bugfix: .env.example files updated. some minor changes in jwt strategy to avoid failing when .env files does not contain needed keys.

backend/src/configs/configurations.ts

@@ -1,4 +1,36 @@
 // backend/src/config/configuration.ts
+
+/** Matches values accepted by jsonwebtoken `expiresIn` (via ms), e.g. 7d, 15m, or plain seconds. */
+const JWT_TIMESPAN_PATTERN =
+  /^\d+(\.\d+)?(ms|s|m|h|d|w|y)?$/i;
+
+function assertJwtSecret(value: string, envKey: string): string {
+  const trimmed = value.trim();
+  if (!trimmed) {
+    throw new Error(`❌ Environment variable ${envKey} is required but not set`);
+  }
+  if (trimmed.length < 16) {
+    throw new Error(`❌ ${envKey} must be at least 16 characters`);
+  }
+  if (/CHANGE_ME/i.test(trimmed)) {
+    throw new Error(`❌ ${envKey} must be changed from the placeholder value`);
+  }
+  return trimmed;
+}
+
+function assertJwtTimespan(value: string, envKey: string): string {
+  const trimmed = value.trim();
+  if (!trimmed) {
+    throw new Error(`❌ Environment variable ${envKey} is required but not set`);
+  }
+  if (!/^\d+$/.test(trimmed) && !JWT_TIMESPAN_PATTERN.test(trimmed)) {
+    throw new Error(
+      `❌ ${envKey}="${value}" is invalid. Use a duration like 7d, 15m, 30d, or a number of seconds.`,
+    );
+  }
+  return trimmed;
+}
+
 export interface Config {
   port: number;
   database: {
@@ -7,6 +39,8 @@ export interface Config {
   jwt: {
     secret: string;
     expiresIn: string;
+    refreshSecret: string;
+    refreshExpiresIn: string;
   };
   throttle: {
     ttl: number;
@@ -24,9 +58,10 @@ export default (): Config => {
     return value;
   };
 
-  // Helper for optional env vars with defaults
+  // Helper for optional env vars with defaults (whitespace-only counts as unset)
   const getEnvVarWithDefault = (key: string, defaultValue: string): string => {
-    return process.env[key] || defaultValue;
+    const value = process.env[key]?.trim();
+    return value ? value : defaultValue;
   };
 
   const getEnvVarAsNumber = (key: string, defaultValue: number): number => {
@@ -36,14 +71,30 @@ export default (): Config => {
     return isNaN(parsed) ? defaultValue : parsed;
   };
 
+  const jwtSecret = assertJwtSecret(getEnvVar('JWT_SECRET'), 'JWT_SECRET');
+  const jwtExpiresIn = assertJwtTimespan(
+    getEnvVarWithDefault('JWT_EXPIRES_IN', '7d'),
+    'JWT_EXPIRES_IN',
+  );
+  const jwtRefreshSecret = assertJwtSecret(
+    getEnvVarWithDefault('JWT_REFRESH_SECRET', jwtSecret),
+    'JWT_REFRESH_SECRET',
+  );
+  const jwtRefreshExpiresIn = assertJwtTimespan(
+    getEnvVarWithDefault('JWT_REFRESH_EXPIRES_IN', '30d'),
+    'JWT_REFRESH_EXPIRES_IN',
+  );
+
   return {
     port: getEnvVarAsNumber('PORT', 3000),
     database: {
       url: getEnvVar('DATABASE_URL'),
     },
     jwt: {
-      secret: getEnvVar('JWT_SECRET'),
-      expiresIn: getEnvVarWithDefault('JWT_EXPIRES_IN', '7d'),
+      secret: jwtSecret,
+      expiresIn: jwtExpiresIn,
+      refreshSecret: jwtRefreshSecret,
+      refreshExpiresIn: jwtRefreshExpiresIn,
     },
     throttle: {
       ttl: getEnvVarAsNumber('THROTTLE_TTL', 60),