From 099e625e0149fb2a6c5b06f0ad0ddaf9678e1b89 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Dietrich?= <andredietrich@web.de>
Date: Thu, 7 Sep 2023 19:23:23 +0200
Subject: [PATCH] Add initial websocket support

---
 client/components/Modules.vue | 69 +++++++++++++++++++++++-----
 server/data_web.ts            | 85 +++++++++++++++++++++++++++++++++++
 2 files changed, 144 insertions(+), 10 deletions(-)

diff --git a/client/components/Modules.vue b/client/components/Modules.vue
index 794c683..c677ed3 100644
--- a/client/components/Modules.vue
+++ b/client/components/Modules.vue
@@ -38,7 +38,7 @@ export default {
   name: "Modules",
   props: ["role", "username", "liveClassProxy"],
   data() {
-    return {};
+    return { ws: null };
   },
   computed: {
     roomName() {
@@ -93,16 +93,65 @@ export default {
       }
     },
     async sendMessage(subject, body, module_url) {
-      if (body !== undefined)
-        await this.$axios.$post(
-          "/data/sendMessage/" + this.$store.state.class_.id,
-          {
-            from: this.username /* Email if teacher, name if station */,
-            subject: subject,
-            body: body,
-            module: module_url,
-          }
+      if (this.ws === null) {
+        const self = this;
+        const socket = new WebSocket(
+          "ws://localhost:8000/data/wss/" +
+            this.$store.state.class_.id +
+            "/" +
+            this.username
         );
+
+        socket.onopen = function (e) {
+          console.warn("[open] Connection established");
+          self.sendMessage(subject, body, module_url);
+        };
+
+        const iframes = document.getElementsByTagName("iframe");
+
+        socket.onmessage = function (event) {
+          const data = JSON.parse(event.data);
+          data["event"] = "message";
+
+          for (let i = 0; i < iframes.length; i++) {
+            iframes[i].contentWindow.postMessage(data, "*");
+          }
+        };
+
+        socket.onclose = function (event) {
+          if (event.wasClean) {
+            console.warn(
+              `[close] Connection closed cleanly, code=${event.code} reason=${event.reason}`
+            );
+          } else {
+            console.warn("[close] Connection died");
+          }
+        };
+
+        socket.onerror = function (error) {
+          console.warn("error =>", error);
+        };
+
+        this.ws = socket;
+      }
+
+      if (body !== undefined) {
+        const data = {
+          from: this.username /* Email if teacher, name if station */,
+          subject: subject,
+          body: body,
+          module: module_url,
+        };
+
+        if (this.ws) {
+          this.ws.send(JSON.stringify(data));
+        } else {
+          await this.$axios.$post(
+            "/data/sendMessage/" + this.$store.state.class_.id,
+            data
+          );
+        }
+      }
     },
   },
 };
diff --git a/server/data_web.ts b/server/data_web.ts
index 85dab53..d89b730 100644
--- a/server/data_web.ts
+++ b/server/data_web.ts
@@ -6,6 +6,7 @@ import * as env from './env.ts'
  * Main in-memory data storage for all current classes on this instance
  */
 const classes: data.LiveClasses = {}
+const ws: Record<string, oak.WebSocket> = {}
 
 export const router = new oak.Router()
   /**
@@ -496,6 +497,52 @@ export const router = new oak.Router()
 
     ctx.response.status = 200
   })
+
+  .get('/wss/:class_id/:from', async (ctx) => {
+    const class_id = ctx?.params?.class_id
+    const from = ctx?.params?.from
+
+    if (!ctx.isUpgradable) {
+      ctx.throw(501)
+    }
+
+    const user_role =
+      classes[class_id]?.users[ctx.state.user]?.role || data.RoleName.Student
+
+    if (from) {
+      const socket = ctx.upgrade()
+
+      socket.onopen = () => {}
+
+      socket.onmessage = (message) => {
+        message = JSON.parse(message.data)
+
+        if (
+          !class_id ||
+          !data.validate_message(message, user_role)
+          //data.validate_email(message.from) ||
+          //(!data.validate_email(message.from) && user_role == 'student')
+        ) {
+          return
+        }
+
+        broadcastMessage(class_id, message)
+      }
+
+      socket.onclose = () => {
+        console.log('Disconnected from client')
+        ws[from] = undefined
+      }
+
+      socket.onerror = (e) => {
+        console.log('Error from client', e)
+        ws[from] = undefined
+      }
+
+      ws[from] = socket
+    }
+  })
+
   /**
    * Broadcast message within a class room
    * @param message JSON formatted: {from, subject, body}
@@ -606,3 +653,41 @@ function sendMessage(class_id: string, message: data.LiveMessage): boolean {
 
   return true
 }
+
+/**
+ * Broadcast message within a class
+ * @param class_id Only this class will be updated
+ * @param message Message to broadcase
+ * @returns Success
+ */
+function broadcastMessage(class_id: string, message: data.LiveMessage) {
+  const live_class = classes[class_id]
+
+  if (!live_class) return false
+
+  /*
+  const info = JSON.stringify(message)
+
+  log.debug(
+    `Message to be sent (${class_id}) => ${
+      info.length > 100 ? `${info.slice(0, 100)}...` : info
+    }`
+  )
+  */
+
+  /* Don't send message if not in room in class */
+  const user_from = live_class.users[message.from]
+
+  if (!user_from) return true
+
+  /* Send message to users within the target room */
+  const user_conns_in_room = Object.entries(classes[class_id]?.users || [])
+    .filter((u) => u[1].room == user_from.room)
+    .flatMap((u) => u[0])
+
+  for (const user_id of user_conns_in_room) {
+    if (user_id !== message.from) {
+      ws[user_id].send(JSON.stringify(message))
+    }
+  }
+}