,7 @@ See storage extension documentation for any storage specific settings needed ([e
 
 Source supports an optional `Delimiter` parameter (`,` by default) and an optional `HasHeader` parameter (`true` by default). For files without a header, column names will be generated based on the `ColumnNameFormat` setting, which uses a default value of `column_{0}` to produce columns `column_0`, `column_1`, etc.
 
+
 ```json
 {
     "Delimiter": ",",
@@ -35,9 +36,17 @@ Source supports an optional `Delimiter` parameter (`,` by default) and an option
 
 Sink supports an optional `Delimiter` parameter (`,` by default) and an optional `IncludeHeader` parameter (`true` by default) to add a leading row of column names.
 
+Formatting options, or locale, can be set with an optional `Culture` setting (`"Invariant"` by default). 
+This specifies how e.g., numbers and dates are formatted according to a specific culture. 
+Set to `"Current"` to use the system's or process' current locale setting 
+(see [CultureInfo.CurrentCulture](https://learn.microsoft.com/en-us/dotnet/api/system.globalization.cultureinfo.currentculture)),
+or e.g., `"en"`, `"en-GB"`, or `"en-US"` for English standards (period, `.`, as decimal separator and other regional standards), 
+"da-DK" for Danish (comma, `,`, as decimal separator), etc.
+
 ```json
 {
     "Delimiter": ",",
-    "IncludeHeader": true
+    "IncludeHeader": true,
+    "Culture": "Invariant"
 }
 ```