Converting a JSON string to CSV using CSVHelper

Question

I'm working with JSON/CSV files in my ASP.NET Web API project and tried using the CSVHelper and ServiceStack.Text libraries to generate a CSV, but couldn't make it work.

The JSON file containing an array is dynamic and may have any number of fields.

I read the file using streamreader and then need to convert it into CSV file to make it downloadable for end users.

example file text

[{"COLUMN1":"a","COLUMN2":"b","COLUMN3":"c","COLUMN4":"d","COLUMN5":"e"},
 {"COLUMN1":"a","COLUMN2":"b","COLUMN3":"c","COLUMN4":"d","COLUMN5":"e"}]

JSON to CSV

public static string jsonStringToCSV(string content)
{
    var jsonContent = (JArray)JsonConvert.DeserializeObject(content);
    
    var csv = ServiceStack.Text.CsvSerializer.SerializeToCsv(jsonContent);
    return csv;
}

This doesn't result me CSV data

Then some files are of a delimited type with comma or tab, and and I want to utilize CSVHelper to convert CSV string to an IEnumerable dynamically.

public static IEnumerable StringToList(string data, string delimiter, bool HasHeader)
{
    using (var csv = new CsvReader(new StringReader(data)))
    {
         csv.Configuration.SkipEmptyRecords = true;
         csv.Configuration.HasHeaderRecord = HasHeader;
         csv.Configuration.Delimiter = delimiter;

         var records = csv.GetRecords();
         return records;
     }
}

Answer 1

I was able to solve it by deserializing using DeserializeObject to a datatable.

To convert JSON string to DataTable with Newtonsoft's Json.NET:

public static DataTable jsonStringToTable(string jsonContent)
{
    DataTable dt = JsonConvert.DeserializeObject<DataTable>(jsonContent);
    return dt;
}

To make a CSV string with CSVHelper:

public static string jsonToCSV(string jsonContent, string delimiter)
{
    StringWriter csvString = new StringWriter();
    using (var csv = new CsvWriter(csvString))
    {
        csv.Configuration.SkipEmptyRecords = true;
        csv.Configuration.WillThrowOnMissingField = false;
        csv.Configuration.Delimiter = delimiter;

        using (var dt = jsonStringToTable(jsonContent))
        {
            foreach (DataColumn column in dt.Columns)
            {
                csv.WriteField(column.ColumnName);
            }
            csv.NextRecord();

            foreach (DataRow row in dt.Rows)
            {
                for (var i = 0; i < dt.Columns.Count; i++)
                {
                    csv.WriteField(row[i]);
                }
                csv.NextRecord();
            }
        }
    }
    return csvString.ToString();
}

Final Usage in WebAPI

string csv = jsonToCSV(content, ",");

HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
result.Content = new StringContent(csv);
result.Content.Headers.ContentType = new MediaTypeHeaderValue("text/csv");
result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileName = "export.csv" };
return result;