From 3cfd550b58f05bcdfcbe2369e1afd7d5dab8189d Mon Sep 17 00:00:00 2001
From: Dani Palou <dani@moodle.com>
Date: Fri, 15 Nov 2024 12:50:13 +0100
Subject: [PATCH 1/2] MOBILE-4693 error: Also display accordion for debug info
 in error modals

---
 src/addons/mod/forum/pages/search/search.ts   |  6 +--
 src/core/classes/errors/error.ts              | 14 ++++-
 src/core/classes/errors/siteerror.ts          | 11 ++--
 src/core/features/login/pages/site/site.ts    |  8 +--
 .../features/login/services/login-helper.ts   | 10 ++--
 .../pages/global-search/global-search.ts      |  6 +--
 src/core/services/error-accordion.ts          | 12 ++---
 src/core/services/error-helper.ts             | 36 ++++++++++++-
 src/core/services/sites.ts                    |  7 ++-
 src/core/services/utils/dom.ts                | 52 +++++++------------
 10 files changed, 95 insertions(+), 67 deletions(-)

diff --git a/src/addons/mod/forum/pages/search/search.ts b/src/addons/mod/forum/pages/search/search.ts
index ddf2e48c5..d95f78a12 100644
--- a/src/addons/mod/forum/pages/search/search.ts
+++ b/src/addons/mod/forum/pages/search/search.ts
@@ -38,7 +38,7 @@ import { CorePromiseUtils } from '@singletons/promise-utils';
 })
 export class AddonModForumSearchPage implements OnInit {
 
-    loadMoreError: string | null = null;
+    loadMoreError = false;
     searchBanner: string | null = null;
     resultsSource = new CoreSearchGlobalSearchResultsSource('', {});
     forum?: AddonModForumData;
@@ -128,7 +128,7 @@ export class AddonModForumSearchPage implements OnInit {
      * Clear search results.
      */
     clearSearch(): void {
-        this.loadMoreError = null;
+        this.loadMoreError = false;
 
         this.resultsSource.setQuery('');
         this.resultsSource.reset();
@@ -152,7 +152,7 @@ export class AddonModForumSearchPage implements OnInit {
         try {
             await this.resultsSource?.load();
         } catch (error) {
-            this.loadMoreError = CoreDomUtils.getErrorMessage(error);
+            this.loadMoreError = true;
         } finally {
             complete();
         }
diff --git a/src/core/classes/errors/error.ts b/src/core/classes/errors/error.ts
index cccd985ba..44ed1a7d2 100644
--- a/src/core/classes/errors/error.ts
+++ b/src/core/classes/errors/error.ts
@@ -24,14 +24,26 @@ import { CoreErrorObject } from '@services/error-helper';
  */
 export class CoreError extends Error {
 
-    constructor(message?: string) {
+    debug?: CoreErrorDebug;
+
+    constructor(message?: string, debug?: CoreErrorDebug) {
         super(message);
 
         // Fix prototype chain: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-2.html#support-for-newtarget
         this.name = new.target.name;
         Object.setPrototypeOf(this, new.target.prototype);
+
+        this.debug = debug;
     }
 
 }
 
+/**
+ * Debug information of the error.
+ */
+export type CoreErrorDebug = {
+    code?: string; // Technical error code useful for technical assistance.
+    details: string; // Technical error details useful for technical assistance.
+};
+
 export type CoreAnyError = string | CoreError | CoreErrorObject | null | undefined;
diff --git a/src/core/classes/errors/siteerror.ts b/src/core/classes/errors/siteerror.ts
index 9e1f2f569..62dffed76 100644
--- a/src/core/classes/errors/siteerror.ts
+++ b/src/core/classes/errors/siteerror.ts
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import { CoreError } from '@classes/errors/error';
+import { CoreError, CoreErrorDebug } from '@classes/errors/error';
 import { CoreUserSupportConfig } from '@features/user/classes/support/support-config';
 
 /**
@@ -20,7 +20,7 @@ import { CoreUserSupportConfig } from '@features/user/classes/support/support-co
  */
 export class CoreSiteError extends CoreError {
 
-    debug?: CoreSiteErrorDebug;
+    debug?: CoreErrorDebug;
     supportConfig?: CoreUserSupportConfig;
 
     constructor(options: CoreSiteErrorOptions) {
@@ -43,16 +43,11 @@ export class CoreSiteError extends CoreError {
 
 }
 
-export type CoreSiteErrorDebug = {
-    code: string; // Technical error code useful for technical assistance.
-    details: string; // Technical error details useful for technical assistance.
-};
-
 export type CoreSiteErrorOptions = {
     message: string;
 
     // Debugging information.
-    debug?: CoreSiteErrorDebug;
+    debug?: CoreErrorDebug;
 
     // Configuration to use to contact site support. If this attribute is present, it means
     // that the error warrants contacting support.
diff --git a/src/core/features/login/pages/site/site.ts b/src/core/features/login/pages/site/site.ts
index 02d9cb4b5..02df4ee1d 100644
--- a/src/core/features/login/pages/site/site.ts
+++ b/src/core/features/login/pages/site/site.ts
@@ -25,7 +25,7 @@ import {
     CoreLoginSiteFinderSettings,
     CoreLoginSiteSelectorListMethod,
 } from '@features/login/services/login-helper';
-import { CoreError } from '@classes/errors/error';
+import { CoreError, CoreErrorDebug } from '@classes/errors/error';
 import { CoreConstants } from '@/core/constants';
 import { Translate } from '@singletons';
 import { CoreUrl, CoreUrlPartNames } from '@singletons/url';
@@ -34,7 +34,7 @@ import { CoreCustomURLSchemes, CoreCustomURLSchemesHandleError } from '@services
 import { CoreErrorHelper } from '@services/error-helper';
 import { CoreForms } from '@singletons/form';
 import { AlertButton } from '@ionic/core';
-import { CoreSiteError, CoreSiteErrorDebug } from '@classes/errors/siteerror';
+import { CoreSiteError } from '@classes/errors/siteerror';
 import { CoreUserSupport } from '@features/user/services/support';
 import { CoreErrorAccordion } from '@services/error-accordion';
 import { CoreUserSupportConfig } from '@features/user/classes/support/support-config';
@@ -419,7 +419,7 @@ export class CoreLoginSitePage implements OnInit {
      */
     protected async showLoginIssue(url: string, error: CoreError): Promise<void> {
         let errorMessage = CoreDomUtils.getErrorMessage(error);
-        let debug: CoreSiteErrorDebug | undefined;
+        let debug: CoreErrorDebug | undefined;
         let errorTitle: string | undefined;
         let site: CoreUnauthenticatedSite | undefined;
         let supportConfig: CoreUserSupportConfig | undefined;
@@ -480,7 +480,7 @@ export class CoreLoginSitePage implements OnInit {
             const containerElement = alertElement.querySelector('.core-error-accordion-container');
 
             if (containerElement) {
-                await CoreErrorAccordion.render(containerElement, debug.code, debug.details);
+                await CoreErrorAccordion.render(containerElement, debug.details, debug.code);
             }
         }
     }
diff --git a/src/core/features/login/services/login-helper.ts b/src/core/features/login/services/login-helper.ts
index 5b148bdd2..9be527c82 100644
--- a/src/core/features/login/services/login-helper.ts
+++ b/src/core/features/login/services/login-helper.ts
@@ -26,7 +26,7 @@ import { CoreText } from '@singletons/text';
 import { CoreObject } from '@singletons/object';
 import { CoreConstants } from '@/core/constants';
 import { CoreSite } from '@classes/sites/site';
-import { CoreError } from '@classes/errors/error';
+import { CoreError, CoreErrorDebug } from '@classes/errors/error';
 import { CoreWSError } from '@classes/errors/wserror';
 import { DomSanitizer, makeSingleton, Translate } from '@singletons';
 import { CoreLogger } from '@singletons/logger';
@@ -57,7 +57,7 @@ import {
     IDENTITY_PROVIDER_FEATURE_NAME_PREFIX,
 } from '../constants';
 import { LazyRoutesModule } from '@/app/app-routing.module';
-import { CoreSiteError, CoreSiteErrorDebug } from '@classes/errors/siteerror';
+import { CoreSiteError } from '@classes/errors/siteerror';
 import { CoreQRScan } from '@services/qrscan';
 import { CoreLoadings } from '@services/loadings';
 import { CoreErrorHelper } from '@services/error-helper';
@@ -949,7 +949,7 @@ export class CoreLoginHelperProvider {
      * @param site Site instance.
      * @param debug Error debug information.
      */
-    async showAppUnsupportedModal(siteUrl: string, site?: CoreUnauthenticatedSite, debug?: CoreSiteErrorDebug): Promise<void> {
+    async showAppUnsupportedModal(siteUrl: string, site?: CoreUnauthenticatedSite, debug?: CoreErrorDebug): Promise<void> {
         const siteName = await site?.getSiteName() ?? siteUrl;
 
         await CoreDomUtils.showAlertWithOptions({
@@ -974,7 +974,7 @@ export class CoreLoginHelperProvider {
      * @param siteUrl Site url.
      * @param debug Error debug information.
      */
-    async openInBrowserFallback(siteUrl: string, debug?: CoreSiteErrorDebug): Promise<void> {
+    async openInBrowserFallback(siteUrl: string, debug?: CoreErrorDebug): Promise<void> {
         CoreEvents.trigger(APP_UNSUPPORTED_CHURN, { siteUrl, debug });
 
         await CoreOpener.openInBrowser(siteUrl, { showBrowserWarning: false });
@@ -1677,7 +1677,7 @@ declare module '@singletons/events' {
      */
     export interface CoreEventsData {
         [ALWAYS_SHOW_LOGIN_FORM_CHANGED]: { value: number };
-        [APP_UNSUPPORTED_CHURN]: { siteUrl: string; debug?: CoreSiteErrorDebug };
+        [APP_UNSUPPORTED_CHURN]: { siteUrl: string; debug?: CoreErrorDebug };
     }
 
 }
diff --git a/src/core/features/search/pages/global-search/global-search.ts b/src/core/features/search/pages/global-search/global-search.ts
index 9e7091f8c..69f3205e9 100644
--- a/src/core/features/search/pages/global-search/global-search.ts
+++ b/src/core/features/search/pages/global-search/global-search.ts
@@ -39,7 +39,7 @@ import { CorePromiseUtils } from '@singletons/promise-utils';
 export class CoreSearchGlobalSearchPage implements OnInit, OnDestroy, AfterViewInit {
 
     courseId: number | null = null;
-    loadMoreError: string | null = null;
+    loadMoreError = false;
     searchBanner: string | null = null;
     resultsSource = new CoreSearchGlobalSearchResultsSource('', {});
     private filtersObserver?: CoreEventObserver;
@@ -128,7 +128,7 @@ export class CoreSearchGlobalSearchPage implements OnInit, OnDestroy, AfterViewI
      * Clear search results.
      */
     clearSearch(): void {
-        this.loadMoreError = null;
+        this.loadMoreError = false;
 
         this.resultsSource.setQuery('');
         this.resultsSource.reset();
@@ -172,7 +172,7 @@ export class CoreSearchGlobalSearchPage implements OnInit, OnDestroy, AfterViewI
         try {
             await this.resultsSource?.load();
         } catch (error) {
-            this.loadMoreError = CoreDomUtils.getErrorMessage(error);
+            this.loadMoreError = true;
         } finally {
             complete();
         }
diff --git a/src/core/services/error-accordion.ts b/src/core/services/error-accordion.ts
index b87a46aba..6394422e9 100644
--- a/src/core/services/error-accordion.ts
+++ b/src/core/services/error-accordion.ts
@@ -38,11 +38,11 @@ export class CoreErrorAccordionService {
      * Render an instance of the component into an HTML string.
      *
      * @param element Root element.
-     * @param errorCode Error code.
      * @param errorDetails Error details.
+     * @param errorCode Error code.
      */
-    async render(element: Element, errorCode: string, errorDetails: string): Promise<void> {
-        const html = this.html(errorCode, errorDetails);
+    async render(element: Element, errorDetails: string, errorCode?: string): Promise<void> {
+        const html = this.html(errorDetails, errorCode);
 
         element.innerHTML = html;
 
@@ -56,15 +56,15 @@ export class CoreErrorAccordionService {
      * @param errorDetails Error details.
      * @returns HTML.
      */
-    private html(errorCode: string, errorDetails: string): string {
+    private html(errorDetails: string, errorCode?: string): string {
         const contentId = CoreForms.uniqueId('error-accordion-content');
-        const errorCodeLabel = Translate.instant('core.errorcode', { errorCode });
+        const errorCodeLabel = errorCode ? Translate.instant('core.errorcode', { errorCode }) : undefined;
         const hideDetailsLabel = Translate.instant('core.errordetailshide');
         const showDetailsLabel = Translate.instant('core.errordetailsshow');
 
         return `
             <div class="core-error-accordion">
-                <h3 class="core-error-accordion--code">${errorCodeLabel}</h3>
+                ${errorCodeLabel ? `<h3 class="core-error-accordion--code">${errorCodeLabel}</h3>` : ''}
                 <div id="${contentId}" class="core-error-accordion--details" role="region" aria-hidden="true">
                     <p>${errorDetails}</p>
                 </div>
diff --git a/src/core/services/error-helper.ts b/src/core/services/error-helper.ts
index 3d82a7672..8de5307b3 100644
--- a/src/core/services/error-helper.ts
+++ b/src/core/services/error-helper.ts
@@ -13,10 +13,11 @@
 // limitations under the License.
 
 import { Injectable } from '@angular/core';
-import { CoreAnyError, CoreError } from '@classes/errors/error';
+import { CoreAnyError, CoreError, CoreErrorDebug } from '@classes/errors/error';
 import { makeSingleton, Translate } from '@singletons';
 import { AlertButton } from '@ionic/angular';
 import { CoreWSError } from '@classes/errors/wserror';
+import { CoreText } from '@singletons/text';
 
 /**
  * Provider to provide some helper functions regarding files and packages.
@@ -130,6 +131,39 @@ export class CoreErrorHelperService {
         return builtMessage;
     }
 
+    /**
+     * Get the debug info from an error object.
+     *
+     * @param error Error.
+     * @returns Error debug info, undefined if not found.
+     */
+    getDebugInfoFromError(error?: CoreAnyError): CoreErrorDebug | undefined {
+        if (!error || typeof error === 'string') {
+            return;
+        }
+
+        if ('debug' in error) {
+            return error.debug;
+        }
+
+        // Escape the HTML of debug info so it is displayed as it is in the view.
+        const debugMessages: string[] = [];
+        if ('debuginfo' in error && error.debuginfo) {
+            debugMessages.push(CoreText.escapeHTML(error.debuginfo, false));
+        }
+        if ('backtrace' in error && error.backtrace) {
+            debugMessages.push(CoreText.replaceNewLines(
+                CoreText.escapeHTML(error.backtrace, false),
+                '<br>',
+            ));
+        }
+
+        const debugMessage = debugMessages.join('<br><br>');
+        if (debugMessage) {
+            return { details: debugMessage };
+        }
+    }
+
     /**
      * Get the error message from an error object.
      *
diff --git a/src/core/services/sites.ts b/src/core/services/sites.ts
index b402491b3..0a6d676d5 100644
--- a/src/core/services/sites.ts
+++ b/src/core/services/sites.ts
@@ -27,7 +27,7 @@ import {
     CoreSiteConfig,
 } from '@classes/sites/site';
 import { SQLiteDB, SQLiteDBRecordValues, SQLiteDBTableSchema } from '@classes/sqlitedb';
-import { CoreError } from '@classes/errors/error';
+import { CoreError, CoreErrorDebug } from '@classes/errors/error';
 import { CoreLoginError, CoreLoginErrorOptions } from '@classes/errors/loginerror';
 import { makeSingleton, Translate, Http } from '@singletons';
 import { CoreLogger } from '@singletons/logger';
@@ -64,7 +64,6 @@ import { CoreSiteInfo, CoreSiteInfoResponse, CoreSitePublicConfigResponse } from
 import { CoreSiteWSPreSets } from '@classes/sites/authenticated-site';
 import { firstValueFrom } from 'rxjs';
 import { CoreHTMLClasses } from '@singletons/html-classes';
-import { CoreSiteErrorDebug } from '@classes/errors/siteerror';
 import { CoreErrorHelper } from './error-helper';
 import { CoreQueueRunner } from '@classes/queue-runner';
 import { CoreAppDB } from './app-db';
@@ -459,7 +458,7 @@ export class CoreSitesProvider {
             critical: true,
             title: Translate.instant('core.cannotconnect'),
             message: Translate.instant('core.siteunavailablehelp', { site: siteUrl }),
-            supportConfig: error.supportConfig,
+            supportConfig: 'supportConfig' in error ? error.supportConfig : undefined,
             debug: error.debug,
         };
 
@@ -688,7 +687,7 @@ export class CoreSitesProvider {
      * @returns A promise rejected with the error info.
      */
     protected async treatInvalidAppVersion(result: number, siteId?: string): Promise<never> {
-        let debug: CoreSiteErrorDebug | undefined;
+        let debug: CoreErrorDebug | undefined;
         let errorKey: string | undefined;
         let translateParams = {};
 
diff --git a/src/core/services/utils/dom.ts b/src/core/services/utils/dom.ts
index 2881e40c6..bf759aa79 100644
--- a/src/core/services/utils/dom.ts
+++ b/src/core/services/utils/dom.ts
@@ -449,17 +449,6 @@ export class CoreDomUtilsProvider {
 
         if (typeof error === 'object') {
             if (this.debugDisplay) {
-                // Get the debug info. Escape the HTML so it is displayed as it is in the view.
-                if ('debuginfo' in error && error.debuginfo) {
-                    extraInfo = '<br><br>' + CoreText.escapeHTML(error.debuginfo, false);
-                }
-                if ('backtrace' in error && error.backtrace) {
-                    extraInfo += '<br><br>' + CoreText.replaceNewLines(
-                        CoreText.escapeHTML(error.backtrace, false),
-                        '<br>',
-                    );
-                }
-
                 // eslint-disable-next-line no-console
                 console.error(error);
             }
@@ -1061,36 +1050,35 @@ export class CoreDomUtilsProvider {
 
         if (typeof error !== 'string' && 'buttons' in error && typeof error.buttons !== 'undefined') {
             alertOptions.buttons = error.buttons;
-        } else if (error instanceof CoreSiteError) {
-            if (error.debug) {
-                alertOptions.message = `<p>${alertOptions.message}</p><div class="core-error-accordion-container"></div>`;
-            }
-
-            const supportConfig = error.supportConfig;
-
-            alertOptions.buttons = [Translate.instant('core.ok')];
-
-            if (supportConfig?.canContactSupport()) {
-                alertOptions.buttons.push({
-                    text: Translate.instant('core.contactsupport'),
-                    handler: () => CoreUserSupport.contact({
-                        supportConfig,
-                        subject: alertOptions.header,
-                        message: `${error.debug?.code}\n\n${error.debug?.details}`,
-                    }),
-                });
-            }
         } else {
             alertOptions.buttons = [Translate.instant('core.ok')];
         }
 
+        // For site errors, always show debug info.
+        const showDebugInfo = this.debugDisplay || error instanceof CoreSiteError;
+        const debugInfo = showDebugInfo && CoreErrorHelper.getDebugInfoFromError(error);
+        if (debugInfo) {
+            alertOptions.message = `<p>${message}</p><div class="core-error-accordion-container"></div>`;
+        }
+
+        if (error instanceof CoreSiteError && error.supportConfig?.canContactSupport()) {
+            alertOptions.buttons.push({
+                text: Translate.instant('core.contactsupport'),
+                handler: () => CoreUserSupport.contact({
+                    supportConfig: error.supportConfig,
+                    subject: alertOptions.header,
+                    message: `${error.debug?.code}\n\n${error.debug?.details}`,
+                }),
+            });
+        }
+
         const alertElement = await this.showAlertWithOptions(alertOptions, autocloseTime);
 
-        if (error instanceof CoreSiteError && error.debug) {
+        if (debugInfo) {
             const containerElement = alertElement.querySelector('.core-error-accordion-container');
 
             if (containerElement) {
-                await CoreErrorAccordion.render(containerElement, error.debug.code, error.debug.details);
+                await CoreErrorAccordion.render(containerElement, debugInfo.details, debugInfo.code);
             }
         }
 

From c14646b7e2ff9292f1bfc01790ee483636d89c0b Mon Sep 17 00:00:00 2001
From: Dani Palou <dani@moodle.com>
Date: Mon, 18 Nov 2024 08:17:09 +0100
Subject: [PATCH 2/2] MOBILE-4693 core: Add more debugging to invalid site
 errors

---
 .../login/pages/credentials/credentials.ts    |  2 +-
 src/core/features/login/pages/site/site.ts    |  6 +-
 src/core/services/sites.ts                    |  8 ++-
 src/core/services/urlschemes.ts               | 55 +++++++++++++++----
 4 files changed, 55 insertions(+), 16 deletions(-)

diff --git a/src/core/features/login/pages/credentials/credentials.ts b/src/core/features/login/pages/credentials/credentials.ts
index b8638cab5..9ee00529a 100644
--- a/src/core/features/login/pages/credentials/credentials.ts
+++ b/src/core/features/login/pages/credentials/credentials.ts
@@ -181,7 +181,7 @@ export class CoreLoginCredentialsPage implements OnInit, OnDestroy {
 
         try {
             if (!this.siteCheck) {
-                this.siteCheck = await CoreSites.checkSite(this.site.siteUrl, protocol);
+                this.siteCheck = await CoreSites.checkSite(this.site.siteUrl, protocol, 'Credentials page');
                 this.siteCheck.config && this.site.setPublicConfig(this.siteCheck.config);
             }
 
diff --git a/src/core/features/login/pages/site/site.ts b/src/core/features/login/pages/site/site.ts
index 02df4ee1d..a454bd12e 100644
--- a/src/core/features/login/pages/site/site.ts
+++ b/src/core/features/login/pages/site/site.ts
@@ -333,14 +333,14 @@ export class CoreLoginSitePage implements OnInit {
             let checkResult: CoreSiteCheckResponse;
 
             try {
-                checkResult = await CoreSites.checkSite(url);
+                checkResult = await CoreSites.checkSite(url, undefined, 'Site URL page');
             } catch (error) {
                 // Attempt guessing the domain if the initial check failed
                 const domain = CoreUrl.guessMoodleDomain(url);
 
                 if (domain && domain != url) {
                     try {
-                        checkResult = await CoreSites.checkSite(domain);
+                        checkResult = await CoreSites.checkSite(domain, undefined, 'Site URL page');
                     } catch (secondError) {
                         // Try to use the first error.
                         modal.dismiss();
@@ -608,7 +608,7 @@ export class CoreLoginSitePage implements OnInit {
 
         try {
             // Check if site uses SSO.
-            const siteCheck = await CoreSites.checkSite(siteUrl);
+            const siteCheck = await CoreSites.checkSite(siteUrl, undefined, 'Site URL page');
 
             await CoreSites.checkApplication(siteCheck.config);
 
diff --git a/src/core/services/sites.ts b/src/core/services/sites.ts
index 0a6d676d5..1dfdd725e 100644
--- a/src/core/services/sites.ts
+++ b/src/core/services/sites.ts
@@ -286,14 +286,18 @@ export class CoreSitesProvider {
      *
      * @param siteUrl URL of the site to check.
      * @param protocol Protocol to use first.
+     * @param origin Origin of this check site call.
      * @returns A promise resolved when the site is checked.
      */
-    async checkSite(siteUrl: string, protocol: string = 'https://'): Promise<CoreSiteCheckResponse> {
+    async checkSite(siteUrl: string, protocol: string = 'https://', origin = 'unknown'): Promise<CoreSiteCheckResponse> {
         // The formatURL function adds the protocol if is missing.
         siteUrl = CoreUrl.formatURL(siteUrl);
 
         if (!CoreUrl.isHttpURL(siteUrl)) {
-            throw new CoreError(Translate.instant('core.login.invalidsite'));
+            throw new CoreError(Translate.instant('core.login.invalidsite'), {
+                code: 'invalidprotocol',
+                details: `URL contains an invalid protocol when checking site.<br><br>Origin: ${origin}.<br><br>URL: ${siteUrl}.`,
+            });
         }
 
         if (!CoreNetwork.isOnline()) {
diff --git a/src/core/services/urlschemes.ts b/src/core/services/urlschemes.ts
index f7131a788..65cd87bc4 100644
--- a/src/core/services/urlschemes.ts
+++ b/src/core/services/urlschemes.ts
@@ -44,6 +44,22 @@ export class CoreCustomURLSchemesProvider {
         this.logger = CoreLogger.getInstance('CoreCustomURLSchemesProvider');
     }
 
+    /**
+     * Create a CoreCustomURLSchemesHandleError to be used when treating a URL that doesn't have a valid scheme.
+     *
+     * @param url URL that caused the error.
+     * @param data Data obtained from the URL (if any).
+     * @returns Error.
+     */
+    protected createInvalidSchemeError(url: string, data?: CoreCustomURLSchemesParams): CoreCustomURLSchemesHandleError {
+        const defaultError = new CoreError(Translate.instant('core.login.invalidsite'), {
+            code: 'invalidurlscheme',
+            details: `Error when treating a URL scheme, it seems the URL is not valid.<br><br>URL: ${url}`,
+        });
+
+        return new CoreCustomURLSchemesHandleError(defaultError, data);
+    }
+
     /**
      * Given some data of a custom URL with a token, create a site if it needs to be created.
      *
@@ -62,7 +78,7 @@ export class CoreCustomURLSchemesProvider {
 
             if (!data.siteUrl.match(/^https?:\/\//)) {
                 // URL doesn't have a protocol and it's required to be able to create the site. Check which one to use.
-                const result = await CoreSites.checkSite(data.siteUrl);
+                const result = await CoreSites.checkSite(data.siteUrl, undefined, 'URL scheme create site');
 
                 data.siteUrl = result.siteUrl;
 
@@ -90,7 +106,13 @@ export class CoreCustomURLSchemesProvider {
      */
     async handleCustomURL(url: string): Promise<void> {
         if (!this.isCustomURL(url)) {
-            throw new CoreCustomURLSchemesHandleError(null);
+            throw this.createInvalidSchemeError(url);
+        }
+
+        // Check if there is nothing valid after the URL scheme.
+        const urlWithoutScheme = this.removeCustomURLScheme(url).trim();
+        if (!urlWithoutScheme || urlWithoutScheme.match(/^\/?(#.*)?\/?$/)) {
+            throw this.createInvalidSchemeError(url);
         }
 
         /* First check that this URL hasn't been treated a few seconds ago. The function that handles custom URL schemes already
@@ -202,7 +224,7 @@ export class CoreCustomURLSchemesProvider {
 
             } else {
                 // Site not stored. Try to add the site.
-                const result = await CoreSites.checkSite(data.siteUrl);
+                const result = await CoreSites.checkSite(data.siteUrl, undefined, `URL scheme redirect: ${url}`);
 
                 // Site exists. We'll allow to add it.
                 modal.dismiss(); // Dismiss modal so it doesn't collide with confirms.
@@ -211,7 +233,12 @@ export class CoreCustomURLSchemesProvider {
             }
 
         } catch (error) {
-            throw new CoreCustomURLSchemesHandleError(error, data);
+            if (!error || !CoreErrorHelper.getErrorMessageFromError(error)) {
+                // Use a default error.
+                this.createInvalidSchemeError(url, data);
+            } else {
+                throw new CoreCustomURLSchemesHandleError(error, data);
+            }
         } finally {
             modal.dismiss();
 
@@ -230,7 +257,7 @@ export class CoreCustomURLSchemesProvider {
      */
     protected async getCustomURLData(url: string): Promise<CoreCustomURLSchemesParams> {
         if (!this.isCustomURL(url)) {
-            throw new CoreCustomURLSchemesHandleError(null);
+            throw this.createInvalidSchemeError(url);
         }
 
         // App opened using custom URL scheme.
@@ -283,7 +310,7 @@ export class CoreCustomURLSchemesProvider {
      */
     protected async getCustomURLLinkData(url: string): Promise<CoreCustomURLSchemesParams> {
         if (!this.isCustomURLLink(url)) {
-            throw new CoreCustomURLSchemesHandleError(null);
+            throw this.createInvalidSchemeError(url);
         }
 
         // App opened using custom URL scheme.
@@ -345,7 +372,7 @@ export class CoreCustomURLSchemesProvider {
      */
     protected async getCustomURLTokenData(url: string): Promise<CoreCustomURLSchemesParams> {
         if (!this.isCustomURLToken(url)) {
-            throw new CoreCustomURLSchemesHandleError(null);
+            throw this.createInvalidSchemeError(url);
         }
 
         if (CoreSSO.isSSOAuthenticationOngoing()) {
@@ -358,6 +385,7 @@ export class CoreCustomURLSchemesProvider {
         this.logger.debug('App launched by URL with an SSO');
 
         // Delete the sso scheme from the URL.
+        const originalUrl = url;
         url = this.removeCustomURLTokenScheme(url);
 
         // Some platforms like Windows add a slash at the end. Remove it.
@@ -371,7 +399,11 @@ export class CoreCustomURLSchemesProvider {
             // Error decoding the parameter.
             this.logger.error('Error decoding parameter received for login SSO');
 
-            throw new CoreCustomURLSchemesHandleError(null);
+            throw new CoreCustomURLSchemesHandleError(new CoreError(Translate.instant('core.login.invalidsite'), {
+                code: 'errordecodingparameter',
+                details: `Error when trying to decode base 64 string.<br><br>URL: ${originalUrl}<br><br>Text to decode: ${url}` +
+                    `<br><br>Error: ${CoreErrorHelper.getErrorMessageFromError(err)}`,
+            }));
         }
 
         const data: CoreCustomURLSchemesParams = await CoreLoginHelper.validateBrowserSSOLogin(url);
@@ -491,14 +523,17 @@ export class CoreCustomURLSchemesProvider {
      * @param error Error data.
      */
     treatHandleCustomURLError(error: CoreCustomURLSchemesHandleError): void {
-        if (error.error == 'Duplicated') {
+        if (error.error === 'Duplicated') {
             // Duplicated request
         } else if (CoreWSError.isWebServiceError(error.error) && error.data && error.data.isSSOToken) {
             // An error occurred, display the error and logout the user.
             CoreLoginHelper.treatUserTokenError(error.data.siteUrl, <CoreWSError> error.error);
             CoreSites.logout();
         } else {
-            CoreDomUtils.showErrorModalDefault(error.error, Translate.instant('core.login.invalidsite'));
+            CoreDomUtils.showErrorModal(error.error ?? new CoreError(Translate.instant('core.login.invalidsite'), {
+                code: 'unknownerror',
+                details: 'Unknown error when treating a URL scheme.',
+            }));
         }
     }