answered the questions; add route to upload file; added docFactory; a…

…dded dotenv (for local dev);

.env

@@ -1,10 +1,11 @@
 HTTP_PORT=3000
 
-#DB_HOST=postgres  # for running in docker-compose
-DB_HOST=localhost
+#DB_HOST=localhost # for running locally
+DB_HOST=postgres
 DB_PORT=5432
 DB_USERNAME=curex
 DB_PASSWORD=dbpassword
 DB_NAME=curex-db
 DB_SYNCHRONIZE=true # todo: add more controll on this env var (on prod)
 
+UPLOAD_FILE_MAX_SIZE_BITES=123000

README.md

@@ -1,6 +1,10 @@
 
 ## Description
-A test tasks for AYA (parser) 
+`curex-app` is test task for AYA to parse file with indents, and import parsed data into PostgreSQL.
+
+[File format example](imports/import.txt)
+
+The logic for parsing a file is in `./src/db/file-importer`
 
 ## Installation
 
@@ -12,20 +16,20 @@ $ npm install
 
 ```bash
 # import data from /imports/import.txt into Postgres DB
-npm run start:import
+$ npm run start:import
 
-# watch mode
-$ npm run start:dev
+# run curex-app (with DB and adminer)
+$ docker-compose up
 
-# production mode
-$ npm run start:prod
+# run server locally
+$ npm run start:dev
 ```
 
 ## Env vars (.env)
 
 ```bash
 HTTP_PORT=3000
-DB_HOST=localhost
+DB_HOST=postgres
 DB_PORT=5432
 DB_USERNAME=curex
 DB_PASSWORD=dbpassword
@@ -34,15 +38,37 @@ DB_SYNCHRONIZE=true
 ```
 
 
-## Test
+## Answers
+
+1. _How to change the code to support different file format versions?_ 
+
+
+   For handling different file formats I'd suggest creating separate classes, which implement `IDocument`,
+   and `FileImporter` will use (see method _makeJsonFromText_) needed instances of `IDocument` through `documentFactory`.
+   Version of the format could be identified dynamically (based on content), or passed as param to the factory.
+   `DbImportService` is responsible for actual storing data in DB, and doesn't know anything about file format     
+---
+
+2. _How will the import system change if in the future we need to get this data from a web API?_
+
+
+   I don't see a necessity to change import system in case getting the file content through API.
+   Reading file from disk OR receiving it from API are just "transport details" in scope of parsing. 
+   `FileImporter` doesn't know where from content to parse is coming. It has 2 methods:
+
+   - _makeJsonFromText( content )_ - "Main" method for parsing raw file content, and convert it in JSON structure, which holds
+     information about domain entities to be stored in DB;
+
+   - _importFromFile( fileName? )_ - Which accepts fileName (if not passed, used default name), read file from disk, and call
+     the makeJsonFromText() method  
+
+   Current implementation has 3 methods to import data to DB:
+
+   - using script: `npm run start:import`, which reads file from disk, parse it and store in DB (without spinning up http-server)
+   - `GET localhost:3000/db/import?filename=import.txt`, which accepts optional _filename_, and does the same as script above
+   - `POST localhost:3000/db/import-file`, which accepts fileContent as _form-data_ 
+
+     https://i.imgur.com/yKvgJcy.png
 
-```bash
-# unit tests
-$ npm run test
 
-# e2e tests
-$ npm run test:e2e
 
-# test coverage
-$ npm run test:cov
-```

docker-compose.yml

@@ -5,9 +5,9 @@ services:
     build:
       context: .
       dockerfile: Dockerfile
-      target: prod
+      target: dev
     restart: always
-#    command: npm run start:dev
+    command: npm run start:dev
     ports:
       - "127.0.0.1:3000:${HTTP_PORT}"
     env_file: .env

imports/import.txt

@@ -33,6 +33,12 @@ exchange-offices
     id = 2
     name = Exchanger 2
     country = UKR
+    exchanges
+      exchange
+        from = AUD
+        to = CAD
+        ask = 100
+        date = 2023-04-25 22:55:33
     rates
       rate
         from = AUD

package.json

@@ -1,18 +1,18 @@
 {
   "name": "exchange-office",
   "version": "0.0.1",
-  "description": "",
-  "author": "",
+  "description": "Test task for AYA",
+  "author": "[email protected]",
   "private": true,
   "license": "UNLICENSED",
   "scripts": {
     "build": "nest build",
     "format": "prettier --write \"src/**/*.ts\" \"test/**/*.ts\"",
     "start": "nest start",
-    "start:dev": "nest start --watch",
-    "start:debug": "nest start --debug --watch",
+    "start:dev": "NODE_OPTIONS='-r dotenv/config' nest start --watch",
+    "start:debug": "NODE_OPTIONS='-r dotenv/config' nest start --debug --watch",
+    "start:import": "NODE_OPTIONS='-r dotenv/config' ts-node src/main-import-file.ts",
     "start:prod": "node dist/main",
-    "start:import": "ts-node src/main-import-file.ts",
     "lint": "eslint \"{src,apps,libs,test}/**/*.ts\" --fix",
     "test": "jest",
     "test:watch": "jest --watch",
@@ -37,10 +37,12 @@
     "@nestjs/testing": "^9.0.0",
     "@types/express": "^4.17.13",
     "@types/jest": "29.5.1",
+    "@types/multer": "^1.4.7",
     "@types/node": "18.16.12",
     "@types/supertest": "^2.0.11",
     "@typescript-eslint/eslint-plugin": "^5.0.0",
     "@typescript-eslint/parser": "^5.0.0",
+    "dotenv": "^16.3.1",
     "eslint": "^8.0.1",
     "eslint-config-prettier": "^8.3.0",
     "eslint-plugin-prettier": "^4.0.0",

src/config/index.ts

@@ -11,3 +11,9 @@ export const pgDbConfig = (): TypeOrmModuleOptions => ({
   database: env.DB_NAME,
   synchronize: env.DB_SYNCHRONIZE === 'true',
 });
+
+export const fileUploadOptions = Object.freeze({
+  limits: {
+    fileSize: parseInt(env.UPLOAD_FILE_MAX_SIZE_BITES, 10) || 800,
+  },
+});

src/db/db-import.service.ts

@@ -26,10 +26,19 @@ export class DbImportService {
     private readonly exchangeOfficeRepo: Repository<ExchangeOffice>,
   ) {}
 
-  async importFileContentToDb() {
-    const content: TJsonContent = await this.loadContentFromFile();
+  async importFileFromDiskToDb(fileName?: string) {
+    const content: TJsonContent = await this.loadContentFromFile(fileName);
+    return this.storeFileContentInDb(content);
+  }
+
+  async uploadFileToDb(file: string) {
+    const content = this.parseFileToJson(file);
+    return this.storeFileContentInDb(content);
+  }
+
+  private async storeFileContentInDb(content: TJsonContent) {
     if (!content) {
-      this.logger.warn(`Failed to load content from import file`);
+      this.logger.warn(`No content for storing in DB`);
       return {
         countries: [],
         offices: [],
@@ -40,15 +49,17 @@ export class DbImportService {
     const offices = await this.importExchangeOffices(
       content[exchangeOfficesField],
     );
-    this.logger.log('importFromFile is done');
+    this.logger.log('storeFileContentInDb is done');
 
     return {
       countries,
       offices,
     };
   }
 
-  async importCountries(countryList: TCountryList): Promise<Country[] | []> {
+  private async importCountries(
+    countryList: TCountryList,
+  ): Promise<Country[] | []> {
     const codes = countryList.map((c) => c.code);
     const dbData = await this.countryRepo.findBy({ code: In(codes) });
 
@@ -63,7 +74,7 @@ export class DbImportService {
     return this.countryRepo.save(countries);
   }
 
-  async importExchangeOffices(
+  private async importExchangeOffices(
     eoList: TExchangeOfficeList,
   ): Promise<ExchangeOffice[] | []> {
     const ids = eoList.map((eo) => Number(eo.id));
@@ -81,7 +92,13 @@ export class DbImportService {
   }
   // todo: move common logic of filtering existing entities to one place
 
-  async loadContentFromFile(fileName?: string): Promise<TJsonContent | null> {
+  private async loadContentFromFile(
+    fileName?: string,
+  ): Promise<TJsonContent | null> {
     return this.fileImporter.importFromFile(fileName);
   }
+
+  private parseFileToJson(file: string): TJsonContent | null {
+    return this.fileImporter.makeJsonFromText(file);
+  }
 }

src/db/db.controller.ts

@@ -1,13 +1,29 @@
-import { Controller, Get } from '@nestjs/common';
+import {
+  Controller,
+  Get,
+  Post,
+  Query,
+  UploadedFile,
+  UseInterceptors,
+} from '@nestjs/common';
+import { FileInterceptor } from '@nestjs/platform-express';
+import { Express } from 'express';
+
+import { fileUploadOptions } from '../config';
 import { DbImportService } from './db-import.service';
 
 @Controller('db')
 export class DbController {
   constructor(private readonly dbImportService: DbImportService) {}
 
   @Get('import')
-  async import() {
-    // todo: think, which params to accept if we need to import from uploaded file
-    return this.dbImportService.importFileContentToDb();
+  async import(@Query('filename') fileName?: string) {
+    return this.dbImportService.importFileFromDiskToDb(fileName);
+  }
+
+  @Post('import-file')
+  @UseInterceptors(FileInterceptor('file', fileUploadOptions))
+  async handleFileImport(@UploadedFile() file: Express.Multer.File) {
+    return this.dbImportService.uploadFileToDb(file.buffer.toString());
   }
 }

src/db/entities/index.ts

@@ -8,21 +8,36 @@ import {
   JoinColumn,
 } from 'typeorm';
 
+export type Currencies = 'CAD' | 'AUD' | 'EUR' | 'UAH' | 'USD';
+
 abstract class CommonRateExchangeInfo {
   @PrimaryGeneratedColumn()
   id: number;
 
-  @Column()
+  @Column({ length: 3 })
   from: Currencies;
 
-  @Column()
+  @Column({ length: 3 })
   to: Currencies;
 
   @Column()
   date: Date;
 }
 
-export type Currencies = 'EUR' | 'USD' | 'UAH';
+@Entity()
+export class Country {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({
+    unique: true,
+    length: 3,
+  })
+  code: string;
+
+  @Column({ length: 50 })
+  name: string;
+}
 
 @Entity()
 export class ExchangeOffice {
@@ -32,9 +47,12 @@ export class ExchangeOffice {
   @Column({ length: 100 })
   name: string;
 
-  @ManyToOne(() => Country, (c) => c.code)
-  @JoinColumn({ referencedColumnName: 'code' })
-  country: Currencies;
+  @ManyToOne(() => Country, (c) => c.code, { nullable: false })
+  @JoinColumn({
+    name: 'country',
+    referencedColumnName: 'code',
+  })
+  country: Country;
 
   @OneToMany(() => Exchange, (exchange) => exchange.exchangeOffice, {
     cascade: true,
@@ -45,6 +63,7 @@ export class ExchangeOffice {
     cascade: true,
   })
   rates: Rate[];
+  // think, if we need createdAt/updateAd-fields
 }
 
 @Entity()
@@ -76,20 +95,3 @@ export class Rate extends CommonRateExchangeInfo {
   @JoinColumn()
   exchangeOffice: ExchangeOffice;
 }
-
-@Entity()
-export class Country {
-  @PrimaryGeneratedColumn()
-  id: number;
-
-  @Column({
-    unique: true,
-    length: 3,
-  })
-  code: Currencies;
-
-  @Column({ length: 50 })
-  name: string;
-
-  // think, if we need createdAt-field
-}

src/db/file-importer/document-factory.ts

@@ -0,0 +1,7 @@
+import { IDocument } from './interfaces';
+import { Document } from './document';
+
+export const documentFactory = (): IDocument => {
+  // todo: define separate doc classes for any new file formats
+  return new Document();
+};