Update GNOME proxy support for GNOME 3 and Python 3

GConf is replaced by dconf and the GSettings API in GNOME 3.

doc/changelog.txt

@@ -2,6 +2,7 @@
 
 Changes:
 - cmdline: Remove options replaced by plugins and made ineffective in 9.0
+- configuration: Update proxy settings support for GNOME 3.
 
 9.4 "just passing by" (released 12.4.2018)
 

doc/en/linkchecker.1

@@ -1,4 +1,4 @@
-.TH LINKCHECKER 1 2020-04-24 "LinkChecker" "LinkChecker User Manual"
+.TH LINKCHECKER 1 2020-06-05 "LinkChecker" "LinkChecker User Manual"
 .SH NAME
 linkchecker \- command line client to check HTML documents and websites for broken links
 .SH SYNOPSIS
@@ -298,7 +298,7 @@ To use a proxy on Unix or Windows set the $http_proxy, $https_proxy or $ftp_prox
 environment variables to the proxy URL. The URL should be of the form
 \fBhttp://\fP[\fIuser\fP\fB:\fP\fIpass\fP\fB@\fP]\fIhost\fP[\fB:\fP\fIport\fP].
 LinkChecker also detects manual proxy settings of Internet Explorer under
-Windows systems, and gconf or KDE on Linux systems.
+Windows systems, and GNOME or KDE on Linux systems.
 On a Mac use the Internet Config to select a proxy.
 .PP
 You can also set a comma-separated domain list in the $no_proxy environment

doc/install.txt

@@ -54,7 +54,8 @@ First, install the required software.
    ClamAv from https://www.clamav.net/
 
 7. *Optional, for GNOME proxy setting parsing:*
-    Python Gtk from http://www.pygtk.org/downloads.html
+    PyGObject and GIO.
+    Best installed from your distribution e.g. ``python3-gi``
 
 8. *Optional, to run the WSGI web interface:*
    Apache from https://httpd.apache.org/

doc/web/media/man1/linkchecker.1.html

@@ -308,7 +308,7 @@ To use a proxy on Unix or Windows set the $http_proxy, $https_proxy or
   form
   <b>http://</b>[<i>user</i><b>:</b><i>pass</i><b>@</b>]<i>host</i>[<b>:</b><i>port</i>].
   LinkChecker also detects manual proxy settings of Internet Explorer under
-  Windows systems, and gconf or KDE on Linux systems. On a Mac use the Internet
+  Windows systems, and GNOME or KDE on Linux systems. On a Mac use the Internet
   Config to select a proxy.
 <p class="Pp">You can also set a comma-separated domain list in the $no_proxy
     environment variables to ignore any proxy settings for these domains.</p>
@@ -518,7 +518,7 @@ Copyright &#x00A9; 2000-2014 Bastian Kleineidam
 </div>
 <table class="foot">
   <tr>
-    <td class="foot-date">2020-04-24</td>
+    <td class="foot-date">2020-06-05</td>
     <td class="foot-os">LinkChecker</td>
   </tr>
 </table>

linkcheck/configuration/__init__.py

@@ -70,7 +70,7 @@ Modules = (
     ("pygeoip", "GeoIP", 'lib_version'),  # on Windows systems
     ("sqlite3", "Pysqlite", 'version'),
     ("sqlite3", "Sqlite", 'sqlite_version'),
-    ("gconf", "Gconf", '__version__'),
+    ("gi", "PyGObject", '__version__'),
     ("meliae", "Meliae", '__version__'),
 )
 
@@ -331,11 +331,11 @@ class Configuration(dict):
         if os.name != 'posix':
             return
         if "http" not in self["proxy"]:
-            http_proxy = get_gconf_http_proxy() or get_kde_http_proxy()
+            http_proxy = get_gnome_proxy() or get_kde_http_proxy()
             if http_proxy:
                 self["proxy"]["http"] = http_proxy
         if "ftp" not in self["proxy"]:
-            ftp_proxy = get_gconf_ftp_proxy() or get_kde_ftp_proxy()
+            ftp_proxy = get_gnome_proxy(protocol="FTP") or get_kde_ftp_proxy()
             if ftp_proxy:
                 self["proxy"]["ftp"] = ftp_proxy
 
@@ -440,43 +440,26 @@ def get_user_config():
     return userconf
 
 
-def get_gconf_http_proxy():
-    """Return host:port for GConf HTTP proxy if found, else None."""
+def get_gnome_proxy(protocol="HTTP"):
+    """Return host:port for a GNOME proxy if found, else None."""
     try:
-        import gconf
+        import gi
+        gi.require_version('Gio', '2.0')
+        from gi.repository import Gio
     except ImportError:
         return None
     try:
-        client = gconf.client_get_default()
-        if client.get_bool("/system/http_proxy/use_http_proxy"):
-            host = client.get_string("/system/http_proxy/host")
-            port = client.get_int("/system/http_proxy/port")
-            if host:
-                if not port:
-                    port = 8080
-                return "%s:%d" % (host, port)
-    except Exception as msg:
-        log.debug(LOG_CHECK, "error getting HTTP proxy from gconf: %s", msg)
-        pass
-    return None
-
-
-def get_gconf_ftp_proxy():
-    """Return host:port for GConf FTP proxy if found, else None."""
-    try:
-        import gconf
-    except ImportError:
-        return None
-    try:
-        client = gconf.client_get_default()
-        host = client.get_string("/system/proxy/ftp_host")
-        port = client.get_int("/system/proxy/ftp_port")
+        settings = Gio.Settings.new("org.gnome.system.proxy.%s" % protocol.lower())
+        if protocol == "HTTP" and not settings.get_boolean("enabled"):
+            return None
+        host = settings.get_string("host")
+        port = settings.get_int("port")
         if host:
             if not port:
                 port = 8080
             return "%s:%d" % (host, port)
     except Exception as msg:
-        log.debug(LOG_CHECK, "error getting FTP proxy from gconf: %s", msg)
+        log.debug(LOG_CHECK, "error getting %s proxy from GNOME: %s", (protocol, msg))
         pass
     return None
 

linkchecker

@@ -84,7 +84,7 @@ To use a proxy on Unix or Windows set $http_proxy, $https_proxy or $ftp_proxy
 to the proxy URL. The URL should be of the form
 "http://[<user>:<pass>@]<host>[:<port>]".
 LinkChecker also detects manual proxy settings of Internet Explorer under
-Windows systems, and gconf or KDE on Linux systems.
+Windows systems, and GNOME or KDE on Linux systems.
 On a Mac use the Internet Config to select a proxy.
 
 LinkChecker honors the $no_proxy environment variable. It can be a list

setup.py

@@ -386,7 +386,7 @@ setup(
     # See also doc/install.txt for more detailed dependency documentation.
     # extra_requires = {
     #    "IP country info": ['GeoIP'], # https://pypi.org/project/GeoIP/
-    #    "GNOME proxies": ['pygtk'], # http://www.pygtk.org/downloads.html
+    #    "GNOME proxies": ['PyGObject'], # https://pypi.org/project/PyGObject/
     #    "Bash completion": ['argcomplete'], # https://pypi.org/project/argcomplete/
     #    "Memory debugging": ['meliae'], # https://pypi.org/project/meliae/
     # }