feat: add creatWithExpiration function (#9)

Author: eordano

src/index.js

@@ -39,7 +39,26 @@ const create = (privateKey, value, seq, lifetime, callback) => {
   // Validity in ISOString with nanoseconds precision and validity type EOL
   const isoValidity = nanoDateEol.toISOStringFull()
   const validityType = ipnsEntryProto.ValidityType.EOL
+  _create(privateKey, value, seq, isoValidity, validityType, callback)
+}
+
+/**
+ * Same as create(), but instead of generating a new Date, it receives the intended expiration time
+ * WARNING: nano precision is not standard, make sure the value in seconds is 9 orders of magnitude lesser than the one provided.
+ * @param {Object} privateKey private key for signing the record.
+ * @param {string} value value to be stored in the record.
+ * @param {number} seq number representing the current version of the record.
+ * @param {string} expiration expiration time of the record (in nanoseconds).
+ * @param {function(Error, entry)} [callback]
+ * @return {Void}
+ */
+const createWithExpiration = (privateKey, value, seq, expiration, callback) => {
+  const bnExpiration = new NanoDate(new Big(expiration).toString()).toISOStringFull()
+  const validityType = ipnsEntryProto.ValidityType.EOL
+  _create(privateKey, value, seq, bnExpiration, validityType, callback)
+}
 
+const _create = (privateKey, value, seq, isoValidity, validityType, callback) => {
   sign(privateKey, value, validityType, isoValidity, (error, signature) => {
     if (error) {
       log.error('record signature creation failed')
@@ -294,6 +313,8 @@ const validator = {
 module.exports = {
   // create ipns entry record
   create,
+  // create ipns entry record specifying the expiration time
+  createWithExpiration,
   // validate ipns entry record
   validate,
   // embed public key in the record

test/index.spec.js

@@ -82,6 +82,23 @@ describe('ipns', function () {
     })
   })
 
+  it('should be able to create a record with a fixed expiration', (done) => {
+    const sequence = 0
+    // 2033-05-18T03:33:20.000000000Z
+    const expiration = 2000000000 * 1000000000
+
+    ipns.createWithExpiration(rsa, cid, sequence, expiration, (err, entry) => {
+      expect(err).to.not.exist()
+
+      ipns.validate(rsa.public, entry, (err) => {
+        expect(err).to.not.exist()
+        expect(entry).to.have.a.property('validity')
+        expect(entry.validity).to.equal('2033-05-18T03:33:20.000000000Z')
+        done()
+      })
+    })
+  })
+
   it('should create an ipns record and validate it correctly', (done) => {
     const sequence = 0
     const validity = 1000000