Refactor and cleanup Any? json deserialization

CHANGELOG.md

@@ -6,12 +6,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
-* Update dependencies. See [#17](https://github.com/collectiveidea/twirp-kmp/pull/17)
+ * Runtime - Refactor and cleanup `Any?` JSON deserialization. See [#19](https://github.com/collectiveidea/twirp-kmp/pull/19). 
+ * Update dependencies. See [#17](https://github.com/collectiveidea/twirp-kmp/pull/17).
     * Bump Kotlin from 2.0.20 to 2.0.21
     * Runtime - Bump Ktor to 3.0.1
     * Runtime - Bump kotlinx-serialization to 1.7.3
     * Bump pbandk to 0.16.0
- * **BREAKING** Rename project from twirp-kmm to twirp-kmp. See [#16](https://github.com/collectiveidea/twirp-kmm/pull/16)
+ * **BREAKING** Rename project from twirp-kmm to twirp-kmp. See [#16](https://github.com/collectiveidea/twirp-kmm/pull/16).
  * Generator - Ensure generator .jar artifact is built for Java 8. See [#15](https://github.com/collectiveidea/twirp-kmm/pull/15).
 
 ## [0.4.0] - 2024-09-03

runtime/src/commonMain/kotlin/com/collectiveidea/serialization/json/AnySerializer.kt

@@ -0,0 +1,79 @@
+package com.collectiveidea.serialization.json
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.json.JsonArray
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonNull
+import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.JsonPrimitive
+
+// `Any?` does not appear to be supported out of the box in kotlinx-serialization.
+//
+// With a little help from https://github.com/Kotlin/kotlinx.serialization/issues/746 and
+// https://github.com/Kotlin/kotlinx.serialization/issues/296 we can write a custom
+// `KSerializer` to do the work for us.
+
+internal object AnySerializer : KSerializer<Any?> {
+    private val delegateSerializer = JsonElement.serializer()
+    override val descriptor = delegateSerializer.descriptor
+
+    override fun serialize(
+        encoder: Encoder,
+        value: Any?,
+    ) {
+        encoder.encodeSerializableValue(delegateSerializer, value.toJsonElement())
+    }
+
+    override fun deserialize(decoder: Decoder): Any? = decoder.decodeSerializableValue(delegateSerializer).toAnyOrNull()
+}
+
+//
+// Serialize
+//
+
+internal fun Any?.toJsonElement(): JsonElement = when (this) {
+    is Number -> JsonPrimitive(this)
+    is Boolean -> JsonPrimitive(this)
+    is String -> JsonPrimitive(this)
+    is Map<*, *> -> toJsonObject()
+    is Collection<*> -> toJsonArray()
+    is JsonElement -> this
+    else -> JsonNull
+}
+
+private fun Collection<*>.toJsonArray() = JsonArray(map { it.toJsonElement() })
+
+private fun Map<*, *>.toJsonObject() = JsonObject(mapKeys { it.key.toString() }.mapValues { it.value.toJsonElement() })
+
+//
+// Deserialize
+//
+
+internal fun JsonElement.toAnyOrNull(): Any? = when (this) {
+    is JsonNull -> null
+    is JsonPrimitive -> toAnyValue()
+    is JsonObject -> map { it.key to it.value.toAnyOrNull() }.toMap()
+    is JsonArray -> map { it.toAnyOrNull() }
+}
+
+private fun JsonPrimitive.toAnyValue(): Any? {
+    val content = this.content
+    if (isString) {
+        return content
+    }
+    if (content.equals("null", ignoreCase = true)) {
+        return null
+    }
+    if (content.equals("true", ignoreCase = true)) {
+        return true
+    }
+    if (content.equals("false", ignoreCase = true)) {
+        return false
+    }
+    return content.toIntOrNull()
+        ?: content.toLongOrNull()
+        ?: content.toDoubleOrNull()
+        ?: throw Exception("Cannot convert JSON $content to value")
+}

runtime/src/commonMain/kotlin/com/collectiveidea/twirp/ErrorResponse.kt

@@ -1,26 +1,16 @@
 package com.collectiveidea.twirp
 
+import com.collectiveidea.serialization.json.AnySerializer
 import io.ktor.http.HttpStatusCode
-import kotlinx.serialization.KSerializer
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
-import kotlinx.serialization.encoding.Decoder
-import kotlinx.serialization.encoding.Encoder
-import kotlinx.serialization.json.JsonArray
-import kotlinx.serialization.json.JsonElement
-import kotlinx.serialization.json.JsonNull
-import kotlinx.serialization.json.JsonObject
-import kotlinx.serialization.json.JsonPrimitive
 
 @Serializable
 public data class ErrorResponse(
     val code: ErrorCode = ErrorCode.Unknown,
     val msg: String,
-    val meta: Map<
-        String,
-        @Serializable(with = AnySerializer::class)
-        Any?,
-    >? = null,
+    @Suppress("ktlint:standard:annotation")
+    val meta: Map<String, @Serializable(with = AnySerializer::class) Any?>? = null,
 )
 
 // See: https://github.com/twitchtv/twirp/blob/main/docs/spec_v7.md#error-codes
@@ -82,83 +72,3 @@ public enum class ErrorCode(
     @SerialName("dataloss")
     Dataloss(HttpStatusCode.InternalServerError.value),
 }
-
-// `Any?` does not appear to be supported out of the box in kotlinx-serialization. With
-// a little help from https://github.com/Kotlin/kotlinx.serialization/issues/746 and
-// https://github.com/Kotlin/kotlinx.serialization/issues/296 we can write a custom
-// `KSerializer` to do the work for us.
-
-//
-// Serialize
-//
-
-internal fun Any?.toJsonElement(): JsonElement = when (this) {
-    is Number -> JsonPrimitive(this)
-    is Boolean -> JsonPrimitive(this)
-    is String -> JsonPrimitive(this)
-    is Map<*, *> -> this.toJsonObject()
-    is Collection<*> -> this.toJsonArray()
-    is JsonElement -> this
-    else -> JsonNull
-}
-
-internal fun Collection<*>.toJsonArray() = JsonArray(map { it.toJsonElement() })
-
-internal fun Map<*, *>.toJsonObject() = JsonObject(mapKeys { it.key.toString() }.mapValues { it.value.toJsonElement() })
-
-//
-// Deserialize
-//
-
-private fun JsonPrimitive.toAnyValue(): Any? {
-    val content = this.content
-    if (this.isString) {
-        return content
-    }
-    if (content.equals("null", ignoreCase = true)) {
-        return null
-    }
-    if (content.equals("true", ignoreCase = true)) {
-        return true
-    }
-    if (content.equals("false", ignoreCase = true)) {
-        return false
-    }
-    val intValue = content.toIntOrNull()
-    if (intValue != null) {
-        return intValue
-    }
-    val longValue = content.toLongOrNull()
-    if (longValue != null) {
-        return longValue
-    }
-    val doubleValue = content.toDoubleOrNull()
-    if (doubleValue != null) {
-        return doubleValue
-    }
-    throw Exception("Cannot convert JSON $content to value")
-}
-
-internal fun JsonElement.toAnyOrNull(): Any? = when (this) {
-    is JsonNull -> null
-    is JsonPrimitive -> toAnyValue()
-    is JsonObject -> this.map { it.key to it.value.toAnyOrNull() }.toMap()
-    is JsonArray -> this.map { it.toAnyOrNull() }
-}
-
-internal object AnySerializer : KSerializer<Any?> {
-    private val delegateSerializer = JsonElement.serializer()
-    override val descriptor = delegateSerializer.descriptor
-
-    override fun serialize(
-        encoder: Encoder,
-        value: Any?,
-    ) {
-        encoder.encodeSerializableValue(delegateSerializer, value.toJsonElement())
-    }
-
-    override fun deserialize(decoder: Decoder): Any? {
-        val jsonElement = decoder.decodeSerializableValue(delegateSerializer)
-        return jsonElement.toAnyOrNull()
-    }
-}

runtime/src/commonTest/kotlin/com/collectiveidea/twirp/ErrorResponseTest.kt

@@ -46,36 +46,38 @@ class ErrorResponseTest {
                     "nestedKey3": 17,
                     "nestedKey4": [9, null]
                 },
-                "key6": null
+                "key6": null,
+                "key7": 12.53,
+                "key8": 4000000000
             }
         }
             """.trimIndent(),
         )
 
         val meta = error.meta
         assertNotNull(meta)
-        assertEquals("a string", meta["key1"])
-        assertEquals(false, meta["key2"])
-        assertEquals(51, meta["key3"])
-
-        val key4Array = meta["key4"] as ArrayList<*>
-        assertEquals(4, key4Array.size)
-        assertEquals(true, key4Array[0])
-        assertEquals(1, key4Array[1])
-        assertEquals("test", key4Array[2])
-        val key4ArrayNestedMap = key4Array[3] as Map<*, *>
-        assertEquals(1, key4ArrayNestedMap.keys.size)
-        assertEquals("yup", key4ArrayNestedMap["nestedKey0"])
-
-        val key5Map = meta["key5"] as Map<*, *>
-        assertEquals("another string", key5Map["nestedKey1"])
-        assertEquals(true, key5Map["nestedKey2"])
-        assertEquals(17, key5Map["nestedKey3"])
-        val key5NestedArray = key5Map["nestedKey4"] as ArrayList<*>
-        assertEquals(2, key5NestedArray.size)
-        assertEquals(9, key5NestedArray[0])
-        assertEquals(null, key5NestedArray[1])
-
-        assertEquals(null, meta["key6"])
+        assertEquals(
+            mapOf(
+                "key1" to "a string",
+                "key2" to false,
+                "key3" to 51,
+                "key4" to listOf(
+                    true,
+                    1,
+                    "test",
+                    mapOf("nestedKey0" to "yup"),
+                ),
+                "key5" to mapOf(
+                    "nestedKey1" to "another string",
+                    "nestedKey2" to true,
+                    "nestedKey3" to 17,
+                    "nestedKey4" to listOf(9, null),
+                ),
+                "key6" to null,
+                "key7" to 12.53,
+                "key8" to 4000000000,
+            ),
+            meta,
+        )
     }
 }