Merge pull request #36 from spaceapi-community/timestamps

Serialize and deserialize timestamp fields as `Instant`

CHANGELOG.md

@@ -13,6 +13,10 @@ Possible log types:
 
 ### Unreleased
 
+- [changed] Serialize and deserialize timestamp fields as `Instant` (#36)
+- [changed] If you're using this library on Android, this requires at least API
+  level 26 (Android 8), or a backport of the `java.time` APIs! (#36)
+
 ### v0.4.1 (2023-04-25)
 
 - [fixed] Make `spacefed.spacephone` a non-required field (#34)

src/main/kotlin/io/spaceapi/types/Event.kt

@@ -16,13 +16,14 @@
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see <https://www.gnu.org/licenses/>.
  */
-@file:UseSerializers(RoundingLongSerializer::class)
+@file:UseSerializers(TimestampSerializer::class)
 
 package io.spaceapi.types
 
-import io.spaceapi.types.serializers.RoundingLongSerializer
+import io.spaceapi.types.serializers.TimestampSerializer
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.UseSerializers
+import java.time.Instant
 
 @Serializable
 data class Event(
@@ -31,7 +32,7 @@ data class Event(
     @JvmField
     var type: String,
     @JvmField
-    var timestamp: Long,
+    var timestamp: Instant,
     @JvmField
     var extra: String? = null,
 )

src/main/kotlin/io/spaceapi/types/State.kt

@@ -16,22 +16,23 @@
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see <https://www.gnu.org/licenses/>.
  */
-@file:UseSerializers(URLSerializer::class, RoundingLongSerializer::class)
+@file:UseSerializers(URLSerializer::class, TimestampSerializer::class)
 
 package io.spaceapi.types
 
-import io.spaceapi.types.serializers.RoundingLongSerializer
+import io.spaceapi.types.serializers.TimestampSerializer
 import io.spaceapi.types.serializers.URLSerializer
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.UseSerializers
 import java.net.URL
+import java.time.Instant
 
 @Serializable
 data class State(
     @JvmField
     var open: Boolean? = null,
     @JvmField
-    var lastchange: Long? = null,
+    var lastchange: Instant? = null,
     @JvmField
     var trigger_person: String? = null,
     @JvmField

src/main/kotlin/io/spaceapi/types/serializers/Serializers.kt

@@ -20,26 +20,25 @@ package io.spaceapi.types.serializers
 
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
-import kotlinx.serialization.Serializer
 import kotlinx.serialization.descriptors.PrimitiveKind
 import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
 import kotlinx.serialization.descriptors.SerialDescriptor
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
 import java.net.URI
 import java.net.URL
+import java.time.Instant
+import java.util.Date
 import kotlin.math.round
 
 @ExperimentalSerializationApi
-@Serializer(forClass = URL::class)
 object URLSerializer : KSerializer<URL> {
     override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URL", PrimitiveKind.STRING)
     override fun serialize(encoder: Encoder, value: URL) = encoder.encodeString(value.toString())
     override fun deserialize(decoder: Decoder): URL = URL(decoder.decodeString())
 }
 
 @ExperimentalSerializationApi
-@Serializer(forClass = URI::class)
 object URISerializer : KSerializer<URI> {
     override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URI", PrimitiveKind.STRING)
     override fun serialize(encoder: Encoder, value: URI) = encoder.encodeString(value.toString())
@@ -51,9 +50,21 @@ object URISerializer : KSerializer<URI> {
  * by rounding to the closest integer.
  */
 @ExperimentalSerializationApi
-@Serializer(forClass = Long::class)
 object RoundingLongSerializer : KSerializer<Long> {
     override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("RoundingLong", PrimitiveKind.LONG)
     override fun serialize(encoder: Encoder, value: Long) = encoder.encodeLong(value)
     override fun deserialize(decoder: Decoder): Long = round(decoder.decodeDouble()).toLong()
 }
+
+/**
+ * Serialize and deserialize Unix timestamps (in seconds).
+ *
+ * Deserializing numbers with fractional seconds is supported,
+ * but the fractional part is ignored.
+ */
+@ExperimentalSerializationApi
+object TimestampSerializer : KSerializer<Instant> {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("Timestamp", PrimitiveKind.DOUBLE)
+    override fun serialize(encoder: Encoder, value: Instant) = encoder.encodeLong(value.epochSecond)
+    override fun deserialize(decoder: Decoder): Instant = Instant.ofEpochSecond(round(decoder.decodeDouble()).toLong())
+}

src/test/kotlin/io/spaceapi/ParserTestKotlin.kt

@@ -1,14 +1,17 @@
 package io.spaceapi
 
 import io.spaceapi.types.Contact
+import io.spaceapi.types.MemberCount
 import io.spaceapi.types.SpaceFed
 import io.spaceapi.types.State
+import io.spaceapi.types.serializers.TimestampSerializer
 import kotlinx.serialization.decodeFromString
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonObject
 import org.junit.Assert
 import java.net.URL
+import java.time.Instant
 import kotlin.test.Test
 import kotlin.test.assertEquals
 
@@ -52,7 +55,6 @@ class ParserTestKotlin {
         assertEquals(false, parsed.state!!.open)
         assertEquals(null, parsed.state!!.lastchange)
         assertEquals("Open Mondays from 20:00", parsed.state!!.message)
-        assertEquals("Open Mondays from 20:00", parsed.state!!.message)
 
         assertEquals("[email protected]", parsed.contact.email)
         assertEquals("irc://freenode.net/#coredump", parsed.contact.irc)
@@ -103,7 +105,6 @@ class ParserTestKotlin {
         assertEquals(false, parsed.state!!.open)
         assertEquals(null, parsed.state!!.lastchange)
         assertEquals("Open Mondays from 20:00", parsed.state!!.message)
-        assertEquals("Open Mondays from 20:00", parsed.state!!.message)
 
         assertEquals("[email protected]", parsed.contact.email)
         assertEquals("irc://freenode.net/#coredump", parsed.contact.irc)
@@ -156,14 +157,10 @@ class ParserTestKotlin {
      */
     @Test
     fun parseFloatAsInteger() {
-        val parsed: State = Json.decodeFromString("""{
-            "open": false,
-            "message": "Open Mondays from 20:00",
-            "lastchange": 1605400210.0
+        val parsed: MemberCount = Json.decodeFromString("""{
+            "value": 42.0
         }""")
-        assertEquals(false, parsed.open)
-        assertEquals("Open Mondays from 20:00", parsed.message)
-        assertEquals(1605400210L, parsed.lastchange)
+        assertEquals(42L, parsed.value)
     }
 
     /**
@@ -275,4 +272,30 @@ class ParserTestKotlin {
         @Suppress("DEPRECATION")
         assertEquals(false, parsed.spacephone)
     }
+
+    @Test
+    fun parseTimestampsAsInstant() {
+        val parsed: State = Json.decodeFromString("""{
+            "open": true,
+            "lastchange": 1693685542
+        }""")
+        assertEquals(true, parsed.open)
+        assertEquals(Instant.ofEpochSecond(1693685542), parsed.lastchange)
+    }
+
+    @Test
+    fun parseFloatTimestampsAsInstant() {
+        val parsed: State = Json.decodeFromString("""{
+            "open": true,
+            "lastchange": 1693685542.1234321
+        }""")
+        assertEquals(true, parsed.open)
+        assertEquals(Instant.ofEpochMilli(1693685542000), parsed.lastchange)
+    }
+
+    @Test
+    fun serializeInstantsAsLong() {
+        val serialized = Json.encodeToString(TimestampSerializer, Instant.ofEpochSecond(1693685542))
+        assertEquals("1693685542", serialized)
+    }
 }