add writable parts of server and client

ServerPart/build.gradle

@@ -33,6 +33,7 @@ dependencies {
 
     api "io.ktor:ktor-server:$ktor_version"
     api "io.ktor:ktor-server-core:$ktor_version"
+    api "io.ktor:ktor-websockets:$ktor_version"
 }
 
 compileKotlin {

ServerPart/src/main/kotlin/com/insanusmokrassar/postssystem/core/server/Commons.kt

@@ -8,8 +8,10 @@ import io.ktor.http.ContentType
 import io.ktor.http.HttpStatusCode
 import io.ktor.response.respond
 import io.ktor.response.respondText
+import kotlinx.serialization.InternalSerializationApi
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.internal.ArrayListSerializer
+import kotlinx.serialization.internal.NullableSerializer
 import kotlinx.serialization.json.Json
 
 
@@ -27,11 +29,12 @@ internal val Post.asSimplePost
         else -> SimplePost(id, content, meta)
     }
 
-internal suspend fun <T> ApplicationCall.answer(
+@InternalSerializationApi
+internal suspend fun <T : Any> ApplicationCall.answer(
     serializer: KSerializer<T>,
-    answerObject: T
+    answerObject: T?
 ) = respondText(ContentType.Application.Json) {
-    Json.plain.stringify(serializer, answerObject)
+    Json.plain.stringify(NullableSerializer(serializer), answerObject)
 }
 
 internal suspend fun ApplicationCall.answerBadRequest(

ServerPart/src/main/kotlin/com/insanusmokrassar/postssystem/core/server/WriteModules.kt

@@ -0,0 +1,54 @@
+package com.insanusmokrassar.postssystem.core.server
+
+import com.insanusmokrassar.postssystem.core.api.WritePostsAPI
+import com.insanusmokrassar.postssystem.core.clientserver.common.*
+import com.insanusmokrassar.postssystem.core.clientserver.common.models.UpdatePostRequest
+import com.insanusmokrassar.postssystem.core.post.*
+import io.ktor.application.call
+import io.ktor.http.cio.websocket.Frame
+import io.ktor.request.receiveOrNull
+import io.ktor.routing.Route
+import io.ktor.routing.post
+import io.ktor.websocket.webSocket
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collect
+import kotlinx.serialization.InternalSerializationApi
+import kotlinx.serialization.internal.BooleanSerializer
+import kotlinx.serialization.json.Json
+
+private inline fun Route.createWebsocket(path: String, flow: Flow<Post>) {
+    webSocket("/$path") {
+        flow.collect {
+            val simplePost = it.asSimplePost
+            outgoing.send(Frame.Text(Json.plain.stringify(SimplePost.serializer(), simplePost)))
+        }
+    }
+}
+
+@InternalSerializationApi
+fun Route.includePostsCoreWriteModules(
+    writePostsAPI: WritePostsAPI
+) {
+    createWebsocket(eventPostsCreatedAddress, writePostsAPI.postCreatedFlow)
+    createWebsocket(eventPostsDeletedAddress, writePostsAPI.postDeletedFlow)
+    createWebsocket(eventPostsUpdatedAddress, writePostsAPI.postUpdatedFlow)
+
+    post(createPostAddress) {
+        call.receiveOrNull<PostContents>() ?.also { contents ->
+            val post = writePostsAPI.createPost(contents)
+
+            call.answer(SimplePost.serializer(), post ?.asSimplePost)
+        } ?: call.answerBadRequest("Contents (List of Content)")
+    }
+
+    post(deletePostAddress) {
+        call.receiveOrNull<PostId>() ?.also { postId ->
+            call.answer(BooleanSerializer, writePostsAPI.deletePost(postId))
+        } ?: call.answerBadRequest("Post Id (String)")
+    }
+    post(deletePostAddress) {
+        call.receiveOrNull<UpdatePostRequest>() ?.also { (postId, contents) ->
+            call.answer(BooleanSerializer, writePostsAPI.updatePostContent(postId, contents))
+        } ?: call.answerBadRequest("Post Id (String)")
+    }
+}