feat: Set iat timestamp by default instead of nbf (#43)

* refactor: change createJWT to set iat by default instead of nbf

* test: add tests for iat behavior in createJWT

* feat: do not set iat if value in payload is null

* fix: set payload.iat to undefined instead of null to omit from JWT

* fix code style for division

* fix code style

BREAKING CHANGE: expiresIn option passed to createJWT now calculates exp from nbf instead of iat.

Author: mi-xu

src/JWT.ts

@@ -43,6 +43,7 @@ interface JWTPayload {
   iss?: string
   sub?: string
   aud?: string
+  iat?: number
   nbf?: number
   type?: string
   exp?: number
@@ -152,19 +153,19 @@ export function decodeJWT(jwt: string): JWTDecoded {
  */
 // export async function createJWT(payload, { issuer, signer, alg, expiresIn }) {
 export async function createJWT(
-  payload: object,
+  payload: any,
   { issuer, signer, alg, expiresIn }: JWTOptions
 ): Promise<string> {
   if (!signer) throw new Error('No Signer functionality has been configured')
   if (!issuer) throw new Error('No issuing DID has been configured')
   const header: JWTHeader = { typ: 'JWT', alg: alg || defaultAlg }
   const timestamps: Partial<JWTPayload> = {
-    nbf: Math.floor(Date.now() / 1000),
+    iat: Math.floor(Date.now() / 1000),
     exp: undefined
   }
-  if (expiresIn) {
+  if (expiresIn && payload.nbf) {
     if (typeof expiresIn === 'number') {
-      timestamps.exp = timestamps.nbf + Math.floor(expiresIn)
+      timestamps.exp = payload.nbf + Math.floor(expiresIn)
     } else {
       throw new Error('JWT expiresIn is not a number')
     }

src/__tests__/JWT-test.ts

@@ -107,14 +107,48 @@ describe('createJWT()', () => {
 
     it('creates a JWT with expiry in 10000 seconds', () => {
       return createJWT(
-        { requested: ['name', 'phone'] },
+        { requested: ['name', 'phone'], nbf: Math.floor(new Date().getTime() / 1000) },
         { issuer: did, signer, expiresIn: 10000 }
       ).then(jwt => {
         const { payload } = decodeJWT(jwt)
         return expect(payload.exp).toEqual(payload.nbf + 10000)
       })
     })
 
+    it('ignores expiresIn if nbf is not set', async () => {
+      const { payload } = decodeJWT(await createJWT(
+        { requested: ['name', 'phone'] },
+        { issuer: did, signer, expiresIn: 10000 }
+      ))
+      return expect(payload.exp).toBeUndefined()
+    })
+
+    it('sets iat to the current time by default', async () => {
+      const timestamp = Math.floor(Date.now() / 1000)
+      const { payload } = decodeJWT(await createJWT(
+        { requested: ['name', 'phone'] },
+        { issuer: did, signer }
+      ))
+      return expect(payload.iat).toEqual(timestamp)
+    })
+
+    it('sets iat to the value passed in payload', async () => {
+      const timestamp = 2000000
+      const { payload } = decodeJWT(await createJWT(
+        { requested: ['name', 'phone'], iat: timestamp },
+        { issuer: did, signer }
+      ))
+      return expect(payload.iat).toEqual(timestamp)
+    })
+
+    it('does not set iat if value in payload is undefined', async () => {
+      const { payload } = decodeJWT(await createJWT(
+        { requested: ['name', 'phone'], iat: undefined },
+        { issuer: did, signer }
+      ))
+      return expect(payload.iat).toBeUndefined()
+    })
+
     it('throws an error if unsupported algorithm is passed in', () => {
       return createJWT(
         { requested: ['name', 'phone'] },
@@ -152,7 +186,7 @@ describe('createJWT()', () => {
 
     it('creates a JWT with expiry in 10000 seconds', () => {
       return createJWT(
-        { requested: ['name', 'phone'] },
+        { requested: ['name', 'phone'], nbf: Math.floor(new Date().getTime() / 1000) },
         { alg, issuer: did, signer, expiresIn: 10000 }
       ).then(jwt => {
         const { payload } = decodeJWT(jwt)

src/__tests__/__snapshots__/JWT-test.ts.snap

@@ -2,95 +2,96 @@
 
 exports[`createJWT() ES256K creates a JWT with correct format 1`] = `
 Object {
-  "data": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NksifQ.eyJuYmYiOjE0ODUzMjExMzMsInJlcXVlc3RlZCI6WyJuYW1lIiwicGhvbmUiXSwiaXNzIjoiZGlkOnVwb3J0OjJuUXRpUUc2Q2dtMUdZVEJhYUtBZ3I3NnVZN2lTZXhVa3FYIn0",
+  "data": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NksifQ.eyJpYXQiOjE0ODUzMjExMzMsInJlcXVlc3RlZCI6WyJuYW1lIiwicGhvbmUiXSwiaXNzIjoiZGlkOnVwb3J0OjJuUXRpUUc2Q2dtMUdZVEJhYUtBZ3I3NnVZN2lTZXhVa3FYIn0",
   "header": Object {
     "alg": "ES256K",
     "typ": "JWT",
   },
   "payload": Object {
+    "iat": 1485321133,
     "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
-    "nbf": 1485321133,
     "requested": Array [
       "name",
       "phone",
     ],
   },
-  "signature": "a0u5aiRRsxTj0-bVN_pfCl95izb2bDuCsMiODbwH_wrFBH6IcLCQRclByepu0Yu__0CWyw-TQfYuxxdx-wExYw",
+  "signature": "4zZKylwG3_1WPPd0HEpeOt1uUplyXhIGQ7G26wx0T1fnwovYcXQUA-FY3Cp13iA0XwMT8kIlxwsuMFCYMdw1sw",
 }
 `;
 
 exports[`createJWT() ES256K creates a JWT with correct legacy format 1`] = `
 Object {
-  "data": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NksifQ.eyJuYmYiOjE0ODUzMjExMzMsInJlcXVlc3RlZCI6WyJuYW1lIiwicGhvbmUiXSwiaXNzIjoiMm5RdGlRRzZDZ20xR1lUQmFhS0Fncjc2dVk3aVNleFVrcVgifQ",
+  "data": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NksifQ.eyJpYXQiOjE0ODUzMjExMzMsInJlcXVlc3RlZCI6WyJuYW1lIiwicGhvbmUiXSwiaXNzIjoiMm5RdGlRRzZDZ20xR1lUQmFhS0Fncjc2dVk3aVNleFVrcVgifQ",
   "header": Object {
     "alg": "ES256K",
     "typ": "JWT",
   },
   "payload": Object {
+    "iat": 1485321133,
     "iss": "2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
-    "nbf": 1485321133,
     "requested": Array [
       "name",
       "phone",
     ],
   },
-  "signature": "YPk7tICPNhJwm251UAqLR9iskfKKVGloiAks1ndtdZv2SzRk2X9jN2LOxusJQUNoLlH1TkP0yiJb2nU4Rqrjag",
+  "signature": "D1Tx-R9g-pyGAb4C486fx_1Scwf74JcoUC2xYRJ6cZFW9zwBs_NZEZg3bptrMfmNRao_2A2cbCncRKPpV7TycQ",
 }
 `;
 
 exports[`createJWT() Ed25519 creates a JWT with correct format 1`] = `
 Object {
-  "data": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFZDI1NTE5In0.eyJuYmYiOjE0ODUzMjExMzMsInJlcXVlc3RlZCI6WyJuYW1lIiwicGhvbmUiXSwiaXNzIjoiZGlkOm5hY2w6QnZyQjhpSkF6XzFqZnExbVJ4aUVLZnI5cWNuTGZxNURPR3JCZjJFUlVIVSJ9",
+  "data": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFZDI1NTE5In0.eyJpYXQiOjE0ODUzMjExMzMsInJlcXVlc3RlZCI6WyJuYW1lIiwicGhvbmUiXSwiaXNzIjoiZGlkOm5hY2w6QnZyQjhpSkF6XzFqZnExbVJ4aUVLZnI5cWNuTGZxNURPR3JCZjJFUlVIVSJ9",
   "header": Object {
     "alg": "Ed25519",
     "typ": "JWT",
   },
   "payload": Object {
+    "iat": 1485321133,
     "iss": "did:nacl:BvrB8iJAz_1jfq1mRxiEKfr9qcnLfq5DOGrBf2ERUHU",
-    "nbf": 1485321133,
     "requested": Array [
       "name",
       "phone",
     ],
   },
-  "signature": "TVkTb7Copwq40dj9a8iorOi0yk_akAAW0VcsUk-XpzxGJiWMas8nXDwnxUvyPBSQLNGHu3teI0HSRBbzAiZAAg",
+  "signature": "ZoPf01SxW2n5zngunI942FpviEMP6jBZZb9NJ27M_K7AcmjPeeLH8bm2lv0INmJ2u98JVSzELF8YLWQvPYB1Bw",
 }
 `;
 
 exports[`verifyJWT() accepts a valid MNID audience 1`] = `
 Object {
   "aud": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqY",
+  "iat": 1485321133,
   "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
-  "nbf": 1485321133,
 }
 `;
 
 exports[`verifyJWT() accepts a valid audience 1`] = `
 Object {
   "aud": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqY",
+  "iat": 1485321133,
   "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
-  "nbf": 1485321133,
 }
 `;
 
 exports[`verifyJWT() accepts a valid audience using callback_url 1`] = `
 Object {
   "aud": "http://pututu.uport.me/unique",
+  "iat": 1485321133,
   "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
-  "nbf": 1485321133,
 }
 `;
 
 exports[`verifyJWT() accepts a valid exp 1`] = `
 Object {
   "exp": 1485320834,
+  "iat": 1485321133,
   "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
-  "nbf": 1485321133,
 }
 `;
 
 exports[`verifyJWT() accepts a valid nbf 1`] = `
 Object {
+  "iat": 1485321133,
   "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
   "nbf": 1485321433,
 }
@@ -99,16 +100,16 @@ Object {
 exports[`verifyJWT() handles ES256K-R algorithm 1`] = `
 Object {
   "hello": "world",
+  "iat": 1485321133,
   "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqX",
-  "nbf": 1485321133,
 }
 `;
 
 exports[`verifyJWT() handles ES256K-R algorithm with ethereum address 1`] = `
 Object {
   "hello": "world",
+  "iat": 1485321133,
   "iss": "did:uport:2nQtiQG6Cgm1GYTBaaKAgr76uY7iSexUkqY",
-  "nbf": 1485321133,
 }
 `;