refactor(chore): fix sonar code smells (#117)

fix sonar code smells related to cognitive complexity,
empty constructor and method types

GH-116

Author: sf-sahil-jassal

src/providers/casbin-authorization-action.provider.ts

@@ -2,7 +2,6 @@ import {Getter, inject, Provider} from '@loopback/core';
 import {Request} from '@loopback/express';
 import {HttpErrors} from '@loopback/rest';
 import * as casbin from 'casbin';
-
 import {AuthorizationBindings} from '../keys';
 import {
   AuthorizationMetadata,
@@ -63,15 +62,7 @@ export class CasbinAuthorizationProvider
       }
       const subject = this.getUserName(`${user.id}`);
 
-      let desiredPermissions;
-
-      if (metadata.permissions && metadata.permissions.length > 0) {
-        desiredPermissions = metadata.permissions;
-      } else {
-        throw new HttpErrors.Unauthorized(
-          `Permissions are missing in the decorator.`,
-        );
-      }
+      const desiredPermissions = this.getDesiredPermissions(metadata);
 
       // Fetch casbin config by invoking casbin-config-getter-provider
       const casbinConfig = await this.getCasbinEnforcerConfig(
@@ -90,7 +81,7 @@ export class CasbinAuthorizationProvider
         );
       }
       // In case casbin policy is coming via provider, use that to initialise enforcer
-      else if (!metadata.isCasbinPolicy && casbinConfig.allowedRes) {
+      else if (casbinConfig.allowedRes) {
         const policy = this.createCasbinPolicy(
           casbinConfig.allowedRes,
           subject,
@@ -124,6 +115,16 @@ export class CasbinAuthorizationProvider
     return `u${id}`;
   }
 
+  getDesiredPermissions(metadata: AuthorizationMetadata): Array<string> {
+    if (metadata.permissions && metadata.permissions.length > 0) {
+      return metadata.permissions;
+    } else {
+      throw new HttpErrors.Unauthorized(
+        `Permissions are missing in the decorator.`,
+      );
+    }
+  }
+
   // Create casbin policy for user based on ResourcePermission data provided by extension client
   createCasbinPolicy(
     resPermObj: ResourcePermissionObject[],

src/providers/casbin-enforcer-config.provider.ts

@@ -1,15 +1,11 @@
 import {Provider} from '@loopback/context';
 
-import {CasbinEnforcerConfigGetterFn, IAuthUserWithPermissions} from '../types';
 import {HttpErrors} from '@loopback/rest';
+import {CasbinEnforcerConfigGetterFn, IAuthUserWithPermissions} from '../types';
 
 export class CasbinEnforcerProvider
   implements Provider<CasbinEnforcerConfigGetterFn>
 {
-  constructor() {
-    //This is intentional
-  }
-
   value(): CasbinEnforcerConfigGetterFn {
     return async (
       authUser: IAuthUserWithPermissions,

src/providers/user-permissions.provider.ts

@@ -5,10 +5,6 @@ import {UserPermission, UserPermissionsFn} from '../types';
 export class UserPermissionsProvider
   implements Provider<UserPermissionsFn<string>>
 {
-  constructor() {
-    //This is intentional
-  }
-
   value(): UserPermissionsFn<string> {
     return (userPermissions, rolePermissions) =>
       this.action(userPermissions, rolePermissions);

src/types.ts

@@ -3,27 +3,29 @@ import {FileAdapter, Model} from 'casbin';
 import PostgresAdapter from 'casbin-pg-adapter';
 
 /**
- * Authorize action method interface
+ * Authorize action method type
+ *
+ * @param userPermissions - Array of permission keys granted to the user
+ * This is actually a union of permissions picked up based on role
+ * attached to the user and allowed permissions at specific user level
  */
-export interface AuthorizeFn {
-  // userPermissions - Array of permission keys granted to the user
-  // This is actually a union of permissions picked up based on role
-  // attached to the user and allowed permissions at specific user level
-  (userPermissions: string[], request?: Request): Promise<boolean>;
-}
+export type AuthorizeFn = (
+  userPermissions: string[],
+  request?: Request,
+) => Promise<boolean>;
 
 /**
- * Casbin authorize action method interface
+ * Casbin authorize action method type
+ * @param user - User object corresponding to the logged in user
+ * @param resVal - value of the resource for which authorisation is being sought
+ *
  */
-export interface CasbinAuthorizeFn {
-  // user - User object corresponding to the logged in user
-  // resVal - value of the resource for which authorisation is being sought
-  (
-    user: IAuthUserWithPermissions,
-    resVal: string,
-    request: Request,
-  ): Promise<boolean>;
-}
+export type CasbinAuthorizeFn = (
+  user: IAuthUserWithPermissions,
+  resVal: string,
+  request: Request,
+) => Promise<boolean>;
+
 export type PermissionObject = {
   [controller: string]: {
     [method: string]: string[];
@@ -82,40 +84,40 @@ export interface UserPermission<T> {
 }
 
 /**
- * User permissions manipulation method interface.
+ * User permissions manipulation method type.
  *
  * This is where we can add our business logic to read and
  * union permissions associated to user via role with
  * those associated directly to the user.
  *
  */
-export interface UserPermissionsFn<T> {
-  (userPermissions: UserPermission<T>[], rolePermissions: T[]): T[];
-}
+export type UserPermissionsFn<T> = (
+  userPermissions: UserPermission<T>[],
+  rolePermissions: T[],
+) => T[];
 
 /**
- * Casbin enforcer getter method interface
+ * Casbin enforcer getter method type
  *
  * This method provides the Casbin config
  * required to initialise a Casbin enforcer
  */
-export interface CasbinEnforcerConfigGetterFn {
-  (
-    authUser: IAuthUserWithPermissions,
-    resource: string,
-    isCasbinPolicy?: boolean,
-  ): Promise<CasbinConfig>;
-}
+export type CasbinEnforcerConfigGetterFn = (
+  authUser: IAuthUserWithPermissions,
+  resource: string,
+  isCasbinPolicy?: boolean,
+) => Promise<CasbinConfig>;
 
 /**
- * Casbin resource value modifier method interface
+ * Casbin resource value modifier method type
  *
  * This method can help modify the resource value
  * for integration with casbin, as per business logic
  */
-export interface CasbinResourceModifierFn {
-  (pathParams: string[], req: Request): Promise<string>;
-}
+export type CasbinResourceModifierFn = (
+  pathParams: string[],
+  req: Request,
+) => Promise<string>;
 
 /**
  * Casbin config object