pdfParser.ts

import verifyPDF from "@ninja-labs/verify-pdf";
import { PDFName, PDFPage, PDFString } from "pdf-lib";
import { PdfData } from "pdfdataextract";
import { config } from "./config";
import { IgetMetaResponse } from "./types";
const { PDFDocument } = require("pdf-lib");
class PDFparser {
  readonly document;
  readonly config;

  constructor(document: Buffer) {
    this.document = document;
    this.config = config;
  }

  getPDFMeta = async (): Promise<IgetMetaResponse> => {
    try {
      const pdfMeta = await PdfData.extract(this.document, config);
      const signaturesMeta = await verifyPDF(this.document);

      return {
        verified: signaturesMeta.verified,
        authenticity: signaturesMeta.authenticity,
        integrity: signaturesMeta.integrity,
        expired: signaturesMeta.expired,
        meta: {
          certs: signaturesMeta.certs,
        },
        pages: pdfMeta.pages,
        fingerpring: pdfMeta.fingerprint,
        creation_data: pdfMeta.info.CreationDate,
        creator: pdfMeta.info.Creator,
        author: pdfMeta.info.Author,
        title: pdfMeta.info.Title,
        description: pdfMeta.info.Keywords,
        mod_date: pdfMeta.info.ModDate,
      };
    } catch (error) {
      console.error(error);
      throw new Error("Could not get pdf metadata");
    }
  };

  insertQrCode = async (
    imgBytes: ArrayBuffer,
    url: string
  ): Promise<ArrayBuffer> => {
    const pdfDoc = await PDFDocument.load(this.document);
    const img = await pdfDoc.embedPng(imgBytes);

    const scaled = img.scale(0.1);

    const pages = pdfDoc.getPages();

    const firstPage = pages[0];

    firstPage.drawImage(img, {
      x: firstPage.getWidth() / 2 - scaled.width / 2,
      y: firstPage.getHeight() / 2 - scaled.height / 2,
      width: scaled.width,
      height: scaled.height,
    });

    const link = this.createPageLinkAnnotation(firstPage, url, {
      imgXPos: firstPage.getWidth() / 2 - scaled.width / 2,
      imgYPos: firstPage.getHeight() / 2 - scaled.height / 2,
      imgWidth: scaled.width,
      imagHeight: scaled.height,
    });

    firstPage.node.set(PDFName.of("Annots"), pdfDoc.context.obj([link]));

    const pdfBytes = await pdfDoc.save();

    return pdfBytes;
  };

  private createPageLinkAnnotation = (
    page: PDFPage,
    uri: string,
    { imgXPos, imgYPos, imgWidth, imagHeight }
  ) =>
    page.doc.context.register(
      page.doc.context.obj({
        Type: "Annot",
        Subtype: "Link",
        Rect: [imgXPos, imgYPos, imgXPos + imgWidth, imgYPos + imagHeight],
        A: {
          Type: "Action",
          S: "URI",
          URI: PDFString.of(uri),
        },
      })
    );
}

export default PDFparser;