Showing posts from October, 2021

Azure Functions + System.Text.JSON Deserialize exception

If you run into a System.IO.FileNotFoundException exception from the Azure Function when it is deserializing JSON with System.Text.Json to your class, make sure you are not using System.Text.Json 5.0.2.  Issue FileNotFoundException: Could not load file or assembly 'System.Text.Encodings.Web, Version=, Culture=neutral Fix Downgrade to System.Text.Json 5.0.1.  Project description The issue was found while moving code from a working .NET Framework 4.6.1 web api project into a .NET Core 3.1 class library, which is called from an Azure Function 3. The deserialization happens in the class library. The manual and automated testing described in the post were both local to my development machine, not on the Azure Cloud. Initially it was tested by the Azure Function manually. Later, as I thought the issue was about the JSON returned, I added automated programmatic tests to call into the class library in a separate test project. The test project worked so the issue had to be the Azure