Hosting a background task in an ASP.NET core application running on IIS.

In this post, I share how I used the Microsoft.Extensions.Hosting.IHostedService interface and System.Thread.Timer class available in ASP.NET core to run a background job at a specified interval. It is straightforward for the most part, and Microsoft provides good documentation on the libraries. One thing that was not clear from the documents was handling overlapping invocations that happens when an invocation starts but the previous one has not finished within the specified interval. If you host your ASP.NET core on IIS, check out my other post to see how you can have your application and thus your background task auto start and run continuously on IIS.

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Replacing variables in an angular app using Replace Token extension.

In this post, I am going to talk about the Replace Tokens extension, which I have found to be useful for dynamically replace values at build time. For instance, I have used it to display the build number which comes from azure build pipelines in an angular application.

Making the build number readily available to both programmers and non programmers such as business system analysts (BSA) and end users has a couple of benefits. For instance, by displaying the build number in the app, the analysts can quickly tell whether they are testing the expected build after a deployment. As a developer, I often find myself wondering why certain features work on one environment and not the other. Seeing the build number in the app allows me to quickly check whether an issue has to do with the codes or the environment.

Azure Devops provides an easy way to assemble the build number. You can see the options to edit the build number in your build pipelines, under the Options tab.

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Three ways of authenticating a Windows virtual machine against Azure Key Vault.

In this post, I share three ways of gaining a Windows virtual machine access to a key vault. The machine can be an azure virtual machine or a non-azure machine such as your personal computer or a on premise server.

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Send email with attachments using MailKit for .NET core

This post is another example of setting up and using MailKit for .NET core to send an email with attachments.

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Deploy an ASP.NET core application to IIS on Windows Server 2019.

This is part II of the blog post series in which I share some of ways to build and deploy an ASP.NET core application to IIS running on a Windows VM. In the previous post, I cover how to build and published an ASP.NET core application. The end result is an artifact (a published directory). In this post, I go over how to deploy the artifact to IIS. Along the way, we’ll discuss:

• Enabling IIS
• .NET core runtime and hosting bundle
• IIS website and application configuration
• IIS application pool

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Build and publish an ASP.NET core application using Visual Studio.

This is part I of the blog post series in which I share some of the ways I have learned to build and deploy an ASP.NET core 2 application to IIS running on Windows Server VM.

In this post, we’ll cover just the basics of how to build and publish an ASP.NET core 2 application to a folder using Visual Studio 2017. In the process, we’ll discuss some of the concepts you should be familiar with:

• Release vs Debug build.
• Deployment mode: framework dependent deployment vs self contained deployment.

I assume you have a working ASP.NET core application which you want to deploy. If not, you can just create a new ASP.NET core project, following the documentation.

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Azure queue storage: overview, benefits and usage in .NET/ .NET core application.

I have seen applications which use a database to simulate a queue as part of processing some workflow tasks. Using a database to simulate a messaging queue mean you have to write more boilerplate codes, sql queries for the CRUD operations as well as handle concurrency issues if your applications run on multiple nodes.

Microsoft has made it easy to utilize messaging and queueing in your application with azure queue storage, which is what I talk about in this post.

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Write generic codes with Delegate, Func, Action, and Anonymous Functions in C#

In this post, I talk about Delegate, Func, Action, anonymous  methods and lambda expressions in C# and how they help with making the codes more concise and generic.

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Don’t use string when working with dates in javascript/angular and .NET

Sometimes,  I have seen developers (myself included) use simple strings to represent dates. This could lead to unexpected behaviors if you are not careful. For instance, I recently ran into a bug where the PDF document the program generated show the incorrect date, which was a few hours off from the correct one. The date value originated from a data API and did not include a timezone. The intended time zone was  local time, which is Pacific Standard Time (PST) in this case. However, because we were using storing the date in the angular application using string instead of the javascript built-in Date type, when the framework serialized the data into JSON and sent to .NET, it kept the date as is and did not add any timezone. At the backend, .NET deserialized the value back into a DateTime object, and when we attempted to convert the value to local time usingDateTime.ToLocalTime()for displaying in the document, we got an incorrect value because .NET assumed the date was in Universal Coordinated Time (UTC). 

The bug was because of inconsistencies when passing date values and not including timezone information. However, had we used the frameworks’ built-in types for representing dates instead of strings, we could have avoided the issue. 

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Fill out a PDF form using iTextSharp for .NET core.

iTextSharp is a popular library for working with PDF files. The  unofficial port of the v4.16 is available for .NET core. In this post, I show examples of using the library to programmatically read and fill out a PDF form.

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