added users and groups

src/middlewares/existance.js

@@ -0,0 +1,51 @@
+import UserService from '../services/user.js';
+import GroupService from '../services/group.js';
+import log from '../utils/log.js';
+import statuses from '../utils/status.js';
+
+const TAG = "/middlewares/existance.js"
+
+const usernameExists = async (req, res, next) => {
+    try {
+        let { username } = req.body;
+
+        let user = await UserService.getByUsername(username);
+        if (!user || user == statuses.not_found) return res.status(404).send("User not found");
+        next();
+    } catch (e) { return res.status(500).send(log.unknownError(`${TAG}/usernameExists: ${e}`)); }
+};
+
+const usernameDoesntExist = async (req, res, next) => {
+    try {
+        let { username } = req.body;
+
+        let user = await UserService.getByUsername(username);
+        if (user || user != statuses.not_found) return res.status(400).send("Such username already taken");
+        next();
+    } catch (e) { return res.status(500).send(log.unknownError(`${TAG}/usernameDoesntExist: ${e}`)); }
+}
+
+const groupExists = async (req, res, next) => {
+    try {
+
+        const { id } = req.params;
+
+        let group = await GroupService.getById(id);
+
+        if (!group || group == statuses.not_found) return res.status(404).send("Group not found");
+        next();
+    } catch (e) { return res.status(500).send(log.unknownError(`${TAG}/groupExists: ${e}`)) }
+}
+
+const groupDoesntExist = async (req, res, next) => {
+    try {
+
+        const { id } = req.params;
+
+        let group = await GroupService.getById(id);
+
+        if (group || group != statuses.not_found) return res.status(400).send("Such group already exists");
+        next();
+    } catch (e) { return res.status(500).send(log.unknownError(`${TAG}/groupDoesntExist: ${e}`)) }
+}
+export default { usernameExists, usernameDoesntExist, groupExists, groupDoesntExist }