# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443451970 -7200
# Node ID fd9030f95edad9e1a3ba8089e77d91a2c995dae2
# Parent  0036129e8c5357417361c1987995592cd05f5ee2
Added more informative serialisation errors.

diff -r 0036129e8c53 -r fd9030f95eda vContent.py
--- a/vContent.py	Mon Sep 28 15:22:33 2015 +0200
+++ b/vContent.py	Mon Sep 28 16:52:50 2015 +0200
@@ -62,6 +62,12 @@
 
     pass
 
+class WriteError(Exception):
+
+    "General writing errors."
+
+    pass
+
 # Reader and parser classes.
 
 class Reader:
@@ -570,12 +576,15 @@
         encoding = parameters.get("ENCODING")
         charset = parameters.get("CHARSET")
 
-        if encoding == "QUOTED-PRINTABLE":
-            value = quopri.encodestring(value.encode(charset or "iso-8859-1"))
-        elif encoding == "BASE64":
-            value = base64.encodestring(value)
+        try:
+            if encoding == "QUOTED-PRINTABLE":
+                value = quopri.encodestring(value.encode(charset or "iso-8859-1"))
+            elif encoding == "BASE64":
+                value = base64.encodestring(value)
 
-        return self.encode_content(value)
+            return self.encode_content(value)
+        except TypeError:
+            raise WriteError, "Property %r value with parameters %r cannot be encoded: %r" % (name, parameters, value)
 
     # Overrideable methods.