libiso - A library of utilities related to payments, crypto, ISO8583 etc

Creating ISO8583 messages

First, create a yaml file containing the spec definition (for example, see this) and then list that under a file called specs.yaml (ignore the .spec files - they're an older way of defining specs)

Read all the specs defined (the path should contain the file specs.yaml)

if err := iso8583.ReadSpecs(filepath.Join(".", "testdata")); err != nil {
		log.Fatal(err)
		return
}

Once initialized you can construct ISO8583 messages like below (from https://github.com/rkbalgi/libiso/blob/master/v2/iso8583/iso_test.go#L20) -

	specName := "ISO8583-Test"
	spec := iso8583.SpecByName(specName)
	if spec == nil {
		t.Fatal("Unable to find spec - " + specName)
	}

	// Parse a message using an existing hex-dump

	msgData, _ := hex.DecodeString("3131303070386000000080003136343736363937373635343332373737373030343030303030303030303030313039303636363535313230313333353035323239333131333336383236")

	msg := spec.FindTargetMsg(msgData) // if you know the kind of message you are parsing, you can do this - Example: spec.MessageByName("1100 - Authorization")
	if msg != nil {
		parsedMsg, err := msg.Parse(msgData)
		if err != nil {
			t.Fatal(err)
		} else {
			iso := iso8583.FromParsedMsg(parsedMsg)
			assert.Equal(t, "000000001090", iso.Bitmap().Get(4).Value())
			assert.Equal(t, "666551", iso.Bitmap().Get(11).Value())
		}
	} else {
		t.Fatal("Unable to derive the type of message the data represents")
	}

	// OR
	// build a message from scratch

	msg = spec.MessageByName("1100 - Authorization")
	iso := msg.NewIso()
	iso.Set("Message Type", "1100")
	iso.Bitmap().Set(3, "004000")
	iso.Bitmap().Set(4, "4766977654327777") // or iso.Set("PAN","4766977654327777")
	iso.Bitmap().Set(3, "004000")

	iso.Bitmap().Set(49, "336")
	iso.Bitmap().Set(50, "826")

	msgData, _, err := iso.Assemble()
	if err != nil {
		t.Fatal(err)
	}
	assert.Equal(t, "31313030300000000000c00030303430303034373636393737363534333237373737333336383236", hex.EncodeToString(msgData))

Please checkout https://github.com/rkbalgi/isosim project which uses this library.

Benchmarks

With v2.0.1 you can turn off logging (and hence gain some speed and lower allocations) using the new parser API

        parser := iso8583.NewParser(&iso8583.ParserConfig{LogEnabled: false})

        log.SetLevel(log.ErrorLevel)

	specName := "ISO8583-Test"
	spec := iso8583.SpecByName(specName)
	if spec == nil {
		b.Fatal("Unable to find spec - " + specName)
	}
	msgData, _ := hex.DecodeString("3131303070386000000080003136343736363937373635343332373737373030343030303030303030303030313039303636363535313230313333353035323239333131333336383236")

	msg := spec.FindTargetMsg(msgData) // if you know the kind of message you are parse, you can do this - Example: spec.MessageByName("1100 - Authorization")
	parsedMsg, err := parser.Parse(msg,msgData)
	iso := iso8583.FromParsedMsg(parsedMsg)
	assert.Equal(t, "000000001090", iso.Bitmap().Get(4).Value())

PS C:\Users\rkbal\IdeaProjects\libiso\v2\iso8583> go test -bench . -run Benchmark_Parse
time="2020-10-11T09:56:02+05:30" level=debug msg="Available spec files -  [isoSpecs.spec iso_specs.yaml sample_spec.yaml]"
time="2020-10-11T09:56:02+05:30" level=debug msg="Reading file .. isoSpecs.spec"
time="2020-10-11T09:56:02+05:30" level=debug msg="Reading file .. iso_specs.yaml"
time="2020-10-11T09:56:02+05:30" level=debug msg="Reading file .. sample_spec.yaml"
goos: windows
goarch: amd64
pkg: github.com/rkbalgi/libiso/v2/iso8583
Benchmark_ParseWithParserAPI-8            327625              3692 ns/op            4016 B/op         27 allocs/op
Benchmark_ParseWithMsg-8                   85014             14037 ns/op           12121 B/op        154 allocs/op
PASS
ok      github.com/rkbalgi/libiso/v2/iso8583    4.600s
PS C:\Users\rkbal\IdeaProjects\libiso\v2\iso8583>

Just to see the impact of logging , with log level turned to TRACE -

Benchmark_ParseWithMsg-8                   502           2355728 ns/op           24749 B/op        409 allocs/op

Also, a new API for assembling

			asm:=iso8583.NewAssembler(&iso8583.AssemblerConfig{
			  LogEnabled: false,
		    })

			iso := msg.NewIso()
			iso.Set("Message Type", "1100")
			iso.Bitmap().Set(3, "004000")
			iso.Bitmap().Set(4, "4766977654327777")
			iso.Bitmap().Set(3, "004000")

			iso.Bitmap().Set(49, "336")
			iso.Bitmap().Set(50, "826")

			_, _, err := asm.Assemble(iso)

Note:

Message Type and Bitmap are reserved keywords within this library (i.e you cannot call the Bitmap as Primary Bitmap or Bmp etc)
This library has not yet been subjected to any kind of targeted tests (performance or otherwise), so use this with a bit of caution - It's at the moment perhaps best suited for simulators

Paysim

Paysim is an old application that uses this library. You can read more about paysim here - https://github.com/rkbalgi/go/wiki/Paysim

JoelHenn/libiso

libiso - A library of utilities related to payments, crypto, ISO8583 etc

Creating ISO8583 messages

Benchmarks

Note:

Paysim