Opening an URL launches the default browser at address "%u"

[Olivier Tilloy]

revelation is configured to open URLs using the following command: "gnome-open %U".
According to the source package this is the default configuration (stored in gconf as /apps/revelation/launcher/website).

When clicking on a URL inside revelation to open it, it launches firefox (or raises an existing firefox window to the top), but the URL in the address bar is "%u", literally, instead of having been replaced with the actual URL.

As far as I can remember it used to work in Natty and previous releases, this is a regression in Oneiric.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: revelation 0.4.11-9ubuntu1
ProcVersionSignature: Ubuntu 3.0.0-14.23-generic 3.0.9
Uname: Linux 3.0.0-14-generic x86_64
NonfreeKernelModules: nvidia wl
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
CheckboxSubmission: 2c7995ffdf051a6d0adf7ab2c7be5ba9
CheckboxSystem: 7e42599bda39ea7ff8b528272b6ef52b
Date: Fri Dec 16 08:52:18 2011
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
SourcePackage: revelation
UpgradeStatus: No upgrade log present (probably fresh install)

[Olivier Tilloy (osomon)]

This bug is still there in 12.04. Marking confirmed as I can consistently reproduce.

[Olivier Tilloy (osomon)]

I did a bit of investigation, and it appears that revelation uses a gnome.ui.HRef (http://developer.gnome.org/libgnomeui/stable/GnomeHRef.html) to display URLs. It appears that this widget itself is broken, not the way revelation uses it. The following piece of Python code demonstrates the issue:

    #!/usr/bin/python

    import pygtk
    pygtk.require('2.0')
    import gtk
    import gnome.ui

    if __name__ == '__main__':
        href = gnome.ui.HRef('http://ubuntu.com', 'Ubuntu')
        window = gtk.Window(gtk.WINDOW_TOPLEVEL)
        window.add(href)
        href.show()
        window.show()
        gtk.main()

[Olivier Tilloy (osomon)]

I dug further, and the issue also appears in the C implementation, the issue is not in the Python wrapper itself. The following piece of C code demonstrates it:

    // compile with: gcc `pkg-config --cflags --libs gtk+-2.0 libgnomeui-2.0` test.c

    #include <gtk/gtk.h>
    #include <libgnomeui/libgnomeui.h>

    int main(int argc, char **argv)
    {
        gtk_init(&argc, &argv);
        GtkWidget* window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
        GtkWidget* href = gnome_href_new("http://ubuntu.com", "Ubuntu");
        gtk_container_add(GTK_CONTAINER(window), href);
        gtk_widget_show(href);
        gtk_widget_show(window);
        gtk_main();
        return 0;
    }

[Olivier Tilloy (osomon)]

Re-targetting to the libgnomeui source package.

[Olivier Tilloy (osomon)]

Under the covers, gnome.ui.HRef calls gnome_url_show_with_env(...) to open a URL. The following piece of C code demonstrates that the issue seems to be in the implementation of gnome_url_show(...):

    // compile with: gcc test.c `pkg-config --cflags --libs libgnome-2.0`

    #include <libgnome/libgnome.h>

    int main(int argc, char **argv)
    {
        g_type_init();
        gnome_url_show("http://ubuntu.com", NULL);
        return 0;
    }

[Olivier Tilloy (osomon)]

gnome_url_show(...) calls gnome_vfs_url_show(...) under the hood. The issue is present there, as demonstrated by the following piece of C code:

    // compile with: gcc test.c `pkg-config --cflags --libs gnome-vfs-2.0`

    #include <libgnomevfs/gnome-vfs-utils.h>

    int main(int argc, char **argv)
    {
        g_type_init();
        gnome_vfs_url_show("http://ubuntu.com");
        return 0;
    }

[Olivier Tilloy (osomon)]

Re-targetting to the gnome-vfs source package.

[Olivier Tilloy (osomon)]

I dug further into the code of gnome-vfs, and it turns out that it inspects the value of the GConf key /desktop/gnome/url-handlers/http/command when required to open a URL. The code replaces all occurrences of "%s" with the URL passed as a parameter. On my desktop, the default value for this key is "firefox %u". Setting it to "firefox %s" fixes the issue.

[Olivier Tilloy (osomon)]

Interestingly, the default value for this key is defined in /usr/share/gconf/defaults/10_libgnomevfs2-common, and its default value is "sensible-browser %s". It might be that my configuration got messed up with at some point. Marking invalid as this is not an issue with a given package or implementation after all.

[Olivier Tilloy (osomon)]

An additional note on the topic: after inspecting my gconf settings, a number of commands associated to some protocols under /desktop/gnome/url-handlers/ had a "%u" instead of "%s" in their value, which leads me to think that some program corrupted the values as opposed to manual tinkering.