As I’d already shared the Mef libraries for WPF, WinForms and Console Application. So In this post, I would like to share one more Mef library for .Net MVC.

As you may know, The MVC is supporting Areas that allow developing a set of Views, Controllers, and Resources (Images, CSS and Javascript) inside Areas folder. However, the areas are still a part of MVC application, and the resources need to be imported into the _Layout view manually and deploy along with the application. Beside of that, if any changes in the areas may impact to the whole application and need to be tested carefully before going live.

I. HBD.Mef.Mvc Introduction

PM> Install-Package HBD.Mef.Mvc

The Definition.

  • Workspace: this is an MVC website (a Shell) considering as Module container that allows deploying and run multi modules separately.
  • Module: this is a loosely couple MVC area that is implementing independently with Workspace and able to deploy into the Workspace lately.

So, get used of Area in MVC, I would like to introduce my HBD.Mef.Mvc library, it had been implemented based on the Mef technology allows you to build and manage the MVC areas as a module not only in a separate folder but also in different projects.

Before going to details of the library implementation, I would like to discuss a few questions below.

Why do we need the Modularization application?

  1. Let’s imagine, if you have many development teams and try to make the teams are working independently and separately as much as possible. However, if three or four teams are working a the significant changes of a complex application and that application does not support modularization. So when any team needs to deploy the changed to the Stagings or Production environments, they need to inform all the other teams to ensure there is no conflict between the teams. After deployed,  the other teams need to merge the changes into their source code branches. Managing this situation is a nightmare for the project manager.
  2. The other scenario, if the application doesn’t support modularization, so any change even the small one you need to conduct the System Integration Test (SIT) and User Acceptant Test (UAT) for the whole system because of the impact and the efforts will charge back to the business. You know, The business users may surprise why the simple change is costly?
  3. Micro-Services adoption: as you know, Micro-service is new technology that structures an application as a collection of loosely coupled services, which implement business capabilities. The microservice architecture enables the continuous delivery/deployment of large, complex applications. It also enables an organization to evolve its technology stack.
Micro Service Architecture

So the advantage of the Modularization application:

  • Allow the teams are working on the modules independently, parallelly.
  • Speed up and enable continuous development, delivery process: In term of the Agile development process. Normally, the sprint time is two weeks, and the recommendation to the development team is releasing a small workable feature of the application and demo to the Business users on the Sprint demonstration meeting.
  • Help to scale down the impact of the changes and increase the scalability, flexibility, and stability of the application.
  • Developing and maintain the automation tests or UI tests for a module is much easier for the whole complex application.

What is Mvc Module?

As you know, develop a Module is not just a Views and Controllers but also the settings, configuration, resources, Business and Data logics also. On the next sections, I will show you how to build a Workspace and create a module for that Workspace separately by using HBD.Mef.Mvc.

II HBD.Mef.Mvc Features

1. Navigations

Along with a Module is a set of navigation that We need to add into the top menu of the Workspace to allow users to navigate and using your modules functions. Let’s see, if developing a module and the navigation are adding directly to the _Layout view of the Workspace, and overwriting the  _Layout file of the Workspace in every deployment. In this case, the dependence happens again if there are more than one development teams are working the same Workspace and on each team, they also maintain a different version of _Layout view on their modules.

  • INavigationService

So in this library is provided an INavigationService allows registering the navigations into the Main Menu of Workspace dynamically.

Currently, the Main menu is supported two level only. You can add a navigation link directly in the main menu, or add a menu and navigation links are children of that menu.

  • IFooterNavigationService

Similarly, the IFooterNavigationService allows registering the links into Footer portion of the Workspace dynamically.

  • Navigation and Authorization

In the MVC some controller actions are required a particular Roles for the execution. So if the current user doesn’t have the necessary Roles, she is not able to execute that actions. In this case, the Workspace will hide all the navigation related to that actions automatically. If there are no visible children of a menu, the Workspace will hide the parent menu as well. It will help to save the main menu space for the other modules.

2. Resource Bundle Handling.

Working with MVC, you will know that the framework provides a feature called Bundle to allows to import the CSS and javascript files into the views.

Similar to navigation. Including all resources into the _Layout view of the Workspace is not recommended and it may conflict with the resources of the other Areas.

To resolve this issue. I have implemented a helper class in the library allows to register the module resources into the bundles and manage to render that bundles when accessing the module viewsIt means the Workspace will present the resources of the accessing module into the _Layout page at runtime. This feature will ensure that no CSS or java scripts conflicts between the Modules.

3. Controllers scanning.

You may be aware that, if we want to export a class into Mef container, we need to mark the class with Export attribute. What happens if you forgot to mark this attribute to the controllers? No worry this case had been covered in this library. It will scan all controllers in your binaries and export into Mef container automatically.

4. Configuration management.

As you know, running a .Net website the AppSettings and ConnectionStrings will be loaded into ConfigurationManager class of System.Configuration.

Definitely, on each Module, it will have a separate set of App Settings and Connection strings. Instead of adding the configuration into Workspace config file. You can keep it in a Wed.config and place it in the top level of your Module. The library will load and merge into the ConfigurationManager automatically.

Currently. Only AppSettings and ConnectionString sections are supporting. As the configuration will merge into Workspace configuration, so I would recommend using the Module Name as the prefix of the configuration keys.

The sample code to show you how to use all features above will be provided on the Module development below.

III. Develop a new Workspace.

The idea to implement an MVC Workspace as a core foundation application, that allows to add-in the modules and services independently.

I have developed a Workspace named HBD.Mvc.Shell using HBD.Mef.Mvc and published to Github, if you want to develop a new Workspace by yourself you can reference my source code in here.

Workspace

However, I would like to highlight a few things as below.

1. Bootstrapper class in the App_Start folder.

After installed HBD.Mef.Mvc from Nuget, a new Bootstrapper class, will be added to App_Start folder automatically.

Only one thing you need to do is overwrite the RegisterMainNavigation method and add the navigation of Workspace in. Because the Menu bar, Footer bar will be rendering from INavigationService and IFooterNavigationService instead of maintaining the menus manually.

The rest of configuration, modules loading, resources management will be done automatically by Bootstrapper itself. However, all methods of Bootstrapper are in virtually so in case you want to customize the logic you can overwrite them easily.

Please note that the DisplayAt and AlignAtRight only supported int the root menu level for both The main menu and Footer navigation.

The FontAwesome and Glyphicon icons also supported on both levels of menu. If you want to display an image on the menus instead, you can replace the Glyphicon with a virtual path of the image location. When rendering the Workspace will scan the image from both Area and global Workspace folders and display the image properly.

2. Main menu and Footer partial views.

In HBD.Mvc.Shell Workspace, I had moved the main menu and footer of _Layout view to the partial views. So, in future if any changes on the menu rendering we just need to re-deploy the small part view files instead of a whole _Layout file. This will help to minimize the impact of the changes to the Workspace.

 

Navigation Partial Views

3. Navigation Authorization.

As mentioned above. The navigations are supporting the Authorization, and I would like to move to a separate section to show you how the navigation can pick up the Roles from a controller, or you can specify the Roles manually.

  • Auto Pickup the Roles from Authorize attribute.

The sample code to add a navigation for a controller action

With above code, we will add a navigation titled Import Account From File for the ImportFromFile action of ImportController and below is controller code.

The For extension method will check the Authorize attribute of ImportFromFile action to whether any Authorize with Roles had been specified and pick up the Roles for the navigation automatically. If there is no Authorize attribute had been found it will check at the Controller level for the same.

Note that this automation only happens when there is no Roles had been provided. It means if you already provided the Roles for navigation the auto role pick up won’t be executed.

  • Specify the Roles manually.

Below code is a sample for the manual Role specification:

The WithAuthorize is an extension method that allows you to determine the Roles for navigation. If calling WithAuthorize without any parameter provided, it means the navigation just require the current user is authorized.

IV. Quick start Module development.

To prove my library is working. I have implemented a simple module named Azure Notes. This module is a personal notebook and using Azure DocumentDb to store the note items.

Before starting with the Module implementation, we need to create the Azure DocumentDb first. There is two option for the developers.

1. Setup DocumentDb on Azure Portal

If you already had the Azure Subscription, you can log in to the portal and create a DocumentDb account and then create a collection with the following information.

  • Database name: AzureNotes
  • Collection Id: AzureNotes
  • Partition Key: AzureNotes
  • Storage Capacity: 10GB.
  • Throughput Capacity: 400 RU/s

If you don’t have Azure Subscription, you can install Azure DocumentDb Emulator here, and the create a similar collection as above.

2. Module Implementation

  • Create new Module

Create new Mvc Web application and install the latest version of HBD.Mef.Mvc from nuget. After installed you can delete all the redundant files and just keep the below folders and files.

  • Content folder
  • Controllers folder
  • Views folder
  • Scripts folder
  • all configuration files.

And then add a new class named <YourModuleName>AreaRegistration and then inherited from MefAreaRegistration in HBD.Mef.Mvc this class will help to register your module as an Area in the Workspace application.

Your module should look similar as below.

  • Register Module Routing

  • Register Main Menu Navigation

  • Register Footer Navigation

  • Register Module Bundles

  • Update the App Settings of Web.config file
    • Using Azure DocumentDb Emulator

    • Using Azure DocumentDb

The DocumentDB Account URL and Key can be found in the DocumentDb Account Keys

  • Controller and Views Implementation

You shall continue to implement your controllers and views logics as usually. However, remember to add the Export attribute to your Controllers.

3. Module Deployment

To deploy your module into Workspace. All the folder below need to be copied into Areas\<YourModuleName>\ folder. All binaries of your module will be copied to the bin folder of Workspace.

  • Debug Mode

Running your module on the localhost, you can use set below command line into the post-build event of your module. It helps to copy the necessary files and folders into the Workspace on every build.

  • Deploy to Production

Package your module as the structure below for the production deployment. So that, IT guys can help to copy the folder and files quickly or use the auto deployment tool to deploy the zip file into Workspace application.

  • AzureNotes.zip
    • Areas
      • AzureNote
        • Content: all CSS files of your module.
        • Scripts: all javascript files of your module.
        • Views: all *.cshtml files and folders of your modules.
        • Web.config
    • bin
      • AzureInterfaces.dll
      • AzureNote.dll
      • AzureNoteEntities.dll
      • AzureStorage.dll
      • DocumentDB.Spatial.Sql.dll
      • Microsoft.Azure.Documents.Client.dll
      • Microsoft.Azure.Documents.ServiceInterop.dll

After deployed, just recycle the application pool to re-initialize the Workspace to load new module and displayed on the screen.

4. Live Demo

I have hosted the HBD.Mvc.Shell and Azure Notes module onto my Azure, you may want to take a look at the link below. I just have 25$ on my subscription. So hopefully It is not going to down soon.

V. Source Code

  1. HBD.Mef.Mvc
  2. HBD.Mvc.Shell
  3. AzureNotes

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