🗑️ Deprecated extractSignature as it was never public-ready.

Copied it in internal-utils to be used in tests. Will remove from `utils` in a next major release (#206)

CHANGELOG.md

@@ -3,7 +3,8 @@
 ## [next]
 
 * [utils] Added SIG_FLAGS and ANNOTATION_FLAGS to improve readability;
-* [utils] Reworked findByteRange to match in more cases where it was incompatible so far (it didn't allow optional spaces in the array).
+* [utils] Reworked findByteRange to match in more cases where it was incompatible so far (it didn't allow optional spaces in the array);
+* [utils] Deprecated extractSignature as it was never public-ready. Copied it in internal-utils to be used in tests. Will remove from `utils` in a next major release;
 * [placeholder-pdfkit010] Uses SIG_FLAGS and ANNOTATION_FLAGS instead of magic numbers;
 * [placeholder-pdfkit010] Allow passing in widgetRect to override the default [0, 0, 0, 0] one;
 * [placeholder-plain] Allow passing in widgetRect to override the default [0, 0, 0, 0] one;

packages/internal-utils/extractSignature.js

@@ -0,0 +1,64 @@
+function getSubstringIndex(str, substring, n) {
+    var times = 0;
+    var index = null;
+
+    while (times < n && index !== -1) {
+        index = str.indexOf(substring, index + 1);
+        times += 1;
+    }
+
+    return index;
+};
+
+/**
+ * Basic implementation of signature extraction.
+ *
+ * Really basic. Would work in the simplest of cases where there is only one signature
+ * in a document and ByteRange is only used once in it.
+ *
+ * @param {Buffer} pdf
+ * @param {number} signatureCount
+ * @returns {Object} {ByteRange: Number[], signature: Buffer, signedData: Buffer}
+ */
+function extractSignature (pdf, signatureCount) {
+    if (!(pdf instanceof Buffer)) {
+        throw new Error('PDF expected as Buffer.');
+    }
+
+    // const byteRangePos = pdf.indexOf('/ByteRange [');
+    var byteRangePos = getSubstringIndex(pdf, '/ByteRange [', signatureCount || 1);
+    if (byteRangePos === -1) {
+        throw new Error('Failed to locate ByteRange.');
+    }
+
+    var byteRangeEnd = pdf.indexOf(']', byteRangePos);
+    if (byteRangeEnd === -1) {
+        throw new Error('Failed to locate the end of the ByteRange.');
+    }
+
+    var byteRange = pdf.subarray(byteRangePos, byteRangeEnd + 1).toString();
+    var matches = (/\/ByteRange \[(\d+) +(\d+) +(\d+) +(\d+) *\]/).exec(byteRange);
+    if (matches === null) {
+        throw new Error('Failed to parse the ByteRange.');
+    }
+
+    var ByteRange = matches.slice(1).map(Number);
+    var signedData = Buffer.concat([
+        pdf.subarray(ByteRange[0], ByteRange[0] + ByteRange[1]),
+        pdf.subarray(ByteRange[2], ByteRange[2] + ByteRange[3]),
+    ]);
+
+    var signatureHex = pdf.subarray(ByteRange[0] + ByteRange[1] + 1, ByteRange[2])
+        .toString('binary')
+        .replace(/(?:00|>)+$/, '');
+
+    var signature = Buffer.from(signatureHex, 'hex').toString('binary');
+
+    return {
+        ByteRange: matches.slice(1, 5).map(Number),
+        signature: signature,
+        signedData: signedData,
+    };
+};
+
+module.exports = extractSignature;

packages/internal-utils/index.js

@@ -1,7 +1,9 @@
 var readTestResource = require('./readTestResource');
 var createPdfkitDocument = require('./createPdfkitDocument');
+var extractSignature = require('./extractSignature');
 
 module.exports = {
     readTestResource: readTestResource,  
     createPdfkitDocument: createPdfkitDocument,  
+    extractSignature: extractSignature,  
 }

packages/signpdf/src/signpdf.test.js

@@ -1,12 +1,8 @@
 import {pdfkitAddPlaceholder} from '@signpdf/placeholder-pdfkit010';
 import {plainAddPlaceholder} from '@signpdf/placeholder-plain';
 import {P12Signer} from '@signpdf/signer-p12';
-import {
-    extractSignature,
-    Signer,
-    SignPdfError,
-} from '@signpdf/utils';
-import {readTestResource, createPdfkitDocument} from '@signpdf/internal-utils';
+import {Signer, SignPdfError} from '@signpdf/utils';
+import {readTestResource, createPdfkitDocument, extractSignature} from '@signpdf/internal-utils';
 import signpdf from './signpdf';
 
 /**

packages/utils/dist/extractSignature.js

@@ -17,11 +17,13 @@ const getSubstringIndex = (str, substring, n) => {
 /**
  * Basic implementation of signature extraction.
  *
- * Really basic. Would work in the simplest of cases where there is only one signature
- * in a document and ByteRange is only used once in it.
+ * Really basic. Would work in the simplest of cases.
  *
  * @param {Buffer} pdf
+ * @param {number} signatureCount
  * @returns {Object} {ByteRange: Number[], signature: Buffer, signedData: Buffer}
+ *
+ * @deprecated Internally use the version in internal-utils. Will be removed in a major release.
  */
 const extractSignature = (pdf, signatureCount = 1) => {
   if (!(pdf instanceof Buffer)) {

packages/utils/src/extractSignature.js

@@ -14,11 +14,13 @@ const getSubstringIndex = (str, substring, n) => {
 /**
  * Basic implementation of signature extraction.
  *
- * Really basic. Would work in the simplest of cases where there is only one signature
- * in a document and ByteRange is only used once in it.
+ * Really basic. Would work in the simplest of cases.
  *
  * @param {Buffer} pdf
+ * @param {number} signatureCount
  * @returns {Object} {ByteRange: Number[], signature: Buffer, signedData: Buffer}
+ *
+ * @deprecated Internally use the version in internal-utils. Will be removed in a major release.
  */
 export const extractSignature = (pdf, signatureCount = 1) => {
     if (!(pdf instanceof Buffer)) {