'Invalid Verb' error only when Calling Inkscape as a subprocess

Question

When I call the following in the command line it works like a charm:

inkscape --with-gui --batch-process --export-filename=- \
    --actions="select-all;ObjectToPath" \
    /full/path/to/example.svg

But when I open Node.js and make the same call in a subprocess like so:

const cp = require("child_process");
var child = cp.spawn(
    "/usr/bin/inkscape",
    [
        "--with-gui",
        "--batch-process",
        "--export-filename=-",
        '--actions="select-all;ObjectToPath"',
        "/full/path/to/example.svg",
    ],
    {
        cwd: process.cwd(),
        detached: true,
        stdio: "inherit",
    }
);

I get the following error:

Unable to find: "select-all
verbs_action: Invalid verb: "select-all
Unable to find: ObjectToPath"
verbs_action: Invalid verb: ObjectToPath"

and the file is returned (printed to stdout) unchanged. Any Idea why the verbs are not found when running Inkscape as a subprocess but not calling it directly from the terminal? I get this same error on ubuntu (20.04) and OSX using the latest Inkscape (1.0.1+r73).

Answer 1

When you use cp.spawn with an array of arguments, you don't need to internally quote "select-all;ObjectToPath" like you would with a shell. (In a shell, the quotes prevent the shell from tokenizing the command line into two lines. Due to the same mechanism - or lack thereof - attempting to use shell variables such as $$ or environment variables such as $PATH would fail when you use cp.spawn, since there's nothing to parse that.)

I would imagine

const cp = require("child_process");
var child = cp.spawn(
  "/usr/bin/inkscape",
  [
    "--with-gui",
    "--batch-process",
    "--export-filename=-",
    "--actions=select-all;ObjectToPath",
    "/full/path/to/example.svg",
  ],
  {
    cwd: process.cwd(),
    detached: true,
    stdio: "inherit",
  },
);

would do the trick for you.