Merge pull request #1180 from abpframework/Docs-multi-language

Docs multi language

modules/docs/app/VoloDocs.Web/Pages/Index.cshtml.cs

@@ -18,7 +18,7 @@ namespace VoloDocs.Web.Pages
             _projectAppService = projectAppService;
         }
 
-        public async Task<IActionResult> OnGet()
+        public async Task<IActionResult> OnGetAsync()
         {
             Projects = (await _projectAppService.GetListAsync()).Items;
 
@@ -28,6 +28,7 @@ namespace VoloDocs.Web.Pages
                 {
                     projectName = Projects[0].ShortName,
                     version = DocsAppConsts.Latest,
+                    languageCode = await _projectAppService.GetDefaultLanguageCode(Projects[0].ShortName),
                     documentName = Projects[0].DefaultDocumentName
                 });
             }

modules/docs/src/Volo.Docs.Application.Contracts/Volo/Docs/Documents/ContentWithDetailsDto.cs

@@ -25,6 +25,8 @@ namespace Volo.Docs.Documents
 
         public string FileName { get; set; }
 
+        public string CurrentLanguageCode { get; set; }
+
         public ProjectDto Project { get; set; }
 
         public List<DocumentContributorDto> Contributors { get; set; }

modules/docs/src/Volo.Docs.Application.Contracts/Volo/Docs/Documents/GetDefaultDocumentInput.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel.DataAnnotations;
+using Volo.Docs.Language;
 using Volo.Docs.Projects;
 
 namespace Volo.Docs.Documents
@@ -10,5 +11,8 @@ namespace Volo.Docs.Documents
 
         [StringLength(ProjectConsts.MaxVersionNameLength)]
         public string Version { get; set; }
+
+        [StringLength(LanguageConsts.MaxLanguageCodeLength)]
+        public string LanguageCode { get; set; }
     }
 }

modules/docs/src/Volo.Docs.Application.Contracts/Volo/Docs/Documents/GetDocumentInput.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel.DataAnnotations;
+using Volo.Docs.Language;
 using Volo.Docs.Projects;
 
 namespace Volo.Docs.Documents
@@ -14,5 +15,8 @@ namespace Volo.Docs.Documents
 
         [StringLength(ProjectConsts.MaxVersionNameLength)]
         public string Version { get; set; }
+
+        [StringLength(LanguageConsts.MaxLanguageCodeLength)]
+        public string LanguageCode { get; set; }
     }
 }

modules/docs/src/Volo.Docs.Application.Contracts/Volo/Docs/Documents/GetDocumentResourceInput.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel.DataAnnotations;
+using Volo.Docs.Language;
 using Volo.Docs.Projects;
 
 namespace Volo.Docs.Documents
@@ -14,5 +15,8 @@ namespace Volo.Docs.Documents
 
         [StringLength(ProjectConsts.MaxVersionNameLength)]
         public string Version { get; set; }
+
+        [StringLength(LanguageConsts.MaxLanguageCodeLength)]
+        public string LanguageCode { get; set; }
     }
 }

modules/docs/src/Volo.Docs.Application.Contracts/Volo/Docs/Documents/GetNavigationDocumentInput.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel.DataAnnotations;
+using Volo.Docs.Language;
 using Volo.Docs.Projects;
 
 namespace Volo.Docs.Documents
@@ -10,5 +11,8 @@ namespace Volo.Docs.Documents
 
         [StringLength(ProjectConsts.MaxVersionNameLength)]
         public string Version { get; set; }
+
+        [StringLength(LanguageConsts.MaxLanguageCodeLength)]
+        public string LanguageCode { get; set; }
     }
 }

modules/docs/src/Volo.Docs.Application.Contracts/Volo/Docs/Projects/IProjectAppService.cs

@@ -9,6 +9,8 @@ namespace Volo.Docs.Projects
         Task<ListResultDto<ProjectDto>> GetListAsync();
      
         Task<ProjectDto> GetAsync(string shortName);
+
+        Task<string> GetDefaultLanguageCode(string shortName);
         
         Task<ListResultDto<VersionInfoDto>> GetVersionsAsync(string shortName);
     }

modules/docs/src/Volo.Docs.Application.Contracts/Volo/Docs/Projects/ProjectDto.cs

@@ -26,5 +26,7 @@ namespace Volo.Docs.Projects
         public string DocumentStoreType { get; set; }
 
         public Dictionary<string, object> ExtraProperties { get; set; }
+
+        public Dictionary<string, string> Languages { get; set; }
     }
 }

modules/docs/src/Volo.Docs.Application/Volo/Docs/DocsApplicationAutoMapperProfile.cs

@@ -9,10 +9,10 @@ namespace Volo.Docs
     {
         public DocsApplicationAutoMapperProfile()
         {
-            CreateMap<Project, ProjectDto>();
+            CreateMap<Project, ProjectDto>().Ignore(x=>x.Languages);
             CreateMap<VersionInfo, VersionInfoDto>();
             CreateMap<Document, DocumentWithDetailsDto>()
-                .Ignore(x => x.Project).Ignore(x => x.Contributors);
+                .Ignore(x => x.Project).Ignore(x => x.Contributors).Ignore(x => x.CurrentLanguageCode);
             CreateMap<DocumentContributor, DocumentContributorDto>();
             CreateMap<DocumentResource, DocumentResourceDto>();
         }

modules/docs/src/Volo.Docs.Application/Volo/Docs/Documents/DocumentAppService.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
+using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Caching.Distributed;
 using Microsoft.Extensions.Logging;
@@ -15,17 +16,20 @@ namespace Volo.Docs.Documents
         private readonly IProjectRepository _projectRepository;
         private readonly IDocumentStoreFactory _documentStoreFactory;
         protected IDistributedCache<DocumentWithDetailsDto> DocumentCache { get; }
+        protected IDistributedCache<LanguageConfig> LanguageCache { get; }
         protected IDistributedCache<DocumentResourceDto> ResourceCache { get; }
 
         public DocumentAppService(
             IProjectRepository projectRepository,
             IDocumentStoreFactory documentStoreFactory,
             IDistributedCache<DocumentWithDetailsDto> documentCache,
+            IDistributedCache<LanguageConfig> languageCache,
             IDistributedCache<DocumentResourceDto> resourceCache)
         {
             _projectRepository = projectRepository;
             _documentStoreFactory = documentStoreFactory;
             DocumentCache = documentCache;
+            LanguageCache = languageCache;
             ResourceCache = resourceCache;
         }
 
@@ -33,9 +37,10 @@ namespace Volo.Docs.Documents
         {
             var project = await _projectRepository.GetAsync(input.ProjectId);
 
-            return await GetDocumentWithDetailsDto(
+            return await GetDocument(
                 project,
                 input.Name,
+                input.LanguageCode,
                 input.Version
             );
         }
@@ -44,9 +49,10 @@ namespace Volo.Docs.Documents
         {
             var project = await _projectRepository.GetAsync(input.ProjectId);
 
-            return await GetDocumentWithDetailsDto(
+            return await GetDocument(
                 project,
                 project.DefaultDocumentName,
+                input.LanguageCode,
                 input.Version
             );
         }
@@ -55,9 +61,10 @@ namespace Volo.Docs.Documents
         {
             var project = await _projectRepository.GetAsync(input.ProjectId);
 
-            return await GetDocumentWithDetailsDto(
+            return await GetDocument(
                 project,
                 project.NavigationDocumentName,
+                input.LanguageCode,
                 input.Version
             );
         }
@@ -65,12 +72,12 @@ namespace Volo.Docs.Documents
         public async Task<DocumentResourceDto> GetResourceAsync(GetDocumentResourceInput input)
         {
             var project = await _projectRepository.GetAsync(input.ProjectId);
-            var cacheKey = $"Resource@{project.ShortName}#{input.Name}#{input.Version}";
+            var cacheKey = $"Resource@{project.ShortName}#{input.LanguageCode}#{input.Name}#{input.Version}";
 
             async Task<DocumentResourceDto> GetResourceAsync()
             {
                 var store = _documentStoreFactory.Create(project.DocumentStoreType);
-                var documentResource = await store.GetResource(project, input.Name, input.Version);
+                var documentResource = await store.GetResource(project, input.Name, input.LanguageCode, input.Version);
 
                 return ObjectMapper.Map<DocumentResource, DocumentResourceDto>(documentResource);
             }
@@ -92,20 +99,23 @@ namespace Volo.Docs.Documents
             );
         }
 
-        protected virtual async Task<DocumentWithDetailsDto> GetDocumentWithDetailsDto(
+        protected virtual async Task<DocumentWithDetailsDto> GetDocument(
             Project project,
             string documentName,
+            string languageCode,
             string version)
         {
-            var cacheKey = $"Document@{project.ShortName}#{documentName}#{version}";
+            var cacheKey = $"Document@{project.ShortName}#{languageCode}#{documentName}#{version}";
 
             async Task<DocumentWithDetailsDto> GetDocumentAsync()
             {
                 Logger.LogInformation($"Not found in the cache. Requesting {documentName} from the store...");
                 var store = _documentStoreFactory.Create(project.DocumentStoreType);
-                var document = await store.GetDocumentAsync(project, documentName, version);
+                var languages = await GetLanguageListAsync(store, project, version);
+                var language = GetLanguageByCode(languages, languageCode);
+                var document = await store.GetDocumentAsync(project, documentName, language.Code, version);
                 Logger.LogInformation($"Document retrieved: {documentName}");
-                return CreateDocumentWithDetailsDto(project, document);
+                return CreateDocumentWithDetailsDto(project, document, languages, language.Code);
             }
 
             if (Debugger.IsAttached)
@@ -125,11 +135,43 @@ namespace Volo.Docs.Documents
             );
         }
 
-        protected virtual DocumentWithDetailsDto CreateDocumentWithDetailsDto(Project project, Document document)
+        protected virtual LanguageConfigElement GetLanguageByCode(LanguageConfig languageCodes, string languageCode)
+        {
+            var language = languageCodes.Languages.FirstOrDefault(l => l.Code == languageCode);
+
+            return language ?? languageCodes.Languages.Single(l => l.IsDefault);
+        }
+
+        protected virtual async Task<LanguageConfig> GetLanguageListAsync(IDocumentStore store, Project project, string version)
+        {
+            async Task<LanguageConfig> GetLanguagesAsync()
+            {
+                return await store.GetLanguageListAsync(project, version);
+            }
+
+            return await LanguageCache.GetOrAddAsync(
+                project.ShortName,
+                GetLanguagesAsync,
+                () => new DistributedCacheEntryOptions
+                {
+                    AbsoluteExpirationRelativeToNow = TimeSpan.FromHours(24)
+                }
+            );
+        }
+
+        protected virtual DocumentWithDetailsDto CreateDocumentWithDetailsDto(Project project, Document document, LanguageConfig languages, string languageCode)
         {
             var documentDto = ObjectMapper.Map<Document, DocumentWithDetailsDto>(document);
             documentDto.Project = ObjectMapper.Map<Project, ProjectDto>(project);
             documentDto.Contributors = ObjectMapper.Map<List<DocumentContributor>, List<DocumentContributorDto>>(document.Contributors);
+
+            documentDto.Project.Languages = new Dictionary<string, string>();
+            foreach (var language in languages.Languages)
+            {
+                documentDto.Project.Languages.Add(language.Code, language.DisplayName);
+            }
+
+            documentDto.CurrentLanguageCode = languageCode;
             return documentDto;
         }
     }

modules/docs/src/Volo.Docs.Application/Volo/Docs/Projects/ProjectAppService.cs

@@ -16,17 +16,15 @@ namespace Volo.Docs.Projects
         private readonly IProjectRepository _projectRepository;
         private readonly IDistributedCache<List<VersionInfo>> _versionCache;
         private readonly IDocumentStoreFactory _documentStoreFactory;
-        private readonly IGuidGenerator _guidGenerator;
 
         public ProjectAppService(
             IProjectRepository projectRepository,
             IDistributedCache<List<VersionInfo>> versionCache,
-            IDocumentStoreFactory documentStoreFactory, IGuidGenerator guidGenerator)
+            IDocumentStoreFactory documentStoreFactory)
         {
             _projectRepository = projectRepository;
             _versionCache = versionCache;
             _documentStoreFactory = documentStoreFactory;
-            _guidGenerator = guidGenerator;
         }
 
         public async Task<ListResultDto<ProjectDto>> GetListAsync()
@@ -45,6 +43,15 @@ namespace Volo.Docs.Projects
             return ObjectMapper.Map<Project, ProjectDto>(project);
         }
 
+        public async Task<string> GetDefaultLanguageCode(string shortName)
+        {
+            var project = await _projectRepository.GetByShortNameAsync(shortName);
+            var store = _documentStoreFactory.Create(project.DocumentStoreType);
+            var languageList = await store.GetLanguageListAsync(project, project.LatestVersionBranchName);
+
+            return languageList.Languages.Single(l=>l.IsDefault).Code;
+        }
+
         public async Task<ListResultDto<VersionInfoDto>> GetVersionsAsync(string shortName)
         {
             var project = await _projectRepository.GetByShortNameAsync(shortName);

modules/docs/src/Volo.Docs.Domain.Shared/Volo/Docs/Language/LanguageConsts.cs

@@ -0,0 +1,8 @@
+
+namespace Volo.Docs.Language
+{
+    public static class LanguageConsts
+    {
+        public const int MaxLanguageCodeLength = 10;
+    }
+}

modules/docs/src/Volo.Docs.Domain/Volo/Docs/Documents/IDocumentStore.cs

@@ -1,16 +1,19 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using Volo.Abp.Domain.Services;
+using Volo.Docs.GitHub.Documents;
 using Volo.Docs.Projects;
 
 namespace Volo.Docs.Documents
 {
     public interface IDocumentStore : IDomainService
     {
-        Task<Document> GetDocumentAsync(Project project, string documentName, string version);
+        Task<Document> GetDocumentAsync(Project project, string documentName, string languageCode, string version);
 
         Task<List<VersionInfo>> GetVersionsAsync(Project project);
 
-        Task<DocumentResource> GetResource(Project project, string resourceName, string version);
+        Task<DocumentResource> GetResource(Project project, string resourceName, string languageCode, string version);
+
+        Task<LanguageConfig> GetLanguageListAsync(Project project, string version);
     }
 }

modules/docs/src/Volo.Docs.Domain/Volo/Docs/Documents/LanguageConfig.cs

@@ -0,0 +1,9 @@
+using System.Collections.Generic;
+
+namespace Volo.Docs.Documents
+{
+    public class LanguageConfig
+    {
+        public List<LanguageConfigElement> Languages { get; set; }
+    }
+}

modules/docs/src/Volo.Docs.Domain/Volo/Docs/Documents/LanguageConfigElement.cs

@@ -0,0 +1,11 @@
+namespace Volo.Docs.Documents
+{
+    public class LanguageConfigElement
+    {
+        public string DisplayName { get; set; }
+
+        public string Code { get; set; }
+
+        public bool IsDefault { get; set; }
+    }
+}

modules/docs/src/Volo.Docs.Domain/Volo/Docs/FileSystem/Documents/FileSystemDocumentStore.cs

@@ -1,7 +1,9 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.IO;
 using System.Security;
 using System.Threading.Tasks;
+using Newtonsoft.Json;
 using Volo.Abp.Domain.Services;
 using Volo.Abp.IO;
 using Volo.Docs.Documents;
@@ -14,10 +16,10 @@ namespace Volo.Docs.FileSystem.Documents
     {
         public const string Type = "FileSystem";
 
-        public async Task<Document> GetDocumentAsync(Project project, string documentName, string version)
+        public async Task<Document> GetDocumentAsync(Project project, string documentName, string languageCode, string version)
         {
             var projectFolder = project.GetFileSystemPath();
-            var path = Path.Combine(projectFolder, documentName);
+            var path = Path.Combine(projectFolder, languageCode, documentName);
 
             CheckDirectorySecurity(projectFolder, path);
             
@@ -46,10 +48,18 @@ namespace Volo.Docs.FileSystem.Documents
             return Task.FromResult(new List<VersionInfo>());
         }
 
-        public async Task<DocumentResource> GetResource(Project project, string resourceName, string version)
+        public async Task<LanguageConfig> GetLanguageListAsync(Project project, string version)
+        {
+            var path = Path.Combine(project.GetFileSystemPath(), "languageConfig.json");
+            var configAsJson = await FileHelper.ReadAllTextAsync(path);
+
+            return JsonConvert.DeserializeObject<LanguageConfig>(configAsJson);
+        }
+
+        public async Task<DocumentResource> GetResource(Project project, string resourceName, string languageCode, string version)
         {
             var projectFolder = project.GetFileSystemPath();
-            var path = Path.Combine(projectFolder, resourceName);
+            var path = Path.Combine(projectFolder, languageCode, resourceName);
 
             if (!DirectoryHelper.IsSubDirectoryOf(projectFolder, path))
             {

modules/docs/src/Volo.Docs.Domain/Volo/Docs/GitHub/Documents/GithubDocumentStore.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
+using Newtonsoft.Json;
 using Volo.Abp.Domain.Services;
 using Volo.Docs.Documents;
 using Volo.Docs.GitHub.Projects;
@@ -27,14 +28,14 @@ namespace Volo.Docs.GitHub.Documents
             _githubRepositoryManager = githubRepositoryManager;
         }
         
-        public virtual async Task<Document> GetDocumentAsync(Project project, string documentName, string version)
+        public virtual async Task<Document> GetDocumentAsync(Project project, string documentName, string languageCode, string version)
         {
             var token = project.GetGitHubAccessTokenOrNull();
             var rootUrl = project.GetGitHubUrl(version);
-            var rawRootUrl = CalculateRawRootUrl(rootUrl);
+            var userAgent = project.GetGithubUserAgentOrNull();
+            var rawRootUrl = CalculateRawRootUrlWithLanguageCode(rootUrl, languageCode);
             var rawDocumentUrl = rawRootUrl + documentName;
             var commitHistoryUrl = project.GetGitHubUrlForCommitHistory() + documentName;
-            var userAgent = project.GetGithubUserAgentOrNull();
             var isNavigationDocument = documentName == project.NavigationDocumentName;
             var editLink = rootUrl.ReplaceFirst("/tree/", "/blob/") + documentName;
             var localDirectory = "";
@@ -90,9 +91,9 @@ namespace Volo.Docs.GitHub.Documents
             return versions;
         }
 
-        public async Task<DocumentResource> GetResource(Project project, string resourceName, string version)
+        public async Task<DocumentResource> GetResource(Project project, string resourceName, string languageCode, string version)
         {
-            var rawRootUrl = CalculateRawRootUrl(project.GetGitHubUrl(version));
+            var rawRootUrl = CalculateRawRootUrlWithLanguageCode(project.GetGitHubUrl(version), languageCode);
             var content = await DownloadWebContentAsByteArrayAsync(
                 rawRootUrl + resourceName,
                 project.GetGitHubAccessTokenOrNull(),
@@ -102,6 +103,19 @@ namespace Volo.Docs.GitHub.Documents
             return new DocumentResource(content);
         }
 
+        public async Task<LanguageConfig> GetLanguageListAsync(Project project, string version)
+        {
+            var token = project.GetGitHubAccessTokenOrNull();
+            var rootUrl = project.GetGitHubUrl(version);
+            var userAgent = project.GetGithubUserAgentOrNull();
+
+            var url = CalculateRawRootUrl(rootUrl) + "languageConfig.json";
+
+            var configAsJson = await DownloadWebContentAsStringAsync(url, token, userAgent);
+
+            return JsonConvert.DeserializeObject<LanguageConfig>(configAsJson);
+        }
+
         private async Task<IReadOnlyList<Release>> GetReleasesAsync(Project project)
         {
             var url = project.GetGitHubUrl();
@@ -202,6 +216,16 @@ namespace Volo.Docs.GitHub.Documents
             return contributors;
         }
 
+        private static string CalculateRawRootUrlWithLanguageCode(string rootUrl, string languageCode)
+        {
+            return (rootUrl
+                .Replace("github.com", "raw.githubusercontent.com")
+                .ReplaceFirst("/tree/", "/")
+                .EnsureEndsWith('/')
+                + languageCode
+                ).EnsureEndsWith('/');
+        }
+
         private static string CalculateRawRootUrl(string rootUrl)
         {
             return rootUrl

modules/docs/src/Volo.Docs.HttpApi/Volo/Docs/Projects/DocsProjectController.cs

@@ -34,6 +34,13 @@ namespace Volo.Docs.Projects
             return ProjectAppService.GetAsync(shortName);
         }
 
+        [HttpGet]
+        [Route("{shortName}/defaultLanguage")]
+        public Task<string> GetDefaultLanguageCode(string shortName)
+        {
+            return ProjectAppService.GetDefaultLanguageCode(shortName);
+        }
+
         [HttpGet]
         [Route("{shortName}/versions")]
         public virtual Task<ListResultDto<VersionInfoDto>> GetVersionsAsync(string shortName)

modules/docs/src/Volo.Docs.Web/Areas/Documents/TagHelpers/TreeTagHelper.cs

@@ -35,6 +35,9 @@ namespace Volo.Docs.Areas.Documents.TagHelpers
         [HtmlAttributeName("project-format")]
         public string ProjectFormat { get; set; }
 
+        [HtmlAttributeName("language")]
+        public string LanguageCode { get; set; }
+
         public override void Process(TagHelperContext context, TagHelperOutput output)
         {
             var content = new StringBuilder();
@@ -107,7 +110,7 @@ namespace Volo.Docs.Areas.Documents.TagHelpers
             }
             else
             {
-                listInnerItem = string.Format(ListItemAnchor, NormalizePath(node.Path, node.HasChildItems), textCss, node.Text.IsNullOrEmpty() ? "?" : node.Text);
+                listInnerItem = string.Format(ListItemAnchor, NormalizePath(node.Path), textCss, node.Text.IsNullOrEmpty() ? "?" : node.Text);
             }
 
             return string.Format(LiItemTemplateWithLink,
@@ -117,7 +120,7 @@ namespace Volo.Docs.Areas.Documents.TagHelpers
                 content);
         }
 
-        private string NormalizePath(string path, bool hasChildItems)
+        private string NormalizePath(string path)
         {
             if (UrlHelper.IsExternalLink(path))
             {
@@ -131,7 +134,7 @@ namespace Volo.Docs.Areas.Documents.TagHelpers
                 return "javascript:;";
             }
 
-            return  "/documents/" + ProjectName + "/" + Version + "/" + pathWithoutFileExtension;
+            return  "/documents/" + LanguageCode + "/" + ProjectName + "/" + Version + "/" + pathWithoutFileExtension;
         }
 
         private string RemoveFileExtensionFromPath(string path)

modules/docs/src/Volo.Docs.Web/DocsWebModule.cs

@@ -39,8 +39,8 @@ namespace Volo.Docs
             {
                 //TODO: Make configurable!
                 options.Conventions.AddPageRoute("/Documents/Project/Index", "documents/{projectName}");
-
-                options.Conventions.AddPageRoute("/Documents/Project/Index", "documents/{projectName}/{version}/{*documentName}");
+                options.Conventions.AddPageRoute("/Documents/Project/Index", "documents/{languageCode}/{projectName}");
+                options.Conventions.AddPageRoute("/Documents/Project/Index", "documents/{languageCode}/{projectName}/{version}/{*documentName}");
             });
 
             Configure<AbpAutoMapperOptions>(options =>

modules/docs/src/Volo.Docs.Web/Pages/Documents/Index.cshtml.cs

@@ -17,7 +17,7 @@ namespace Volo.Docs.Pages.Documents
             _projectAppService = projectAppService;
         }
 
-        public async Task<IActionResult> OnGet()
+        public async Task<IActionResult> OnGetAsync()
         {
             var listResult = await _projectAppService.GetListAsync();
 
@@ -27,6 +27,7 @@ namespace Volo.Docs.Pages.Documents
                 {
                     projectName = listResult.Items[0].ShortName,
                     version = DocsAppConsts.Latest,
+                    languageCode = await _projectAppService.GetDefaultLanguageCode(listResult.Items[0].ShortName),
                     documentName = listResult.Items[0].DefaultDocumentName
                 });
             }

modules/docs/src/Volo.Docs.Web/Pages/Documents/Project/Index.cshtml

@@ -107,7 +107,7 @@
                         </div>
                     }
 
-                    <div class="docs-version"> 
+                    <div class="docs-version">
                         <div class="version-select">
                             <div class="input-group">
                                 <div class="input-group-prepend">
@@ -116,7 +116,7 @@
 
                                 <input class="form-control" type="search" placeholder="Filter topics" aria-label="Filter">
                             </div>
-                        </div> 
+                        </div>
                     </div>
 
                     @if (Model.Navigation == null || Model.Navigation.Content.IsNullOrEmpty())
@@ -132,6 +132,7 @@
                             project-name="@Model.ProjectName"
                             project-format="@Model.Project.Format"
                             selected-document-name="@Model.DocumentNameWithExtension"
+                            language="@Model.LanguageCode"
                             id="sidebar-scroll"
                             class="nav nav-list"></ul>
                     }
@@ -158,10 +159,17 @@
                         </a>
                     </div>
 
-                    @if (!string.IsNullOrEmpty(Model.Document.EditLink))
-                    {
-                        <a href="@Model.Document.EditLink" target="_blank"> <i class="fa fa-edit"></i> @L["Edit"]</a>
-                    }
+                    <div class="float-right">
+                        @if (Model.LanguageSelectListItems.Count > 1)
+                        {
+                                <select asp-items="Model.LanguageSelectListItems" class="mr-2" onchange="window.location.replace(this.value)"></select>
+                        }
+
+                        @if (!string.IsNullOrEmpty(Model.Document.EditLink))
+                        {
+                            <a href="@Model.Document.EditLink" target="_blank"> <i class="fa fa-edit"></i> @L["Edit"]</a>
+                        }
+                    </div>
                 </div>
 
                 <div class="docs-content-field">

modules/docs/src/Volo.Docs.Web/Pages/Documents/Project/Index.cshtml.cs

@@ -5,6 +5,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using Volo.Abp.AspNetCore.Mvc.UI.RazorPages;
+using Volo.Abp.Localization;
 using Volo.Docs.Documents;
 using Volo.Docs.HtmlConverting;
 using Volo.Docs.Models;
@@ -23,8 +24,13 @@ namespace Volo.Docs.Pages.Documents.Project
         [BindProperty(SupportsGet = true)]
         public string DocumentName { get; set; }
 
+        [BindProperty(SupportsGet = true)]
+        public string LanguageCode { get; set; }
+
         public ProjectDto Project { get; set; }
 
+        public List<SelectListItem> LanguageSelectListItems { get; set; }
+
         public string DocumentNameWithExtension { get; private set; }
 
         public DocumentWithDetailsDto Document { get; private set; }
@@ -58,6 +64,8 @@ namespace Volo.Docs.Pages.Documents.Project
             await SetVersionAsync();
             await SetDocumentAsync();
             await SetNavigationAsync();
+            SetLanguageSelectListItems();
+            AddLanguageCodePrefixToLinks();
         }
 
         private async Task SetProjectAsync()
@@ -72,7 +80,7 @@ namespace Volo.Docs.Pages.Documents.Project
             ProjectSelectItems = projects.Items.Select(p => new SelectListItem
             {
                 Text = p.Name,
-                Value = p.Id != Project.Id ? "/documents/" + p.ShortName + "/" + DocsAppConsts.Latest : null,
+                Value = p.Id != Project.Id ? "/documents/" + LanguageCode + "/" + p.ShortName + "/" + DocsAppConsts.Latest : null,
                 Selected = p.Id == Project.Id
             }).ToList();
         }
@@ -133,6 +141,7 @@ namespace Volo.Docs.Pages.Documents.Project
                     new GetNavigationDocumentInput
                     {
                         ProjectId = Project.Id,
+                        LanguageCode = LanguageCode,
                         Version = Version
                     }
                 );
@@ -144,6 +153,8 @@ namespace Volo.Docs.Pages.Documents.Project
                 return;
             }
 
+            LanguageCode = Document.CurrentLanguageCode;
+
             Navigation.ConvertItems();
         }
 
@@ -154,7 +165,7 @@ namespace Volo.Docs.Pages.Documents.Project
                 version = DocsAppConsts.Latest;
             }
 
-            var link = "/documents/" + ProjectName + "/" + version;
+            var link = "/documents/" + LanguageCode + "/" + ProjectName + "/" + version;
 
             if (documentName != null)
             {
@@ -193,6 +204,7 @@ namespace Volo.Docs.Pages.Documents.Project
                         new GetDefaultDocumentInput
                         {
                             ProjectId = Project.Id,
+                            LanguageCode = LanguageCode,
                             Version = Version
                         }
                     );
@@ -204,20 +216,46 @@ namespace Volo.Docs.Pages.Documents.Project
                         {
                             ProjectId = Project.Id,
                             Name = DocumentNameWithExtension,
+                            LanguageCode = LanguageCode,
                             Version = Version
                         }
                     );
                 }
+
             }
             catch (DocumentNotFoundException)
             {
-                //TODO: Handle it!
-                throw;
+                Document = await _documentAppService.GetDefaultAsync(
+                    new GetDefaultDocumentInput
+                    {
+                        ProjectId = Project.Id,
+                        LanguageCode = LanguageCode,
+                        Version = Version
+                    }
+                );
             }
 
+            LanguageCode = Document.CurrentLanguageCode;
+
             ConvertDocumentContentToHtml();
         }
 
+        private void SetLanguageSelectListItems()
+        {
+            LanguageSelectListItems = new List<SelectListItem>();
+
+            foreach (var language in Document.Project.Languages)
+            {
+                LanguageSelectListItems.Add(
+                    new SelectListItem(
+                        language.Value,
+                        "/documents/" + language.Key + "/" + Project.ShortName + "/" + Version + "/" + DocumentName,
+                        language.Key == LanguageCode
+                        )
+                    );
+            }
+        }
+
         private void ConvertDocumentContentToHtml()
         {
             var converter = _documentToHtmlConverterFactory.Create(Document.Format ?? Project.Format);
@@ -238,5 +276,10 @@ namespace Volo.Docs.Pages.Documents.Project
 
             Document.Content = content;
         }
+
+        private void AddLanguageCodePrefixToLinks()
+        {
+            Document.Content = Document.Content.Replace("href=\"/documents", "href=\"/documents/" + LanguageCode);
+        }
     }
 }

modules/docs/src/Volo.Docs.Web/Pages/Documents/Project/index.js

@@ -1,11 +1,11 @@
 (function ($) {
 
     $(function () {
-
         var initNavigationFilter = function (navigationContainerId) {
          
             var $navigation = $("#" + navigationContainerId);
 
+
             var getShownDocumentLinks = function () {
                 return $navigation.find(".mCSB_container > li a:visible").not(".tree-toggle");
             };

modules/docs/test/Volo.Docs.Domain.Tests/Volo/Docs/GithubDocumentStore_Tests.cs

@@ -28,7 +28,7 @@ namespace Volo.Docs
             var project = await _projectRepository.FindAsync(_testData.PorjectId);
             project.ShouldNotBeNull();
 
-            var document = await store.GetDocumentAsync(project, "index2", "0.123.0");
+            var document = await store.GetDocumentAsync(project, "index2", "en", "0.123.0");
             document.ShouldNotBeNull();
 
             document.Title.ShouldBe("index2");
@@ -60,7 +60,7 @@ namespace Volo.Docs
             var project = await _projectRepository.FindAsync(_testData.PorjectId);
             project.ShouldNotBeNull();
 
-            var documentResource = await store.GetResource(project, "index.md", "0.123.0");
+            var documentResource = await store.GetResource(project, "index.md", "en", "0.123.0");
             documentResource.ShouldNotBeNull();
 
             documentResource.Content.ShouldBe(new byte[]