From ca8852b434dae02b271ba2a1dddadfdf56ea3320 Mon Sep 17 00:00:00 2001 From: Joey Hess Date: Fri, 21 Mar 2008 15:12:15 -0400 Subject: external: Work around XML RPC's lack of support for null by passing a special sentinal value. --- doc/plugins/write/external.mdwn | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'doc/plugins/write') diff --git a/doc/plugins/write/external.mdwn b/doc/plugins/write/external.mdwn index 4492cd0da..bda34b771 100644 --- a/doc/plugins/write/external.mdwn +++ b/doc/plugins/write/external.mdwn @@ -79,6 +79,19 @@ Other languages might not find it so easy. If not, it might be a good idea to convert these named parameters into something more natural for the language as part of their XML RPC interface. +## undef + +XML RPC has a limitation that it does not have a way to pass +undef/NULL/None. There is an extension to the protocol that supports this, +but it is not yet available in the [[cpan XML::RPC]] library used by +ikiwiki. + +Until the extension is available, ikiwiki allows undef to be communicated +over XML RPC by passing a sentinal value, a hash with a single key "null" +with a value of an empty string. External plugins that need to communicate +null values to or from ikiwiki will have to translate between undef and +the sentinal. + ## Function injection Some parts of ikiwiki are extensible by adding functions. For example, the -- cgit v1.2.3