Fixed data loading

- fixed multiple loading requests on pending data load

src/lib/MemoryCache.ts

@@ -1,5 +1,5 @@
-import {EventEmitter} from "events";
 import * as crypto from "crypto";
+import {EventEmitter} from "events";
 
 export class MemoryCache extends EventEmitter {
     private cacheItems: any = {};

src/lib/dataaccess/DataObject.ts

@@ -1,10 +1,14 @@
 /**
  * abstact DataObject class
  */
-export abstract class DataObject {
+import {EventEmitter} from "events";
+
+export abstract class DataObject extends EventEmitter {
     protected dataLoaded: boolean = false;
+    private loadingData: boolean = false;
 
     constructor(public id: number, protected row?: any) {
+        super();
         this.id = Number(id);
     }
 
@@ -22,8 +26,15 @@ export abstract class DataObject {
      * Loads data from the database if data has not been loaded
      */
     protected async loadDataIfNotExists() {
-        if (!this.dataLoaded) {
+        if (!this.dataLoaded && !this.loadingData) {
+            this.loadingData = true;
             await this.loadData();
+            this.loadingData = false;
+            this.emit("loaded");
+        } else if (this.loadingData) {
+            return new Promise((res) => {
+                this.on("loaded", () => res());
+            });
         }
     }
 }

src/lib/dataaccess/Post.ts

@@ -16,6 +16,7 @@ export class Post extends DataObject {
      */
     public async upvotes(): Promise<number> {
         const result = await queryHelper.first({
+            cache: true,
             text: "SELECT COUNT(*) count FROM votes WHERE item_id = $1 AND vote_type = 'UPVOTE'",
             values: [this.id],
         });
@@ -27,6 +28,7 @@ export class Post extends DataObject {
      */
     public async downvotes(): Promise<number> {
         const result = await queryHelper.first({
+            cache: true,
             text: "SELECT COUNT(*) count FROM votes WHERE item_id = $1 AND vote_type = 'DOWNVOTE'",
             values: [this.id],
         });
@@ -80,6 +82,7 @@ export class Post extends DataObject {
      */
     public async userVote(userId: number): Promise<dataaccess.VoteType> {
         const result = await queryHelper.first({
+            cache: true,
             text: "SELECT vote_type FROM votes WHERE user_id = $1 AND item_id = $2",
             values: [userId, this.id],
         });
@@ -127,6 +130,7 @@ export class Post extends DataObject {
             result = this.row;
         } else {
             result = await queryHelper.first({
+                cache: true,
                 text: "SELECT * FROM posts WHERE posts.id = $1",
                 values: [this.id],
             });

src/lib/dataaccess/index.ts

@@ -115,6 +115,7 @@ namespace dataaccess {
      * @param type
      */
     export async function createPost(content: string, authorId: number, type?: string): Promise<Post> {
+        type = type || "MISC";
         const result = await queryHelper.first({
             text: "INSERT INTO posts (content, author, type) VALUES ($1, $2, $3) RETURNING *",
             values: [content, authorId, type],

src/public/graphql/schema.graphql

@@ -53,7 +53,7 @@ type Mutation {
     sendMessage(chatId: ID!, content: String!): ChatMessage
 
     "create the post"
-    createPost(content: String!): Boolean
+    createPost(content: String!): Post
 
     "delete the post for a given post id"
     deletePost(postId: ID!): Boolean
@@ -150,6 +150,9 @@ type Profile implements UserData {
 "represents a single user post"
 type Post {
 
+    "The id of the post."
+    id: ID!
+
     "the text of the post"
     content: String
 
@@ -166,7 +169,7 @@ type Post {
     author: User!
 
     "date the post was created"
-    creationDate: String!
+    createdAt: String!
 
     "the type of vote the user performed on the post"
     userVote: VoteType