Handling Optional Parameters about smpp34

[CodeMonkeyKevin]

x, _ := smpp.ParsePdu(b)

// Writing Normal Fields
x.SetField("data_coding", 1)
x.SetField("destination_addr", "15156855111")
x.SetField("validity_period", "")

// Reading all Normal Fields
for _, v := range x.MandatoryFieldsList() {
  f := x.GetField(v)
  fmt.Println(v, ":", f, "|")
}

// Writing Optional Fields
x.SetTLVField(30, 2, []byte{0, 0})

// Reading Optional Fields
for t, v := range x.TLVFields() {
  fmt.Println(t, ":", v.Value())
}

[jaroszan]

Thanks, I have checked in the code and from I've found (fair warning: my golang knowledge is rather crude) it seems that I can't extend examples (trx_example.go in particular) with this code and some deeper code manipulation is required.

In particular it seems that I need to extend smpp34/smpp.go to accept extra parameter for the TLV fields for the selected PDU. Is it a proper way to go?

Or may be the optimal way would be to copy code from smpp.go and build PDU in the example code from the ground up?

[CodeMonkeyKevin]

You won't have the change smpp.go. You can set any TLV using SetTLVField. Which PDU are you trying to set TLV for and what is the TLV you are trying to set?

[jaroszan]

I am trying to set user_message_reference, payload_type and message_payload TLVs for submit_sm in transceiver mode and I am looking at transceiver example.

It looks that the following line does both building and sending PDU:

seq, err := trx.SubmitSm("test", "test2", "msg", &smpp.Params{})

When I look at smpp.go I see that only regular fields are processed as params and no handling of TLV fields is done on that level. I suspect that setting TLVs should be done on the lower level (I have been trying to understand in details how library works but so far not everything is clear to me)

[CodeMonkeyKevin]

Jaroszan,

I see what you mean. This will require a trx api change to SubmitSm I'll put it out in the next release but you use the below code as a drop in replacement and a work around before the api change.

// create SubmitSm PDU without writing it to the write
pdu, err := trx.Smpp.SubmitSm("test", "test2", "msg", &smpp.Params{})

// set TLV
pdu.SetTLVField(30, 2, []byte{0, 0})

// write PDU to write
if err := trx.Write(p); err != nil {
    // sending PDU error
}

[jaroszan]

Thanks, it worked almost outside the box:

if err := trx.Write(pdu); err != nil {
// sending PDU error
}

It seems that setting TLV field in the following way is rather prone:

pdu.SetTLVField(30, 2, []byte{0, 0})

I am setting it in the following way:

message_payload := []byte{0x73, 0x73, 0x73}
length_mp := len(message_payload)
seq.SetTLVField(1060, length_mp, message_payload)

I guess SetTLVField could be optimized to accept 2 parameters and calculate payload length inside this function:

func (s *SubmitSm) SetTLVField(t int, v []byte) error {
    l := len(v) 
    s.tlvFields[uint16(t)] = &TLVField{uint16(t), uint16(l), v}
    return nil
}

But I haven't checked it yet.

As far as I am concerned this particular issue is clarified and can be closed.

[kharry5]

Was any change ever made to support this at the transmitter / transceiver level?