websub: Detect MAINTENANCE mode and show useful message. (#380)

Author: microbit-carlos

js/partial-flashing.js

@@ -180,8 +180,17 @@ class DAPWrapper {
     }
 
     allocBoardInfo() {
+        if (!this.device) {
+            throw new Error('Could not obtain device info.');
+        }
+        // Check if the micro:bit is connected in MAINTENANCE mode (DAPLink bootloader)
+        if (this.device.deviceClass == "0") {
+            // This message is intercepted by python-main.js/webusbErrorHandler()
+            // so ensure changes are reflected there as well
+            throw new Error('device-bootloader');
+        }
         // The micro:bit board ID is the serial number first 4 hex digits
-        if (!(this.device && this.device.serialNumber)) {
+        if (!this.device.serialNumber) {
             throw new Error('Could not detected ID from connected board.');
         }
         this.boardId = this.device.serialNumber.substring(0,4);

js/python-main.js

@@ -1085,7 +1085,10 @@ function web_editor(config) {
     }
 
     function showDisconnectError(event) {
-        var error = {"name": "device-disconnected", "message": config["translate"]["webusb"]["err"]["device-disconnected"]};
+        var error = {
+            "name": "device-disconnected",
+            "message": config["translate"]["webusb"]["err"]["device-disconnected"]
+        };
         document.dispatchEvent(new CustomEvent('webusb', { 'detail': {
             'flash-type': usePartialFlashing ? 'partial-flash' : 'full-flash',
             'event-type': 'info',
@@ -1158,23 +1161,38 @@ function web_editor(config) {
                 }
 
                 // Determine error type
+                // TODO: Checking for strings provided by DAPJs is brittle, we
+                // should add some kind of tests to ensure these still exist
                 if (err.message === "No valid interfaces found.") {
+                    // Generated by DAPJs?
                     errorTitle = config["translate"]["webusb"]['err']['update-req-title'];
                     errorType = 'update-req';
                     err.message = ''
                     errorDescription = config["translate"]["webusb"]["err"][errorType];
                 } else if (err.message === "Unable to claim interface.") {
+                    // Generated by DAPJs?
                     errorType = "clear-connect";
                     errorTitle = err.message;
                     errorDescription = config["translate"]["webusb"]["err"][errorType];
                 } else if (err.name === "device-disconnected") {
-                    // If the device has been disconnected we don't show an error modal any more
-                    // the editor UI should be already updated and in "not connected" mode
+                    // Generated by the editor when the browser WebUSB connection
+                    // triggers a disconnected event.
+                    // In this case we don't show an error modal any more, the
+                    // editor UI should be already updated and in "not connected" mode
                     return;
                 } else if (err.name === "timeout-error") {
+                    // From time outs triggered in the editor to ensure we don't get stuck
                     errorType = "timeout-error";
-                    errorTitle = "Connection Timed Out";
+                    errorTitle = config["translate"]["webusb"]["err"]["timeout-error-title"];
                     errorDescription = config["translate"]["webusb"]["err"]["reconnect-microbit"];
+                } else if (err.message === 'device-bootloader') {
+                    // Triggered from partial-flashing.js when micro:bit is in MAINTENANCE mode
+                    errorType = 'reconnect-microbit';
+                    errorTitle = config['translate']['webusb']['err']['device-bootloader-title'];
+                    errorDescription = config['translate']['webusb']['err']['device-bootloader'];
+                    // Add URL to the description
+                    errorDescription += ' <a href="https://support.microbit.org/support/solutions/articles/19000082598-maintenance-mode" target="_blank">';
+                    errorDescription += 'https://support.microbit.org/support/articles/19000082598</a>'
                 } else {
                     // Unhandled error. User will need to reconnect their micro:bit
                     errorType = "reconnect-microbit";

lang/en.js

@@ -74,7 +74,10 @@ var LANGUAGE = {
       'reconnect-microbit': 'Please reconnect your micro:bit and try again.',
       'partial-flashing-disable': 'If the errors persist, try disabling Quick Flash in the beta options.',
       'device-disconnected': 'Device disconnected.',
+      'device-bootloader': 'Please unplug the micro:bit and connect it again without pressing the reset button.<br>More info:',
+      'device-bootloader-title': 'micro:bit in MAINTENANCE mode',
       'timeout-error': 'Unable to connect to the micro:bit',
+      'timeout-error-title': 'Connection Timed Out',
       'unavailable': 'With WebUSB you can program your micro:bit and connect to the serial console directly from the online editor.<br/>Unfortunately, WebUSB is not supported in this browser. We recommend Chrome, or a Chrome-based browser to use WebUSB.',
       'find-more': 'Find Out More'
     },