/// <summary>
/// Reads a reader as comma separated values.
/// </summary>
/// <param name="context">
/// The context.
/// </param>
/// <param name="rowBuilder">
/// The data Set.
/// </param>
/// <param name="reader">
/// The stream.
/// </param>
/// <param name="fields">
/// The fields, or <c>null</c> to retrieve all fields.
/// </param>
/// <returns>
/// The rows.
/// </returns>
public IEnumerable <Row> Read([NotNull] IFileFormatExecutionContext context, IRowBuilder rowBuilder, StreamReader reader, HashSet <string> fields)
{
var separator = context.GetDefault("SEPARATOR", false) as string ?? ",";
var splitter = CsvFileFormat.GetSplitter(separator);
var headers = CsvFileFormat.GetHeaders(splitter, reader, separator);
if (headers.Length == 1 && string.IsNullOrEmpty(headers[0]))
{
yield break;
}
var idx = 0L;
do
{
var line = splitter.Matches($"{reader.ReadLine()}{separator}")
.Cast <Match>()
.Select(match => match.Groups[1].Value)
.Select(value => value.Trim())
.Select(value => CsvFileFormat.EscapedString.IsMatch(value) ? value.Substring(1, value.Length - 2).Replace("\"\"", "\"") : value)
.ToArray();
if (line.Length == headers.Length)
{
// ReSharper disable once AccessToDisposedClosure
yield return(rowBuilder.CreateRow(idx++, headers.Select((header, i) => new KeyValuePair <string, object>(header, line[i]))));
}
}while (!reader.EndOfStream);
}
/// <summary>
/// Writes rows to the file.
/// </summary>
/// <param name="context">
/// The context.
/// </param>
/// <param name="writer">
/// The stream.
/// </param>
/// <param name="rows">
/// The rows to write.
/// </param>
/// <param name="upsert">
/// True to upsert, false to insert.
/// </param>
/// <returns>
/// The number of rows that were written.
/// </returns>
public long WriteRows(IFileFormatExecutionContext context, StreamWriter writer, [NotNull] IEnumerable <Row> rows, bool upsert)
{
var count = 0L;
foreach (var row in rows)
{
writer.WriteLine(string.Join(",", row.ColumnNames.Select(c => CsvFileFormat.Escape(row[c]))));
count++;
}
return(count);
}
/// <summary>
/// Gets the descriptor for this data source.
/// </summary>
/// <param name="alias">
/// The alias.
/// </param>
/// <param name="context">
/// The execution context.
/// </param>
/// <param name="reader">
/// The reader.
/// </param>
/// <returns>
/// The <see cref="System.Threading.Tasks.Task" />.
/// </returns>
public Task <IDataSourceDescriptor> GetDataSourceDescriptorAsync(string alias, [NotNull] IFileFormatExecutionContext context, StreamReader reader)
{
var separator = context.GetDefault("SEPARATOR", false) as string ?? ",";
return(Task.FromResult(Descriptor.ForDataSource(alias, CsvFileFormat.GetHeaders(CsvFileFormat.GetSplitter(separator), reader, separator).Where(header => header.Length > 0).Select(column => Descriptor.ForColumn(column, typeof(string))))));
}
