Integrierte Mehrsprachigkeit (Deutsch und Englisch) mit Cookie-basierter Sprachauswahl

2024-05-15 16:11:26 +02:00
parent cf9286e4c3
commit 68714c2937
32 changed files with 282 additions and 253 deletions
--- a/EnvelopeGenerator.Web/Controllers/HomeController.cs
+++ b/EnvelopeGenerator.Web/Controllers/HomeController.cs
@@ -11,10 +11,10 @@ using DigitalData.Core.API;
 using EnvelopeGenerator.Application;
 using Microsoft.Extensions.Localization;
 using DigitalData.Core.DTO;
-using EnvelopeGenerator.Application.Resources;
 using EnvelopeGenerator.Application.DTOs;
 using Microsoft.AspNetCore.Localization;
 using System.Text.Encodings.Web;
+using EnvelopeGenerator.Web.Models;

 namespace EnvelopeGenerator.Web.Controllers
 {
@@ -26,8 +26,9 @@ namespace EnvelopeGenerator.Web.Controllers
        private readonly IStringLocalizer<Resource> _localizer;
        private readonly IConfiguration _configuration;
        private readonly UrlEncoder _urlEncoder;
+        private readonly Cultures _cultures;

-        public HomeController(DatabaseService databaseService, EnvelopeOldService envelopeOldService, ILogger<HomeController> logger, IEnvelopeReceiverService envelopeReceiverService, IEnvelopeHistoryService historyService, IStringLocalizer<Resource> localizer, IConfiguration configuration, UrlEncoder urlEncoder) : base(databaseService, logger)
+        public HomeController(DatabaseService databaseService, EnvelopeOldService envelopeOldService, ILogger<HomeController> logger, IEnvelopeReceiverService envelopeReceiverService, IEnvelopeHistoryService historyService, IStringLocalizer<Resource> localizer, IConfiguration configuration, UrlEncoder urlEncoder, Cultures cultures) : base(databaseService, logger)
        {
            this.envelopeOldService = envelopeOldService;
            _envRcvService = envelopeReceiverService;
@@ -35,6 +36,7 @@ namespace EnvelopeGenerator.Web.Controllers
            _localizer = localizer;
            _configuration = configuration;
            _urlEncoder = urlEncoder;
+            _cultures = cultures;
        }
        
        [HttpGet("EnvelopeKey/{envelopeReceiverId}")]
@@ -68,7 +70,7 @@ namespace EnvelopeGenerator.Web.Controllers
            }
            catch(Exception ex)
            {
-                _logger.LogEnvelopeError(envelopeEeceiverId: envelopeReceiverId, exception:ex, message: _localizer[MessageKey.UnexpectedError]);
+                _logger.LogEnvelopeError(envelopeEeceiverId: envelopeReceiverId, exception:ex, message: _localizer[WebKey.UnexpectedError]);
                return this.ViewInnerServiceError();
            }
        }
@@ -79,7 +81,6 @@ namespace EnvelopeGenerator.Web.Controllers
            try
            {
                envelopeReceiverId = _urlEncoder.Encode(envelopeReceiverId);
-                ViewData["Languages"] = _configuration.GetSection("Languages").Get<string[]>()!;
                ViewData["UserLanguage"] = UserLanguage;

                return await _envRcvService.IsExisting(envelopeReceiverId: envelopeReceiverId).ThenAsync(
@@ -107,7 +108,7 @@ namespace EnvelopeGenerator.Web.Controllers

                if(uuid is null || signature is null)
                {
-                    _logger.LogEnvelopeError(uuid: uuid, signature: signature, message: _localizer[MessageKey.WrongEnvelopeReceiverId]);
+                    _logger.LogEnvelopeError(uuid: uuid, signature: signature, message: _localizer[WebKey.WrongEnvelopeReceiverId]);
                    return Unauthorized();
                }

@@ -229,50 +230,75 @@ namespace EnvelopeGenerator.Web.Controllers
        [NonAction]
        public IActionResult GetLanguage() => Ok(UserLanguage);

-        [HttpPost("lang")]
-        public IActionResult SetLanguage([FromForm] string language)
+        [HttpPost("lang/{language}")]
+        public IActionResult SetLanguage([FromRoute] string language)
        {
            try
            {
-                language = _urlEncoder.Encode(language);
-                var cookieOptions = new CookieOptions()
+                if (Languages is null)
                {
-                    Expires = DateTimeOffset.UtcNow.AddYears(1),
-                    Secure = false,
-                    Path = "/",
-                    SameSite = SameSiteMode.Strict,
-                    HttpOnly = true
-                };
+                    _logger.LogWarning("There is no language assigned under languages key in appesettings.json");
+                    return StatusCode(statusCode: StatusCodes.Status500InternalServerError);
+                }
+                else if (!language.Contains(language))
+                    return BadRequest();

-                Response.Cookies.Append(
-                    CookieRequestCultureProvider.DefaultCookieName,
-                    CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(language)),
-                    cookieOptions);
+                language = _urlEncoder.Encode(language);
+
+                UserLanguage = language;

                return Redirect(Request.Headers["Referer"].ToString());
            }
            catch(Exception ex)
            {
-                _logger.LogError(ex, ex.Message);
-                return this.ViewEnvelopeNotFound();
+                _logger.LogError(ex, "{Message}", ex.Message);
+                return StatusCode(statusCode: StatusCodes.Status500InternalServerError);
            }
        }

+        [HttpGet("lang")]
+        public IActionResult GetLanguages()
+        {
+            if(Languages is null)
+            {
+                _logger.LogWarning("There is no language assigned under languages key in appesettings.json");
+                return StatusCode(statusCode: StatusCodes.Status500InternalServerError);
+            }
+            else
+                return Ok(Languages);
+        }
+
        private string UserLanguage
        {
            get
            {
-                return Request.Cookies[CookieRequestCultureProvider.DefaultCookieName] ?? _configuration.GetSection("Languages").Get<string[]>()![0];
+                var cookieValue = Request.Cookies[CookieRequestCultureProvider.DefaultCookieName];
+
+                if (string.IsNullOrEmpty(cookieValue))
+                    return _cultures.Default.Language;       
+
+                var culture = CookieRequestCultureProvider.ParseCookieValue(cookieValue)?.Cultures[0];
+                return culture?.Value ?? _cultures.Default.Language;
            }
            set
            {
-                Response.Cookies.Append(CookieRequestCultureProvider.DefaultCookieName, CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(value)), new CookieOptions()
+                var cookieOptions = new CookieOptions()
                {
                    Expires = DateTimeOffset.UtcNow.AddYears(1),
-                });
+                    Secure = false,
+                    SameSite = SameSiteMode.Strict,
+                    HttpOnly = true
+                };
+
+                Response.Cookies.Append(
+                    CookieRequestCultureProvider.DefaultCookieName,
+                    CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(value)),
+                    cookieOptions);
            }
        }

+        private string[]? Languages => _configuration.GetSection("Languages").Get<string[]>();
+
        public IActionResult Error404() => this.ViewError404();
    }
 }
--- a/EnvelopeGenerator.Web/Controllers/Test/TestLocalizerController.cs
+++ b/EnvelopeGenerator.Web/Controllers/Test/TestLocalizerController.cs
@@ -1,5 +1,6 @@
-using EnvelopeGenerator.Application;
-using EnvelopeGenerator.Application.Resources;
+using AngleSharp.Common;
+using EnvelopeGenerator.Application;
+using EnvelopeGenerator.Web.Models;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Localization;

@@ -10,10 +11,21 @@ namespace EnvelopeGenerator.Web.Controllers.Test
    public class TestLocalizerController : ControllerBase
    {
        private readonly IStringLocalizer _localizer;
+        private readonly Cultures _cultures;

-        public TestLocalizerController(IStringLocalizer<Resource> localizer) => _localizer = localizer;
+        public TestLocalizerController(IStringLocalizer<Resource> localizer, Cultures cultures)
+        {
+            _localizer = localizer;
+            _cultures = cultures;
+        }

        [HttpGet]
-        public IActionResult Localize([FromQuery] string key = "Hello") => Ok(_localizer[key]);
+        public IActionResult Localize([FromQuery] string key = "de_DE") => Ok(_localizer[key]);
+
+        [HttpGet("fi-class")]
+        public IActionResult GetFIClass(string? lang = null) => lang is null ? Ok(_cultures.FIClasses) : Ok(_cultures.FIClassOf(lang));
+
+        [HttpGet("culture")]
+        public IActionResult GetCultures(string? lang = null) => lang is null ? Ok(_cultures) : Ok(_cultures.CultureOf(lang));
    }
 }
--- a/EnvelopeGenerator.Web/MessageKey.cs
+++ b/EnvelopeGenerator.Web/MessageKey.cs
@@ -1,12 +0,0 @@
-namespace EnvelopeGenerator.Web
-{
-    public static class MessageKey
-    {
-        public static readonly string ServiceOutputNullError = "ServiceOutputNullError";
-        public static readonly string UnexpectedError = "UnexpectedError";
-        public static readonly string FailedToSendAccessCode = "FailedToSendAccessCode";
-        public static readonly string WrongEnvelopeReceiverId = "WrongEnvelopeReceiverId";
-        public static readonly string DataIntegrityError = "DataIntegrityError";
-        public static readonly string NonDecodableEnvelopeReceiverId = "NonDecodableEnvelopeReceiverId";
-    }
-}
--- a/EnvelopeGenerator.Web/Models/Culture.cs
+++ b/EnvelopeGenerator.Web/Models/Culture.cs
@@ -0,0 +1,8 @@
+namespace EnvelopeGenerator.Web.Models
+{
+    public class Culture
+    {
+        public string Language { get; init; } = string.Empty;
+        public string FIClass { get; init; } = string.Empty;
+    }
+}
--- a/EnvelopeGenerator.Web/Models/Cultures.cs
+++ b/EnvelopeGenerator.Web/Models/Cultures.cs
@@ -0,0 +1,15 @@
+namespace EnvelopeGenerator.Web.Models
+{
+    public class Cultures : List<Culture>
+    {
+        public IEnumerable<string> Languages => this.Select(c => c.Language);
+
+        public IEnumerable<string> FIClasses => this.Select(c => c.FIClass);
+
+        public Culture? CultureOf(string? language) => language is null ? null : this.Where(c => c.Language == language).FirstOrDefault();
+
+        public Culture Default => this.First();
+
+        public string FIClassOf(string? language) => language is null ? string.Empty : CultureOf(language)?.FIClass ?? string.Empty;
+    }
+}
--- a/EnvelopeGenerator.Web/Program.cs
+++ b/EnvelopeGenerator.Web/Program.cs
@@ -16,7 +16,7 @@ using EnvelopeGenerator.Web.Models;
 using DigitalData.Core.DTO;
 using System.Text.Encodings.Web;
 using Ganss.Xss;
-using EnvelopeGenerator.Web;
+using Microsoft.Extensions.Options;

 var logger = LogManager.Setup().LoadConfigurationFromAppSettings().GetCurrentClassLogger();
 logger.Info("Logging initialized!");
@@ -156,8 +156,8 @@ try

    builder.Services.AddCookieConsentSettings();

-    builder.Services.AddCookieBasedLocalizer();
-
+    builder.Services.AddCookieBasedLocalizer("Resources");
+    
    builder.Services.AddSingleton(HtmlEncoder.Default);
    builder.Services.AddSingleton(UrlEncoder.Default);
    builder.Services.AddSingleton(_ =>
@@ -167,6 +167,10 @@ try
        return sanitizer;
    });

+    // Register the FlagIconCssClass instance as a singleton
+    builder.Services.Configure<Cultures>(builder.Configuration.GetSection("Cultures"));
+    builder.Services.AddSingleton(sp => sp.GetRequiredService<IOptions<Cultures>>().Value);
+
    var app = builder.Build();

    // Configure the HTTP request pipeline.
@@ -177,6 +181,14 @@ try
        app.UseHsts();
    }

+    //Content-Security-Policy
+    if (config.GetValue<bool>("TestCSP") || !app.Environment.IsDevelopment())
+    {
+        var csp_list = config.GetSection("Content-Security-Policy").Get<string[]>();
+        if (csp_list is not null)
+            app.UseCSPMiddleware($"{string.Join("; ", csp_list)};");
+    }
+
    if (config.GetValue<bool>("EnableSwagger"))
    {
        app.UseSwagger();
@@ -185,26 +197,33 @@ try

    app.UseHttpsRedirection();

-    var csp_list = config.GetSection("Content-Security-Policy").Get<string[]>();
-    if(csp_list is not null)
-        app.UseCSPMiddleware($"{string.Join("; ", csp_list)};");
-
    app.UseStaticFiles();

-    app.UseCookiePolicy();
+    //app.UseCookiePolicy();

    app.UseRouting();

    app.UseAuthentication();
    app.UseAuthorization();

-    var languages = config.GetSection("Languages").Get<string[]>() ??
-    throw new InvalidOperationException("Languages section is missing in the configuration.");
-    if(languages.Length == 0)
-        throw new InvalidOperationException("There is no languages in languages section.");
+    var cultures = app.Services.GetRequiredService<Cultures>();
+    if(cultures.Any())
+        throw new InvalidOperationException(@"Languages section is missing in the appsettings. Please configure like following.
+            Language is both a name of the culture and the name of the resx file such as Resource.de-DE.resx
+            FIClass is the css class (in wwwroot/lib/flag-icons-main) for the flag of country.
+            ""Cultures"": [
+            {
+                ""Language"": ""de-DE"",
+                ""FIClass"": ""fi-de""
+            },
+            {
+                ""Language"": ""en-US"",
+                ""FIClass"": ""fi-us""
+            }
+            ]");

    if(!config.GetValue<bool>("DisableMultiLanguage"))
-        app.UseCookieBasedLocalizer(languages);
+        app.UseCookieBasedLocalizer(cultures.Languages.ToArray());

    app.UseCors("SameOriginPolicy");

--- a/EnvelopeGenerator.Web/Views/Home/EnvelopeLocked.cshtml
+++ b/EnvelopeGenerator.Web/Views/Home/EnvelopeLocked.cshtml
@@ -4,7 +4,6 @@
@{
    ViewData["Title"] = "Dokument geschützt";
    var userLanguage = ViewData["UserLanguage"] as string;
-    var languages = ViewData["Languages"] as string[];
 }
 <div class="page container py-5 px-2">
    <header class="text-center">
@@ -14,72 +13,60 @@
                <path d="M9.5 6.5a1.5 1.5 0 0 1-1 1.415l.385 1.99a.5.5 0 0 1-.491.595h-.788a.5.5 0 0 1-.49-.595l.384-1.99a1.5 1.5 0 1 1 2-1.415" />
            </svg>
        </div>
-        <h1>Dokument erfordert einen Zugriffscode</h1>
+        <h1>@_localizer[WebKey.LockedTitle]</h1>
    </header>
    <section class="text-center">
-        <p>Wir haben Ihnen gerade den Zugriffscode an die hinterlegte Email Adresse gesendet. Dies kann evtl. einige Minuten dauern.</p>
+        <p>@_localizer[WebKey.LockedBody]</p>
    </section>
-    <div class="row m-0 p-0">
+    <div class="row m-0 p-0 justify-content-center">
        <div class="col-8">
            <form id="form-access-code" class="form ms-5" method="post">
                <div class="input">
-                    <label class="visually-hidden" for="access_code">Zugriffscode</label>
-                    <input type="password" id="access_code" class="form-control" name="access_code" placeholder="Zugriffscode" required="required">
+                    <label class="visually-hidden" for="access_code">@_localizer[WebKey.LockedTitle]</label>
+                    <input type="password" id="access_code" class="form-control" name="access_code" placeholder="@_localizer[WebKey.LockedAccessCode]" required="required">
                </div>
                <div class="button">
-                    <button type="submit" class="btn btn-primary">Öffnen</button>
+                    <button type="submit" class="btn btn-primary">@_localizer[WebKey.LocakedOpen]</button>
                </div>
            </form>
        </div>
-        <div class="col-4">
-            <form class="form ps-4" method="post" action="/lang">
-                <div class="dropdown dropdown-flag">
-                    <select class="form-select select-flag" name="language" onchange="this.form.submit()">
-                @if (languages is not null)
-                    foreach (var lang in languages)
-                    {
-                        <option class="select-option option-flag" value="@lang.TrySanitize(_sanitizer)">@_localizer[lang].Value.TrySanitize(_sanitizer)</option>
-                    }
-                    </select>
-                </div>
-            </form>
+        <div class="col-4 d-flex justify-content-center align-items-center">
+            <div class="dropdown">
+                <button class="btn btn-outline-secondary dropdown-toggle" type="button" id="langDropdownMenuButton" data-bs-toggle="dropdown" aria-expanded="false">
+                    <span class="fi @_cultures.FIClassOf(userLanguage).TrySanitize(_sanitizer) me-2" id="selectedFlag"></span><span id="selectedLanguage"></span>
+                </button>
+                <ul class="dropdown-menu" aria-labelledby="langDropdownMenuButton">
+                @foreach(var lang in _cultures.Languages)
+                {
+                    <li>
+                        <a class="dropdown-item" data-language="@lang.TrySanitize(_sanitizer)" data-flag="@_cultures.FIClassOf(lang).TrySanitize(_sanitizer)">
+                            <span class="fi @_cultures.FIClassOf(lang).TrySanitize(_sanitizer) me-2"></span>@_localizer[lang].Value.TrySanitize(_sanitizer)
+                        </a>
+                    </li>
+                }
+                </ul>
+            </div>
        </div>
    </div>
    <section class="text-center">
        <details>
-            <summary>Sie haben keinen Zugriffscode erhalten?</summary>
-            <p>Bitte überprüfen Sie Ihr Email Postfach inklusive Spam-Ordner. Sie können auch den Absender bitten, Ihnen den Code auf anderem Wege zukommen zu lassen.</p>
+            <summary>@_localizer[WebKey.LockedFooterTitle]</summary>
+            <p>@_localizer[WebKey.LockedFooterBody]</p>
        </details>
    </section>
 </div>
 <footer class="container" id="page-footer">&copy; SignFlow 2023-2024 <a href="https://digitaldata.works">Digital Data GmbH</a></footer>
 <script nonce="@nonce">
-    $(document).ready(function () {
-        $('.select-flag').select2({
-            templateResult: formatResult,
-            templateSelection: formatSelection
+    document.addEventListener('DOMContentLoaded', function () {
+        var dropdownItems = document.querySelectorAll('.dropdown-item');
+        dropdownItems.forEach(function (item) {
+            item.addEventListener('click', async function(event) {
+                event.preventDefault();
+                var language = this.getAttribute('data-language');
+                var flagCode = this.getAttribute('data-flag');
+                document.getElementById('selectedFlag').className = 'fi ' + flagCode + ' me-2';
+                await setLanguage(language);
+            });
        });
    });
-
-    function formatResult(state) {
-        if (!state.id) {
-            return state.text;
-        }
-        var baseUrl = "/img/flags";
-        var $state = $(
-            `<span><img src="${baseUrl}/${state.element.value}.png" class="img-flag me-3" />${state.text}</span>`
-        );
-        return $state;
-    };
-
-    function formatSelection(state) {
-        if (!state.id) {
-            return state.text;
-        }
-        var baseUrl = "/img/flags";
-        var $state = $(
-            `<span class="d-flex justify-content-center align-items-center"><img src="${baseUrl}/${state.element.value}.png" class="img-flag pt-1"/></span>`
-        );
-        return $state;
-    };
-</script>
+</script>
--- a/EnvelopeGenerator.Web/Views/Shared/_Layout.cshtml
+++ b/EnvelopeGenerator.Web/Views/Shared/_Layout.cshtml
@@ -8,6 +8,7 @@
    <link rel="stylesheet" href="~/lib/sweetalert2/sweetalert2.min.css" />
    <link rel="stylesheet" href="~/css/site.css" asp-append-version="true"/>
    <link rel="stylesheet" href="~/EnvelopeGenerator.Web.styles.css" asp-append-version="true"/>
+    <link rel="stylesheet" href="~/lib/flag-icons-main/css/flag-icons.min.css" asp-append-version="true" />
    <link href="~/lib/select2/dist/css/select2.min.css" rel="stylesheet"/>
 </head>
 <body>
--- a/EnvelopeGenerator.Web/Views/_ViewImports.cshtml
+++ b/EnvelopeGenerator.Web/Views/_ViewImports.cshtml
@@ -1,9 +1,10 @@
@using EnvelopeGenerator.Web
@using EnvelopeGenerator.Web.Models
-@using Microsoft.Extensions.Localization;
-@using EnvelopeGenerator.Application.Resources;
-@inject IStringLocalizer<Resource> _localizer;
+@using Microsoft.Extensions.Localization
+@using EnvelopeGenerator.Application
+@inject IStringLocalizer<Resource> _localizer
@inject System.Text.Encodings.Web.UrlEncoder _encoder
@inject Ganss.Xss.HtmlSanitizer _sanitizer
@inject Microsoft.AspNetCore.Http.IHttpContextAccessor _accessor
+@inject Cultures _cultures
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
--- a/EnvelopeGenerator.Web/WebKey.cs
+++ b/EnvelopeGenerator.Web/WebKey.cs
@@ -0,0 +1,20 @@
+namespace EnvelopeGenerator.Web
+{
+    public static class WebKey
+    {
+        public static readonly string ServiceOutputNullError = nameof(ServiceOutputNullError);
+        public static readonly string UnexpectedError = nameof(UnexpectedError);
+        public static readonly string FailedToSendAccessCode = nameof(FailedToSendAccessCode);
+        public static readonly string WrongEnvelopeReceiverId = nameof(WrongEnvelopeReceiverId);
+        public static readonly string DataIntegrityError = nameof(DataIntegrityError);
+        public static readonly string NonDecodableEnvelopeReceiverId = nameof(NonDecodableEnvelopeReceiverId);
+        public static readonly string de_DE = nameof(de_DE).Replace("_", "-");
+        public static readonly string en_US = nameof(en_US).Replace("_", "-");
+        public static readonly string LockedTitle = nameof(LockedTitle);
+        public static readonly string LockedBody = nameof(LockedBody);
+        public static readonly string LocakedOpen = nameof(LocakedOpen);
+        public static readonly string LockedAccessCode = nameof(LockedAccessCode);
+        public static readonly string LockedFooterTitle = nameof(LockedFooterTitle);
+        public static readonly string LockedFooterBody = nameof(LockedFooterBody);
+    }
+}
--- a/EnvelopeGenerator.Web/appsettings.json
+++ b/EnvelopeGenerator.Web/appsettings.json
@@ -12,6 +12,7 @@
  },
  "PSPDFKitLicenseKey": null,
  /* The first format parameter {0} will be replaced by the nonce value. */
+  "TestCSP": false,
  "Content-Security-Policy": [
    "default-src 'self'",
    "script-src 'self' 'nonce-{0}'",
@@ -94,6 +95,15 @@
  /* Resx naming format is -> Resource.language.resx (eg: Resource.de_DE.resx). 
     To add a new language, first you should write the required resx file.
     first is the default culture name. */
-  "Languages": [ "de_DE", "en_US" ],
-  "DisableMultiLanguage": true
+  "Cultures": [
+    {
+      "Language": "en-US",
+      "FIClass": "fi-us"
+    },
+    {
+      "Language": "de-DE",
+      "FIClass": "fi-de"
+    }
+  ],
+  "DisableMultiLanguage": false
 }
--- a/EnvelopeGenerator.Web/wwwroot/css/site.css
+++ b/EnvelopeGenerator.Web/wwwroot/css/site.css
@@ -209,4 +209,8 @@ footer#page-footer a:focus {

 .lang-item {
    font-size: 0.85rem;
+}
+
+#langDropdownMenuButton{
+    min-width: 4vw;
 }
--- a/EnvelopeGenerator.Web/wwwroot/js/network.js
+++ b/EnvelopeGenerator.Web/wwwroot/js/network.js
@@ -159,3 +159,39 @@ class WrappedResponse {
        this.fatal = (data === null && error === null)
    }
 }
+
+async function setLangAsync(language, flagCode) {
+    document.getElementById('selectedFlag').className = 'fi ' + flagCode + ' me-2';
+
+    await fetch(`/lang/${language}`, {
+        method: 'POST',
+        headers: {
+            'Content-Type': 'application/json'
+        }
+    })
+}
+
+async function setLanguage(language) {
+
+    const hasLang = await fetch('/lang', {
+        method: 'GET',
+        headers: {
+            'Content-Type': 'application/json'
+        }
+    })
+    .then(res => res.json())
+    .then(langs => langs.includes(language))
+    .catch(err => false);
+
+    if(hasLang)
+        return await fetch(`/lang/${language}`, {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' }
+        })
+        .then(response => {
+            if (response.redirected)
+                window.location.href = response.url;
+            else if (!response.ok)
+                return Promise.reject('Failed to set language');
+        });
+}