Enable tilde and environment variable expansion on some items

Expand environment variables in the following configuration items:
- general.pythonfile;
- general.metadata;
- mbnames.filename;
- Repository.localfolders.
- Repository.sslcacertfile.

Make tilde and environment variable expansion in the following
configuration items:
- Repository.sslclientcert;
- Repository.sslclientkey.

GitHub pull request: https://github.com/OfflineIMAP/offlineimap/pull/113
Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>

Changelog.rst

@@ -8,6 +8,18 @@ ChangeLog
 OfflineIMAP v6.5.6.1 (YYYY-MM-DD)
 =================================
 
+* Expand environment variables in the following
+  configuration items:
+  - general.pythonfile;
+  - general.metadata;
+  - mbnames.filename;
+  - Repository.localfolders.
+  - Repository.sslcacertfile.
+  Make tilde and environment variable expansion in the following
+  configuration items:
+  - Repository.sslclientcert;
+  - Repository.sslclientkey.
+
 * Updated bundled imaplib2 to 2.37:
   - add missing idle_lock in _handler()
 

offlineimap.conf

@@ -23,6 +23,12 @@
 
 # NOTE2: This implies that any '%' needs to be encoded as '%%'
 
+# NOTE3: Any variables that are subject to the environment variables
+# ($NAME) and tilde (~username/~) expansions will receive tilde
+# expansion first and only after this environment variables will be
+# expanded in the resulting string.  This behaviour is intentional
+# as it coincides with typical shell expansion strategy.
+
 ##################################################
 # General definitions
 ##################################################
@@ -31,6 +37,8 @@
 
 # This specifies where offlineimap is to store its metadata.
 # This directory will be created if it does not already exist.
+#
+# Tilde and environment variable expansions will be performed.
 
 #metadata = ~/.offlineimap
 
@@ -89,6 +97,8 @@ accounts = Test
 # source file and call them from this config file.  You can find
 # an example of this in the manual.
 #
+# Tilde and environment variable expansions will be performed.
+#
 # pythonfile = ~/.offlineimap.py
 #
 
@@ -135,6 +145,9 @@ accounts = Test
 # - foldername: the name of the folder;
 # - localfolders: path to the local directory hosting all Maildir
 #   folders for the account.
+#
+# Tilde and environment variable expansions will be performed
+# for "filename" knob.
 
 enabled = no
 filename = ~/Mutt/muttrc.mailboxes
@@ -375,9 +388,15 @@ remotehost = examplehost
 ssl = yes
 
 # SSL Client certificate (optional)
+#
+# Tilde and environment variable expansions will be performed.
+
 # sslclientcert = /path/to/file.crt
 
 # SSL Client key (optional)
+#
+# Tilde and environment variable expansions will be performed.
+
 # sslclientkey = /path/to/file.key
 
 # SSL CA Cert(s) to verify the server cert against (optional).
@@ -385,6 +404,9 @@ ssl = yes
 # specified, the CA Cert(s) need to verify the Server cert AND
 # match the hostname (* wildcard allowed on the left hand side)
 # The certificate should be in PEM format.
+#
+# Tilde and environment variable expansions will be performed.
+
 # sslcacertfile = /path/to/cacertfile.crt
 
 # If you connect via SSL/TLS (ssl=true) and you have no CA certificate

offlineimap/CustomConfig.py

@@ -94,7 +94,7 @@ class CustomConfigParser(SafeConfigParser):
             return default
 
     def getmetadatadir(self):
-        xforms = [os.path.expanduser]
+        xforms = [os.path.expanduser, os.path.expandvars]
         d = self.getdefault("general", "metadata", "~/.offlineimap")
         metadatadir = self.apply_xforms(d, xforms)
         if not os.path.exists(metadatadir):
@@ -102,7 +102,7 @@ class CustomConfigParser(SafeConfigParser):
         return metadatadir
 
     def getlocaleval(self):
-        xforms = [os.path.expanduser]
+        xforms = [os.path.expanduser, os.path.expandvars]
         if self.has_option("general", "pythonfile"):
             path = self.apply_xforms(self.get("general", "pythonfile"), xforms)
         else:

offlineimap/mbnames.py

@@ -49,12 +49,14 @@ def write():
 def __genmbnames():
     """Takes a configparser object and a boxlist, which is a list of hashes
     containing 'accountname' and 'foldername' keys."""
+    xforms = [os.path.expanduser, os.path.expandvars]
     mblock.acquire()
     try:
         localeval = config.getlocaleval()
         if not config.getdefaultboolean("mbnames", "enabled", 0):
             return
-        file = open(os.path.expanduser(config.get("mbnames", "filename")), "wt")
+        path = config.apply_xform(config.get("mbnames", "filename"), xforms)
+        file = open(path, "wt")
         file.write(localeval.eval(config.get("mbnames", "header")))
         folderfilter = lambda accountname, foldername: 1
         if config.has_option("mbnames", "folderfilter"):

offlineimap/repository/IMAP.py

@@ -194,14 +194,16 @@ class IMAPRepository(BaseRepository):
         return self.getconfboolean('ssl', 0)
 
     def getsslclientcert(self):
-        return self.getconf('sslclientcert', None)
+        xforms = [os.path.expanduser, os.path.expandvars, os.path.abspath]
+        return self.getconf_xform('sslclientcert', xforms, None)
 
     def getsslclientkey(self):
-        return self.getconf('sslclientkey', None)
+        xforms = [os.path.expanduser, os.path.expandvars, os.path.abspath]
+        return self.getconf_xform('sslclientkey', xforms, None)
 
     def getsslcacertfile(self):
         """Return the absolute path of the CA certfile to use, if any"""
-        xforms = [os.path.expanduser, os.path.abspath]
+        xforms = [os.path.expanduser, os.path.expandvars, os.path.abspath]
         cacertfile = self.getconf_xform('sslcacertfile', xforms,
           get_os_sslcertfile())
         if cacertfile is None: