Java says "ghidra" is unknown protocol when creating project on linux

Question

Update: I installed Eclipse and PyDev in Linux and my code works now. This confirms it was an issue setting up the Python/Jython paths. I would still like to know how to import ghidra.jar into jython so that I can use the command line in the future. Any help here would be greatly appreciated.

I am making a ghidra project on Linux. I am using a Ghidra jar and jython to code my application. I am adding ghidra to my path with system.path.append() and I am running my program with jython main.py.

My code worked with Pydev in Eclipse on Windows, but on Linux I am getting

java.lang.IllegalArgumentException: java.lang.IllegalArgumentException: java.net.MalformedURLException: unknown protocol: ghidra

when I reach ghidraProject.createProject(). I investigated the source and I found that the error occurs when Java tries to make a url from a string. I know Ghidra has a protocol handler which should be handling the protocol "ghidra". I assume Java doesn't register the protocol handler somehow. I tried Handler.registerHandler() with no luck.

Why is "ghidra" an unknown protocol on Linux, but the same code works (save for the PyDev environment) in Eclipse/Windows?

Error printout:

Answer 1

You are trying to use Ghidra without initializing it first, Ghidra isn't really designed as a typical Java library which you could use like any other .jar. If you want to check out how the Ghidra provided pythonRun entry point handles a minimal jython REPL embedded inside Ghidra, check out: https://github.com/NationalSecurityAgency/ghidra/blob/da94eb86bd2b89c8b0ab9bd89e9f0dc5a3157055/Ghidra/Features/Python/src/main/java/ghidra/python/PythonRun.java

The crucial part here is:

ApplicationConfiguration configuration = new HeadlessGhidraApplicationConfiguration();
Application.initializeApplication(layout, configuration);

which runs through various initialization steps that the overall Ghidra code assumes to have happened when being executed, one of them being the setup for the ghidra:// protocol handler. Specifically the call to ghidra.framework.protocol.ghidra.Handler.registerHandler() happens inside ghidra.ProjectInitializer#run.