Add support for resizing the lab window

Add an observer to the JavaScript code to detect lab size changes
on the LMS page and send the new dimensions to the guacamole client.

For RDP connections, implement the `resize-method` display setting
with both available options. (https://guacamole.apache.org/doc/1.5.5/gug/configuring-guacamole.html#rdp-display-settings)

Changelog.md

@@ -1,3 +1,11 @@
+Unreleased
+-------------------------
+* [Enhancement] Add the possibility to dynamically resize the lab on the 
+  LMS page. For RDP connections, implement the options provided by 
+  Apache Guacamole, to `display-update` or `reconnect` (the default), 
+  when the client display size changes. The given options are explained 
+  in more detail in the README.
+
 Version 8.2.0 (2025-01-03)
 -------------------------
 * [Enhancement] Add support for Apache Guacamole 1.5.5;

README.md

@@ -198,6 +198,15 @@ This is a brief explanation of each:
 * `enable_fullscreen`: An option to allow learners to launch a lab in fullsceen mode,
   in a separate browser window. (Default: `false`)
 
+* `lab_resize_method`: A [display setting](https://guacamole.apache.org/doc/1.5.5/gug/configuring-guacamole.html#rdp-display-settings) for RDP connections to update the RDP server
+  when the width and height of the client display changes. Possible values are:
+
+  * `display-update` *Only supported with Windows RDP 8.1 or xrdp 0.10.1 (and higher)*. 
+    Uses the "Display Update" channel to request the server to change the display size.
+
+  * `reconnect` (the default) Automatically disconnects the RDP session when the client 
+    display size has changed, and reconnects with the new size.
+
 * `lab_usage_limit`: Allocate limited time per user for labs across the platform,
   in seconds. (Default is `None`, meaning there is no time limit).
 

hastexo/common.py

@@ -185,7 +185,8 @@
     "providers": {},
     "guacamole_js_version": '1.5.5',
     "lab_usage_limit": None,
-    "lab_usage_limit_breach_policy": None
+    "lab_usage_limit_breach_policy": None,
+    "lab_resize_method": "reconnect"
 }
 
 SUPPORTED_LANGUAGES = [

hastexo/public/js/client.js

@@ -240,6 +240,10 @@ function HastexoGuacamoleClient(configuration) {
 
         onidle(pause) {
             return pause;
+        },
+
+        sendSize(height, width) {
+            guac_client.sendSize(height, width);
         }
     }
 

hastexo/public/js/main.js

@@ -90,6 +90,15 @@ function HastexoXBlock(runtime, element, configuration) {
         /* Show the terminal.  */
         $("#terminal").append(terminal_element);
 
+        // Observe the lab size in the browser and adjust when necessary
+        var lab = $('#terminal')[0];
+        const resizeObserver = new ResizeObserver(entries => {
+            for (const entry of entries) {
+                terminal_client.sendSize(entry.contentRect.width, entry.contentRect.height);
+            }
+        });
+        resizeObserver.observe(lab);
+
         /* Disconnect on tab close. */
         window.onunload = function() {
             terminal_client.disconnect();

hastexo_guacamole_client/consumers.py

@@ -38,6 +38,7 @@ async def connect(self):
             protocol=stack.protocol,
             width=params.get('width', [1024])[0],
             height=params.get('height', [768])[0],
+            resize_method=settings.get("lab_resize_method"),
             hostname=stack.ip,
             port=params.get('port', [default_port])[0],
             username=stack.user,