Allow omitting the recipient list when creating a notification to pull a dynamic list from DB defined in strategy

Author: CarsonF

src/components/notification-system/system-notification.resolver.ts

@@ -6,7 +6,7 @@ import {
   ObjectType,
   Resolver,
 } from '@nestjs/graphql';
-import { ID, LoggedInSession, Session, UnauthorizedException } from '~/common';
+import { LoggedInSession, Session, UnauthorizedException } from '~/common';
 import { MarkdownScalar } from '~/common/markdown.scalar';
 import { isAdmin } from '~/common/session';
 import { NotificationService } from '../notifications';
@@ -34,13 +34,7 @@ export class SystemNotificationResolver {
       throw new UnauthorizedException();
     }
 
-    // @ts-expect-error this is just for testing
-    const allUsers = await this.notifications.repo.db
-      .query<{ id: ID }>('match (u:User) return u.id as id')
-      .map('id')
-      .run();
-
-    return await this.notifications.create(SystemNotification, allUsers, {
+    return await this.notifications.create(SystemNotification, null, {
       message,
     });
   }

src/components/notification-system/system-notification.strategy.ts

@@ -1,5 +1,11 @@
+import { node, Query } from 'cypher-query-builder';
 import { INotificationStrategy, NotificationStrategy } from '../notifications';
 import { SystemNotification } from './system-notification.dto';
 
 @NotificationStrategy(SystemNotification)
-export class SystemNotificationStrategy extends INotificationStrategy<SystemNotification> {}
+export class SystemNotificationStrategy extends INotificationStrategy<SystemNotification> {
+  recipientsForNeo4j() {
+    return (query: Query) =>
+      query.match(node('recipient', 'User')).return('recipient');
+  }
+}

src/components/notifications/notification.repository.ts

@@ -1,4 +1,5 @@
 import { forwardRef, Inject, Injectable } from '@nestjs/common';
+import { Nil } from '@seedcompany/common';
 import { inArray, node, Query, relation } from 'cypher-query-builder';
 import { omit } from 'lodash';
 import { DateTime } from 'luxon';
@@ -39,7 +40,7 @@ export class NotificationRepository extends CommonRepository {
   }
 
   async create(
-    recipients: ReadonlyArray<ID<'User'>>,
+    recipients: ReadonlyArray<ID<'User'>> | Nil,
     type: ResourceShape<any>,
     input: Record<string, any>,
     session: Session,
@@ -65,8 +66,15 @@ export class NotificationRepository extends CommonRepository {
       )
       .subQuery(['node', 'requestingUser'], (sub) =>
         sub
-          .match(node('recipient', 'User'))
-          .where({ 'recipient.id': inArray(recipients) })
+          .apply((q) =>
+            recipients == null
+              ? q.subQuery(
+                  this.service.getStrategy(type).recipientsForNeo4j(input),
+                )
+              : q
+                  .match(node('recipient', 'User'))
+                  .where({ 'recipient.id': inArray(recipients) }),
+          )
           .create([
             node('node'),
             relation('out', '', 'recipient', { unread: variable('true') }),

src/components/notifications/notification.service.ts

@@ -1,6 +1,6 @@
 import { DiscoveryService } from '@golevelup/nestjs-discovery';
 import { forwardRef, Inject, Injectable, OnModuleInit } from '@nestjs/common';
-import { mapEntries } from '@seedcompany/common';
+import { mapEntries, Nil } from '@seedcompany/common';
 import {
   ID,
   ResourceShape,
@@ -30,9 +30,12 @@ export abstract class NotificationService {
   @Inject(GqlContextHost)
   protected readonly gqlContextHost: GqlContextHost;
 
+  /**
+   * If the recipient list is given (not nil), it will override the strategy's recipient resolution.
+   */
   async create<T extends ResourceShape<Notification>>(
     type: T,
-    recipients: ReadonlyArray<ID<'User'>>,
+    recipients: ReadonlyArray<ID<'User'>> | Nil,
     input: T extends { Input: infer Input } ? Input : InputOf<T['prototype']>,
   ) {
     const session = sessionFromContext(this.gqlContextHost.context);

src/components/notifications/notification.strategy.ts

@@ -21,6 +21,14 @@ export abstract class INotificationStrategy<
   TNotification extends Notification,
   TInput = InputOf<TNotification>,
 > {
+  /**
+   * Expected to return rows with a user as `recipient`
+   */
+  // eslint-disable-next-line @seedcompany/no-unused-vars
+  recipientsForNeo4j(input: TInput) {
+    return (query: Query) => query.unwind([], 'recipient').return('recipient');
+  }
+
   saveForNeo4j(input: TInput) {
     return (query: Query) => query.setValues({ node: input }, true);
   }