more tweaking to server consent flow and changing servers on preview

css/main.css

@@ -179,6 +179,11 @@ input[type='text'].large {
     box-sizing: border-box;
 }
 
+.OpenLinkView .previewSource {
+    color: var(--grey);
+    font-size: 12px;
+}
+
 .ServerConsentView .actions {
     margin-top: 24px;
     display: flex;

src/Link.js

@@ -15,6 +15,7 @@ limitations under the License.
 */
 
 import {createEnum} from "./utils/enum.js";
+import {orderedUnique} from "./utils/unique.js";
 
 const ROOMALIAS_PATTERN = /^#([^:]*):(.+)$/;
 const ROOMID_PATTERN = /^!([^:]*):(.+)$/;
@@ -56,16 +57,6 @@ export const LinkKind = createEnum(
 	"Event"
 )
 
-function orderedUnique(array) {
-	const copy = [];
-	for (let i = 0; i < array.length; ++i) {
-		if (i === 0 || array.lastIndexOf(array[i], i - 1) === -1) {
-			copy.push(array[i]);
-		}
-	}
-	return copy;
-}
-
 export class Link {
 	static parse(fragment) {
 		if (!fragment) {

src/Preferences.js

@@ -15,9 +15,11 @@ limitations under the License.
 */
 
 import {Platform} from "./Platform.js";
+import {EventEmitter} from "./utils/ViewModel.js";
 
-export class Preferences {
+export class Preferences extends EventEmitter {
 	constructor(localStorage) {
+        super();
 		this._localStorage = localStorage;
 		this.clientId = null;
 		// used to differentiate web from native if a client supports both
@@ -41,11 +43,15 @@ export class Preferences {
 		platform = Platform[platform];
 		this.platform = platform;
 		this._localStorage.setItem("preferred_client", JSON.stringify({id, platform}));
+        this.emit("canClear")
 	}
 
-	setHomeservers(homeservers) {
+	setHomeservers(homeservers, persist) {
         this.homeservers = homeservers;
-        this._localStorage.setItem("consented_servers", JSON.stringify(homeservers));
+        if (persist) {
+            this._localStorage.setItem("consented_servers", JSON.stringify(homeservers));
+            this.emit("canClear");
+        }
 	}
 
 	clear() {

src/RootViewModel.js

@@ -29,6 +29,9 @@ export class RootViewModel extends ViewModel {
 		this.openLinkViewModel = null;
 		this.createLinkViewModel = null;
         this.loadServerPolicyViewModel = null;
+        this.preferences.on("canClear", () => {
+            this.emitChange();
+        });
 	}
 
 	_updateChildVMs(oldLink) {
@@ -37,7 +40,7 @@ export class RootViewModel extends ViewModel {
 			if (!oldLink || !oldLink.equals(this.link)) {
 				this.openLinkViewModel = new OpenLinkViewModel(this.childOptions({
 					link: this.link,
-					clients: createClients()
+					clients: createClients(),
 				}));
 			}
 		} else {

src/open/OpenLinkView.js

@@ -39,7 +39,11 @@ class ShowLinkView extends TemplateView {
                 onClick: () => vm.showClients()
             }, vm => vm.showClientsLabel)),
             t.mapView(vm => vm.clientsViewModel, childVM => childVM ? new ClientListView(childVM) : null),
-            t.p({className: {hidden: vm => !vm.previewDomain}}, ["Preview provided by ", vm => vm.previewDomain]),
+            t.p({className: {previewSource: true, hidden: vm => !vm.previewDomain}}, [
+                vm => vm.previewFailed ? `${vm.previewDomain} did not return a preview.` : `Preview provided by ${vm.previewDomain}.`,
+                " ",
+                t.button({className: "text", onClick: () => vm.changeServer()}, "Change"),
+            ]),
         ]);
     }
 }

src/open/OpenLinkViewModel.js

@@ -32,18 +32,22 @@ export class OpenLinkViewModel extends ViewModel {
         this.clientsViewModel = null;
 		this.previewLoading = false;
         if (this.preferences.homeservers === null) {
-            this.serverConsentViewModel = new ServerConsentViewModel(this.childOptions({
-                servers: this._link.servers,
-                done: () => {
-                    this.serverConsentViewModel = null;
-                    this._showLink();
-                }
-            }));
+            this._showServerConsent();
         } else {
             this._showLink();
         }
 	}
 
+    _showServerConsent() {
+        this.serverConsentViewModel = new ServerConsentViewModel(this.childOptions({
+            servers: this._link.servers,
+            done: () => {
+                this.serverConsentViewModel = null;
+                this._showLink();
+            }
+        }));
+    }
+
     async _showLink() {
         const preferredClient = this.preferences.clientId ? this._clients.find(c => c.id === this.preferences.clientId) : null;
         this.clientsViewModel = preferredClient ? new ClientListViewModel(this.childOptions({
@@ -63,13 +67,24 @@ export class OpenLinkViewModel extends ViewModel {
     }
 
 	get previewDomain() {
-		return this.previewViewModel.previewDomain;
+		return this.previewViewModel?.domain;
 	}
 
+    get previewFailed() {
+        return this.previewViewModel?.failed;
+    }
+
 	get showClientsLabel() {
 		return getLabelForLinkKind(this._link.kind);
 	}
 
+    changeServer() {
+        this.previewViewModel = null;
+        this.clientsViewModel = null;
+        this._showServerConsent();
+        this.emitChange();
+    }
+
 	showClients() {
 		if (!this.clientsViewModel) {
 			this.clientsViewModel = new ClientListViewModel(this.childOptions({

src/open/ServerConsentView.js

@@ -50,7 +50,7 @@ export class ServerConsentView extends TemplateView {
             t.form({action: "#", onSubmit: evt => this._onSubmit(evt)}, [
                 t.mapView(vm => vm.showSelectServer, show => show ? new ServerOptions(vm) : null),
                 t.div({className: "actions"}, [
-                    t.label([t.input({type: "checkbox", name: "persist"}), "Ask every time"]),
+                    t.label([t.input({type: "checkbox", name: "askEveryTime"}), "Ask every time"]),
                     t.input({type: "submit", value: "Continue", className: "primary fullwidth"})
                 ])
             ])
@@ -59,7 +59,8 @@ export class ServerConsentView extends TemplateView {
 
     _onSubmit(evt) {
         evt.preventDefault();
-        this.value.continueWithSelection();
+        const {askEveryTime} = evt.target.elements;
+        this.value.continueWithSelection(askEveryTime.checked);
     }
 }
 

src/open/ServerConsentViewModel.js

@@ -19,6 +19,7 @@ import {ClientListViewModel} from "./ClientListViewModel.js";
 import {ClientViewModel} from "./ClientViewModel.js";
 import {PreviewViewModel} from "../preview/PreviewViewModel.js";
 import {getLabelForLinkKind} from "../Link.js";
+import {orderedUnique} from "../utils/unique.js";
 
 export class ServerConsentViewModel extends ViewModel {
 	constructor(options) {
@@ -47,7 +48,7 @@ export class ServerConsentViewModel extends ViewModel {
         try {
             const domain = new URL(urlStr).hostname;
             if (/((?:[0-9a-zA-Z][0-9a-zA-Z-]{1,61}\.)+)(xn--[a-z0-9]+|[a-z]+)/.test(domain) || domain === "localhost") {
-                this.selectServer(urlStr);
+                this.selectServer(domainOrUrl);
                 return true;
             }
         } catch (err) {}
@@ -55,11 +56,11 @@ export class ServerConsentViewModel extends ViewModel {
         return false;
     }
 
-    continueWithSelection() {
+    continueWithSelection(askEveryTime) {
         // keep previously consented servers
         const homeservers = this.preferences.homeservers || [];
         homeservers.unshift(this.selectedServer);
-        this.preferences.setHomeservers(homeservers);
+        this.preferences.setHomeservers(orderedUnique(homeservers), !askEveryTime);
         this.done();
     }
 

src/preview/PreviewViewModel.js

@@ -32,13 +32,13 @@ export class PreviewViewModel extends ViewModel {
 		this.identifier = null;
 		this.memberCount = null;
 		this.topic = null;
-		this.previewDomain = null;
+		this.domain = null;
+        this.failed = false;
 	}
 
 	async load() {
 		this.loading = true;
 		this.emitChange();
-        // await new Promise(r => setTimeout(r, 5000));
 		for (const server of this._consentedServers) {
 			try {
 				const homeserver = await resolveServer(this.request, server);
@@ -51,7 +51,7 @@ export class PreviewViewModel extends ViewModel {
 						break;
 				}
 				// assume we're done if nothing threw
-				this.previewDomain = server;
+				this.domain = server;
                 this.loading = false;
         		this.emitChange();
                 return;
@@ -59,8 +59,13 @@ export class PreviewViewModel extends ViewModel {
 				continue;
 			}
 		}
+
 		this._setNoPreview(this._link);
         this.loading = false;
+        if (this._consentedServers.length) {
+            this.domain = this._consentedServers[this._consentedServers.length - 1];
+            this.failed = true;
+        }
         this.emitChange();
 	}
 

src/utils/ViewModel.js

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-class EventEmitter {
+export class EventEmitter {
     constructor() {
         this._handlersByName = {};
     }

src/utils/unique.js

@@ -0,0 +1,25 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export function orderedUnique(array) {
+    const copy = [];
+    for (let i = 0; i < array.length; ++i) {
+        if (i === 0 || array.lastIndexOf(array[i], i - 1) === -1) {
+            copy.push(array[i]);
+        }
+    }
+    return copy;
+}