Edi Wang

.NET and Azure Developer

.NET C# Programming Language and .NET Platform

Cloud Architecture Design of My Email Notification Infrastructure on Azure

My blog system "Moonglade" needs to send email notifications to blog owner when there are events like new comments, new pingbacks, and send email to readers when their comments are replied.  I've been building my own infrastructure in the last few years. I will share the journey of how this email infrastructure evolved and the things I learnt. …

ASP.NET Azure Azure Function Azure Storage Queue

Get Client IP When Your ASP.NET Core App is behind Reversed Proxy on Azure App Service

Problem I have a web app with a web front end and API backend both deployed to Azure App Service. I reversed proxy the API using this method I described before, so that my web front end can access API without having CORS issue, and the end users won't need to access my API address directly. However, for the API code, the client IP address I got is always Azure app service's outbound IP instead …

.NET Azure App Service

Move CRON Expression from Hard Code to Configuration in Azure Function App

When creating Azure Function with Timer trigger, we usually write CRON expression in our function code. But when you need to dynamically adjust your timer based on business needs, you will have to update your code and redeploy the function. Let's see how we can remove the hard code CRON expression and put it into configuration that we can easily update on the Azure Portal without redeploy the code …

Azure Azure Function

System Fonts on Azure App Service for Linux

In early this year, I am upgrading my Captcha library, the code that renders text on images blow up when running under Azure App Service for Linux. I can tell from the error message that the font I am using is not installed on Azure App Service's hosting machine. To fix this, I need to find out what fonts are there in Azure App Service for Linux. Let's see how to do it. …

Azure Linux

Adding Azure Cache for Redis in My Elf Project

ASP.NET Core Memory cache has its own limits. It is difficult to scale in a cloud environment with multiple instances. Azure Cache for Redis provides a fully managed distributed cache service for cloud applications. It is built on top of Redis, a popular cache and messaging product. Integrating Redis into cloud applications can improve performance and scalability. …

Azure Redis

How to Get Access Token for Azure REST APIs in .NET

I am recently working on a project that requires front-end to call Azure REST APIs. Microsoft document describes how to get Access Token in postman via Jon Gallant's blog post. However, placing secret keys in front-end is very dangerous. In my project, I must get the Access Token from server side in .NET. Let's see how to do it. …

Azure Azure AD

Log User Identity Information to Azure Application Insights

Azure Application Insights is a very powerful APM tool for monitoring web applications. However, not all features that we sometimes require come out of the box. I now have an ASP.NET Core Web API application that uses JWT authentication. I would like to log user's identity when there is a failed request. Let's see how to do it. …

Azure Application Insight

ASP.NET Core Unit Test: How to Mock HttpClient.GetStringAsync()

In ASP.NET Core unit tests, if you want to mock HttpClient.GetStringAsync(), here's the trick. Problem Given the following code var html = await _httpClient.GetStringAsync(sourceUrl); When I tried to mock HttpClient.GetStringAsync() like this var httpClientMock = new Mock<HttpClient>(); httpClientMock .Setup(p => p.GetStringAsync(It.IsAny<string>())) .Returns(Task.FromResult("...")); Moq …

ASP.NET Unit Test