chore(EventSource): drop no longer needed legacy fallback

core/src/OC/eventsource.js

@@ -20,88 +20,31 @@ function OCEventSource(src, data) {
 	let joinChar
 	this.typelessListeners = []
 	this.closed = false
-	this.listeners = {}
 	if (data) {
 		for (name in data) {
 			dataStr += name + '=' + encodeURIComponent(data[name]) + '&'
 		}
 	}
 	dataStr += 'requesttoken=' + encodeURIComponent(getRequestToken())
-	if (!this.useFallBack && typeof EventSource !== 'undefined') {
-		joinChar = '&'
-		if (src.indexOf('?') === -1) {
-			joinChar = '?'
-		}
-		this.source = new EventSource(src + joinChar + dataStr)
-		this.source.onmessage = function(e) {
-			for (let i = 0; i < this.typelessListeners.length; i++) {
-				this.typelessListeners[i](JSON.parse(e.data))
-			}
-		}.bind(this)
-	} else {
-		const iframeId = 'oc_eventsource_iframe_' + OCEventSource.iframeCount
-		OCEventSource.fallBackSources[OCEventSource.iframeCount] = this
-		const iframe = document.createElement('iframe')
-		iframe.id = iframeId
-		iframe.style.display = 'none'
-
-		joinChar = '&'
-		if (src.indexOf('?') === -1) {
-			joinChar = '?'
-		}
-		iframe.src = src + joinChar + 'fallback=true&fallback_id=' + OCEventSource.iframeCount + '&' + dataStr
-
-		this.iframe = iframe
-		document.body.appendChild(this.iframe)
-		this.useFallBack = true
-		OCEventSource.iframeCount++
+	joinChar = '&'
+	if (src.indexOf('?') === -1) {
+		joinChar = '?'
 	}
+	this.source = new EventSource(src + joinChar + dataStr)
+	this.source.onmessage = function(e) {
+		for (let i = 0; i < this.typelessListeners.length; i++) {
+			this.typelessListeners[i](JSON.parse(e.data))
+		}
+	}.bind(this)
 	// add close listener
 	this.listen('__internal__', function(data) {
 		if (data === 'close') {
 			this.close()
 		}
 	}.bind(this))
 }
-OCEventSource.fallBackSources = []
-OCEventSource.iframeCount = 0// number of fallback iframes
-OCEventSource.fallBackCallBack = function(id, type, data) {
-	OCEventSource.fallBackSources[id].fallBackCallBack(type, data)
-}
 OCEventSource.prototype = {
 	typelessListeners: [],
-	iframe: null,
-	listeners: {}, // only for fallback
-	useFallBack: false,
-	/**
-	 * Fallback callback for browsers that don't have the
-	 * native EventSource object.
-	 *
-	 * Calls the registered listeners.
-	 *
-	 * @private
-	 * @param {string} type event type
-	 * @param {object} data received data
-	 */
-	fallBackCallBack: function(type, data) {
-		let i
-		// ignore messages that might appear after closing
-		if (this.closed) {
-			return
-		}
-		if (type) {
-			if (typeof this.listeners.done !== 'undefined') {
-				for (i = 0; i < this.listeners[type].length; i++) {
-					this.listeners[type][i](data)
-				}
-			}
-		} else {
-			for (i = 0; i < this.typelessListeners.length; i++) {
-				this.typelessListeners[i](data)
-			}
-		}
-	},
-	lastLength: 0, // for fallback
 	/**
 	 * Listen to a given type of events.
 	 *
@@ -111,20 +54,13 @@ OCEventSource.prototype = {
 	listen: function(type, callback) {
 		if (callback && callback.call) {
 			if (type) {
-				if (this.useFallBack) {
-					if (!this.listeners[type]) {
-						this.listeners[type] = []
+				this.source.addEventListener(type, function(e) {
+					if (typeof e.data !== 'undefined') {
+						callback(JSON.parse(e.data))
+					} else {
+						callback('')
 					}
-					this.listeners[type].push(callback)
-				} else {
-					this.source.addEventListener(type, function(e) {
-						if (typeof e.data !== 'undefined') {
-							callback(JSON.parse(e.data))
-						} else {
-							callback('')
-						}
-					}, false)
-				}
+				}, false)
 			} else {
 				this.typelessListeners.push(callback)
 			}
@@ -135,9 +71,7 @@ OCEventSource.prototype = {
 	 */
 	close: function() {
 		this.closed = true
-		if (typeof this.source !== 'undefined') {
-			this.source.close()
-		}
+		this.source.close()
 	},
 }
 

lib/private/EventSource.php

@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 /**
- * SPDX-FileCopyrightText: 2020-2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-FileCopyrightText: 2020-2026 Nextcloud GmbH and Nextcloud contributors
  * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
  * SPDX-License-Identifier: AGPL-3.0-only
  */
@@ -12,8 +12,6 @@
 use OCP\IRequest;
 
 class EventSource implements IEventSource {
-	private bool $fallback = false;
-	private int $fallBackId = 0;
 	private bool $started = false;
 
 	public function __construct(
@@ -31,25 +29,7 @@ protected function init(): void {
 		\OC_Util::obEnd();
 		header('Cache-Control: no-cache');
 		header('X-Accel-Buffering: no');
-		$this->fallback = isset($_GET['fallback']) && $_GET['fallback'] == 'true';
-		if ($this->fallback) {
-			$this->fallBackId = (int)$_GET['fallback_id'];
-			/**
-			 * FIXME: The default content-security-policy of ownCloud forbids inline
-			 * JavaScript for security reasons. IE starting on Windows 10 will
-			 * however also obey the CSP which will break the event source fallback.
-			 *
-			 * As a workaround thus we set a custom policy which allows the execution
-			 * of inline JavaScript.
-			 *
-			 * @link https://github.com/owncloud/core/issues/14286
-			 */
-			header("Content-Security-Policy: default-src 'none'; script-src 'unsafe-inline'");
-			header('Content-Type: text/html');
-			echo str_repeat('<span></span>' . PHP_EOL, 10); //dummy data to keep IE happy
-		} else {
-			header('Content-Type: text/event-stream');
-		}
+		header('Content-Type: text/event-stream');
 		if (!$this->request->passesStrictCookieCheck()) {
 			header('Location: ' . \OC::$WEBROOT);
 			exit();
@@ -63,16 +43,10 @@ protected function init(): void {
 	}
 
 	/**
-	 * send a message to the client
-	 *
-	 * @param string $type
-	 * @param mixed $data
-	 *
 	 * @throws \BadMethodCallException
-	 *                                 if only one parameter is given, a typeless message will be send with that parameter as data
 	 * @suppress PhanDeprecatedFunction
 	 */
-	public function send($type, $data = null) {
+	public function send(string $type, mixed $data = null): void {
 		if ($data && !preg_match('/^[A-Za-z0-9_]+$/', $type)) {
 			throw new \BadMethodCallException('Type needs to be alphanumeric (' . $type . ')');
 		}
@@ -81,24 +55,15 @@ public function send($type, $data = null) {
 			$data = $type;
 			$type = null;
 		}
-		if ($this->fallback) {
-			$response = '<script type="text/javascript">window.parent.OC.EventSource.fallBackCallBack('
-				. $this->fallBackId . ',"' . ($type ?? '') . '",' . json_encode($data, JSON_HEX_TAG) . ')</script>' . PHP_EOL;
-			echo $response;
-		} else {
-			if ($type) {
-				echo 'event: ' . $type . PHP_EOL;
-			}
-			echo 'data: ' . json_encode($data, JSON_HEX_TAG) . PHP_EOL;
+		if ($type) {
+			echo 'event: ' . $type . PHP_EOL;
 		}
+		echo 'data: ' . json_encode($data, JSON_HEX_TAG) . PHP_EOL;
 		echo PHP_EOL;
 		flush();
 	}
 
-	/**
-	 * close the connection of the event source
-	 */
-	public function close() {
+	public function close(): void {
 		$this->send('__internal__', 'close'); //server side closing can be an issue, let the client do it
 	}
 }

lib/public/IEventSource.php

@@ -1,5 +1,6 @@
 <?php
 
+declare(strict_types=1);
 /**
  * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
  * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
@@ -8,31 +9,31 @@
 namespace OCP;
 
 /**
- * wrapper for server side events (http://en.wikipedia.org/wiki/Server-sent_events)
- * includes a fallback for older browsers and IE
+ * Wrapper for Server-Sent Events (SSE).
  *
- * use server side events with caution, to many open requests can hang the server
+ * Use SSE with caution: too many concurrent open requests can overload or stall the server.
  *
- * The event source will initialize the connection to the client when the first data is sent
+ * The connection is opened lazily when the first event is sent.
+ *
+ * @see https://developer.mozilla.org/docs/Web/API/Server-sent_events
  * @since 8.0.0
  */
 interface IEventSource {
 	/**
-	 * send a message to the client
+	 * Sends an event to the client.
 	 *
-	 * @param string $type One of success, notice, error, failure and done. Used in core/js/update.js
-	 * @param mixed $data
-	 * @return void
+	 * @param string $type Event type/name.
+	 * @param mixed $data Event payload.
 	 *
-	 * if only one parameter is given, a typeless message will be send with that parameter as data
+	 * If only one argument is provided, it is sent as a typeless payload (legacy behavior).
 	 * @since 8.0.0
 	 */
-	public function send($type, $data = null);
+	public function send(string $type, mixed $data = null): void;
 
 	/**
-	 * close the connection of the event source
-	 * @return void
+	 * Closes the SSE connection.
+	 *
 	 * @since 8.0.0
 	 */
-	public function close();
+	public function close(): void;
 }