Merge pull request #276 from SCVApp/master

db procedure for lockers

Author: urbankrepel

db_migrations/locker_function.sql

@@ -0,0 +1,26 @@
+CREATE OR REPLACE FUNCTION check_locker_availability()
+RETURNS TRIGGER AS $$
+DECLARE
+    old_controller_id INT;
+    new_locker_id INT;
+BEGIN
+    IF OLD.locker_id IS NULL OR  NEW.locker_id != OLD.locker_id THEN
+        IF EXISTS(SELECT 1 FROM lockers_users WHERE locker_id = NEW.locker_id AND start_time < NOW() AND (end_time IS NULL OR end_time > NOW())) THEN
+            SELECT controller_id INTO old_controller_id FROM lockers WHERE id = NEW.locker_id;
+            SELECT id INTO new_locker_id FROM lockers WHERE controller_id = old_controller_id AND id NOT IN (SELECT locker_id FROM lockers_users WHERE start_time < NOW() AND (end_time IS NULL OR end_time > NOW()));
+            IF new_locker_id IS NULL THEN
+                RAISE EXCEPTION 'No available lockers';
+            ELSE
+                NEW.locker_id := new_locker_id;
+            END IF;
+        END IF;
+    END IF;
+
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER validate_locker
+BEFORE INSERT OR UPDATE ON lockers_users
+FOR EACH ROW
+EXECUTE FUNCTION check_locker_availability();

src/lockers/lockers.service.ts

@@ -135,14 +135,31 @@ export class LockersService {
     if (!firstAvailableLocker) {
       throw new NotFoundException('No lockers available');
     }
-    const success = await this.openLocker(firstAvailableLocker);
+
+    // This is the check from db, becouse we have a trigger on lockers_users table and if we insert already used locker, it will change the locker with the first available one
+    const result = await this.lockersUsersRepository
+      .insert({
+        user,
+        locker: firstAvailableLocker,
+      })
+      .catch(() => {
+        throw new InternalServerErrorException('No lockers available');
+      });
+    if (!result) {
+      throw new NotFoundException('No lockers available');
+    }
+    const assignedLocker = await this.getUsersActiveLocker(user);
+    if (!assignedLocker) {
+      throw new NotFoundException('No lockers available');
+    }
+    const success = await this.openLocker(assignedLocker);
     if (!success) {
+      await this.lockersUsersRepository.delete({
+        user,
+        locker: assignedLocker,
+      });
       throw new InternalServerErrorException('Failed to open locker');
     }
-    await this.lockersUsersRepository.save({
-      user,
-      locker: firstAvailableLocker,
-    });
     return { success: true };
   }