Error when using node JS pdf-lib: Expected xref at NaN but found other content

[CristiCh]

I am using pdf-lib in a node JS project and I get the same error when trying to modify the pdf. Does anyone know why this is happening? Thanks!

exports.transformPdf = onObjectFinalized({}, async (event) => {
    const bucket = admin.storage().bucket()
    const fileBucket = event.data.bucket; // Storage bucket containing the file.
    const filePath = event.data.name; // File path in the bucket.
    const contentType = event.data.contentType; // File content type.
    console.log(filePath);
    const file = await bucket.file(filePath);
    const fileDir = path.dirname(filePath);
    const fileBasename = path.basename(filePath);
    console.log(fileDir);
    if (fileDir != 'uploads') { return; }

    getRawBody(file.createReadStream())
    .then(async (pdfBuffer) => {
        console.log(pdfBuffer.length + ' bytes submitted');
        const pdfDoc = await PDFDocument.load(pdfBuffer, { capNumbers: true });
        console.log(pdfDoc);

        const timesRomanFont = await pdfDoc.embedFont(StandardFonts.TimesRoman);
        // const page = pdfDoc.addPage();
        const pagesCount = pdfDoc.getPageCount();
        const page = pdfDoc.getPage(pagesCount-1);
        const { width, height } = page.getSize();
        const fontSize = 20;
        page.drawText('Signed By Cristi C.', {
            x: width - 10 * fontSize,
            y: height - 40 * fontSize,
            size: fontSize,
            font: timesRomanFont,
            color: rgb(0, 0.53, 0.71),
        });
        const pdfBytes = await pdfDoc.save();
        bucket.file('transformed/'+fileBasename).save(pdfBytes).then(function (res) {}); //Save file in folder signed with the original name
        console.log('Document transformed');
    });

The error is: Expected xref at NaN but found other content

Thanks!

[Vanderson159]

I also came across this problem, did you find any solution?

[exilonX]

I'm having the same issue with PDF version 1.7 exported from sql reporting services.

Seems that the issue comes from how the trailer information is interpreted

1.4 from the contributing.pdf example :

trailer
<</Size 25
/Root 12 0 R
/Info 1 0 R>>
startxref
72203
%%EOF

1.7 example from my pdf

<< /Type /XRef 
/Index [0 50]
/W [1 4 3]
/Filter /FlateDecode /Size 50 /Length 195 /Root 47 0 R /Info 48 0 R >>
stream
X   c`
endstream
endobj
startxref
444002
%%EOF

SignPdfError: Expected xref at NaN but found other content. at getXref (C:\Users\ionel\Desktop\code\reges\reges-process\node_modules\@signpdf\placeholder-plain\dist\readRefTable.js:26:13) at getFullXref (C:\Users\ionel\Desktop\code\reges\reges-process\node_modules\@signpdf\placeholder-plain\dist\readRefTable.js:75:25) at getFullXrefTable (C:\Users\ionel\Desktop\code\reges\reges-process\node_modules\@signpdf\placeholder-plain\dist\readRefTable.js:90:10) at readRefTable (C:\Users\ionel\Desktop\code\reges\reges-process\node_modules\@signpdf\placeholder-plain\dist\readRefTable.js:106:25) at readPdf (C:\Users\ionel\Desktop\code\reges\reges-process\node_modules\@signpdf\placeholder-plain\dist\readPdf.js:56:46) at plainAddPlaceholder (C:\Users\ionel\Desktop\code\reges\reges-process\node_modules\@signpdf\placeholder-plain\dist\plainAddPlaceholder.js:70:37) at work (C:\Users\ionel\Desktop\code\reges\reges-process\scripts\test.js:32:28) {

My typescript code:

async signPdf(pdfBuffer: Buffer, pdfId: string): Promise<Buffer> {
    // Step 3: Add a signature placeholder using pdfkitAddPlaceholder
    try {
      const normalized = await this.addXrefTable(pdfBuffer);
      console.log(normalized.lastIndexOf('startxref'));
      const pdfWithPlaceholder = plainAddPlaceholder({
        pdfBuffer: normalized,
        reason: 'Document digitally signed',
        location: 'Location',
        contactInfo: 'contact@example.com',
        name: 'Signature',
        widgetRect: [100, 100, 300, 200], // Adjust coordinates as needed
        // signatureLength: 8192,
      });

      // Step 4: Generate signature hash from the external signing service
      const signatureHash = await this.generateSignature(pdfBuffer, pdfId);

      const signPdf = new SignPdf();
      const signedPdf = signPdf.sign(pdfWithPlaceholder, signatureHash);

      return signedPdf;
    } catch (error) {
      console.error('Error adding signature placeholder:', error);
      console.error(error);
    }
  }