Swift MT940 parser in C#

Question

How to parse a MT940 swift message using C#?
Below is the message that I have to parse:

:20:MT940-1411201901
:25:1234567837710016 
:28C:008/201
:60F:C171224SAR145597,13
:61:2107221722D17000,NCHK219120//14218-102431Abnamb
:61:2107221722D17000,NCHK219120//14218-102431Abnamb VSP
:62F:C291124SAR145597,13

How can I realize that?

Answer 1

You should use this library this library instead of reinventing the wheel!

I was trying to create a parser that worked until I face some banks customisations that were MT940 compliant but my code could not manage that.

Answer 2

Try code like below :

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Text.RegularExpressions;
using System.Globalization;

namespace ConsoleApplication1
{
    class Program
    {
        const string FILENAME = @"c:\temp\test.txt";
        static void Main(string[] args)
        {
            MT940 mt940 = new MT940(FILENAME);
        }
    }
    public class MT940
    {
        const string TAG_PATTERN = @"^:(?'tag'[^:]+):(?'value'.*)";

        public string senderReference { get; set; }  //code 20
        public string authorisation { get; set; } // tag 25
        public string messageIndexTotal { get; set; } //tag 28D
        public Currency openingBalance { get; set; }  //60F
        public string firstTransaction { get; set; } //61
        public string secondTransaction { get; set; } //61
        public Currency closingBalance { get; set; } //62F

        public MT940(string filename)
        {
            StreamReader reader = new StreamReader(filename);
            string line = "";
            int transactionCount = 0;

            while ((line = reader.ReadLine()) != null)
            {
                if (line.StartsWith(":"))
                {
                    Match match = Regex.Match(line, TAG_PATTERN);
                    string tag = match.Groups["tag"].Value;
                    string value = match.Groups["value"].Value;

                    switch (tag)
                    {
                        case "20":
                            senderReference = value;
                            break;

                        case "25":
                            authorisation = value;
                            break;

                        case "28C":
                            messageIndexTotal = value;
                            break;

                        case "60F":
                            openingBalance = new Currency(value);
                            break;
                        case "61":
                            if (++transactionCount == 1)
                            {
                                firstTransaction = value;
                            }
                            else
                            {
                                secondTransaction = value;
                            }
                            break;

                        case "62F":
                            closingBalance = new Currency(value);
                            break;
                        default:
                            break;
                    }
                }
            }
        }

    }
    public class Currency
    {
        const string BALANCE_PATTERN = @"^(?'credit_debit'.)(?'date'.{6})(?'country_code'.{3})(?'amount'.*)";
        static CultureInfo culture = CultureInfo.GetCultureInfoByIetfLanguageTag("da");

        public DateTime date { get; set; }
        public string currencyCode { get; set; }
        public decimal amount { get; set; }

        public Currency(string input)
        {
            Match match = Regex.Match(input, BALANCE_PATTERN);

            string credit_debit = match.Groups["credit_debit"].Value;

            string dateStr = match.Groups["date"].Value;
            date = DateTime.ParseExact(dateStr, "yyMMdd", CultureInfo.InvariantCulture);

            currencyCode = match.Groups["country_code"].Value;

            string amountStr = match.Groups["amount"].Value;
            amount = decimal.Parse(amountStr, culture);
            amount *= credit_debit == "D" ? -1 : 1;
        }
    }
}