Add polling

src/commonMain/kotlin/de/kif/common/Message.kt

@@ -18,7 +18,15 @@ data class Message(
     val type: MessageType,
     val repository: RepositoryType,
     val id: Long
-)
+) {
+    companion object {
+        val empty = Message(
+            MessageType.UPDATE,
+            RepositoryType.ANNOUNCEMENT,
+            0L
+        )
+    }
+}
 
 enum class MessageType {
     CREATE, UPDATE, DELETE

src/jsMain/kotlin/de/kif/frontend/PushServiceClient.kt

@@ -13,7 +13,7 @@ import org.w3c.xhr.XMLHttpRequest
 import kotlin.browser.document
 import kotlin.browser.window
 
-class WebSocketClient {
+class PushServiceClient {
     private val prefix = js("prefix")
     private val url = "$prefix/api/updates"
     private val body = document.body ?: createHtmlView()

src/jsMain/kotlin/de/kif/frontend/main.kt

@@ -12,7 +12,7 @@ import de.westermann.kwebview.components.init
 import kotlin.browser.document
 
 fun main() = init {
-    WebSocketClient()
+    PushServiceClient()
 
     if (document.getElementsByClassName("calendar").length > 0) {
         initCalendar()

src/jsMain/kotlin/de/kif/frontend/repository/AnnouncementRepository.kt

@@ -21,15 +21,15 @@ object AnnouncementRepository {
 
     suspend fun getAnnouncement(): String {
         val json = repositoryGet("$prefix/api/announcement") ?: return ""
-        return parser.parse(json, String.serializer())
+        return json as String
     }
 
     suspend fun setAnnouncement(value: String){
-        return repositoryPost("$prefix/api/announcement", Serialization.stringify(String.serializer(), value))
+        return repositoryPost("$prefix/api/announcement", value)
             ?: throw IllegalStateException("Cannot set announcement!")
     }
 
-    val handler = object : MessageHandler(RepositoryType.ROOM) {
+    val handler = object : MessageHandler(RepositoryType.ANNOUNCEMENT) {
 
         override fun onCreate(id: Long) {}
 

src/jsMain/kotlin/de/kif/frontend/views/Announcements.kt

@@ -18,4 +18,4 @@ fun initAnnouncement() {
             span.textContent = text
         }
     }
-}
+}

src/jvmMain/kotlin/de/kif/backend/util/PushService.kt

@@ -14,7 +14,9 @@ import io.ktor.routing.get
 
 object PushService {
 
-    var leastValidTimestamp = System.currentTimeMillis()
+    private var leastValidTimestamp = System.currentTimeMillis()
+
+    private val messages: MutableList<Pair<Long, Message>> = mutableListOf()
 
     /**
      * Save the message with the current timestamp
@@ -22,6 +24,21 @@ object PushService {
     fun notify(type: MessageType, repository: RepositoryType, id: Long) {
         val timestamp = System.currentTimeMillis()
         val message = Message(type, repository, id)
+
+        synchronized(messages) {
+            messages += Pair(timestamp, message)
+        }
+    }
+
+    private fun getIndexOfTimestamp(timestamp: Long): Int {
+        val index = messages.binarySearch(Pair(timestamp, Message.empty), compareBy { it.first })
+        val i = if (index < 0) {
+            -index - 1
+        } else {
+            index
+        }
+
+        return if (i < 0) 0 else i
     }
 
     /**
@@ -29,12 +46,25 @@ object PushService {
      * The return Box has the current timestamp. If the leastValidTimestamp is less then the current timestamp set the
      * valid flag to false and return an empty message list.
      */
-    fun getMessages(timestamp: Long?): MessageBox {
+    fun getMessages(timestamp: Long): MessageBox {
-        return MessageBox(
+        return if (timestamp < leastValidTimestamp) {
-            System.currentTimeMillis(),
+            MessageBox(
-            timestamp != null && timestamp > leastValidTimestamp,
+                System.currentTimeMillis(),
-            emptyList()
+                false,
-        )
+                emptyList()
+            )
+        } else {
+            val m = synchronized(messages) {
+                val index = getIndexOfTimestamp(timestamp)
+                messages.drop(index)
+            }
+
+            MessageBox(
+                System.currentTimeMillis(),
+                true,
+                m.map { it.second }
+            )
+        }
     }
 
     /**
@@ -42,13 +72,19 @@ object PushService {
      */
     fun gc(timestamp: Long) {
         leastValidTimestamp = timestamp
+
+        synchronized(messages) {
+            messages.removeIf {
+                it.first < timestamp
+            }
+        }
     }
 }
 
 fun Route.pushService() {
     get("/api/updates") {
         try {
-            val timestamp = call.request.queryParameters["timestamp"]?.toLongOrNull()
+            val timestamp = call.request.queryParameters["timestamp"]?.toLongOrNull() ?: 0
 
             val messageBox = PushService.getMessages(timestamp)