pdf-signer-brazil
Version:
A JavaScript PDF signer with certificate A1 ICP-Brasil for NodeJS.
59 lines (58 loc) • 2.59 kB
JavaScript
;
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const const_1 = require("./const");
const remove_trailing_new_line_1 = __importDefault(require("./remove-trailing-new-line"));
exports.addSignatureToPdf = (pdf, sigContentsPosition, signature) => {
pdf = Buffer.concat([
pdf.slice(0, sigContentsPosition),
Buffer.from(`<${signature}>`),
pdf.slice(sigContentsPosition),
]);
return pdf;
};
exports.replaceByteRangeInPdf = (pdfBuffer) => {
if (!(pdfBuffer instanceof Buffer)) {
throw new Error('PDF expected as Buffer.');
}
let pdf = remove_trailing_new_line_1.default(pdfBuffer);
const byteRangePlaceholder = [
0,
`/${const_1.DEFAULT_BYTE_RANGE_PLACEHOLDER}`,
`/${const_1.DEFAULT_BYTE_RANGE_PLACEHOLDER}`,
`/${const_1.DEFAULT_BYTE_RANGE_PLACEHOLDER}`,
];
const byteRangeString = `/ByteRange [${byteRangePlaceholder.join(' ')}]`;
const byteRangePos = pdf.indexOf(byteRangeString);
if (byteRangePos === -1) {
throw new Error(`Could not find ByteRange placeholder: ${byteRangeString}`);
}
const byteRangeEnd = byteRangePos + byteRangeString.length;
const contentsTagPos = pdf.indexOf('/Contents ', byteRangeEnd);
const placeholderPos = pdf.indexOf('<', contentsTagPos);
const placeholderEnd = pdf.indexOf('>', placeholderPos);
const placeholderLengthWithBrackets = placeholderEnd + 1 - placeholderPos;
const placeholderLength = placeholderLengthWithBrackets - 2;
const byteRange = getByteRange(placeholderPos, placeholderLengthWithBrackets, pdf.length);
let actualByteRange = `/ByteRange [${byteRange.join(' ')}]`;
actualByteRange += ' '.repeat(byteRangeString.length - actualByteRange.length);
pdf = Buffer.concat([
pdf.slice(0, byteRangePos),
Buffer.from(actualByteRange),
pdf.slice(byteRangeEnd),
]);
pdf = Buffer.concat([
pdf.slice(0, byteRange[1]),
pdf.slice(byteRange[2], byteRange[2] + byteRange[3]),
]);
return { pdf, placeholderLength, byteRange };
};
const getByteRange = (placeholderPos, placeholderLengthWithBrackets, pdfLength) => {
const byteRange = [0, 0, 0, 0];
byteRange[1] = placeholderPos;
byteRange[2] = byteRange[1] + placeholderLengthWithBrackets;
byteRange[3] = pdfLength - byteRange[2];
return byteRange;
};