Persist and maintain identity server in account data

Fixes https://github.com/vector-im/riot-web/issues/10094

MSC: https://github.com/matrix-org/matrix-doc/pull/2230

src/components/structures/MatrixChat.js

@@ -446,6 +446,29 @@ export default React.createClass({
         }
 
         switch (payload.action) {
+            case 'MatrixActions.accountData':
+                // XXX: This is a collection of several hacks to solve a minor problem. We want to
+                // update our local state when the ID server changes, but don't want to put that in
+                // the js-sdk as we'd be then dictating how all consumers need to behave. However,
+                // this component is already bloated and we probably don't want this tiny logic in
+                // here, but there's no better place in the react-sdk for it. Additionally, we're
+                // abusing the MatrixActionCreator stuff to avoid errors on dispatches.
+                if (payload.event_type === 'm.identity_server') {
+                    const fullUrl = payload.event_content ? payload.event_content['base_url'] : null;
+                    if (!fullUrl) {
+                        MatrixClientPeg.get().setIdentityServerUrl(null);
+                        localStorage.removeItem("mx_is_access_token");
+                        localStorage.removeItem("mx_is_url");
+                    } else {
+                        MatrixClientPeg.get().setIdentityServerUrl(fullUrl);
+                        localStorage.removeItem("mx_is_access_token"); // clear token
+                        localStorage.setItem("mx_is_url", fullUrl); // XXX: Do we still need this?
+                    }
+
+                    // redispatch the change with a more specific action
+                    dis.dispatch({action: 'id_server_changed'});
+                }
+                break;
             case 'logout':
                 Lifecycle.logout();
                 break;

src/components/views/settings/SetIdServer.js

@@ -106,6 +106,31 @@ export default class SetIdServer extends React.Component {
         };
     }
 
+    componentDidMount(): void {
+        this.dispatcherRef = dis.register(this.onAction);
+    }
+
+    componentWillUnmount(): void {
+        dis.unregister(this.dispatcherRef);
+    }
+
+    onAction = (payload) => {
+        // We react to changes in the ID server in the event the user is staring at this form
+        // when changing their identity server on another device. If the user is trying to change
+        // it in two places, we'll end up stomping all over their input, but at that point we
+        // should question our UX which led to them doing that.
+        if (payload.action !== "id_server_changed") return;
+
+        const fullUrl = MatrixClientPeg.get().getIdentityServerUrl();
+        let abbr = '';
+        if (fullUrl) abbr = abbreviateUrl(fullUrl);
+
+        this.setState({
+            currentClientIdServer: fullUrl,
+            idServer: abbr,
+        });
+    };
+
     _onIdentityServerChanged = (ev) => {
         const u = ev.target.value;
 
@@ -131,10 +156,10 @@ export default class SetIdServer extends React.Component {
     };
 
     _continueTerms = (fullUrl) => {
-        MatrixClientPeg.get().setIdentityServerUrl(fullUrl);
-        localStorage.removeItem("mx_is_access_token");
-        localStorage.setItem("mx_is_url", fullUrl);
-        dis.dispatch({action: 'id_server_changed'});
+        // Account data change will update localstorage, client, etc through dispatcher
+        MatrixClientPeg.get().setAccountData("m.identity_server", {
+            base_url: fullUrl,
+        });
         this.setState({idServer: '', busy: false, error: null});
     };
 
@@ -237,9 +262,10 @@ export default class SetIdServer extends React.Component {
     };
 
     _disconnectIdServer = () => {
-        MatrixClientPeg.get().setIdentityServerUrl(null);
-        localStorage.removeItem("mx_is_access_token");
-        localStorage.removeItem("mx_is_url");
+        // Account data change will update localstorage, client, etc through dispatcher
+        MatrixClientPeg.get().setAccountData("m.identity_server", {
+            base_url: null, // clear
+        });
 
         let newFieldVal = '';
         if (SdkConfig.get()['validated_server_config']['isUrl']) {