New ONReceiver MVP

src/main/kotlin/kweb/Element.kt

@@ -6,6 +6,10 @@ import kweb.dom.element.events.ONImmediateReceiver
 import kweb.dom.element.events.ONReceiver
 import kweb.dom.element.read.ElementReader
 import kweb.dom.style.StyleReceiver
+import kweb.html.events.EventGenerator
+import kweb.html.events.KeyboardEvents
+import kweb.html.events.MouseEvents
+import kweb.html.events.NewOnReceiver
 import kweb.plugins.KwebPlugin
 import kweb.state.KVal
 import kweb.state.KVar
@@ -15,7 +19,8 @@ import java.util.concurrent.ConcurrentSkipListSet
 import kotlin.reflect.KClass
 
 @KWebDSL
-open class Element(open val browser: WebBrowser, val creator: ElementCreator<*>?, open var jsExpression: String, val tag: String? = null, val id: String?) {
+open class Element(open val browser: WebBrowser, val creator: ElementCreator<*>?, open var jsExpression: String, val tag: String? = null, val id: String?) :
+        EventGenerator<Element>, KeyboardEvents, MouseEvents {
     constructor(element: Element) : this(element.browser, element.creator, jsExpression = element.jsExpression, tag = element.tag, id = element.id)
     /*********
      ********* Low level methods
@@ -313,7 +318,7 @@ open class Element(open val browser: WebBrowser, val creator: ElementCreator<*>?
         browser.evaluate(wrappedJS)
     }
 
-    fun addEventListener(eventName: String, returnEventFields: Set<String> = Collections.emptySet(), retrieveJs: String?, callback: (Any) -> Unit): Element {
+    override fun addEventListener(eventName: String, returnEventFields: Set<String>, retrieveJs: String?, callback: (Any) -> Unit): Element {
         val callbackId = Math.abs(random.nextInt())
         val retrieveJs = if (retrieveJs != null) ", \"retrieved\" : ($retrieveJs)" else ""
         val eventObject = "{" + returnEventFields.map { "\"$it\" : event.$it" }.joinToString(separator = ", ") + retrieveJs + "}"
@@ -331,6 +336,7 @@ open class Element(open val browser: WebBrowser, val creator: ElementCreator<*>?
         return this
     }
 
+
     fun delete() {
         execute("$jsExpression.parentNode.removeChild($jsExpression);")
     }
@@ -352,6 +358,8 @@ open class Element(open val browser: WebBrowser, val creator: ElementCreator<*>?
      */
     val on: ONReceiver get() = ONReceiver(this)
 
+    val newOn: NewOnReceiver<Element> get() = NewOnReceiver(this)
+
     /**
      * You can supply a javascript expression `retrieveJs` which will
      * be available via [Event.retrieveJs]

src/main/kotlin/kweb/demos/todo/TodoApp.kt

@@ -4,6 +4,8 @@ import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.future.await
 import kotlinx.coroutines.launch
 import kweb.*
+import kweb.html.events.click
+import kweb.html.events.keypress
 import kweb.plugins.fomanticUI.fomantic
 import kweb.plugins.fomanticUI.fomanticUIPlugin
 import kweb.state.*
@@ -138,7 +140,7 @@ class TodoApp {
         }
         div(fomantic.ui.action.input).new {
             val input = input(InputType.text, placeholder = "Add Item")
-            input.on.keypress { ke ->
+            input.newOn.keypress { ke ->
                 if (ke.code == "Enter") {
                     handleAddItem(input, list)
                 }
@@ -165,7 +167,7 @@ class TodoApp {
         button.new {
             i(fomantic.trash.icon)
         }
-        button.on.click {
+        button.newOn.click {
             state.items.remove(item.value.uid)
         }
     }

src/main/kotlin/kweb/html/events/EventGenerator.kt

@@ -0,0 +1,7 @@
+package kweb.html.events
+
+import java.util.*
+
+interface EventGenerator<T> {
+    fun addEventListener(eventName: String, returnEventFields: Set<String> = Collections.emptySet(), retrieveJs: String?, callback: (Any) -> Unit): T
+}

src/main/kotlin/kweb/html/events/KeyboardEvents.kt

@@ -0,0 +1,8 @@
+package kweb.html.events
+
+import kweb.dom.element.events.ONReceiver
+
+interface KeyboardEvents
+
+fun <ON, T> ON.keypress(callback: (event: ONReceiver.KeyboardEvent) -> Unit) where ON: NewOnReceiver<T>, T: KeyboardEvents =
+    event("keypress", eventType = ONReceiver.KeyboardEvent::class, callback = callback)

src/main/kotlin/kweb/html/events/MouseEvents.kt

@@ -0,0 +1,8 @@
+package kweb.html.events
+
+import kweb.dom.element.events.ONReceiver
+
+interface MouseEvents
+
+fun <ON, T> ON.click(callback: (event: ONReceiver.MouseEvent) -> Unit) where ON: NewOnReceiver<T>, T: KeyboardEvents =
+        event("click", eventType = ONReceiver.MouseEvent::class, callback = callback)

src/main/kotlin/kweb/html/events/NewOnReceiver.kt

@@ -0,0 +1,39 @@
+package kweb.html.events
+
+import com.github.salomonbrys.kotson.fromJson
+import kweb.dom.element.events.ONReceiver
+import kweb.gson
+import mu.KotlinLogging
+import java.util.concurrent.ConcurrentHashMap
+import kotlin.reflect.KClass
+import kotlin.reflect.full.memberProperties
+
+class NewOnReceiver<T : EventGenerator<T>>(private val source: T, private val retrieveJs: String? = null) {
+
+    val logger = KotlinLogging.logger {}
+
+    fun event(eventName: String, returnEventFields: Set<String> = emptySet(), callback: (event: String) -> Unit): T {
+        source.addEventListener(eventName, returnEventFields = returnEventFields, callback = { callback(it.toString()) }, retrieveJs = retrieveJs)
+        return source
+    }
+
+    inline fun <reified U : Any> event(eventName: String, eventType: KClass<U>, crossinline callback: (event: U) -> Unit): T {
+        // TODO: Should probably cache this rather than do the reflection every time
+        val eventPropertyNames = memberProperties(eventType)
+        return event(eventName, eventPropertyNames) { propertiesAsString ->
+            val props: U = gson.fromJson(propertiesAsString)
+            try {
+                callback(props)
+            } catch (e: Exception) {
+                logger.error(e) { "Exception thrown by callback in response to $eventName event" }
+            }
+        }
+    }
+
+    companion object {
+        val memberPropertiesCache: ConcurrentHashMap<KClass<*>, Set<String>> = ConcurrentHashMap()
+        inline fun <reified T : Any> memberProperties(clazz: KClass<T>) =
+                memberPropertiesCache.get(clazz)
+                        ?: T::class.memberProperties.map { it.name }.toSet().also { memberPropertiesCache.put(clazz, it) }
+    }
+}