split out remotedb to it's own file, add gpg signed list support, some pyflakes cleanup

5 files changed, 457 insertions, 224 deletions

diff --git a/etc/layman.cfg b/etc/layman.cfg
index a99ab9d..8a39ab9 100644
--- a/etc/layman.cfg
+++ b/etc/layman.cfg
@@ -36,8 +36,42 @@ make_conf : %(storage)s/make.conf
 #            http://dev.gentoo.org/~wrobel/layman/global-overlays.xml
 #            http://mydomain.org/my-layman-list.xml
 #            file:///var/lib/layman/my-list.xml
+#
+##### NEW ##### GPG signed lists #####
+#
+#  gpg_signed_lists :
+#       These can be clearsigned or signed (compressed) overlay lists
+#       Each url will be one complete file to download, verify, decrypt.
+#       layman will automatically verify and decrypt the list before saving
+#       One url per line, indented
+#
+#   e.g.:
+#    gpg_signed_lists :
+#        http://someserver.somewhere.com/someoverlays.xml.asc
+#
+gpg_signed_lists :
+
+#
+# gpg_detached_lists:
+#       These url's involve downloading 2 files
+#       The first url listed will be the overlays xml list.
+#       The second url will be the detached signature file
+#           with one of {.gpg, .asc, .sig} extension
+#       Both url's must be on the same line space separated and indented
+#
+#   e.g.:
+#    gpg_detached_lists :
+#        http://distfiles.gentoo.org/overlays.xml http://distfiles.gentoo.org/overlays.xml.asc
+#        http://someserver.somewhere.com/someoverlays.xml http://someserver.somewhere.com/someoverlays.xml.gpg
+
+gpg_detached_lists :
+#    http://distfiles.gentoo.org/overlays.xml http://distfiles.gentoo.org/overlays.xml.asc
+
+#  original unsigned lists and definitions
+#  one url per line, indented
 
-overlays  : http://www.gentoo.org/proj/en/overlays/repositories.xml
+overlays  :
+    http://www.gentoo.org/proj/en/overlays/repositories.xml
 
 #-----------------------------------------------------------
 # The directory to scan for xml overlay definition files to include
diff --git a/layman/api.py b/layman/api.py
index 8dda224..11534fd 100755
--- a/layman/api.py
+++ b/layman/api.py
@@ -13,16 +13,16 @@
 #              Brian Dolbec <dol-sen@sourceforge.net>
 #
 
-from sys import stderr
 import os
 
 from layman.config import BareConfig
 
 from layman.dbbase import UnknownOverlayException, UnknownOverlayMessage
-from layman.db import DB, RemoteDB
+from layman.db import DB
+from layman.remotedb import RemoteDB
 from layman.overlays.source import require_supported
 #from layman.utils import path, delete_empty_directory
-from layman.compatibility import encode, fileopen
+from layman.compatibility import encode
 
 
 UNKNOWN_REPO_ID = "Repo ID '%s' " + \
@@ -499,8 +499,8 @@ class LaymanAPI(object):
 
     def reload(self):
         """reloads the installed and remote db's to the data on disk"""
-        result = self.get_available(dbreload=True)
-        result = self.get_installed(dbreload=True)
+        self.get_available(dbreload=True)
+        self.get_installed(dbreload=True)
 
 
     def _error(self, message):
@@ -599,7 +599,7 @@ def create_fd():
     """
     fd_r, fd_w = os.pipe()
     write = os.fdopen(fd_w, 'w')
-    rread = os.fdopen(fd_r, 'r')
+    read = os.fdopen(fd_r, 'r')
     return (read, write, fd_r, fd_w)
 
 
diff --git a/layman/config.py b/layman/config.py
index 1f5bc34..bb15abb 100644
--- a/layman/config.py
+++ b/layman/config.py
@@ -53,9 +53,9 @@ def read_layman_config(config=None, defaults=None, output=None):
         filelist = [f for f in filelist if f.endswith('.xml')]
         overlays = set(config.get('MAIN', 'overlays').split('\n'))
         for _file in filelist:
-            path = os.path.join(config.get('MAIN', 'overlay_defs'), _file)
-            if os.path.isfile(path):
-                overlays.update(["file://" + path])
+            _path = os.path.join(config.get('MAIN', 'overlay_defs'), _file)
+            if os.path.isfile(_path):
+                overlays.update(["file://" + _path])
         config.set('MAIN', 'overlays', '\n'.join(overlays))
 
 
@@ -105,6 +105,8 @@ class BareConfig(object):
                     'umask'     : '0022',
                     'news_reporter': 'portage',
                     'custom_news_pkg': '',
+                    'gpg_detached_lists': '',
+                    'gpg_signed_lists': '',
                     'overlays'  :
                     'http://www.gentoo.org/proj/en/overlays/repositories.xml',
                     'overlay_defs': '%(configdir)s/overlays',
diff --git a/layman/db.py b/layman/db.py
index e2d740c..8dc968e 100644
--- a/layman/db.py
+++ b/layman/db.py
@@ -27,17 +27,11 @@ __version__ = "$Id: db.py 309 2007-04-09 16:23:38Z wrobel $"
 #-------------------------------------------------------------------------------
 
 import os, os.path
-import sys
-import urllib2
-import hashlib
 
-from   layman.utils             import path, delete_empty_directory, encoder
+from   layman.utils             import path, delete_empty_directory
 from   layman.dbbase            import DbBase
 from   layman.makeconf          import MakeConf
-from   layman.version           import VERSION
-from layman.compatibility       import fileopen
 
-#from   layman.debug             import OUT
 
 #===============================================================================
 #
@@ -238,213 +232,6 @@ class DB(DbBase):
                             '" returned status ' + str(result) + '!' +
                             '\ndb.sync()')
 
-#===============================================================================
-#
-# Class RemoteDB
-#
-#-------------------------------------------------------------------------------
-
-class RemoteDB(DbBase):
-    '''Handles fetching the remote overlay list.'''
-
-    def __init__(self, config, ignore_init_read_errors=False):
-
-        self.config = config
-        self.output = config['output']
-
-        self.proxies = {}
-
-        if config['proxy']:
-            self.proxies['http'] = config['proxy']
-        elif os.getenv('http_proxy'):
-            self.proxies['http'] = os.getenv('http_proxy')
-
-        if self.proxies:
-            proxy_handler = urllib2.ProxyHandler(self.proxies)
-            opener = urllib2.build_opener(proxy_handler)
-            urllib2.install_opener(opener)
-
-        self.urls  = [i.strip() for i in config['overlays'].split('\n') if len(i)]
-
-        paths = [self.filepath(i) + '.xml' for i in self.urls]
-
-        if config['nocheck']:
-            ignore = 2
-        else:
-            ignore = 0
-
-        #quiet = int(config['quietness']) < 3
-
-        DbBase.__init__(self, config, paths=paths, ignore=ignore,
-            ignore_init_read_errors=ignore_init_read_errors)
-
-    # overrider
-    def _broken_catalog_hint(self):
-        return 'Try running "sudo layman -f" to re-fetch that file'
-
-    def cache(self):
-        '''
-        Copy the remote overlay list to the local cache.
-
-        >>> import tempfile
-        >>> here = os.path.dirname(os.path.realpath(__file__))
-        >>> tmpdir = tempfile.mkdtemp(prefix="laymantmp_")
-        >>> cache = os.path.join(tmpdir, 'cache')
-        >>> myoptions = {'overlays' :
-        ...           ['file://' + here + '/tests/testfiles/global-overlays.xml'],
-        ...           'cache' : cache,
-        ...           'nocheck'    : 'yes',
-        ...           'proxy' : None}
-        >>> from layman.config import OptionConfig
-        >>> config = OptionConfig(myoptions)
-        >>> config.set_option('quietness', 3)
-        >>> a = RemoteDB(config)
-        >>> a.cache()
-        (True, True)
-        >>> b = fileopen(a.filepath(config['overlays'])+'.xml')
-        >>> b.readlines()[24]
-        '      A collection of ebuilds from Gunnar Wrobel [wrobel@gentoo.org].\\n'
-
-        >>> b.close()
-        >>> os.unlink(a.filepath(config['overlays'])+'.xml')
-
-        >>> a.overlays.keys()
-        [u'wrobel', u'wrobel-stable']
-
-        >>> import shutil
-        >>> shutil.rmtree(tmpdir)
-        '''
-        has_updates = False
-        # succeeded reset when a failure is detected
-        succeeded = True
-        for url in self.urls:
-
-            filepath = self.filepath(url)
-            mpath = filepath + '.xml'
-            tpath = filepath + '.timestamp'
-
-            # check when the cache was last updated
-            # and don't re-fetch it unless it has changed
-            request = urllib2.Request(url)
-            opener = urllib2.build_opener()
-            opener.addheaders = [('User-Agent', 'Layman-' + VERSION)]
-
-            if os.path.exists(tpath):
-                with fileopen(tpath,'r') as previous:
-                    timestamp = previous.read()
-                request.add_header('If-Modified-Since', timestamp)
-
-            if not self.check_path([mpath]):
-                continue
-
-            try:
-                connection = opener.open(request)
-                # py2, py3 compatibility, since only py2 returns keys as lower()
-                headers = dict((x.lower(), x) for x in connection.headers.keys())
-                if 'last-modified' in headers:
-                    timestamp = connection.headers[headers['last-modified']]
-                elif 'date' in headers:
-                    timestamp = connection.headers[headers['date']]
-                else:
-                    timestamp = None
-            except urllib2.HTTPError, e:
-                if e.code == 304:
-                    self.output.info('Remote list already up to date: %s'
-                        % url, 4)
-                    self.output.info('Last-modified: %s' % timestamp, 4)
-                else:
-                    self.output.error('RemoteDB.cache(); HTTPError was:\n'
-                        'url: %s\n%s'
-                        % (url, str(e)))
-                    succeeded = False
-                continue
-            except IOError, error:
-                self.output.error('RemoteDB.cache(); Failed to update the '
-                    'overlay list from: %s\nIOError was:%s\n'
-                    % (url, str(error)))
-                succeeded = False
-                continue
-            else:
-                if url.startswith('file://'):
-                    quieter = 1
-                else:
-                    quieter = 0
-                self.output.info('Fetching new list... %s' % url, 4 + quieter)
-                if timestamp is not None:
-                    self.output.info('Last-modified: %s' % timestamp, 4 + quieter)
-                # Fetch the remote list
-                olist = connection.read()
-
-                # Create our storage directory if it is missing
-                if not os.path.exists(os.path.dirname(mpath)):
-                    try:
-                        os.makedirs(os.path.dirname(mpath))
-                    except OSError, error:
-                        raise OSError('Failed to create layman storage direct'
-                                      + 'ory ' + os.path.dirname(mpath) + '\n'
-                                      + 'Error was:' + str(error))
-
-                # Before we overwrite the old cache, check that the downloaded
-                # file is intact and can be parsed
-                try:
-                    self.read(olist, origin=url)
-                except Exception, error:
-                    raise IOError('Failed to parse the overlays list fetched fr'
-                                  'om ' + url + '\nThis means that the download'
-                                  'ed file is somehow corrupt or there was a pr'
-                                  'oblem with the webserver. Check the content '
-                                  'of the file. Error was:\n' + str(error))
-
-                # the folowing is neded for py3 only
-                if sys.hexversion >= 0x3000000 and hasattr(olist, 'decode'):
-                    olist = olist.decode("UTF-8")
-                # Ok, now we can overwrite the old cache
-                try:
-                    out_file = fileopen(mpath, 'w')
-                    out_file.write(olist)
-                    out_file.close()
-
-                    if timestamp is not None:
-                        out_file = fileopen(tpath, 'w')
-                        out_file.write(str(timestamp))
-                        out_file.close()
-
-                    has_updates = True
-
-                except Exception, error:
-                    raise IOError('Failed to temporarily cache overlays list in'
-                                  ' ' + mpath + '\nError was:\n' + str(error))
-        self.output.debug("RemoteDB.cache() returning:  has_updates, succeeded"
-            " %s, %s" % (str(has_updates), str(succeeded)), 4)
-        return has_updates, succeeded
-
-
-    def filepath(self, url):
-        '''Return a unique file name for the url.'''
-
-        base = self.config['cache']
-
-        self.output.debug('Generating cache path.', 6)
-        url_encoded = encoder(url, "UTF-8")
-
-        return base + '_' + hashlib.md5(url_encoded).hexdigest()
-
-
-    def check_path(self, paths, hint=True):
-        '''Check for sufficient privileges'''
-        self.output.debug('RemoteDB.check_path; paths = ' + str(paths), 8)
-        is_ok = True
-        for path in paths:
-            if os.path.exists(path) and not os.access(path, os.W_OK):
-                if hint:
-                    self.output.warn(
-                        'You do not have permission to update the cache (%s).'
-                        % path)
-                    import getpass
-                    if getpass.getuser() != 'root':
-                        self.output.warn('Hint: You are not root.\n')
-                is_ok = False
-        return is_ok
 
 #===============================================================================
 #
diff --git a/layman/remotedb.py b/layman/remotedb.py
new file mode 100644
index 0000000..851b89b
--- /dev/null
+++ b/layman/remotedb.py
@@ -0,0 +1,410 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+#################################################################################
+# LAYMAN OVERLAY DB
+#################################################################################
+# File:       db.py
+#
+#             Access to the db of overlays
+#
+# Copyright:
+#             (c) 2005 - 2008 Gunnar Wrobel
+#             Distributed under the terms of the GNU General Public License v2
+#
+# Author(s):
+#             Gunnar Wrobel <wrobel@gentoo.org>
+#
+'''Handles different storage files.'''
+
+from __future__ import with_statement
+
+__version__ = "$Id: db.py 309 2007-04-09 16:23:38Z wrobel $"
+
+#===============================================================================
+#
+# Dependencies
+#
+#-------------------------------------------------------------------------------
+
+import os, os.path
+import sys
+import urllib2
+import hashlib
+
+from pygpg.config import GPGConfig
+from pygpg.gpg import GPG
+
+from   layman.utils             import encoder
+from   layman.dbbase            import DbBase
+from   layman.version           import VERSION
+from layman.compatibility       import fileopen
+
+class RemoteDB(DbBase):
+    '''Handles fetching the remote overlay list.'''
+
+    def __init__(self, config, ignore_init_read_errors=False):
+
+        self.config = config
+        self.output = config['output']
+
+        self.proxies = {}
+
+        if config['proxy']:
+            self.proxies['http'] = config['proxy']
+        elif os.getenv('http_proxy'):
+            self.proxies['http'] = os.getenv('http_proxy')
+
+        if self.proxies:
+            proxy_handler = urllib2.ProxyHandler(self.proxies)
+            opener = urllib2.build_opener(proxy_handler)
+            urllib2.install_opener(opener)
+
+        self.urls  = [i.strip()
+            for i in config['overlays'].split('\n') if len(i)]
+
+        #pair up the list url and detached sig url
+        d_urls = [i.strip()
+            for i in config['gpg_detached_lists'].split('\n') if len(i)]
+        self.detached_urls = []
+        #for index in range(0, len(d_urls), 2):
+        #    self.detached_urls.append((d_urls[index], d_urls[index+1]))
+        for i in d_urls:
+            u = i.split()
+            self.detached_urls.append((u[0], u[1]))
+
+        self.signed_urls = [i.strip()
+            for i in config['gpg_signed_lists'].split('\n') if len(i)]
+
+        self.output.debug('RemoteDB.__init__(), url lists= \nself.urls: %s\nself.detached_urls: %s\nself.signed_urls: %s' % (str(self.urls), str(self.detached_urls), str(self.signed_urls)), 2)
+
+        # add up the lists to load for display, etc.
+        # unsigned overlay lists
+        paths = [self.filepath(i) + '.xml' for i in self.urls]
+        # detach-signed lists
+        paths.extend([self.filepath(i[0]) + '.xml' for i in self.detached_urls])
+        # single file signed, compressed, clearsigned
+        paths.extend([self.filepath(i) + '.xml' for i in self.signed_urls])
+
+        self.output.debug('RemoteDB.__init__(), paths to load = %s' %str(paths), 2)
+
+        if config['nocheck']:
+            ignore = 2
+        else:
+            ignore = 0
+
+        #quiet = int(config['quietness']) < 3
+
+        DbBase.__init__(self, config, paths=paths, ignore=ignore,
+            ignore_init_read_errors=ignore_init_read_errors)
+
+        self.gpg = None
+        self.gpg_config = None
+
+
+    # overrider
+    def _broken_catalog_hint(self):
+        return 'Try running "sudo layman -f" to re-fetch that file'
+
+
+    def cache(self):
+        '''
+        Copy the remote overlay list to the local cache.
+
+        >>> import tempfile
+        >>> here = os.path.dirname(os.path.realpath(__file__))
+        >>> tmpdir = tempfile.mkdtemp(prefix="laymantmp_")
+        >>> cache = os.path.join(tmpdir, 'cache')
+        >>> myoptions = {'overlays' :
+        ...           ['file://' + here + '/tests/testfiles/global-overlays.xml'],
+        ...           'cache' : cache,
+        ...           'nocheck'    : 'yes',
+        ...           'proxy' : None}
+        >>> from layman.config import OptionConfig
+        >>> config = OptionConfig(myoptions)
+        >>> config.set_option('quietness', 3)
+        >>> a = RemoteDB(config)
+        >>> a.cache()
+        (True, True)
+        >>> b = fileopen(a.filepath(config['overlays'])+'.xml')
+        >>> b.readlines()[24]
+        '      A collection of ebuilds from Gunnar Wrobel [wrobel@gentoo.org].\\n'
+
+        >>> b.close()
+        >>> os.unlink(a.filepath(config['overlays'])+'.xml')
+
+        >>> a.overlays.keys()
+        [u'wrobel', u'wrobel-stable']
+
+        >>> import shutil
+        >>> shutil.rmtree(tmpdir)
+        '''
+        has_updates = False
+        self._create_storage(self.config['storage'])
+        # succeeded reset when a failure is detected
+        succeeded = True
+        url_lists = [self.urls, self.detached_urls, self.signed_urls]
+        need_gpg = [False, True, True]
+        for index in range(0, 3):
+            self.output.debug("RemoteDB.cache() index = %s" %str(index),2)
+            urls = url_lists[index]
+            if need_gpg[index] and len(urls) and self.gpg is None:
+                #initialize our gpg instance
+                self.init_gpg()
+            # main working loop
+            for url in urls:
+                sig = ''
+                self.output.debug("RemoteDB.cache() url = %s is a tuple=%s"
+                    %(str(url), str(isinstance(url, tuple))),2)
+                filepath, mpath, tpath, sig = self._paths(url)
+
+                if sig:
+                    success, olist, timestamp = self._fetch_url(
+                        url[0], mpath, tpath)
+                else:
+                    success, olist, timestamp = self._fetch_url(
+                        url, mpath, tpath)
+                if not success:
+                    #succeeded = False
+                    continue
+
+                self.output.debug("RemoteDB.cache() len(olist) = %s" %str(len(olist)),2)
+                # GPG handling
+                if need_gpg[index]:
+                    olist, verified = self.verify_gpg(url, sig, olist)
+                    if not verified:
+                        self.output.debug("RemoteDB.cache() gpg returned "
+                            "verified = %s" %str(verified),2)
+                        succeeded = False
+                        filename = os.path.join(self.config['storage'], "Failed-to-verify-sig")
+                        self.write_cache(olist, filename)
+                        continue
+
+                # Before we overwrite the old cache, check that the downloaded
+                # file is intact and can be parsed
+                if isinstance(url, tuple):
+                    olist = self._check_download(olist, url[0])
+                else:
+                    olist = self._check_download(olist, url)
+
+                # Ok, now we can overwrite the old cache
+                has_updates = max(has_updates,
+                    self.write_cache(olist, mpath, tpath, timestamp))
+
+            self.output.debug("RemoteDB.cache() self.urls:  has_updates, succeeded"
+                " %s, %s" % (str(has_updates), str(succeeded)), 4)
+        return has_updates, succeeded
+
+
+    def _paths(self, url):
+        self.output.debug("RemoteDB._paths(), url is tuple %s" % str(url),2)
+        if isinstance(url, tuple):
+            filepath = self.filepath(url[0])
+            sig = filepath + '.sig'
+        else:
+            filepath = self.filepath(url)
+            sig = ''
+        mpath = filepath + '.xml'
+        tpath = filepath + '.timestamp'
+        return filepath, mpath, tpath, sig
+
+
+    @staticmethod
+    def _create_storage(mpath):
+            # Create our storage directory if it is missing
+            if not os.path.exists(os.path.dirname(mpath)):
+                try:
+                    os.makedirs(os.path.dirname(mpath))
+                except OSError, error:
+                    raise OSError('Failed to create layman storage direct'
+                                  + 'ory ' + os.path.dirname(mpath) + '\n'
+                                  + 'Error was:' + str(error))
+            return
+
+
+    def filepath(self, url):
+        '''Return a unique file name for the url.'''
+
+        base = self.config['cache']
+
+        self.output.debug('Generating cache path.', 6)
+        url_encoded = encoder(url, "UTF-8")
+
+        return base + '_' + hashlib.md5(url_encoded).hexdigest()
+
+
+    def _fetch_url(self, url, mpath, tpath=None):
+        self.output.debug('RemoteDB._fetch_url() url = %s' % url, 2)
+        # check when the cache was last updated
+        # and don't re-fetch it unless it has changed
+        request = urllib2.Request(url)
+        opener = urllib2.build_opener()
+        opener.addheaders = [('Accept-Charset', 'utf-8'),
+            ('User-Agent', 'Layman-' + VERSION)]
+        #opener.addheaders[('User-Agent', 'Layman-' + VERSION)]
+
+        if tpath and os.path.exists(tpath):
+            with fileopen(tpath,'r') as previous:
+                timestamp = previous.read()
+            request.add_header('If-Modified-Since', timestamp)
+
+        if not self.check_path([mpath]):
+            return (False, '', '')
+
+        try:
+            self.output.debug('RemoteDB._fetch_url() connecting to opener', 2)
+            connection = opener.open(request)
+            # py2, py3 compatibility, since only py2 returns keys as lower()
+            headers = dict((x.lower(), x) for x in connection.headers.keys())
+            if 'last-modified' in headers:
+                timestamp = connection.headers[headers['last-modified']]
+            elif 'date' in headers:
+                timestamp = connection.headers[headers['date']]
+            else:
+                timestamp = None
+        except urllib2.HTTPError, e:
+            if e.code == 304:
+                self.output.info('Remote list already up to date: %s'
+                    % url, 4)
+                self.output.info('Last-modified: %s' % timestamp, 4)
+            else:
+                self.output.error('RemoteDB.cache(); HTTPError was:\n'
+                    'url: %s\n%s'
+                    % (url, str(e)))
+                return (False, '', '')
+            return (False, '', '')
+        except IOError, error:
+            self.output.error('RemoteDB.cache(); Failed to update the '
+                'overlay list from: %s\nIOError was:%s\n'
+                % (url, str(error)))
+            return (False, '', '')
+        else:
+            if url.startswith('file://'):
+                quieter = 1
+            else:
+                quieter = 0
+            self.output.info('Fetching new list... %s' % url, 4 + quieter)
+            if timestamp is not None:
+                self.output.info('Last-modified: %s' % timestamp, 4 + quieter)
+            # Fetch the remote list
+            olist = connection.read()
+            self.output.debug('RemoteDB._fetch_url(), olist type = %s' %str(type(olist)),2)
+
+            return (True, olist, timestamp)
+
+
+    def check_path(self, paths, hint=True):
+        '''Check for sufficient privileges'''
+        self.output.debug('RemoteDB.check_path; paths = ' + str(paths), 8)
+        is_ok = True
+        for path in paths:
+            if os.path.exists(path) and not os.access(path, os.W_OK):
+                if hint:
+                    self.output.warn(
+                        'You do not have permission to update the cache (%s).'
+                        % path)
+                    import getpass
+                    if getpass.getuser() != 'root':
+                        self.output.warn('Hint: You are not root.\n')
+                is_ok = False
+        return is_ok
+
+
+    def _check_download(self, olist, url):
+
+        try:
+            self.read(olist, origin=url)
+        except Exception, error:
+            self.output.debug("RemoteDB._check_download(), url=%s \nolist:\n" % url,2)
+            self.output.debug(olist,2)
+            raise IOError('Failed to parse the overlays list fetched fr'
+                          'om ' + url + '\nThis means that the download'
+                          'ed file is somehow corrupt or there was a pr'
+                          'oblem with the webserver. Check the content '
+                          'of the file. Error was:\n' + str(error))
+
+        # the folowing is neded for py3 only
+        if sys.hexversion >= 0x3000000 and hasattr(olist, 'decode'):
+            olist = olist.decode("UTF-8")
+        return olist
+
+
+    @staticmethod
+    def write_cache(olist, mpath, tpath=None, timestamp=None):
+        has_updates = False
+        try:
+            out_file = fileopen(mpath, 'w')
+            out_file.write(olist)
+            out_file.close()
+
+            if timestamp is not None and tpath is not None:
+                out_file = fileopen(tpath, 'w')
+                out_file.write(str(timestamp))
+                out_file.close()
+
+            has_updates = True
+
+        except Exception, error:
+            raise IOError('Failed to temporarily cache overlays list in'
+                          ' ' + mpath + '\nError was:\n' + str(error))
+        return has_updates
+
+    def verify_gpg(self, url, sig, olist):
+        '''Verify and decode it.'''
+        self.output.debug("RemoteDB: verify_gpg(), verify & decrypt olist: "
+            " %s, type(olist)=%s" % (str(url),str(type(olist))), 2)
+        #self.output.debug(olist, 2)
+
+        # detached sig
+        if sig:
+            self.output.debug("RemoteDB.verify_gpg(), detached sig", 2)
+            self.dl_sig(url[1], sig)
+            gpg_result = self.gpg.verify(
+                inputtxt=olist,
+                inputfile=sig)
+        # armoured signed file, compressed or clearsigned
+        else:
+            self.output.debug("RemoteDB.verify_gpg(), single signed file", 2)
+            gpg_result = self.gpg.decrypt(
+                inputtxt=olist)
+            olist = gpg_result.output
+        # verify and report
+        self.output.debug("gpg_result, verified=%s, len(olist)=%s"
+            % (gpg_result.verified[0], str(len(olist))),1)
+        if gpg_result.verified[0]:
+            self.output.info("GPG verification succeeded for gpg-signed url.", 4)
+            self.output.info('\tSignature result:' + str(gpg_result.verified), 4)
+        else:
+            self.output.error("GPG verification failed for gpg-signed url.")
+            self.output.error('\tSignature result:' + str(gpg_result.verified))
+            olist = ''
+        return olist, gpg_result.verified[0]
+
+
+    def dl_sig(self, url, sig):
+        self.output.debug("RemoteDB.dl_sig() url=%s, sig=%s" % (url, sig),2)
+        success, newsig, timestamp = self._fetch_url(url, sig)
+        if success:
+            success = self.write_cache(newsig, sig)
+        return success
+
+
+    def init_gpg(self):
+        self.output.debug("RemoteDB.init_gpg(), initializing",2)
+        if not self.gpg_config:
+            self.gpg_config = GPGConfig()
+
+        if not self.gpg:
+            self.gpg = GPG(self.gpg_config)
+        self.output.debug("RemoteDB.init_gpg(), initialized :D",2)
+
+
+if __name__ == '__main__':
+    import doctest
+
+    # Ignore warnings here. We are just testing
+    from warnings     import filterwarnings, resetwarnings
+    filterwarnings('ignore')
+
+    doctest.testmod(sys.modules[__name__])
+
+    resetwarnings()