feat(tokenprovider): support setting a static system time

README.md

@@ -175,6 +175,7 @@ fun loginWithIdTokenForAcrClaimEqualsLevel4() {
 }
 ~~~
 
+
 ##### Testing an API requiring access_token (e.g. a signed JWT)
 
 ```kotlin
@@ -183,6 +184,20 @@ val token: SignedJWT = oAuth2Server.issueToken(issuerId, "someclientid", Default
 val request = // ....
 request.addHeader("Authorization", "Bearer ${token.serialize()}")
 ```
+If you for some reason need to manipulate the system time/clock you can configure the OAuth2TokenProvider to use a specific time, resulting in the `iat` claim being set to that time:
+
+```kotlin
+@Test
+fun testWithSpecificTime() {
+    val server = MockOAuth2Server(
+        config = OAuth2Config(
+            tokenProvider = OAuth2TokenProvider(systemTime = Instant.parse("2020-01-21T00:00:00Z")
+        )
+    )
+    val token = server.issueToken(issuerId = "issuer1")
+    // do whatever token testing you need to do here and assert the token has iat=2020-01-21T00:00:00Z
+}
+```
 
 ##### More examples 
 
@@ -285,6 +300,17 @@ add this to your config with preferred `JWS algorithm`:
 }
 ```
 
+A token provider can also support a static "systemTime", i.e. the time for when the token is issued (`iat` claim) if you have tests that require a specific time.
+The following configuration will set the system time to `2020-01-21T00:00:00Z`:
+
+```json
+{
+  "tokenProvider" : {
+    "systemTime" : "2020-01-21T00:00:00Z"
+  }
+}
+```
+
 | Property             | Description                                                                                                                                                                                                                                                                       |
 |----------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | `interactiveLogin`   | `true` or `false`, enables login screen when redirecting to server `/authorize` endpoint                                                                                                                                                                                          |
@@ -294,7 +320,7 @@ add this to your config with preferred `JWS algorithm`:
 | `httpServer`         | A string identifying the httpserver to use. Must match one of the following enum values: `MockWebServerWrapper` or `NettyWrapper`                                                                                                                                                 |
 | `tokenCallbacks`     | A list of [`RequestMappingTokenCallback`](src/main/kotlin/no/nav/security/mock/oauth2/token/OAuth2TokenCallback.kt) that lets you specify which token claims to return when a token request matches the specified condition.                                                      |
 
-*From the JSON example above:* 
+*From the first JSON example above:* 
 
 A token request to `http://localhost:8080/issuer1/token` with parameter `scope` equal to `scope1` will match the first `tokenCallback`:
 

src/main/kotlin/no/nav/security/mock/oauth2/OAuth2Config.kt

@@ -19,6 +19,7 @@ import no.nav.security.mock.oauth2.token.OAuth2TokenCallback
 import no.nav.security.mock.oauth2.token.OAuth2TokenProvider
 import no.nav.security.mock.oauth2.token.RequestMappingTokenCallback
 import java.io.File
+import java.time.Instant
 
 data class OAuth2Config
     @JvmOverloads
@@ -37,6 +38,7 @@ data class OAuth2Config
         class OAuth2TokenProviderDeserializer : JsonDeserializer<OAuth2TokenProvider>() {
             data class ProviderConfig(
                 val keyProvider: KeyProviderConfig?,
+                val systemTime: String?,
             )
 
             data class KeyProviderConfig(
@@ -60,11 +62,17 @@ data class OAuth2Config
                         listOf(JWK.parse(it))
                     } ?: emptyList()
 
+                val systemTime =
+                    config.systemTime?.let {
+                        Instant.parse(it)
+                    }
+
                 return OAuth2TokenProvider(
                     KeyProvider(
                         jwks,
                         config.keyProvider?.algorithm ?: JWSAlgorithm.RS256.name,
                     ),
+                    systemTime,
                 )
             }
         }

src/main/kotlin/no/nav/security/mock/oauth2/StandaloneMockOAuth2Server.kt

@@ -1,16 +1,16 @@
 package no.nav.security.mock.oauth2
 
 import ch.qos.logback.classic.ClassicConstants
-import java.io.File
-import java.io.FileNotFoundException
-import java.net.InetAddress
-import java.net.InetSocketAddress
 import no.nav.security.mock.oauth2.StandaloneConfig.hostname
 import no.nav.security.mock.oauth2.StandaloneConfig.oauth2Config
 import no.nav.security.mock.oauth2.StandaloneConfig.port
 import no.nav.security.mock.oauth2.http.NettyWrapper
 import no.nav.security.mock.oauth2.http.OAuth2HttpResponse
 import no.nav.security.mock.oauth2.http.route
+import java.io.File
+import java.io.FileNotFoundException
+import java.net.InetAddress
+import java.net.InetSocketAddress
 
 object StandaloneConfig {
     const val JSON_CONFIG = "JSON_CONFIG"

src/main/kotlin/no/nav/security/mock/oauth2/token/OAuth2TokenProvider.kt

@@ -23,6 +23,7 @@ class OAuth2TokenProvider
     @JvmOverloads
     constructor(
         private val keyProvider: KeyProvider = KeyProvider(),
+        val systemTime: Instant? = null,
     ) {
         @JvmOverloads
         fun publicJwkSet(issuerId: String = "default"): JWKSet {
@@ -66,7 +67,7 @@ class OAuth2TokenProvider
             issuerUrl: HttpUrl,
             claimsSet: JWTClaimsSet,
             oAuth2TokenCallback: OAuth2TokenCallback,
-        ) = Instant.now().let { now ->
+        ) = systemTime.orNow().let { now ->
             JWTClaimsSet.Builder(claimsSet)
                 .issuer(issuerUrl.toString())
                 .expirationTime(Date.from(now.plusSeconds(oAuth2TokenCallback.tokenExpiry())))
@@ -86,7 +87,7 @@ class OAuth2TokenProvider
             issuerId: String = "default",
         ): SignedJWT =
             JWTClaimsSet.Builder().let { builder ->
-                val now = Instant.now()
+                val now = systemTime.orNow()
                 builder
                     .issueTime(Date.from(now))
                     .notBeforeTime(Date.from(now))
@@ -150,7 +151,7 @@ class OAuth2TokenProvider
             additionalClaims: Map<String, Any>,
             expiry: Long,
         ) = JWTClaimsSet.Builder().let { builder ->
-            val now = Instant.now()
+            val now = systemTime.orNow()
             builder.subject(subject)
                 .audience(audience)
                 .issuer(issuerUrl.toString())
@@ -163,4 +164,6 @@ class OAuth2TokenProvider
             builder.addClaims(additionalClaims)
             builder.build()
         }
+
+        private fun Instant?.orNow(): Instant = this ?: Instant.now()
     }

src/test/kotlin/no/nav/security/mock/oauth2/OAuth2ConfigTest.kt

@@ -74,6 +74,21 @@ internal class OAuth2ConfigTest {
         }.message shouldContain "Unsupported algorithm: EdDSA"
     }
 
+    @Test
+    fun `create config from json with tokenprovider system time set`() {
+        val config =
+            OAuth2Config.fromJson(
+                """
+                {
+                  "tokenProvider" : {
+                    "systemTime" : "2020-01-21T00:00:00Z"
+                  }
+                }
+                """.trimIndent(),
+            )
+        config.tokenProvider.systemTime shouldBe Instant.parse("2020-01-21T00:00:00Z")
+    }
+
     @Test
     fun `create NettyWrapper with https enabled and provided keystore`() {
         val server = OAuth2Config.fromJson(nettyWithProvidedKeystore).httpServer as NettyWrapper

src/test/kotlin/no/nav/security/mock/oauth2/token/OAuth2TokenCallbackTest.kt

@@ -161,7 +161,6 @@ internal class OAuth2TokenCallbackTest {
                 it.addClaims(tokenRequest) shouldContainAll mapOf("tid" to "test-tid")
             }
         }
-
     }
 
     private fun authCodeRequest(vararg formParams: Pair<String, String>) =

src/test/kotlin/no/nav/security/mock/oauth2/token/OAuth2TokenProviderRSATest.kt

@@ -16,6 +16,9 @@ import okhttp3.HttpUrl.Companion.toHttpUrl
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.params.ParameterizedTest
 import org.junit.jupiter.params.provider.ValueSource
+import java.time.Instant
+import java.time.temporal.ChronoUnit
+import java.util.Date
 
 internal class OAuth2TokenProviderRSATest {
     private val tokenProvider = OAuth2TokenProvider()
@@ -94,6 +97,27 @@ internal class OAuth2TokenProviderRSATest {
         }
     }
 
+    @Test
+    fun `token should have issuedAt set to systemTime if set, otherwise use now()`() {
+        val yesterDay = Instant.now().minus(1, ChronoUnit.DAYS)
+        val tokenProvider = OAuth2TokenProvider(systemTime = yesterDay)
+
+        tokenProvider.exchangeAccessToken(
+            tokenRequest =
+                nimbusTokenRequest(
+                    "id",
+                    "grant_type" to GrantType.CLIENT_CREDENTIALS.value,
+                    "scope" to "scope1",
+                ),
+            issuerUrl = "http://default_if_not_overridden".toHttpUrl(),
+            claimsSet = tokenProvider.jwt(mapOf()).jwtClaimsSet,
+            oAuth2TokenCallback = DefaultOAuth2TokenCallback(),
+        ).asClue {
+            it.jwtClaimsSet.issueTime shouldBe Date.from(tokenProvider.systemTime)
+            println(it.serialize())
+        }
+    }
+
     private fun idToken(issuerUrl: String): SignedJWT =
         tokenProvider.idToken(
             tokenRequest =