From b3523b4c631c4f507ec612715062e40f0bc14a3f Mon Sep 17 00:00:00 2001
From: Einhornimmond <git@einhornimmond.de>
Date: Mon, 21 Feb 2022 12:03:19 +0100
Subject: [PATCH] generic filtering, prevent overfetching from db

---
 backend/src/graphql/resolver/AdminResolver.ts | 40 +++++++++++-------
 backend/src/typeorm/repository/User.ts        | 41 +++----------------
 2 files changed, 32 insertions(+), 49 deletions(-)

diff --git a/backend/src/graphql/resolver/AdminResolver.ts b/backend/src/graphql/resolver/AdminResolver.ts
index 937ed8567..4a2e59644 100644
--- a/backend/src/graphql/resolver/AdminResolver.ts
+++ b/backend/src/graphql/resolver/AdminResolver.ts
@@ -2,7 +2,7 @@
 /* eslint-disable @typescript-eslint/explicit-module-boundary-types */
 
 import { Resolver, Query, Arg, Args, Authorized, Mutation, Ctx } from 'type-graphql'
-import { getCustomRepository, Raw } from '@dbTools/typeorm'
+import { getCustomRepository, ObjectLiteral, Raw } from '@dbTools/typeorm'
 import { UserAdmin, SearchUsersResult } from '../model/UserAdmin'
 import { PendingCreation } from '../model/PendingCreation'
 import { CreatePendingCreations } from '../model/CreatePendingCreations'
@@ -27,6 +27,13 @@ import { LoginEmailOptIn } from '@entity/LoginEmailOptIn'
 // const EMAIL_OPT_IN_REGISTER = 1
 // const EMAIL_OPT_UNKNOWN = 3 // elopage?
 
+/*
+parent:any,
+args:any,
+context:any,
+info:any
+*/
+
 @Resolver()
 export class AdminResolver {
   @Authorized([RIGHTS.SEARCH_USERS])
@@ -35,21 +42,25 @@ export class AdminResolver {
     @Args() { searchText, currentPage = 1, pageSize = 25, notActivated = false }: SearchUsersArgs,
   ): Promise<SearchUsersResult> {
     const userRepository = getCustomRepository(UserRepository)
-    let users: dbUser[]
-    let count: number
+
+    const filterCriteria: ObjectLiteral[] = []
     if (notActivated) {
-      [users, count] = await userRepository.findBySearchCriteriaPagedNotActivated(
-        searchText,
-        currentPage,
-        pageSize,
-      )
-    } else {
-      [users, count] = await userRepository.findBySearchCriteriaPaged(
-        searchText,
-        currentPage,
-        pageSize,
-      )
+      filterCriteria.push({ emailChecked: false })
     }
+    // prevent overfetching data from db, select only needed columns
+    // prevent reading and transmitting data from db at least 300 Bytes
+    // one of my example dataset shrink down from 342 Bytes to 42 Bytes, that's ~88% saved db bandwith
+    const userFields = ['id', 'firstName', 'lastName', 'email', 'emailChecked']
+    const [users, count] = await userRepository.findBySearchCriteriaPagedFiltered(
+      userFields.map((fieldName) => {
+        return 'user.' + fieldName
+      }),
+      searchText,
+      filterCriteria,
+      currentPage,
+      pageSize,
+    )
+
     const adminUsers = await Promise.all(
       users.map(async (user) => {
         const adminUser = new UserAdmin()
@@ -70,6 +81,7 @@ export class AdminResolver {
                 updatedAt: 'DESC',
                 createdAt: 'DESC',
               },
+              select: ['updatedAt', 'createdAt'],
             },
           )
           if (emailOptIn) {
diff --git a/backend/src/typeorm/repository/User.ts b/backend/src/typeorm/repository/User.ts
index 6045c402a..e7ef7f0bc 100644
--- a/backend/src/typeorm/repository/User.ts
+++ b/backend/src/typeorm/repository/User.ts
@@ -1,4 +1,4 @@
-import { Brackets, EntityRepository, Repository } from '@dbTools/typeorm'
+import { Brackets, EntityRepository, ObjectLiteral, Repository } from '@dbTools/typeorm'
 import { User } from '@entity/User'
 
 @EntityRepository(User)
@@ -31,44 +31,15 @@ export class UserRepository extends Repository<User> {
     return usersIndiced
   }
 
-  async findBySearchCriteria(searchCriteria: string): Promise<User[]> {
-    return await this.createQueryBuilder('user')
-      .where(
-        'user.firstName like :name or user.lastName like :lastName or user.email like :email',
-        {
-          name: `%${searchCriteria}%`,
-          lastName: `%${searchCriteria}%`,
-          email: `%${searchCriteria}%`,
-        },
-      )
-      .getMany()
-  }
-
-  async findBySearchCriteriaPaged(
-    searchCriteria: string,
-    currentPage: number,
-    pageSize: number,
-  ): Promise<[User[], number]> {
-    return await this.createQueryBuilder('user')
-      .where(
-        'user.firstName like :name or user.lastName like :lastName or user.email like :email',
-        {
-          name: `%${searchCriteria}%`,
-          lastName: `%${searchCriteria}%`,
-          email: `%${searchCriteria}%`,
-        },
-      )
-      .take(pageSize)
-      .skip((currentPage - 1) * pageSize)
-      .getManyAndCount()
-  }
-
-  async findBySearchCriteriaPagedNotActivated(
+  async findBySearchCriteriaPagedFiltered(
+    select: string[],
     searchCriteria: string,
+    filterCriteria: ObjectLiteral[],
     currentPage: number,
     pageSize: number,
   ): Promise<[User[], number]> {
     return await this.createQueryBuilder('user')
+      .select(select)
       .where(
         new Brackets((qb) => {
           qb.where(
@@ -81,7 +52,7 @@ export class UserRepository extends Repository<User> {
           )
         }),
       )
-      .andWhere({ emailChecked: false })
+      .andWhere(filterCriteria)
       .take(pageSize)
       .skip((currentPage - 1) * pageSize)
       .getManyAndCount()