B4J Question CAN DBC file parser

[Didier99]

I am in the process of writing a CAN DBC database parser so of course first approach is to Google it to see if there is one already. On first look, I have found one in Java (CANBabel on GitHub) but not much in Visual Basic or another language that would be easier to convert into B4J.
I know I should learn how to create a B4J library from the GitHub Java code, but as always, I do not have the time to learn to do that now...

Any suggestion appreciated.

 

[Erel]

I'm not really familiar with CAN DBC, however maybe this example, based on PyBridge, will help you get started.
It is a port of: https://github.com/cantools/cantools/blob/master/examples/hello_world.py

Installation:
pip install cantools

    Dim cantools_db As PyWrapper = Py.ImportModule("cantools").GetField("database")
    Dim db As PyWrapper = cantools_db.Run("load_string").Arg(File.ReadString(File.DirAssets, "motohawk.dbc"))
    Dim message As Map = CreateMap("Temperature": 250.1, _
        "AverageRadius": 3.2, _
        "Enable": "Enabled")
    Dim encoded As PyWrapper = db.Run("encode_message").Arg("ExampleMessage").Arg(message)
    Dim decoded As PyWrapper = db.Run("decode_message").Arg("ExampleMessage").Arg(encoded)
    decoded.Print
    Wait For (encoded.Fetch) Complete (encoded As PyWrapper)
    Dim b() As Byte = encoded.Value
    Dim bc As ByteConverter
    Log(bc.HexFromBytes(b))

 

[Didier99]

I'm not really familiar with CAN DBC, however maybe this example, based on PyBridge, will help you get started.
It is a port of: https://github.com/cantools/cantools/blob/master/examples/hello_world.py

Installation:
pip install cantools

    Dim cantools_db As PyWrapper = Py.ImportModule("cantools").GetField("database")
    Dim db As PyWrapper = cantools_db.Run("load_string").Arg(File.ReadString(File.DirAssets, "motohawk.dbc"))
    Dim message As Map = CreateMap("Temperature": 250.1, _
        "AverageRadius": 3.2, _
        "Enable": "Enabled")
    Dim encoded As PyWrapper = db.Run("encode_message").Arg("ExampleMessage").Arg(message)
    Dim decoded As PyWrapper = db.Run("decode_message").Arg("ExampleMessage").Arg(encoded)
    decoded.Print
    Wait For (encoded.Fetch) Complete (encoded As PyWrapper)
    Dim b() As Byte = encoded.Value
    Dim bc As ByteConverter
    Log(bc.HexFromBytes(b))

Thank you Erel, that will definitely help!

 

[Didier99]

OK, I must admit to be very unfamiliar with python, but I
1) installed Python3
2) installed cantools

\user\AppData\Local\Programs\Python\Python313\Scripts' which is not on PATH.
Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.
Successfully installed argparse_addons-0.12.0 bitstruct-8.21.0 cantools-40.2.2 crccheck-1.3.0 diskcache-5.6.3 packaging-25.0 python-can-4.5.0 textparser-0.24.0 typing_extensions-4.14.0 wrapt-1.17.2

3) downloaded the Bleak library that includes a library that I apparently also needed

So the IDE is happy with the project but when I try to run it I get this error:

B4J Version: 10.20
Parsing code. (0.03s)
Java Version: 8
Building folders structure. (0.14s)
Compiling code. (0.60s)
Compiling layouts code. (0.01s)
Organizing libraries. (0.00s)
Compiling generated Java code. Error
javac 1.8.0_321
src\b4j\example\pyutils.java:1286: error: cannot find symbol
public static void registerMultipleKeys(java.util.List<Object> objects, java.util.List<Integer> keys, java.lang.ref.Cleaner cleaner) {
^
symbol: class Cleaner
location: package java.lang.ref
1 error

Should I add the PATH recommended in the installation of cantools?

 

[Erel]

You don't need to install Python.
You don't need to add anything to the path.

See this thread: https://www.b4x.com/android/forum/threads/pybridge-the-very-basics.165654/#content

1. Practically you can open the project I've uploaded.
2. Create a local Python runtime

3. Open it with the link and run: pip install cantools

 

[teddybear]

If you are familiar with java, perhaps the CAN-do-parser can help you