Add validateParticipantID to participant routes

middlewares/validateParticipantID.js

@@ -0,0 +1,26 @@
+const Participant = require('../api/models/participantModel');
+
+async function validateParticipantID(req, res, next) {
+	const { account_id, meeting_id } = req.params;
+
+	try {
+		const participant = await Participant.getParticipantById(
+			account_id,
+			meeting_id,
+		);
+		if (typeof participant == 'undefined') {
+			res.status(404).json({
+				message: `Participant with id ${id} doesn't exist.`,
+			});
+		} else {
+			next();
+		}
+	} catch (error) {
+		res.status(500).json({
+			message: `Failed to get participant with id ${account_id}-${meeting_id}.`,
+			error,
+		});
+	}
+}
+
+exports.validateParticipantID = validateParticipantID;