ui: Reimplement message monitor as web component, closes #128

ui/src/Main.elm

@@ -111,9 +111,6 @@ pageSubscriptions page =
         Mailbox subModel ->
             Sub.map MailboxMsg (Mailbox.subscriptions subModel)
 
-        Monitor subModel ->
-            Sub.map MonitorMsg (Monitor.subscriptions subModel)
-
         Status subModel ->
             Sub.map StatusMsg (Status.subscriptions subModel)
 
@@ -251,8 +248,7 @@ changeRouteTo route model =
     let
         session =
             getSession model
-
-        ( newModel, newCmd ) =
+    in
     case route of
         Route.Unknown path ->
             let
@@ -296,14 +292,6 @@ changeRouteTo route model =
         Route.Status ->
             Status.init session
                 |> updateWith Status StatusMsg model
-    in
-    case model.page of
-        Monitor _ ->
-            -- Leaving Monitor page, shut down the web socket.
-            ( newModel, Cmd.batch [ Ports.monitorCommand False, newCmd ] )
-
-        _ ->
-            ( newModel, newCmd )
 
 
 getSession : Model -> Session

ui/src/Page/Monitor.elm

@@ -1,4 +1,4 @@
-module Page.Monitor exposing (Model, Msg, init, subscriptions, update, view)
+module Page.Monitor exposing (Model, Msg, init, update, view)
 
 import Data.MessageHeader as MessageHeader exposing (MessageHeader)
 import Data.Session as Session exposing (Session)
@@ -7,7 +7,6 @@ import Html exposing (..)
 import Html.Attributes exposing (..)
 import Html.Events as Events
 import Json.Decode as D
-import Ports
 import Route
 import Time exposing (Posix)
 
@@ -23,34 +22,9 @@ type alias Model =
     }
 
 
-type MonitorMessage
-    = Connected Bool
-    | Message MessageHeader
-
-
 init : Session -> ( Model, Cmd Msg )
 init session =
-    ( Model session False []
-    , Ports.monitorCommand True
-    )
-
-
-
--- SUBSCRIPTIONS
-
-
-subscriptions : Model -> Sub Msg
-subscriptions model =
-    let
-        monitorMessage =
-            D.oneOf
-                [ D.map Message MessageHeader.decoder
-                , D.map Connected D.bool
-                ]
-                |> D.decodeValue
-                |> Ports.monitorMessage
-    in
-    Sub.map MessageReceived monitorMessage
+    ( Model session False [], Cmd.none )
 
 
 
@@ -58,23 +32,31 @@ subscriptions model =
 
 
 type Msg
-    = MessageReceived (Result D.Error MonitorMessage)
+    = Connected Bool
+    | MessageReceived D.Value
     | OpenMessage MessageHeader
 
 
 update : Msg -> Model -> ( Model, Cmd Msg )
 update msg model =
     case msg of
-        MessageReceived (Ok (Connected status)) ->
-            ( { model | connected = status }, Cmd.none )
+        Connected True ->
+            ( { model | connected = True, messages = [] }, Cmd.none )
 
-        MessageReceived (Ok (Message header)) ->
-            ( { model | messages = header :: model.messages }, Cmd.none )
+        Connected False ->
+            ( { model | connected = False }, Cmd.none )
 
-        MessageReceived (Err err) ->
+        MessageReceived value ->
+            case D.decodeValue (MessageHeader.decoder |> D.at [ "detail" ]) value of
+                Ok header ->
+                    ( { model | messages = header :: model.messages }
+                    , Cmd.none
+                    )
+
+                Err err ->
                     let
                         flash =
-                    { title = "Decoding failed"
+                            { title = "Message decoding failed"
                             , table = [ ( "Error", D.errorToString err ) ]
                             }
                     in
@@ -110,6 +92,11 @@ view model =
                     )
                 ]
             ]
+        , node "monitor-messages"
+            [ Events.on "connected" (D.map Connected <| D.at [ "detail" ] <| D.bool)
+            , Events.on "message" (D.map MessageReceived D.value)
+            ]
+            []
         , table [ class "monitor" ]
             [ thead []
                 [ th [] [ text "Date" ]
@@ -143,6 +130,8 @@ shortDate zone date =
         , DF.hourNumber
         , DF.text ":"
         , DF.minuteFixed
+        , DF.text ":"
+        , DF.secondFixed
         , DF.text " "
         , DF.amPmUppercase
         ]

ui/src/Ports.elm

@@ -1,19 +1,11 @@
 port module Ports exposing
-    ( monitorCommand
-    , monitorMessage
-    , onSessionChange
+    ( onSessionChange
     , storeSession
     )
 
 import Json.Encode exposing (Value)
 
 
-port monitorCommand : Bool -> Cmd msg
-
-
-port monitorMessage : (Value -> msg) -> Sub msg
-
-
 port onSessionChange : (Value -> msg) -> Sub msg
 
 

ui/src/index.js

@@ -1,7 +1,7 @@
 import './main.css'
 import '@fortawesome/fontawesome-free/css/all.css'
 import { Elm } from './Main.elm'
-import registerMonitorPorts from './registerMonitor'
+import './monitorMessages'
 import './renderedHtml'
 
 // Initial configuration from Inbucket server to Elm App.
@@ -16,9 +16,6 @@ var app = Elm.Main.init({
   flags: flags,
 })
 
-// Message monitor.
-registerMonitorPorts(app)
-
 // Session storage.
 app.ports.storeSession.subscribe(function (session) {
   localStorage.session = JSON.stringify(session)

ui/src/monitorMessages.js

@@ -0,0 +1,38 @@
+// monitor-messages connects to the Inbucket backend via WebSocket to monitor
+// incoming messages.
+customElements.define(
+  'monitor-messages',
+  class MonitorMessages extends HTMLElement {
+    constructor() {
+      const self = super()
+      // TODO make URI/URL configurable.
+      var uri = '/api/v1/monitor/messages'
+      self._url = ((window.location.protocol === 'https:') ? 'wss://' : 'ws://') + window.location.host + uri
+      self._socket = null
+    }
+
+    connectedCallback() {
+      const self = this
+      self._socket = new WebSocket(self._url)
+      var ws = self._socket
+      ws.addEventListener('open', function (e) {
+        self.dispatchEvent(new CustomEvent('connected', { detail: true }))
+      })
+      ws.addEventListener('close', function (e) {
+        self.dispatchEvent(new CustomEvent('connected', { detail: false }))
+      })
+      ws.addEventListener('message', function (e) {
+        self.dispatchEvent(new CustomEvent('message', {
+          detail: JSON.parse(e.data),
+        }))
+      })
+    }
+
+    disconnectedCallback() {
+      var ws = this._socket
+      if (ws) {
+        ws.close()
+      }
+    }
+  }
+)

ui/src/registerMonitor.js

@@ -1,46 +0,0 @@
-// Register the websocket listeners for the monitor API.
-export default function registerMonitorPorts(app) {
-  var uri = '/api/v1/monitor/messages'
-  var url = ((window.location.protocol === "https:") ? "wss://" : "ws://") + window.location.host + uri
-
-  // Current handler.
-  var handler = null
-
-  app.ports.monitorCommand.subscribe(function (cmd) {
-    if (handler != null) {
-      handler.down()
-      handler = null
-    }
-    if (cmd) {
-      // Command is up.
-      handler = websocketHandler(url, app.ports.monitorMessage)
-      handler.up()
-    }
-  })
-}
-
-// Creates a handler responsible for connecting, disconnecting from web socket.
-function websocketHandler(url, port) {
-  var ws = null
-
-  return {
-    up: () => {
-      ws = new WebSocket(url)
-
-      ws.addEventListener('open', function (e) {
-        port.send(true)
-      })
-      ws.addEventListener('close', function (e) {
-        port.send(false)
-      })
-      ws.addEventListener('message', function (e) {
-        var msg = JSON.parse(e.data)
-        port.send(msg)
-      })
-    },
-
-    down: () => {
-      ws.close()
-    }
-  }
-}