res_ari_channels: Return a 404 response when a requested channel variable does not exist.

This change makes it so that if a channel variable is requested and it does not exist
a 404 response will be returned instead of an allocation failed response. This makes
it easier to debug and figure out what is going on for a user.

ASTERISK-24677 #close
Reported by: Joshua Colp
........

Merged revisions 432154 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@432155 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/ari/resource_channels.c

@@ -1242,6 +1242,11 @@ void ast_ari_channels_get_channel_var(struct ast_variable *headers,
 
 	ast_assert(response != NULL);
 
+	if (!value) {
+		ast_ari_response_alloc_failed(response);
+		return;
+	}
+
 	if (ast_strlen_zero(args->variable)) {
 		ast_ari_response_error(
 			response, 400, "Bad Request",
@@ -1280,7 +1285,9 @@ void ast_ari_channels_get_channel_var(struct ast_variable *headers,
 		}
 	} else {
 		if (!ast_str_retrieve_variable(&value, 0, channel, NULL, args->variable)) {
-			ast_ari_response_alloc_failed(response);
+			ast_ari_response_error(
+				response, 404, "Variable Not Found",
+				"Provided variable was not found");
 			return;
 		}
 	}

res/res_ari_channels.c

@@ -2173,7 +2173,7 @@ static void ast_ari_channels_get_channel_var_cb(
 	case 500: /* Internal Server Error */
 	case 501: /* Not Implemented */
 	case 400: /* Missing variable parameter. */
-	case 404: /* Channel not found */
+	case 404: /* Channel or variable not found */
 	case 409: /* Channel not in a Stasis application */
 		is_valid = 1;
 		break;

rest-api/api-docs/channels.json

@@ -1199,7 +1199,7 @@
 						},
 						{
 							"code": 404,
-							"reason": "Channel not found"
+							"reason": "Channel or variable not found"
 						},
 						{
 							"code": 409,