initial commit

apps/OpenSignServer/cloud/parsefunction/pdf/customSignPdf/getPageRef.js

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+import getPagesDictionaryRef from "./getPagesDictionaryRef.js";
+import findObject from "./findObject.js";
+
+/**
+ * Finds the reference to a page.
+ *
+ * @param {Buffer} pdfBuffer
+ * @param {Object} info As extracted from readRef()
+ * @param {Number} Page is pageNo on which we want widget/sign
+ */
+export default function getPageRef(pdfBuffer, info, Page) {
+  const pagesRef = getPagesDictionaryRef(info);
+  const pagesDictionary = findObject(pdfBuffer, info.xref, pagesRef);
+  const kidsPosition = pagesDictionary.indexOf("/Kids");
+  const kidsStart = pagesDictionary.indexOf("[", kidsPosition) + 1;
+  const kidsEnd = pagesDictionary.indexOf("]", kidsPosition);
+  const pages = pagesDictionary.slice(kidsStart, kidsEnd).toString();
+  // console.log("pages ", pages);
+  // const split = pages.trim().split(" ", 3);
+  //   return `${split[0]} ${split[1]} ${split[2]}`;
+
+  //  below code is used to get pageIndex (10 0 R) from pageNo to add sign widget on it
+  let indices = [];
+  for (var i = 0; i < pages.length; i++) {
+    if (pages[i] === "R") indices.push(i);
+  }
+  let pageIndex = {};
+  let startPosition = 0;
+  indices.forEach((x, index) => {
+    pageIndex = {
+      ...pageIndex,
+      [index + 1]: pages.substring(startPosition + 1, x + 1),
+    };
+    startPosition = x + 1;
+  });
+  // console.log("pageIndex ", pageIndex);
+
+  const pageStr = Page ? pageIndex[Page] : pageIndex[1];
+  // console.log("pageStr ", pageStr);
+  return pageStr;
+}