odd value parsing issue in ISOMessage

[anilgorgec]

Hello,

I have a question regarding odd numbers. for example the Track 2 Data field has a length of 37 characters, which is an odd number. Since ISO 8583 messages are often processed in hexadecimal or BCD format, they need to be byte-aligned.

I tried to parse the iso message in the example below.but I could not get the output as expected output.

Can you help me with this issue?

ISO Message: 020030200580208000000000000000000015001079890071002100375111111211111111d11110000000000000000f5445535430303031

output

MTI..........: 0200
Bitmap HEX...: 3020058020800000
Bitmap bits..:
    [1-8]00110000    [9-16]00100000   [17-24]00000101   [25-32]10000000
  [33-40]00100000   [41-48]10000000   [49-56]00000000   [57-64]00000000
F0   Message Type Indicator.................: 0200
F3   Processing Code........................: 0
F4   Transaction Amount.....................: 1500
F11  Systems Trace Audit Number (STAN)......: 107989
F22  Point of Sale (POS) Entry Mode.........: 007
F24  Function Code..........................: 100
F25  Point of Service Condition Code........: 21
F35  Track 2 Data...........................: =^^
F41  Card Acceptor Terminal Identification..: 37511111

expected output

MTI..........: 0200
Bitmap HEX...: 3020058020800000
Bitmap bits..:
    [1-8]00110000    [9-16]00100000   [17-24]00000101   [25-32]10000000
  [33-40]00100000   [41-48]10000000   [49-56]00000000   [57-64]00000000
F0   Message Type Indicator.................: 0200
F3   Processing Code........................: 0
F4   Transaction Amount.....................: 1500
F11  Systems Trace Audit Number (STAN)......: 107989
F22  Point of Sale (POS) Entry Mode.........: 0071
F24  Function Code..........................: 0021
F25  Point of Service Condition Code........: 00
F35  Track 2 Data...........................: 5111111211111111d11110000000000000000
F41  Card Acceptor Terminal Identification..: TEST0001 ```

[alovak]

Could you please share your (Go) spec here?

[carlosmgc2003]

I've had exactly this problem and solved it by creating a custom Hex field and a custom BCD prefix:

        35: custom.NewTrack2(&field.Spec{
            Length:      37,
            Description: "Track 2 Data",
            Enc:         encoding.Binary,
            Pref:        custom.BCD.LL,
        }),

I could'nt manage to use moov/iso8583 built in types (perhaps it is possible to do so). I can share you this implementation here if you want and moderators allow.

[anilgorgec]

Could you please share your (Go) spec here?

The spec is as follows.

var Spec87 = &iso8583.MessageSpec{
    Name: "ISO",
    Fields: map[int]field.Field{
        0: field.NewString(&field.Spec{
            Length:      4,
            Description: "Message Type Indicator",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
        1: field.NewBitmap(&field.Spec{
            Length:      8,
            Description: "Bitmap",
            Enc:         encoding.BytesToASCIIHex,
            Pref:        prefix.Hex.Fixed,
        }),
        3: field.NewNumeric(&field.Spec{
            Length:      6,
            Description: "Processing Code",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
        4: field.NewString(&field.Spec{
            Length:      12,
            Description: "Transaction Amount",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
            Pad:         padding.Left('0'),
        }),

        11: field.NewString(&field.Spec{
            Length:      6,
            Description: "Systems Trace Audit Number (STAN)",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
        12: field.NewString(&field.Spec{
            Length:      6,
            Description: "Local Transaction Time",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
        13: field.NewString(&field.Spec{
            Length:      4,
            Description: "Local Transaction Date",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
        22: field.NewString(&field.Spec{
            Length:      3,
            Description: "Point of Sale (POS) Entry Mode",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),

        24: field.NewString(&field.Spec{
            Length:      3,
            Description: "Function Code",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
        25: field.NewString(&field.Spec{
            Length:      2,
            Description: "Point of Service Condition Code",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
        35: field.NewTrack2(&field.Spec{
            Length:      37,
            Description: "Track 2 Data",
            Enc:         encoding.ASCIIHexToBytes,
            Pref:        prefix.ASCII.LL,
        }),
        41: field.NewString(&field.Spec{
            Length:      8,
            Description: "Card Acceptor Terminal Identification",
            Enc:         encoding.ASCII,
            Pref:        prefix.ASCII.Fixed,
        }),
    },
}

[anilgorgec]

I've had exactly this problem and solved it by creating a custom Hex field and a custom BCD prefix:

      35: custom.NewTrack2(&field.Spec{
          Length:      37,
          Description: "Track 2 Data",
          Enc:         encoding.Binary,
          Pref:        custom.BCD.LL,
      }),

I could'nt manage to use moov/iso8583 built in types (perhaps it is possible to do so). I can share you this implementation here if you want and moderators allow.

if they allows, I wanna see it. It will give idea at least.