Support schemas

Author: sksamuel

kotest-extensions-ktor-openapi-model/src/main/kotlin/io/kotest/extensions/ktor/openapi/keys.kt

@@ -4,9 +4,11 @@ import io.ktor.server.application.ApplicationCall
 import io.ktor.server.application.call
 import io.ktor.util.AttributeKey
 import io.ktor.util.pipeline.PipelineContext
+import kotlin.reflect.KClass
 
 val DescriptionKey: AttributeKey<String> = AttributeKey("KotestOpenApiDescriptionKey")
 val DeprecatedKey: AttributeKey<Boolean> = AttributeKey("KotestOpenApiDeprecatedKey")
+val SchemaKey: AttributeKey<KClass<*>> = AttributeKey("KotestOpenApiSchemaKey")
 
 fun PipelineContext<*, ApplicationCall>.description(desc: String) {
    call.attributes.put(DescriptionKey, desc)
@@ -15,3 +17,7 @@ fun PipelineContext<*, ApplicationCall>.description(desc: String) {
 fun PipelineContext<*, ApplicationCall>.deprecated(deprecated: Boolean) {
    if (deprecated) call.attributes.put(DeprecatedKey, deprecated)
 }
+
+inline fun <reified T : Any> PipelineContext<*, ApplicationCall>.schema() {
+   call.attributes.put(SchemaKey, T::class)
+}

kotest-extensions-ktor-openapi-plugin/src/main/kotlin/io/kotest/extensions/ktor/openapi/OpenApiBuilder.kt

@@ -44,6 +44,11 @@ class OpenApiBuilder(private val config: OpenApiConfig) {
       val item = PathItem()
       openapi.path(path, item)
 
+      // add all schemas at the top level
+      traces.mapNotNull { it.schema }.forEach { schema ->
+         openapi.components.addSchemas(schema.java.name, schema.toSchema())
+      }
+
       // each http method is an operation
       traces.groupBy { it.method }.forEach { (method, tracesByMethod) ->
 
@@ -75,6 +80,7 @@ class OpenApiBuilder(private val config: OpenApiConfig) {
                   if (contentType != null) {
 
                      val mediaType = MediaType()
+                     mediaType.schema = tracesByContentType.firstNotNullOfOrNull { it.schema }?.toSchema()
 
                      // for each content type that is the same, they are added as multiple examples
                      // to the same MediaType in the response content

kotest-extensions-ktor-openapi-plugin/src/main/kotlin/io/kotest/extensions/ktor/openapi/Tracer.kt

@@ -3,6 +3,7 @@ package io.kotest.extensions.ktor.openapi
 import io.ktor.http.ContentType
 import io.ktor.http.HttpMethod
 import io.ktor.http.HttpStatusCode
+import kotlin.reflect.KClass
 
 /**
  * The tracer is used to collect individual route traces.
@@ -37,6 +38,7 @@ data class Trace(
    var responseBody: String? = null,
    var description: String?,
    var deprecated: Boolean = false,
+   var schema: KClass<*>? = null,
    var pathParameterExamples: Map<String, String?>,
 ) {
    companion object {

kotest-extensions-ktor-openapi-plugin/src/main/kotlin/io/kotest/extensions/ktor/openapi/plugin.kt

@@ -68,6 +68,7 @@ val KotestOpenApi = createApplicationPlugin("OpenApi", createConfiguration = ::O
          trace.status = call.response.status()
          trace.description = call.attributes.getOrNull(DescriptionKey)
          trace.deprecated = call.attributes.getOrNull(DeprecatedKey) ?: false
+         trace.schema = call.attributes.getOrNull(SchemaKey)
          trace.pathParameterExamples = trace.pathParameters.associateWith { call.parameters[it] }
          this@createApplicationPlugin.pluginConfig.tracer.addTrace(trace)
       }

kotest-extensions-ktor-openapi-plugin/src/main/kotlin/io/kotest/extensions/ktor/openapi/schemas.kt

@@ -0,0 +1,34 @@
+package io.kotest.extensions.ktor.openapi
+
+import io.swagger.v3.oas.models.media.Schema
+import kotlin.reflect.KClass
+import kotlin.reflect.full.memberProperties
+import kotlin.reflect.typeOf
+
+object SwaggerSchemas {
+   val string = Schema<String>().apply { type = "string" }
+   val integer = Schema<String>().apply { type = "integer" }
+   val number = Schema<String>().apply { type = "number" }
+   val boolean = Schema<String>().apply { type = "boolean" }
+   val obj = Schema<String>().apply { type = "object" }
+}
+
+fun KClass<*>.toSchema(): Schema<Any> {
+   require(isData)
+   val schema = Schema<Any>()
+   schema.name = this.java.name
+   schema.type = "object"
+   memberProperties.map { prop ->
+      val propSchema = when (prop.returnType) {
+         typeOf<String>() -> SwaggerSchemas.string
+         typeOf<Int>() -> SwaggerSchemas.integer
+         typeOf<Long>() -> SwaggerSchemas.integer
+         typeOf<Float>() -> SwaggerSchemas.number
+         typeOf<Double>() -> SwaggerSchemas.number
+         typeOf<Boolean>() -> SwaggerSchemas.boolean
+         else -> null
+      }
+      schema.addProperty(prop.name, propSchema)
+   }
+   return schema
+}

kotest-extensions-ktor-openapi-plugin/src/test/kotlin/io/kotest/extensions/ktor/openapi/OpenApiTest.kt

@@ -41,6 +41,7 @@ class OpenApiTest : FunSpec() {
                route("/internal") {
                   get("/foo1") {
                      description("Returns the user identified by the foo param")
+                     schema<MyDataClass>()
                      call.respond(HttpStatusCode.OK)
                   }
                   patch("/patchme") {
@@ -65,3 +66,9 @@ class OpenApiTest : FunSpec() {
       }
    }
 }
+
+data class MyDataClass(
+   val a: String,
+   val b: Int,
+   val c: Double,
+)

kotest-extensions-ktor-openapi-plugin/src/test/kotlin/io/kotest/extensions/ktor/openapi/SchemaBuilderTest.kt

@@ -0,0 +1,25 @@
+package io.kotest.extensions.ktor.openapi
+
+import io.kotest.core.spec.style.FunSpec
+import io.kotest.matchers.shouldBe
+import io.swagger.v3.oas.models.media.Schema
+
+class SchemaBuilderTest : FunSpec() {
+   init {
+
+      test("basic property types") {
+         data class Foo(val a: String, val b: Boolean, val c: Int, val d: Long, val e: Float, val f: Double)
+
+         val expected = Schema<Foo>()
+         expected.type = "object"
+         expected.addProperty("a", SwaggerSchemas.string)
+         expected.addProperty("b", SwaggerSchemas.boolean)
+         expected.addProperty("c", SwaggerSchemas.integer)
+         expected.addProperty("d", SwaggerSchemas.integer)
+         expected.addProperty("e", SwaggerSchemas.number)
+         expected.addProperty("f", SwaggerSchemas.number)
+         expected.name = Foo::class.java.name
+         Foo::class.toSchema() shouldBe expected
+      }
+   }
+}