Allow parsing request and writing responses using java streams

This fixes actions-on-google#39

src/main/kotlin/com/google/actions/api/ActionResponse.kt

@@ -20,6 +20,8 @@ import com.google.api.services.actions_fulfillment.v2.model.AppResponse
 import com.google.api.services.actions_fulfillment.v2.model.ExpectedIntent
 import com.google.api.services.actions_fulfillment.v2.model.RichResponse
 import com.google.api.services.dialogflow_fulfillment.v2.model.WebhookResponse
+import java.io.IOException
+import java.io.OutputStream
 
 /**
  * Defines requirements of an object that represents a response from the Actions
@@ -58,6 +60,16 @@ interface ActionResponse {
      */
     val helperIntent: ExpectedIntent?
 
+    /**
+     * Writes the JSON representation of the response to the given output stream.
+     *
+     * This is more efficient than calling [toJson] first and then writing the string.
+     *
+     * @param outputStream The output stream to write to. Must be closed by the caller.
+     */
+    @Throws(IOException::class)
+    fun writeTo(outputStream: OutputStream)
+
     /**
      * Returns the JSON representation of the response.
      */

src/main/kotlin/com/google/actions/api/ActionsSdkApp.kt

@@ -19,6 +19,7 @@ package com.google.actions.api
 import com.google.actions.api.impl.AogRequest
 import com.google.actions.api.response.ResponseBuilder
 import org.slf4j.LoggerFactory
+import java.io.InputStream
 
 /**
  * Implementation of App for ActionsSDK based webhook. Developers must extend
@@ -50,6 +51,11 @@ open class ActionsSdkApp : DefaultApp() {
         return AogRequest.create(inputJson, headers)
     }
 
+    override fun createRequest(inputStream: InputStream, headers: Map<*, *>?): ActionRequest {
+        LOG.info("ActionsSdkApp.createRequest..")
+        return AogRequest.create(inputStream, headers)
+    }
+
     override fun getResponseBuilder(request: ActionRequest): ResponseBuilder {
         val responseBuilder = ResponseBuilder(
                 usesDialogflow = false,

src/main/kotlin/com/google/actions/api/DefaultApp.kt

@@ -18,6 +18,7 @@ package com.google.actions.api
 
 import com.google.actions.api.response.ResponseBuilder
 import org.slf4j.LoggerFactory
+import java.io.InputStream
 import java.util.concurrent.CompletableFuture
 
 /**
@@ -42,6 +43,20 @@ abstract class DefaultApp : App {
     abstract fun createRequest(inputJson: String, headers: Map<*, *>?):
             ActionRequest
 
+    /**
+     * Creates an ActionRequest from the specified input stream and metadata.
+     *
+     * This is semantically equivalent to reading the stream as a String using
+     * UTF-8 encoding and then calling `createRequest` with the resulting
+     * string.
+     *
+     * @param inputStream The input stream. Must be closed by the caller
+     * @param headers Map containing metadata, usually from the HTTP request
+     *   headers.
+     */
+    abstract fun createRequest(inputStream: InputStream, headers: Map<*, *>?):
+            ActionRequest
+
     /**
      * @return A ResponseBuilder for this App.
      */

src/main/kotlin/com/google/actions/api/DialogflowApp.kt

@@ -18,6 +18,7 @@ package com.google.actions.api
 
 import com.google.actions.api.impl.DialogflowRequest
 import com.google.actions.api.response.ResponseBuilder
+import java.io.InputStream
 
 /**
  * Implementation of App for Dialogflow based webhook. Developers must extend
@@ -48,6 +49,10 @@ open class DialogflowApp : DefaultApp() {
         return DialogflowRequest.create(inputJson, headers)
     }
 
+    override fun createRequest(inputStream: InputStream, headers: Map<*, *>?): ActionRequest {
+        return DialogflowRequest.create(inputStream, headers)
+    }
+
     override fun getResponseBuilder(request: ActionRequest): ResponseBuilder {
         val responseBuilder = ResponseBuilder(
                 usesDialogflow = true,

src/main/kotlin/com/google/actions/api/impl/DialogflowRequest.kt

@@ -23,6 +23,8 @@ import com.google.api.services.actions_fulfillment.v2.model.*
 import com.google.api.services.dialogflow_fulfillment.v2.model.*
 import com.google.gson.*
 import com.google.gson.reflect.TypeToken
+import java.io.InputStream
+import java.io.InputStreamReader
 import java.lang.reflect.Type
 import java.util.*
 
@@ -168,38 +170,43 @@ internal class DialogflowRequest internal constructor(
     }
 
     companion object {
-
-        fun create(body: String, headers: Map<*, *>?): DialogflowRequest {
-            val gson = Gson()
-            return create(gson.fromJson(body, JsonObject::class.java), headers)
-        }
-
-        fun create(json: JsonObject, headers: Map<*, *>?): DialogflowRequest {
-            val gsonBuilder = GsonBuilder()
-            gsonBuilder
-                    .registerTypeAdapter(WebhookRequest::class.java,
-                            WebhookRequestDeserializer())
-                    .registerTypeAdapter(QueryResult::class.java,
-                            QueryResultDeserializer())
-                    .registerTypeAdapter(Context::class.java,
-                            ContextDeserializer())
-                    .registerTypeAdapter(OriginalDetectIntentRequest::class.java,
-                            OriginalDetectIntentRequestDeserializer())
-
-            val gson = gsonBuilder.create()
-            val webhookRequest = gson.fromJson<WebhookRequest>(json,
-                    WebhookRequest::class.java)
-            val aogRequest: AogRequest
+        private val gson = GsonBuilder()
+            .registerTypeAdapter(WebhookRequest::class.java,
+                WebhookRequestDeserializer())
+            .registerTypeAdapter(QueryResult::class.java,
+                QueryResultDeserializer())
+            .registerTypeAdapter(Context::class.java,
+                ContextDeserializer())
+            .registerTypeAdapter(OriginalDetectIntentRequest::class.java,
+                OriginalDetectIntentRequestDeserializer())
+            .create()
+
+        fun create(body: String, headers: Map<*, *>?): DialogflowRequest =
+            create(gson.fromJson(body, WebhookRequest::class.java), headers)
+
+        fun create(json: JsonObject, headers: Map<*, *>?): DialogflowRequest =
+            create(gson.fromJson(json, WebhookRequest::class.java), headers)
+
+        fun create(inputStream: InputStream, headers: Map<*, *>?): DialogflowRequest =
+            create(
+                gson.fromJson(InputStreamReader(inputStream), WebhookRequest::class.java),
+                headers
+            )
+
+        private fun create(
+            webhookRequest: WebhookRequest,
+            headers: Map<*, *>?
+        ): DialogflowRequest {
 
             val originalDetectIntentRequest =
-                    webhookRequest.originalDetectIntentRequest
+                webhookRequest.originalDetectIntentRequest
             val payload = originalDetectIntentRequest?.payload
-            if (payload != null) {
-                aogRequest = AogRequest.create(gson.toJson(payload), headers,
-                        partOfDialogflowRequest = true)
+            val aogRequest = if (payload != null) {
+                AogRequest.create(gson.toJson(payload), headers,
+                    partOfDialogflowRequest = true)
             } else {
-                aogRequest = AogRequest.create(JsonObject(), headers,
-                        partOfDialogflowRequest = true)
+                AogRequest.create(JsonObject(), headers,
+                    partOfDialogflowRequest = true)
             }
 
             return DialogflowRequest(webhookRequest, aogRequest)

src/main/kotlin/com/google/actions/api/smarthome/SmartHomeApp.kt

@@ -23,6 +23,7 @@ import com.google.home.graph.v1.HomeGraphApiServiceProto
 import io.grpc.ManagedChannelBuilder
 import io.grpc.auth.MoreCallCredentials
 import java.io.FileInputStream
+import java.io.InputStream
 import java.util.concurrent.CompletableFuture
 
 abstract class SmartHomeApp : App {
@@ -49,6 +50,18 @@ abstract class SmartHomeApp : App {
         return SmartHomeRequest.create(inputJson)
     }
 
+    /**
+     * Builds a [SmartHomeRequest] object from an [InputStream].
+     *
+     * This is semantically equivalent as reading the input stream as an UTF-8 string and then calling createRequest
+     * with the resulting string.
+     *
+     * @param inputStream The input stream to read from. The stream must be closed by the caller.
+     * @return A parsed request object
+     */
+    fun createRequest(inputStream: InputStream): SmartHomeRequest =
+        SmartHomeRequest.create(inputStream)
+
     /**
      * The intent handler for action.devices.SYNC that is implemented in your smart home Action
      *
@@ -140,17 +153,24 @@ abstract class SmartHomeApp : App {
 
         return try {
             val request = createRequest(inputJson)
-            val response = routeRequest(request, headers)
-
-            val future: CompletableFuture<SmartHomeResponse> = CompletableFuture()
-            future.complete(response)
-            future.thenApply { this.getAsJson(it) }
-                  .exceptionally { throwable -> throwable.message }
+            handleRequest(request, headers)
+                .thenApply { getAsJson(it) }
+                .exceptionally { throwable -> throwable.message }
         } catch (e: Exception) {
             handleError(e)
         }
     }
 
+    fun handleRequest(request: SmartHomeRequest, headers: Map<*, *>?): CompletableFuture<SmartHomeResponse> =
+        try {
+            val response = routeRequest(request, headers)
+            CompletableFuture.completedFuture(response)
+        } catch (e: Exception) {
+            CompletableFuture<SmartHomeResponse>()
+                .apply { completeExceptionally(e) }
+        }
+
+
     @Throws(Exception::class)
     private fun routeRequest(request: SmartHomeRequest, headers: Map<*, *>?): SmartHomeResponse {
         when (request.javaClass) {

src/main/kotlin/com/google/actions/api/smarthome/SmartHomeRequest.kt

@@ -16,7 +16,11 @@
 
 package com.google.actions.api.smarthome
 
+import com.google.gson.JsonObject
 import org.json.JSONObject
+import org.json.JSONTokener
+import java.io.IOException
+import java.io.InputStream
 
 /**
  * A representation of the JSON payload received during a smart home request.
@@ -32,8 +36,13 @@ open class SmartHomeRequest {
     }
 
     companion object {
-        fun create(inputJson: String): SmartHomeRequest {
-            val json = JSONObject(inputJson)
+        fun create(inputStream: InputStream): SmartHomeRequest =
+            create(JSONObject(JSONTokener(inputStream)))
+
+        fun create(inputJson: String): SmartHomeRequest =
+            create(JSONObject(inputJson))
+
+        private fun create(json: JSONObject): SmartHomeRequest {
             val requestId = json.getString("requestId")
             val inputs = json.getJSONArray("inputs")
             val request = inputs.getJSONObject(0)

src/main/kotlin/com/google/actions/api/smarthome/SmartHomeResponse.kt

@@ -22,13 +22,25 @@ import com.google.protobuf.Struct
 import com.google.protobuf.util.JsonFormat
 import org.json.JSONException
 import org.json.JSONObject
+import org.json.JSONStringer
+import org.json.JSONTokener
+import org.json.JSONWriter
+import java.io.OutputStream
+import java.io.OutputStreamWriter
+import java.io.StringWriter
 
 /**
  * A representation of the JSON payload that should be sent during a smart home request.
  *
  * @see <a href="https://developers.google.com/actions/smarthome/develop/process-intents">Public documentation</a>
  */
 open class SmartHomeResponse {
+    open fun writeToStream(outputStream: OutputStream) {
+        val writer = OutputStreamWriter(outputStream)
+        build().write(writer)
+        writer.flush()
+    }
+
     open fun build(): JSONObject {
         return JSONObject() // Return empty object
     }