Decode to a temporary message to extract or change data

[amyrprv]

Hi,
I have the below data for example

{
  "a": {
    "b": "",
    "c": {},
    "d": [
      {
        "e": "",
        "f": "s",
        "g": {
          "h": "",
          "i": "",
          "j": ""
        }
      }
    ],
    "k": {}
  },
  "l": {
    "m": { "t": "u" },
    "n": "v",
    "o": {
      "p": "̊w",
      "q": { "x": 1, "y": 1, "z": 1, "a1": 0 },
      "e": a2
    }
  }
}

Now, I aim to modify the e field within this structure. While I lack the Protobuf definition and message name, I possess the field number path to access e. I plan to generate a temporary message using the provided field numbers, decode the binary, modify the value, and then encode it again.

However, I've encountered an issue: when I decode the modified message alongside the actual message and its definition, I experience data loss and the disappearance of other fields.

Please guide on performing this task without experiencing data loss or losing other fields in the process.

[starwing]

You could use the lower level API to complete thus mission. See the document of 'Slice' (for decoding) and 'Buffer' (for encoding).