@signpdf/placeholder-plain
Version:
Try to add a signature placeholder to a PDF using plain string modifications.
124 lines (119 loc) • 4.25 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.plainAddPlaceholder = void 0;
var _placeholderPdfkit = require("@signpdf/placeholder-pdfkit010");
var _utils = require("@signpdf/utils");
var _getIndexFromRef = _interopRequireDefault(require("./getIndexFromRef"));
var _readPdf = _interopRequireDefault(require("./readPdf"));
var _getPageRef = _interopRequireDefault(require("./getPageRef"));
var _createBufferRootWithAcroform = _interopRequireDefault(require("./createBufferRootWithAcroform"));
var _createBufferPageWithAnnotation = _interopRequireDefault(require("./createBufferPageWithAnnotation"));
var _createBufferTrailer = _interopRequireDefault(require("./createBufferTrailer"));
function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
/* eslint-disable no-underscore-dangle */
/**
* @param {string} pdf
* @returns {string | undefined}
*/
const getAcroFormRef = slice => {
const bufferRootWithAcroformRefRegex = /\/AcroForm\s+(\d+\s\d+\sR)/g;
const match = bufferRootWithAcroformRefRegex.exec(slice);
if (match != null && match[1] != null && match[1] !== '') {
return match[1];
}
return undefined;
};
/**
* @typedef {object} InputType
* @property {Buffer} pdfBuffer
* @property {string} reason
* @property {string} contactInfo
* @property {string} name
* @property {string} location
* @property {Date} [signingTime]
* @property {number} [signatureLength]
* @property {string} [subFilter] One of SUBFILTER_* from \@signpdf/utils
* @property {number[]} [widgetRect] [x1, y1, x2, y2] widget rectangle
* @property {string} [appName] Name of the application generating the signature
*/
/**
* Adds a signature placeholder to a PDF Buffer.
*
* This contrasts with the default pdfkit-based implementation.
* Parsing is done using simple string operations.
* Adding is done with `Buffer.concat`.
* This allows node-signpdf to be used on any PDF and
* not only on a freshly created through PDFKit one.
*
* @param {InputType}
* @returns {Buffer}
*/
const plainAddPlaceholder = ({
pdfBuffer,
reason,
contactInfo,
name,
location,
signingTime = undefined,
signatureLength = _utils.DEFAULT_SIGNATURE_LENGTH,
subFilter = _utils.SUBFILTER_ADOBE_PKCS7_DETACHED,
widgetRect = [0, 0, 0, 0],
appName = undefined
}) => {
let pdf = (0, _utils.removeTrailingNewLine)(pdfBuffer);
const info = (0, _readPdf.default)(pdf);
const pageRef = (0, _getPageRef.default)(pdf, info);
const pageIndex = (0, _getIndexFromRef.default)(info.xref, pageRef);
const addedReferences = new Map();
const pdfKitMock = {
ref: (input, knownIndex) => {
info.xref.maxIndex += 1;
const index = knownIndex != null ? knownIndex : info.xref.maxIndex;
addedReferences.set(index, pdf.length + 1); // + 1 new line
pdf = Buffer.concat([pdf, Buffer.from('\n'), Buffer.from(`${index} 0 obj\n`), Buffer.from(_utils.PDFObject.convert(input)), Buffer.from('\nendobj\n')]);
return new _utils.PDFKitReferenceMock(info.xref.maxIndex);
},
page: {
dictionary: new _utils.PDFKitReferenceMock(pageIndex, {
data: {
Annots: []
}
})
},
_root: {
data: {}
}
};
const acroFormRef = getAcroFormRef(info.root);
if (acroFormRef) {
pdfKitMock._root.data.AcroForm = acroFormRef;
}
const {
form,
widget
} = (0, _placeholderPdfkit.pdfkitAddPlaceholder)({
pdf: pdfKitMock,
pdfBuffer,
reason,
contactInfo,
name,
location,
signingTime,
signatureLength,
subFilter,
widgetRect,
appName
});
if (!getAcroFormRef(pdf.toString())) {
const rootIndex = (0, _getIndexFromRef.default)(info.xref, info.rootRef);
addedReferences.set(rootIndex, pdf.length + 1);
pdf = Buffer.concat([pdf, Buffer.from('\n'), (0, _createBufferRootWithAcroform.default)(pdf, info, form)]);
}
addedReferences.set(pageIndex, pdf.length + 1);
pdf = Buffer.concat([pdf, Buffer.from('\n'), (0, _createBufferPageWithAnnotation.default)(pdf, info, pageRef, widget)]);
pdf = Buffer.concat([pdf, Buffer.from('\n'), (0, _createBufferTrailer.default)(pdf, info, addedReferences)]);
return pdf;
};
exports.plainAddPlaceholder = plainAddPlaceholder;