Vala: How to retrieve the names of all files in a zip archive without unzipping it?

Question

Is there any function in vala like zip:list_dir in erlang ? I found libgsf, but I don't want to decompress the zip file.

Answer 1

You can use libarchive.

void check_ok (Archive.Result r) throws IOError {
    if (r == Archive.Result.OK)
        return;
    if (r == Archive.Result.WARN)
        return;
    throw new IOError.FAILED ("libarchive returned an error");
}

int main () {

    try {
        var a = new Archive.Read ();
        check_ok (a.support_filter_all ());
        check_ok (a.support_format_all ());
        check_ok (a.open_filename ("archive.zip", 10240));

        unowned Archive.Entry entry;
        while (a.next_header (out entry) == Archive.Result.OK) {
            stdout.printf ("%s\n", entry.pathname ());
            a.read_data_skip ();
        }
    }
    catch (IOError e) {
        stderr.printf (e.message + "\n");
        return 1;
    }

    return 0;
}

Compile with valac ListZip.vala --pkg libarchive --pkg gio-2.0.

GIO is only needed for the IOError errordomain. In reality, you'd want to extend the check_ok method with some more descriptive message which operation has failed.

You can also restrict libarchive to only allow zip files. I have translated the example from the upstream wiki.