#88 better fix: teach jackson to serialize enums using toString(), wh…

…ich will respect Swagger's ParameterIn and other enums toString() implementation (which is lower-case)

CHANGELOG.md

@@ -4,7 +4,7 @@
 * jdbc: @NoTransaction can now be used on jobs
 * jdbc: fixed usage of multiple different DataSources when there is an active transaction
 * json: TSGenerator will now use more type-safe string template types for java.time classes, e.g. `${number}-${number}-${number}` instead of `string`
-* openapi: fix compliancy: output parameter types as lowercase in OpenAPI spec
+* jackson: serialize enums using their toString() method by default, this fixes `openapi` module usage with `jackson`
 * server: `Server(InetSocketAddress(0))` can now be used to bind to any available port.
 
 # 1.6.9

jackson/src/JsonBody.kt

@@ -1,6 +1,7 @@
 package klite.jackson
 
 import com.fasterxml.jackson.annotation.JsonInclude
+import com.fasterxml.jackson.core.JsonGenerator
 import com.fasterxml.jackson.core.JsonParseException
 import com.fasterxml.jackson.core.JsonParser
 import com.fasterxml.jackson.databind.*
@@ -29,6 +30,7 @@ fun kliteJsonMapper(kotlinModule: KotlinModule = kotlinModule(), javaTimeModule:
   serializationInclusion(JsonInclude.Include.NON_NULL)
   addModule(SimpleModule().apply {
     addDeserializer(String::class.java, EmptyStringToNullDeserializer)
+    addSerializer(Enum::class.java, EnumToStringSerializer)
     addConverterDeserializers()
   })
   withCoercionConfigDefaults {
@@ -43,6 +45,12 @@ object EmptyStringToNullDeserializer: JsonDeserializer<String?>() {
     jsonParser.valueAsString?.trimToNull()
 }
 
+object EnumToStringSerializer: JsonSerializer<Enum<*>>() {
+  override fun serialize(value: Enum<*>, gen: JsonGenerator, serializers: SerializerProvider) {
+    gen.writeString(value.toString())
+  }
+}
+
 fun SimpleModule.addConverterDeserializers() = Converter.forEach { type, converter ->
   @Suppress("UNCHECKED_CAST")
   addDeserializer(type.java as Class<Any>, object: JsonDeserializer<Any>() {

openapi/build.gradle.kts

@@ -1,4 +1,7 @@
 dependencies {
   implementation(project(":server"))
   api("io.swagger.core.v3:swagger-annotations:2.2.22")
+
+  testImplementation(project(":json"))
+  testImplementation(project(":jackson"))
 }

openapi/src/OpenAPI.kt

@@ -87,7 +87,7 @@ internal fun toOperation(route: Route): Pair<String, Any> {
 fun toParameter(p: Param, op: Operation? = null) = mapOf(
   "name" to p.name,
   "required" to (!p.p.isOptional && !p.p.type.isMarkedNullable),
-  "in" to toParameterIn(p.source)?.name?.lowercase(),
+  "in" to toParameterIn(p.source),
   "schema" to p.p.type.toJsonSchema(),
 ) + ((p.p.findAnnotation<Parameter>() ?: op?.parameters?.find { it.name == p.name })?.toNonEmptyValues() ?: emptyMap())
 

openapi/test/JsonSerializationTest.kt

@@ -0,0 +1,18 @@
+package klite.openapi
+
+import ch.tutteli.atrium.api.fluent.en_GB.toEqual
+import ch.tutteli.atrium.api.verbs.expect
+import io.swagger.v3.oas.annotations.enums.ParameterIn.PATH
+import klite.jackson.kliteJsonMapper
+import klite.jackson.render
+import org.junit.jupiter.api.Test
+
+class JsonSerializationTest {
+  @Test fun `ParameterIn serialization using klite-json`() {
+    expect(klite.json.JsonMapper().render(PATH)).toEqual("\"path\"")
+  }
+
+  @Test fun `ParameterIn serialization using jackson`() {
+    expect(kliteJsonMapper().render(PATH)).toEqual("\"path\"")
+  }
+}