ARI: Support channel variables in originate

This adds back in support for specifying channel variables during an
originate without compromising the ability to specify query parameters
in the JSON body. This was accomplished by generating the body-parsing
code in a separate function instead of being integrated with the URI
query parameter parsing code such that it could be called by paths with
body parameters. This is transparent to the user of the API and
prevents manual duplication of code or data structures.

(closes issue ASTERISK-23051)
Review: https://reviewboard.asterisk.org/r/3122/
Reported by: Matt Jordan
........

Merged revisions 406003 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@406006 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/ari/resource_playbacks.h

@@ -72,6 +72,17 @@ struct ast_ari_playbacks_control_args {
 	/*! \brief Operation to perform on the playback. */
 	const char *operation;
 };
+/*!
+ * \brief Body parsing function for /playbacks/{playbackId}/control.
+ * \param body The JSON body from which to parse parameters.
+ * \param[out] args The args structure to parse into.
+ * \retval zero on success
+ * \retval non-zero on failure
+ */
+int ast_ari_playbacks_control_parse_body(
+	struct ast_json *body,
+	struct ast_ari_playbacks_control_args *args);
+
 /*!
  * \brief Control a playback.
  *