electron.clipboard.readText() returns empty string - electron

Question

I try to use require('electron').clipboard.readText() and just get an empty string, although I have some text in the clipboard.
I see this in Console.app (not sure if this is related):
Failed to set up CFPasteboardRef 'Apple CFPasteboard general'. Error: <error: 0x7fffa6d6fda0> { count = 1, transaction: 0, voucher = 0x0, contents =
"XPCErrorDescription" => <string: 0x7fffa6d70048> { length = 18, contents = "Connection invalid" }
}
How can I fix this?

Answer 1

I think this is because the Electron app was started via execve() in a forked process (fork() +daemon()` actually).
One workaround is to execute /usr/bin/open as a wrapper, like so (pseudo code):
open -a argv[0] --args args[1...]
Or basically this code:
char** args = parse_args(cmd);
char* arg0 = find_in_path(args[0]);
pid_t pid = fork();
if (pid == 0) {
daemon(1, 0);
#ifdef __APPLE__
{
// We cannot directly use `execv` for a GUI app on MacOSX
// in a forked process
// (e.g. issues like https://stackoverflow.com/questions/53958926/).
// But using `open` will work around this.
int argc = 0;
for(; args[argc]; ++argc);
char** args_ext = malloc(sizeof(char*) * (argc + 5));
arg0 = "/usr/bin/open";
args_ext[0] = arg0;
args_ext[1] = "-a";
args_ext[2] = args[0];
args_ext[3] = "--args";
for(int i = 0; ; ++i) {
args_ext[i + 4] = args[i + 1];
if(!args[i + 1])
break;
}
args = args_ext;
}
#endif
execv(arg0, args);
exit(-1);
} else if (pid > 0) { // master
// go on ...
free(args);
} else {
// error handling...
}
(Basically via this commit.)