src/csv-parser.ts

   1 import { createHash, Hash } from 'crypto';
   2 import * as csvParse from 'csv-parse';
   3 import { Service } from 'typedi';
   4
   5 @Service()
   6 export class CsvParser {
   7   public async parse(buffer: Buffer): Promise<ICsvRow[]> {
   8     const records = await this.parseCsv(buffer);
   9
  10     return records.map(
  11       (columns: string[]): ICsvRow => {
  12         return {
  13           hash: this.getHash(columns[0]),
  14           lastSeen: new Date(`${columns[2]}Z`).getTime(),
  15           occurrences: parseInt(columns[1], 10),
  16         };
  17       },
  18     );
  19   }
  20
  21   protected async parseCsv(buffer: Buffer): Promise<string[][]> {
  22     return new Promise<string[][]>(
  23       (
  24         resolve: (rows: string[][]) => void,
  25         reject: (err: Error) => void,
  26       ): void => {
  27         csvParse(
  28           buffer.toString(),
  29           { escape: '\\' },
  30           (err: Error | undefined, records: string[][] | undefined) => {
  31             if (err) {
  32               reject(err);
  33             } else {
  34               resolve(records);
  35             }
  36           },
  37         );
  38       },
  39     );
  40   }
  41
  42   protected getHash(input: string): string {
  43     return createHash('sha256')
  44       .update(input)
  45       .digest('hex');
  46   }
  47 }
  48
  49 export interface ICsvRow {
  50   hash: string;
  51   lastSeen: number;
  52   occurrences: number;
  53 }