CsvBuilder.cs

CsvBuilder.cs

    /// <summary>
    /// Class for building CSV outputs
    /// </summary>
    /// <seealso cref="System.IDisposable" />
    public class CsvBuilder : IDisposable
    {
        private readonly StringBuilder _stringBuilder;
        private readonly string _delimiter;

        /// <summary>
        /// Initializes a new instance of the <see cref="CsvBuilder"/> class.
        /// </summary>
        /// <param name="delimiter">The delimiter.</param>
        public CsvBuilder(string delimiter)
        {
            _stringBuilder = new StringBuilder();
            _delimiter = delimiter;
        }

        public void ParseObjectsToCsv<T>(IEnumerable<T> objects)
        {
            if (objects == null || !objects.Any())
            {
                return;
            }

            _stringBuilder.Clear();

            var properties = typeof(T).GetProperties();

            var headers = properties.Select(p => p.Name);

            AddLine(headers);

            var lines = objects.Select(o => properties.Select(p => p.GetValue(o)));

            AddLines(lines);
        }

        /// <summary>
        /// Adds the lines. Each item is a row, and each item in the item is a column.
        /// </summary>
        /// <param name="lines">The lines.</param>
        public void AddLines(IEnumerable<IEnumerable<object>> lines)
        {
            foreach (var line in lines)
            {
                AddLine(line);
            }
        }

        /// <summary>
        /// Adds the line one-column.
        /// </summary>
        /// <param name="line">The line.</param>
        public void AddLine(object line)
        {
            AddLine(new List<object> { line });
        }

        /// <summary>
        /// Adds the line. Each item is a column.
        /// </summary>
        /// <param name="line">The line.</param>
        public void AddLine(IEnumerable<object> line)
        {
            var lineAsStrings = line.Select(col => col?.ToString().Replace(_delimiter, string.Empty)).ToArray();

            _stringBuilder.AppendLine(string.Join(_delimiter, lineAsStrings));
        }

        /// <summary>
        /// Gets the output as a string.
        /// </summary>
        /// <returns></returns>
        public string GetOutput()
        {
            return _stringBuilder.ToString();
        }

        /// <summary>
        /// Returns a FileContentResult with the CSV data.
        /// </summary>
        /// <param name="fileName">Name of the file.</param>
        /// <returns></returns>
        public FileContentResult ToFileContentResult(string fileName)
        {
            var fileContents = Encoding.ASCII.GetBytes(GetOutput());

            var result = new FileContentResult(fileContents, "text/csv")
            {
                FileDownloadName = fileName
            };

            return result;
        }

        public ResponseMessageResult ToResponseMessageResult(string fileName)
        {
            var content = GetOutput();

            var result = new HttpResponseMessage(HttpStatusCode.OK)
            {
                Content = new StringContent(content, Encoding.UTF8, "text/csv")
            };
            result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
            {
                FileName = fileName
            };
            result.Content.Headers.ContentType = new MediaTypeHeaderValue("text/csv");

            return new ResponseMessageResult(result);
        }

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose()
        {
            _stringBuilder.Clear();
        }
    }