Wednesday, April 25, 2018

ASP.Net Core 2 with Postgresql on Linux Part 10: Program, Startup, appsetting.json, etc.

In Part I, I discussed the rationale for porting a ASP.Net Core 2 app to my Linux system replacing SQL Server with Postgresql and place it on Heroku. 

With Part II, we transferred the SQL Server data to Postgres.


In Part III, I create the ASP.Net MVC Core 2.x app, from which we will proceed, and get Entity Framework Core installed.


Then in Part IV, I look at the configuration differences between the ASP.Net MVC app that uses SQL Server and the new app, in preparation of porting the old app to use Postgresql.

Part V, we compared the differences in both the projects' structures and ported the existing project code, starting with the data model layer, to the new project. In addition to this, we got the jquery.countdown jquery plugin installed, that is used to implement a JavaScript timer. More on that in a later article. Finally, we used the dotnet ef dbcontext scaffold command that builds a DbContext and entity types for out Postgresql database. And, oh yes, we added the project to github, which frankly should have been done day one.


In Part VI, we got the NUnit testing framework in place 
in order to test both the new and future code.


Part VII, saw the Service layer setup along with its unit tests.

In Part VIII we imported the Controller classes from the existing app and setup unit tests for them.

Then in Part IX, we will migrated the Razor (*.cshtml) files as well as the associated JavaScript, Cascading Style Sheet (CSS), and image files from the existing app.

In this post, the Program.cs and Startup.cs files as well as the appsettings.json and project files (*.csproj) content will be migrated and then updated from utilizing SQL Server to accessing Postgresql for data.

Here is the compare of those root files:




Since these files are specific to the application, a simple copy and replace cannot be made. Examining the content we see that existing app (on the left) we see the bower.json file .bowerrc, which are part of the Bower Package Manager. This was addressed earlier in Part V where discussed the recommended move from Bower to Yarn

First, let's look at the appsettings.json files. After moving the Logging and Appsettings object settings, the remaining difference was the database connection strings, which specify the database platform used.




Next, when comparing the two apps' project files you see several differences. 



A few the differences are specific residual settings needed when the existing app was moved from .Net Core 1.x to 2.0. For example, the following setting:


<PropertyGroup>
  <UserSecretsId>....</UserSecretsId>
</PropertyGroup>
was need when UserSecrets 1.0.0, that required the existence of the project.json. When moved to a csproj file the above was needed. See this: https://github.com/aspnet/Announcements/issues/209.

AssetTargetFallback below was set so that with the move to .NET Core 2.0, any NuGet package that is compatible with .NET Framework 4.6.1 or higher can be used without additional configuration.


<AssetTargetFallback>$(AssetTargetFallback);portable-net45+win8+wp8+wpa81;</AssetTargetFallback>
The other settings are/were necessary for the current app's functionality.

The final file to consider is the Startup.cs file.



The differences here are the between the SQL Server and Postgresql DbContextOptionsBuilder object that is used in the lambda expression as options:
options => options.UseNpgsql

The DbContextOptionsBuilder object, "provides a simple API surface for configuring DbContextOptions. Databases (and other extensions) typically define extension methods on this object that allow you to configure the database connection (and other options) to be used for a context."

Ok. Now we are ready to run the new ASP.net MVC .Net Core 2.0 app.



Browsing to the https://localhost:5000 URL and we see the initial page.


In the next and final post in this series, we will deploy this app to Heroku via Docker.


Tuesday, April 24, 2018

ASP.Net Core 2 with Postgresql on Linux Part 9: The View Layer

In Part I, I discussed the rationale for porting a ASP.Net Core 2 app to my Linux system replacing SQL Server with Postgresql and place it on Heroku. 

With Part II, we transferred the SQL Server data to Postgres.


In Part III, I create the ASP.Net MVC Core 2.x app, from which we will proceed, and get Entity Framework Core installed.


Then in Part IV, I look at the configuration differences between the ASP.Net MVC app that uses SQL Server and the new app, in preparation of porting the old app to use Postgresql.

Part V, we compared the differences in both the projects' structures and ported the existing project code, starting with the data model layer, to the new project. In addition to this, we got the jquery.countdown jquery plugin installed, that is used to implement a JavaScript timer. More on that in a later article. Finally, we used the dotnet ef dbcontext scaffold command that builds a DbContext and entity types for out Postgresql database. And, oh yes, we added the project to github, which frankly should have been done day one.


In Part VI, we got the NUnit testing framework in place 
in order to test both the new and future code.


In Part VIIwe got the Service layer setup along with its unit tests.

In Part VIII we imported the Controller classes from the existing app and setup unit tests for them.

In this post, we will migrate the Razor (*.cshtml) files as well as the associated JavaScript, Cascading Style Sheet (CSS), and image files from the existing app.

As we have done in past posts, let's use Beyond Compare to see what needs to move. 



So, as with the other tiers, we have some files to move in this layer.

After using Beyond Compare to move the Razor files, here is the view:

Next, let's look at the contents of the wwwroot folder, that holds the JavaScript, Cascading Style Sheet (CSS), and image files.



From here I simply replaced the contents of the new app with the JavaScript, Cascading Style Sheet (CSS), and image files of the existing app. 



Now, we need to build and see what happens. 


So, thus far, all is good. However, we know that the Program.cs and Startup.cs files as well as the appsettings.json and project files (*.csproj) content is still different. In the next post, Part X, we will migrate them from utilizing SQL Server to accessing Postgresql for data.



Monday, April 23, 2018

ASP.Net Core 2 with Postgresql on Linux Part 8: The Controller Layer

In Part I, I discussed the rationale for porting a ASP.Net Core 2 app to my Linux system replacing SQL Server with Postgresql and place it on Heroku. 

With Part II, we transferred the SQL Server data to Postgres.


In Part III, I create the ASP.Net MVC Core 2.x app, from which we will proceed, and get Entity Framework Core installed.


Then in Part IV, I look at the configuration differences between the ASP.Net MVC app that uses SQL Server and the new app, in preparation of porting the old app to use Postgresql.

Part V, we compared the differences in both the projects' structures and ported the existing project code, starting with the data model layer, to the new project. In addition to this, we got the jquery.countdown jquery plugin installed, that is used to implement a JavaScript timer. More on that in a later article. Finally, we used the dotnet ef dbcontext scaffold command that builds a DbContext and entity types for out Postgresql database. And, oh yes, we added the project to github, which frankly should have been done day one.


In Part VI, we got the NUnit testing framework in place 
in order to test both the new and future code.


In Part VIIwe got the Service layer setup along with its unit tests.

In this post, we will import the Controller classes from the existing app and setup unit tests for them.

Here is look at the existing and new Controller folders from Beyond Compare:



First, I copied the existing Controller classes to the new app and then updated the namespace settings as well as adjusted other dependencies. With that done, the Controller classes are moved.


Then, I created unit tests for the main Controller methods. Instead of displaying the code in a screen shot, go to the unit tests github repository to see them all. Moreover, to see the corresponder Controller classes go here to the github repo.

With that done, the next post, Part IX, will detail the migration of the Razor (*.cshtml) files as well as the associated JavaScript, Cascading Style Sheet (CSS), and image files from the existing ASP.Net MVC app to the new app.




Friday, April 20, 2018

The Value of Planning Before Coding

​​​​In the article from The Atlantic, The Coming Software Apocalypse by James Somers (September 26, 2017), Leslie Lamport, a Turing Award–winning computer scientist is quoted to say, "Architects draw detailed plans before a brick is laid or a nail is hammered. But few programmers write even a rough sketch of what their programs will do before they start coding." 




Somers then goes on, "Programmers are drawn to the nitty-gritty of coding because code is what makes programs go; spending time on anything else can seem like a distraction. And there is a patient joy, a meditative kind of satisfaction, to be had from puzzling out the micro-mechanics of code. 

But code, Lamport argues, was never meant to be a medium for thought. 'It really does constrain your ability to ​​think when you’re thinking in terms of a programming language,' he says. Code makes you miss the forest for the trees: It draws your attention to the working of individual pieces, rather than to the bigger picture of how your program fits together, or what it’s supposed to do—and whether it actually does what you think."​ 




In short, take a few minutes and sketch out your algorithms before writing code. It may save you time in the long run.​

Monday, April 16, 2018

ASP.Net Core 2 with Postgresql on Linux Part 7: The Service Layer

In Part I, I discussed the rationale for porting a ASP.Net Core 2 app to my Linux system replacing SQL Server with Postgresql and place it on Heroku. 

With Part II, we transferred the SQL Server data to Postgres.


In Part III, I create the ASP.Net MVC Core 2.x app, from which we will proceed, and get Entity Framework Core installed.


Then in Part IV, I look at the configuration differences between the ASP.Net MVC app that uses SQL Server and the new app, in preparation of porting the old app to use Postgresql.

Part V, we compared the differences in both the projects' structures and ported the existing project code, starting with the data model layer, to the new project. In addition to this, we got the jquery.countdown jquery plugin installed, that is used to implement a JavaScript timer. More on that in a later article. Finally, we used the dotnet ef dbcontext scaffold command that builds a DbContext and entity types for out Postgresql database. And, oh yes, we added the project to github, which frankly should have been done day one.


In Part VI, we got the NUnit testing framework in place 
in order to test both the new and future code.


In this post, we will get the Service layer setup in order to unit test which will test the Data and Model tiers as well.

Using the Beyond Compare tool, let's look at the differences between the existing ASP.Net MVC app and the new project concerning the Service tier:



As you can see, there are no Service classes in the right side, which is the new app, of the folder-level comparison. 

Instead of simply copying all the Service layer code to the new app with Beyond Compare, let's add one class at a time, setting up unit test for each one. 

The first one we will copy is the EsvService.cs class. Also, you will note that in the above image, there is a IEsvService.cs file as well as EsvService. The IEsvService is an interface class. Here is a section of code from the EsvService.cs file:

  public class EsvService : ServiceBase, IEsvService  
 {  
      private static string ApiKey  
      {  
        get { return "myKey"; }  
      }  
      private static DateTime TodaysDate  
      {  
        get { return GetESTDate(); }  
      }  
 //......  
 }  

Here is the updated code that contains the interface class as well as the implementation:


  public interface IEsvService  
 {  
      Task<string> GetVerseAsync(string verseReference);  
      Task<string> GetDailyVerseAsync();  
      Task<string> GetTodaysPsalmAsync();  
 }  
 public class EsvService: ServiceBase, IEsvService  
      {  
      private static string ApiKey  
      {  
        get { return "myKey"; }  
      }  
      private static DateTime TodaysDate  
      {  
        get { return GetESTDate(); }  
      }  
 //...       
 }  

I find this easier to manage when changes are made to the interface since you are already in the correct location to update the implementation class, EsvService, in this case. Also, you will note that the class implements the ServiceBase class. Therefore, I will move that to the new app as well. After updating the namespace in the new code, the project compiled and all is well.

At any time if you want to view the source code, go here.

Next, let's get a reference set to the myApp project from the UnitTest project.


 $ dotnet add reference ../myApp/myApp.csproj  


After adding the myApp project, which is the system under test (SUT), I added a few test methods:



Then, as you can see from above, I issued the dotnet test command and all passed. 

However, we really do not want to run tests we are depending on outside resources each time. While that type of test is valuable, it is what is referred to as an integration test and should only be run as needed. Here, we just want to test our code and not the dependencies. Enter, Moq, the mock testing framework that helps you mock or fake the dependencies and just tests your code.


 $ dotnet add package Moq  




Then, I updated the existing Service test methods and moved integration tests to a separate class. In order to run the standard mocked unit tests separately, I employed NUnit's Category Attribute.




Then, I ran dotnet test --filter TestCategory=Unit, and here is the result:




After this, I ported the remaining Service classes from the existing ASP.Net MVC app to this one. Looking at the comparison there are several classes that were moved.

As I mentioned above, I moved the interface classes into the same file as their implementation classes. Therefore, the classes starting with "I" are not in the new app.

Now that we have the Data, Model, and Service layer classes ported, next in Part VIII, we will import the Controller classes from the existing to the app and setup unit tests for them.



Monday, April 09, 2018

ASP.Net Core 2 with Postgresql on Linux Part 6: Setting up Unit Testing

In In Part I, I discussed the rationale for porting a ASP.Net Core 2 app to my Linux system replacing SQL Server with Postgresql and place it on Heroku. 

With Part II, we transferred the SQL Server data to Postgres.


In Part III, I create the ASP.Net MVC Core 2.x app, from which we will proceed, and get Entity Framework Core installed.


Then in Part IV, I look at the configuration differences between the ASP.Net MVC app that uses SQL Server and the new app, in preparation of porting the old app to use Postgresql.

Part V, we compared the differences in both the projects' structures and ported the existing project code, starting with the data model layer, to the new project. In addition to this, we got the jquery.countdown jquery plugin installed, that is used to implement a JavaScript timer. More on that in a later article. Finally, we used the dotnet ef dbcontext scaffold command that builds a DbContext and entity types for out Postgresql database. And, oh yes, we added the project to github, which frankly should have been done day one.

In this post, Part VI, it would be best to get a unit testing framework in place
in order to test both the new and future code.

First, let's create a new unit test project. I have found that it is best to separate the csproj files so I have created a new folder. So from a separate folder than the myApp folder I issued the following command:


 $ dotnet new classlib -n UnitTests  


Here is the output



Using the new Multi-root workspace feature, I was able to add the new UnitTests project to thew view in VS Code:


Next, within the new UnitTest project folder,  I issued the following in the unit test project directory:


 $ dotnet add package NUnit  


After that:


 $ dotnet add package Microsoft.NET.Test.Sdk  


Then:


 $ dotnet add package NUnit.Console  




The final command to get all the NUnit packages installed was:


 $ dotnet add package NUnit3TestAdapter  


I issued the dotnet restore to make sure that everything was up to date. When doing that I noted the following error:



I then noted that the target framework was not the standard and not the core framework:



After updating the TargetFramework setting to netcoreapp2.0 and running dotnet restore, it was good.

One thing I noted with working with the multi-root workspace feature, the C# extension settings did not take effect until I closed VS Code, opened the new UnitTest project in VS Code by itself, rebuilt the project, closed it, and then re-opened the multi-root workspace.

Next, step was to create an NUnit test to simply test that the NUnit packages are setup properly. This seemed appropriate:



I then invoked the dotnet test command and all is well:



In Part VII, we will get the Service layer setup in order to unit test it as well as the Data and Model tiers.


Monday, April 02, 2018

ASP.Net Core 2 with Postgresql on Linux Part 5: Data Model Layer, Etc.

In In Part I, I discussed the rationale for porting a ASP.Net Core 2 app to my Linux system replacing SQL Server with Postgresql and place it on Heroku. 

With Part II, we transferred the SQL Server data to Postgres.

In Part III, I create the ASP.Net MVC Core 2.x app, from which we will proceed, and get Entity Framework Core installed.


Then in Part IV, I look at the configuration differences between the ASP.Net MVC app that uses SQL Server and the new app, in preparation of porting the old app to use Postgresql.


Here in Part V, we will start comparing the differences in both the projects' structures and porting the existing project code, starting with the data model layer, to the new project.

Since the next step is to look at the existing Windows ASP.Net MVC app using SQL Server and to move it to a Linux system with Postgresql, I thought it best to first look at what the overall differences are in the two projects.




So, using Beyond Compare, as mentioned in the previous post, to look at the differences in the folder structure, here are my initial observations.

First, note that there is a bower package component folder that is not present in the new app. Within the folder bower_components folder you see jquery.countdown. As per their site, they state to use the following to install:



 $ bower install jquery.countdown  

While their github page offers other installation methods via npm, et al, bower is still solid. However, even bower is encouraging a move to yarn...yet bower is still being maintained. 

Looking at further differences, there is a Data folder with Entity Framework Core classes as well as classes that implement them.


Then, I copied the Entity Framework Core classes as well as the implementation classes to a Data folder in myApp. 


Of course, this will not be useful until the controller and view objects are ported as well. Meanwhile, I will get unit tests for the the data model layer...more on this later.

So, given the fact that, as found above, that bower is encouraging a move to yarn, it seems prudent to make that move for this app now. Per Yarn's site, here is what I did:

 $ curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -  
 $ echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list  
 $ sudo apt-get update && sudo apt-get install yarn  

Next, I attempted to install jquery.countdown via yarn with:

 $ yarn install jquery.countdown  

The result was the following:

 yarn install v1.5.1  
 info No lockfile found.  
 error An unexpected error occurred: "`install` has been replaced with `add` to add new dependencies. Run \"yarn add jquery.countdown\" instead.".  
 info If you think this is a bug, please open a bug report with the information provided in "/home/mark/Code/dotnetcore/myApp/yarn-error.log".  
 info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.  


So, per the above instructions:


We will test the install jquery.countdown later, meanwhile let's try to build the myApp project.

As expected, there are things missing and the build fails.


Given that we have just ported classes that have a different name space as well as references to objects that are not in the project, we have a great deal of red text above. Now to make the corrections.

First, I replaced the old reference to the m2prayerVS2017NetCore.Models name space with myApp.Models in each of the migrated Entity Framework Core classes. Also, the Migrations folder were from the previous project and not needed here. 

After commenting the Entity Framework Core code that was calling into missing model files, I issued the following command to get the model objects scaffolded from the Postgres database:

 $ dotnet ef dbcontext scaffold "Host=localhost;Database=postgres;Username=youUserName;Password=yourPassword" Npgsql.EntityFrameworkCore.PostgreSQL -o Models  


Then, I uncommented the Entity Framework Core code and corrected for the lower-case use of table names that are conventional with Postgresql. For example, while SQL Server will have a table named AspNetUsers, Postgres' naming convention entitles it aspnetusers.



Yet, when attempting to build, I found that I was missing the ApplicationUser class from the Models namespace. 



After copying it from the old ASP.Net app and updating the namespace name, the project would then build.

Oh my, I just realized that we do not have this project in any kind of source control! Let's take care of that right now. Essentially, I followed the steps here.

Given that the Entity Framework Core data classes have been moved to the myApp application and the model objects scaffolded, creating unit tests utilizing them is the next step. Therefore, in Part VI we will look at setting up unit testing in order to test both the new and future code.