Adds room name validation logic for web.

doc/debian/jitsi-meet/jitsi-meet.example

     ssl_certificate_key /etc/jitsi/meet/jitsi-meet.example.com.key;
 
     root /usr/share/jitsi-meet;
+    ssi on;
     index index.html index.htm;
     error_page 404 /static/404.html;
 
-    location /config.js {
+    location = /config.js {
         alias /etc/jitsi/meet/jitsi-meet.example.com-config.js;
     }
 
-    location /external_api.js {
+    location = /external_api.js {
         alias /usr/share/jitsi-meet/libs/external_api.min.js;
     }
 
-    location ~ ^/([a-zA-Z0-9=\?]+)$ {
-        rewrite ^/(.*)$ / break;
-    }
-
-    location / {
-        ssi on;
+    #ensure all static content can always be found first
+    location ~ ^/(libs|css|static|images|fonts|lang|sounds|connection_optimization|.well-known)/(.*)$
+    {
+        add_header 'Access-Control-Allow-Origin' '*';
+        alias /usr/share/jitsi-meet/$1/$2;
     }
 
     # BOSH
-    location /http-bind {
+    location = /http-bind {
         proxy_pass      http://localhost:5280/http-bind;
         proxy_set_header X-Forwarded-For $remote_addr;
         proxy_set_header Host $http_host;
     }
+
+    location ~ ^/([^?&:’“]+)$ {
+        try_files $uri @root_path;
+    }
+
+    location @root_path {
+        rewrite ^/(.*)$ / break;
+    }
 }

lang/main.json

         "connectCalendarButton": "Connect your calendar",
         "connectCalendarText": "Connect your calendar to view all your meetings in {{app}}. Plus, add {{provider}} meetings to your calendar and start them with one click.",
         "enterRoomTitle": "Start a new meeting",
-        "onlyAsciiAllowed": "Meeting name should only contain latin characters and numbers.",
+        "roomNameAllowedChars": "Meeting name should not contain any of these characters: ?, &, :, ', \", %, #.",
         "go": "GO",
         "join": "JOIN",
         "info": "Info",

react/features/welcome/components/WelcomePage.web.js

 import { AbstractWelcomePage, _mapStateToProps } from './AbstractWelcomePage';
 import Tabs from './Tabs';
 
+/**
+ * The pattern used to validate room name.
+ * @type {string}
+ */
+export const ROOM_NAME_VALIDATE_PATTERN_STR = '^[^?&:\u0022\u0027%#]+$';
+
 /**
  * The Web container rendering the welcome page.
  *
          */
         this._additionalContentRef = null;
 
+        this._roomInputRef = null;
+
         /**
          * The HTML Element used as the container for additional toolbar content. Used
          * for directly appending the additional content template to the dom.
         this._onRoomChange = this._onRoomChange.bind(this);
         this._setAdditionalContentRef
             = this._setAdditionalContentRef.bind(this);
+        this._setRoomInputRef = this._setRoomInputRef.bind(this);
         this._setAdditionalToolbarContentRef
             = this._setAdditionalToolbarContentRef.bind(this);
         this._onTabSelected = this._onTabSelected.bind(this);
                                     className = 'enter-room-input'
                                     id = 'enter_room_field'
                                     onChange = { this._onRoomChange }
-                                    pattern = '^[a-zA-Z0-9=\?]+$'
+                                    pattern = { ROOM_NAME_VALIDATE_PATTERN_STR }
                                     placeholder = { this.state.roomPlaceholder }
-                                    title = { t('welcomepage.onlyAsciiAllowed') }
+                                    ref = { this._setRoomInputRef }
+                                    title = { t('welcomepage.roomNameAllowedChars') }
                                     type = 'text'
                                     value = { this.state.room } />
                             </form>
                         <div
                             className = 'welcome-page-button'
                             id = 'enter_room_button'
-                            onClick = { this._onJoin }>
+                            onClick = { this._onFormSubmit }>
                             { t('welcomepage.go') }
                         </div>
                     </div>
     _onFormSubmit(event) {
         event.preventDefault();
 
-        this._onJoin();
+        if (!this._roomInputRef || this._roomInputRef.reportValidity()) {
+            this._onJoin();
+        }
     }
 
     /**
         this._additionalToolbarContentRef = el;
     }
 
+    /**
+     * Sets the internal reference to the HTMLInputElement used to hold the
+     * welcome page input room element.
+     *
+     * @param {HTMLInputElement} el - The HTMLElement for the input of the room name on the welcome page.
+     * @private
+     * @returns {void}
+     */
+    _setRoomInputRef(el) {
+        this._roomInputRef = el;
+    }
+
     /**
      * Returns whether or not additional content should be displayed below
      * the welcome page's header for entering a room name.