feat: Added SwaggerUI KTor Plugin (#215)

CHANGELOG.md

@@ -3,10 +3,13 @@
 ## Unreleased
 
 ### Added
+- Brand new SwaggerUI support as a KTor plugin with WebJar under the hood and flexible configuration
 
 ### Changed
+- Playground example `SwaggerPlaygound` now demonstrates new SwaggerUI KTor plugin usage (including OAuth security)
 
 ### Remove
+- Deprecated Swagger Webjar approach was removed from codebase
 
 ---
 
@@ -18,7 +21,7 @@
 ## [2.2.0] - February 25th, 2022
 ### Changed
 - Fixed support Location classes located in other non-location classes
-- Fixed formatting of a custom SimpleSchema
+- Fixed formatting of a custom `SimpleSchema`
 - Multipart form-data multiple file request support
 
 ## [2.1.1] - February 19th, 2022

kompendium-playground/build.gradle.kts

@@ -14,6 +14,7 @@ dependencies {
   implementation(projects.kompendiumCore)
   implementation(projects.kompendiumAuth)
   implementation(projects.kompendiumLocations)
+  implementation(projects.kompendiumSwaggerUi)
 
   // Ktor
   val ktorVersion: String by project
@@ -26,7 +27,6 @@ dependencies {
   implementation(group = "io.ktor", name = "ktor-jackson", version = ktorVersion)
   implementation(group = "io.ktor", name = "ktor-gson", version = ktorVersion)
   implementation(group = "io.ktor", name = "ktor-locations", version = ktorVersion)
-  implementation(group = "io.ktor", name = "ktor-webjars", version = ktorVersion)
 
   // Logging
   implementation("org.apache.logging.log4j:log4j-api-kotlin:1.1.0")

kompendium-playground/src/main/kotlin/io/bkbn/kompendium/playground/SwaggerPlayground.kt

@@ -2,9 +2,12 @@ package io.bkbn.kompendium.playground
 
 import io.bkbn.kompendium.core.Kompendium
 import io.bkbn.kompendium.core.Notarized.notarizedGet
-import io.bkbn.kompendium.core.routes.swagger
+import io.bkbn.kompendium.oas.component.Components
+import io.bkbn.kompendium.oas.security.OAuth
 import io.bkbn.kompendium.oas.serialization.KompendiumSerializersModule
 import io.bkbn.kompendium.playground.util.Util
+import io.bkbn.kompendium.swagger.JsConfig
+import io.bkbn.kompendium.swagger.SwaggerUI
 import io.ktor.application.Application
 import io.ktor.application.call
 import io.ktor.application.install
@@ -15,14 +18,16 @@ import io.ktor.routing.routing
 import io.ktor.serialization.json
 import io.ktor.server.engine.embeddedServer
 import io.ktor.server.netty.Netty
-import io.ktor.webjars.Webjars
+import java.net.URI
 import kotlinx.serialization.json.Json
 import java.util.UUID
+import kotlinx.serialization.ExperimentalSerializationApi
 
 /**
  * Application entrypoint.  Run this and head on over to `localhost:8081/docs`
  * to see a very simple yet beautifully documented API
  */
+@ExperimentalSerializationApi
 fun main() {
   embeddedServer(
     Netty,
@@ -31,7 +36,10 @@ fun main() {
   ).start(wait = true)
 }
 
+const val securitySchemaName = "oauth"
+
 // Application Module
+@ExperimentalSerializationApi
 private fun Application.mainModule() {
   // Installs Simple JSON Content Negotiation
   install(ContentNegotiation) {
@@ -41,17 +49,45 @@ private fun Application.mainModule() {
       explicitNulls = false
     })
   }
-  install(Webjars)
   // Installs the Kompendium Plugin and sets up baseline server metadata
   install(Kompendium) {
-    spec = Util.baseSpec
+    spec = Util.baseSpec.copy(components = Components(securitySchemes = mutableMapOf(
+      securitySchemaName to OAuth(description = "OAuth Auth", flows = OAuth.Flows(
+        authorizationCode = OAuth.Flows.AuthorizationCode(
+          authorizationUrl =  "http://localhost/auth",
+          tokenUrl = "http://localhost/token"
+        )
+      ))
+    )))
   }
+
+  install(SwaggerUI) {
+      swaggerUrl = "/swagger-ui"
+      jsConfig = JsConfig(
+        specs = mapOf(
+          "My API v1" to URI("/openapi.json"),
+          "My API v2" to URI("/openapi.json")
+        ),
+        // This part will be inserted after Swagger UI is loaded in Browser.
+        // Example is prepared according to this documentation: https://swagger.io/docs/open-source-tools/swagger-ui/usage/oauth2/
+        jsInit = {
+          """
+      ui.initOAuth({
+          clientId: 'CLIENT_ID',
+          clientSecret: 'CLIENT_SECRET',
+          realm: 'MY REALM',
+          appName: 'TEST APP',
+          useBasicAuthenticationWithAccessCodeGrant: true
+      });  
+      """
+        }
+      )
+  }
+
   // Configures the routes for our API
   routing {
-    // This is all you need to do to add Swagger! Reachable at `/swagger-ui`
-    swagger()
     // Kompendium infers the route path from the Ktor Route.  This will show up as the root path `/`
-    notarizedGet(BasicPlaygroundToC.simpleGetExample) {
+    notarizedGet(BasicPlaygroundToC.simpleGetExample.copy(securitySchemes = setOf(securitySchemaName))) {
       call.respond(HttpStatusCode.OK, BasicModels.BasicResponse(c = UUID.randomUUID().toString()))
     }
   }

kompendium-swagger-ui/Module.md

@@ -1,3 +1,52 @@
 # Module kompendium-swagger-ui
 
-Contains the code necessary to launch `swagger` as your documentation frontend.
+This module is responsible for frontend part of `SwaggerUI` built on top on WebJar.
+
+Solution is wrapped into KTor plugin that may be tuned with configuration properties according to 
+Swagger UI official documentation (`JsConfig` is responsible for that): 
+
+https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/
+
+Current implementation covers only most important part of specification properties (we'll be adding more time to time)  
+
+# Module configuration
+
+Minimal SwaggerUI plugin configuration:
+
+```kotlin
+import io.bkbn.kompendium.swagger.JsConfig
+import io.bkbn.kompendium.swagger.SwaggerUI
+import io.ktor.application.install
+
+install(SwaggerUI) {
+  swaggerUrl = "/swagger-ui"
+  jsConfig = JsConfig(
+    specs = mapOf(
+      "Your API name" to URI("/openapi.json")
+    )
+  )
+}
+
+```
+
+Additionally, there is a way to add additional initialization code in SwaggerUI JS.
+`JsConfig.jsInit` is responsible for that:
+
+```kotlin
+JsConfig(
+  //...
+  jsInit = {
+    """
+      ui.initOAuth(...)    
+    """
+  } 
+)
+```
+
+# Playground example
+
+There is an example that demonstrates how this plugin is working in `kompendium-playground` module:
+
+```
+io.bkbn.kompendium.playground.SwaggerPlayground.kt
+``` 

kompendium-swagger-ui/build.gradle.kts

@@ -17,7 +17,7 @@ sourdough {
 dependencies {
   val ktorVersion: String by project
   implementation(group = "io.ktor", name = "ktor-server-core", version = ktorVersion)
-  implementation(group = "io.ktor", name = "ktor-webjars", version = ktorVersion)
+  implementation(group = "org.webjars", name = "webjars-locator-core", version = "0.50")
   implementation(group = "org.webjars", name = "swagger-ui", version = "4.5.2")
 }
 

kompendium-swagger-ui/src/main/kotlin/io/bkbn/kompendium/swagger/JsConfig.kt

@@ -0,0 +1,29 @@
+package io.bkbn.kompendium.swagger
+
+import java.net.URI
+
+// This class represents this specification:
+// https://swagger.io/docs/open-source-tools/swagger-ui/usage/configuration/
+data class JsConfig(
+  val specs: Map<String, URI>,
+  val deepLinking: Boolean = true,
+  val displayOperationId: Boolean = true,
+  val displayRequestDuration: Boolean = true,
+  val docExpansion: String = "none",
+  val operationsSorter: String = "alpha",
+  val defaultModelExpandDepth: Int = 4,
+  val defaultModelsExpandDepth: Int = 4,
+  val persistAuthorization: Boolean = true,
+  val tagsSorter: String = "alpha",
+  val tryItOutEnabled: Boolean = false,
+  val validatorUrl: String? = null,
+  val jsInit: () -> String? = { null }
+)
+
+internal fun JsConfig.toJsProps(): String = asMap()
+  .filterKeys { !setOf("specs", "jsInit").contains(it) }
+  .map{ "${it.key}: ${it.value.toJs()}" }
+  .joinToString(separator = ",\n\t\t")
+
+internal fun JsConfig.getSpecUrlsProps(): String =
+  if (specs.isEmpty()) "[]" else specs.map { "{url: ${it.value.toJs()}, name: ${it.key.toJs()}}" }.toString()

kompendium-swagger-ui/src/main/kotlin/io/bkbn/kompendium/swagger/JsUtils.kt

@@ -0,0 +1,14 @@
+package io.bkbn.kompendium.swagger
+
+internal const val JS_UNDEFINED = "undefined"
+
+internal fun String?.toJs(): String = this?.let { "'$it'" } ?: JS_UNDEFINED
+internal fun Boolean?.toJs(): String = this?.toString() ?: JS_UNDEFINED
+internal fun Int?.toJs(): String = this?.toString() ?: JS_UNDEFINED
+
+internal fun Any?.toJs(): String = when(this) {
+  is String? -> toJs()
+  is Int? -> toJs()
+  is Boolean? -> toJs()
+  else -> toString().toJs()
+}

kompendium-swagger-ui/src/main/kotlin/io/bkbn/kompendium/swagger/ReflectionUtils.kt

@@ -0,0 +1,6 @@
+package io.bkbn.kompendium.swagger
+
+import kotlin.reflect.full.memberProperties
+
+internal inline fun<reified T: Any> T.asMap(): Map<String, Any?> =
+  T::class.memberProperties.associate { it.name to it.get(this) }

kompendium-swagger-ui/src/main/kotlin/io/bkbn/kompendium/swagger/SwaggerUI.kt

@@ -1,16 +1,78 @@
 package io.bkbn.kompendium.swagger
 
+import io.ktor.application.Application
+import io.ktor.application.ApplicationFeature
 import io.ktor.application.call
+import io.ktor.http.HttpStatusCode
+import io.ktor.response.respond
 import io.ktor.response.respondRedirect
 import io.ktor.routing.Routing
 import io.ktor.routing.get
+import io.ktor.routing.routing
+import io.ktor.util.AttributeKey
+import java.net.URI
+import org.webjars.WebJarAssetLocator
 
-@Deprecated(
-  "Webjar approach is deprecated",
-  replaceWith = ReplaceWith("swagger()", "io.bkbn.kompendium.core.routes.swagger")
+@Suppress("unused")
+class SwaggerUI(val config: Configuration) {
+
+  class Configuration {
+    // The primary Swagger-UI page (will redirect to target page)
+    var swaggerUrl: String = "/swagger-ui"
+    // The Root path to Swagger resources (in most cases a path to the webjar resources)
+    var swaggerBaseUrl: String = "/webjars/swagger-ui"
+    // Configuration for SwaggerUI JS initialization
+    lateinit var jsConfig: JsConfig
+    // Application context path (for example if application have the following path: http://domain.com/app, use: "/app")
+    var contextPath: String = ""
+  }
+
+  companion object Feature: ApplicationFeature<Application, Configuration, SwaggerUI> {
+
+    private fun Configuration.toInternal(): InternalConfiguration = InternalConfiguration(
+      swaggerUrl = URI(swaggerUrl),
+      swaggerBaseUrl = URI(swaggerBaseUrl),
+      jsConfig = jsConfig,
+      contextPath = contextPath
     )
-fun Routing.swaggerUI(openApiJsonUrl: String = "/openapi.json") {
-  get("/swagger-ui") {
-    call.respondRedirect("/webjars/swagger-ui/index.html?url=$openApiJsonUrl", true)
+
+    private data class InternalConfiguration(
+      val swaggerUrl: URI,
+      val swaggerBaseUrl: URI,
+      val jsConfig: JsConfig,
+      val contextPath: String
+    ) {
+      val redirectIndexUrl: String = "${contextPath}${swaggerBaseUrl}/index.html"
+    }
+
+    private val locator = WebJarAssetLocator()
+
+    private val installRoutes: Routing.(InternalConfiguration) -> Unit = { config ->
+
+      get(config.swaggerUrl.toString()) {
+        call.respondRedirect(config.redirectIndexUrl)
+      }
+
+      get("${config.swaggerBaseUrl}/{filename}") {
+        call.parameters["filename"]!!.let { filename ->
+          when(filename) {
+            "index.html" ->
+              locator.getSwaggerIndexContent(jsConfig = config.jsConfig)
+            else ->
+              locator.getSwaggerResourceContent(path = filename)
+          }
+        }.let { call.respond(HttpStatusCode.OK, it) }
+      }
+    }
+
+    override val key: AttributeKey<SwaggerUI> = AttributeKey("SwaggerUI")
+
+    override fun install(pipeline: Application, configure: Configuration.() -> Unit): SwaggerUI {
+      pipeline.routing { }.let { routing ->
+        val configuration: Configuration = Configuration().apply(configure)
+        installRoutes(routing, configuration.toInternal())
+        return SwaggerUI(config = configuration)
+      }
+    }
   }
 }

kompendium-swagger-ui/src/main/kotlin/io/bkbn/kompendium/swagger/SwaggerWebJarUtils.kt

@@ -0,0 +1,24 @@
+package io.bkbn.kompendium.swagger
+
+import io.ktor.features.NotFoundException
+import io.ktor.http.content.ByteArrayContent
+import java.net.URL
+import org.webjars.WebJarAssetLocator
+
+internal fun WebJarAssetLocator.getSwaggerResource(path: String): URL =
+  this::class.java.getResource(getFullPath("swagger-ui", path).let { if (it.startsWith("/")) it else "/$it" })
+    ?: throw NotFoundException("Resource not found: $path")
+
+internal fun WebJarAssetLocator.getSwaggerResourceContent(path: String): ByteArrayContent =
+  ByteArrayContent(getSwaggerResource(path).readBytes())
+
+internal fun WebJarAssetLocator.getSwaggerIndexContent(jsConfig: JsConfig): ByteArrayContent = ByteArrayContent(
+    getSwaggerResource(path = "index.html").readText()
+      .replaceFirst("url: \"https://petstore.swagger.io/v2/swagger.json\",", "urls: ${jsConfig.getSpecUrlsProps()},")
+      .replaceFirst("deepLinking: true", jsConfig.toJsProps())
+      .let { content ->
+        jsConfig.jsInit()?.let {
+          content.replaceFirst("window.ui = ui", "$it\n\twindow.ui = ui")
+        } ?: content
+      }.toByteArray()
+  )