Create CurrencyConverterModule for telegram bot on NestJS using ScraperModule
Tags: kaufmanbot, nestjs, modules, currency
Published: 2022-02-26 08:42:35


Create new library currency-converter

> npm run -- nx g @nrwl/nest:lib currency-converter/server

```sh
endy@endy-virtual-machine:~/Projects/current/kaufman-bot$ npm run -- nx g @nrwl/nest:lib currency-converter/server

> kaufman-bot@0.0.0 nx
> nx "g" "@nrwl/nest:lib" "currency-converter/server"

CREATE libs/currency-converter/server/README.md
CREATE libs/currency-converter/server/.babelrc
CREATE libs/currency-converter/server/src/index.ts
CREATE libs/currency-converter/server/tsconfig.json
CREATE libs/currency-converter/server/tsconfig.lib.json
UPDATE tsconfig.base.json
CREATE libs/currency-converter/server/project.json
UPDATE workspace.json
CREATE libs/currency-converter/server/.eslintrc.json
CREATE libs/currency-converter/server/jest.config.js
CREATE libs/currency-converter/server/tsconfig.spec.json
CREATE libs/currency-converter/server/src/lib/currency-converter-server.module.ts
```

Create new library html-scraper

> npm run -- nx g @nrwl/nest:lib html-scraper/server

```sh
endy@endy-virtual-machine:~/Projects/current/kaufman-bot$ npm run -- nx g @nrwl/nest:lib html-scraper/server

> kaufman-bot@0.0.0 nx
> nx "g" "@nrwl/nest:lib" "html-scraper/server"

CREATE libs/html-scraper/server/README.md
CREATE libs/html-scraper/server/.babelrc
CREATE libs/html-scraper/server/src/index.ts
CREATE libs/html-scraper/server/tsconfig.json
CREATE libs/html-scraper/server/tsconfig.lib.json
UPDATE tsconfig.base.json
CREATE libs/html-scraper/server/project.json
UPDATE workspace.json
CREATE libs/html-scraper/server/.eslintrc.json
CREATE libs/html-scraper/server/jest.config.js
CREATE libs/html-scraper/server/tsconfig.spec.json
CREATE libs/html-scraper/server/src/lib/html-scraper-server.module.ts
```

Copy exists scraper module to libs/html-scraper/server

> cp -Rf ./libs/plugins/server/src/lib/scraper/\* ./libs/html-scraper/server/src/lib
> rm -r ./libs/html-scraper/server/src/lib/html-scraper-server.module.ts
> npm run generate

Change imports in **apps/server/src/app/app.module.ts**

```ts
import { ScraperModule } from '@kaufman-bot/html-scraper/server';
import { Module } from '@nestjs/common';
import env from 'env-var';
import { TelegrafModule } from 'nestjs-telegraf';
import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
  imports: [
    TelegrafModule.forRoot({
      token: env.get('TELEGRAM_BOT_TOKEN').required().asString(),
    }),
    ScraperModule.forRoot({
      contentSelector:
        '#__next > div:nth-child(2) > div.fluid-container__BaseFluidContainer-qoidzu-0.gJBOzk > section > div:nth-child(2) > div > main > form > div:nth-child(2) > div:nth-child(1) > p.result__BigRate-sc-1bsijpp-1.iGrAod',
      help: 'Scraper help message',
      spyWords: ['scraper'],
      removeWords: ['to', 'convert', 'please'],
      uri: 'https://www.xe.com/currencyconverter/convert/?Amount={{TEXT1}}&From={{TEXT2}}&To={{TEXT3}}',
    }),
  ],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}
```

Change imports in **apps/server/src/app/app.service.ts**

```ts
import { ScraperService } from '@kaufman-bot/html-scraper/server';
import { Injectable, Logger } from '@nestjs/common';
import { Hears, Help, Message, On, Start, Update } from 'nestjs-telegraf';
import { Context } from 'telegraf';

@Update()
@Injectable()
export class AppService {
  private readonly logger = new Logger(AppService.name);

  constructor(private readonly scraperService: ScraperService) {}

  getData(): { message: string } {
    return { message: 'Welcome to server!' };
  }

  @Start()
  async startCommand(ctx: Context) {
    await ctx.reply('Welcome');
  }

  @Help()
  async helpCommand(ctx: Context) {
    await ctx.reply('Send me a sticker');
  }

  @On('sticker')
  async onSticker(ctx: Context) {
    await ctx.reply('👍');
  }

  @Hears('hi')
  async hearsHi(ctx: Context) {
    await ctx.reply('Hey there');
  }

  @On('text')
  async onMessage(@Message() msg) {
    try {
      const scraperReplayMessage = await this.scraperService.onMessage(msg);
      return scraperReplayMessage;
    } catch (err) {
      this.logger.error(err, err.stack);
    }
  }
}
```

Remove old library

> npm run -- nx g @nrwl/workspace:remove plugins-server
> npm run generate

Install needed libraries

> npm i --save class-validator-multi-lang class-transformer-global-storage

```sh
endy@endy-virtual-machine:~/Projects/current/kaufman-bot$ npm i --save class-validator-multi-lang class-transformer-global-storage

added 4 packages, and audited 888 packages in 4s

109 packages are looking for funding
  run `npm fund` for details

found 0 vulnerabilities
```

Create new service **libs/currency-converter/server/src/lib/currency-converter-services/currency-converter.service.ts**

```ts
import { ScraperService } from '@kaufman-bot/html-scraper/server';
import { Injectable } from '@nestjs/common';

@Injectable()
export class CurrencyConverterService {
  constructor(private readonly scraperService: ScraperService) {}

  async onMessage(msg) {
    const result = await this.scraperService.onMessage(msg);
    if (result && /^[.,0-9]+$/.test(result.split(' ')[0])) {
      return result.split(' ')[0];
    }
    return result;
  }
}
```

Create new module **libs/currency-converter/server/src/lib/currency-converter.module.ts**

```ts
import { ScraperModule } from '@kaufman-bot/html-scraper/server';
import { DynamicModule, Module } from '@nestjs/common';
import { getText } from 'class-validator-multi-lang';
import { CurrencyConverterService } from './currency-converter-services/currency-converter.service';

@Module({})
export class CurrencyConverterModule {
  static forRoot(): DynamicModule {
    return {
      module: CurrencyConverterModule,
      imports: [
        ScraperModule.forRoot({
          contentSelector:
            '#__next > div:nth-child(2) > div.fluid-container__BaseFluidContainer-qoidzu-0.gJBOzk > section > div:nth-child(2) > div > main > form > div:nth-child(2) > div:nth-child(1) > p.result__BigRate-sc-1bsijpp-1.iGrAod',
          help: getText('Currency converter'),
          spyWords: [getText('convert')],
          removeWords: [getText('to'), getText('please')],
          uri: 'https://www.xe.com/currencyconverter/convert/?Amount={{TEXT1}}&From={{TEXT2}}&To={{TEXT3}}',
        }),
      ],
      providers: [CurrencyConverterService],
      exports: [ScraperModule, CurrencyConverterService],
    };
  }
}
```

Add new files to index.ts in libraries and prepare translate words

> npm run generate

Update **apps/server/src/app/app.module.ts**

```ts
import { CurrencyConverterModule } from '@kaufman-bot/currency-converter/server';
import { Module } from '@nestjs/common';
import env from 'env-var';
import { TelegrafModule } from 'nestjs-telegraf';
import { AppController } from './app.controller';
import { AppService } from './app.service';

@Module({
  imports: [
    TelegrafModule.forRoot({
      token: env.get('TELEGRAM_BOT_TOKEN').required().asString(),
    }),
    CurrencyConverterModule.forRoot(),
  ],
  controllers: [AppController],
  providers: [AppService],
})
export class AppModule {}
```

Update **apps/server/src/app/app.service.ts**

```ts
import { CurrencyConverterService } from '@kaufman-bot/currency-converter/server';
import { Injectable, Logger } from '@nestjs/common';
import { Hears, Help, Message, On, Start, Update } from 'nestjs-telegraf';
import { Context } from 'telegraf';

@Update()
@Injectable()
export class AppService {
  private readonly logger = new Logger(AppService.name);

  constructor(
    private readonly currencyConverterService: CurrencyConverterService
  ) {}

  getData(): { message: string } {
    return { message: 'Welcome to server!' };
  }

  @Start()
  async startCommand(ctx: Context) {
    await ctx.reply('Welcome');
  }

  @Help()
  async helpCommand(ctx: Context) {
    await ctx.reply('Send me a sticker');
  }

  @On('sticker')
  async onSticker(ctx: Context) {
    await ctx.reply('👍');
  }

  @Hears('hi')
  async hearsHi(ctx: Context) {
    await ctx.reply('Hey there');
  }

  @On('text')
  async onMessage(@Message() msg) {
    try {
      const replayMessage = await this.currencyConverterService.onMessage(msg);
      return replayMessage;
    } catch (err) {
      this.logger.error(err, err.stack);
    }
  }
}
```

Test from telegram
![Image description](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/psk75zs5ejlgxtupjkfq.png)