C# – How to add request headers when using HttpClient

There are two ways add request headers when using HttpClient: Add headers for all requests using HttpClient.DefaultRequestHeaders. Add headers per request using HttpRequestMessage.Headers. In this article, I’ll show examples of both ways to add request headers. Add an unchanging header for all requests Let’s say you’re adding an API Key header. It needs to be … Read more

C# – How to use Polly to do retries

Whenever you’re dealing with code that can run into transient errors, it’s a good idea to implement retries. Transient errors, by definition, are temporary and subsequent attempts should succeed. When you retry with a delay, it means you think the the transient error will go away by itself after a short period of time. When … Read more

C# – How to change the HttpClient timeout per request

It’s best practice to reuse the same HttpClient instance for multiple requests. When you’re using the same instance repeatedly, and you want to change the timeout per request, you can pass in a CancellationToken, like this: You can’t change HttpClient.Timeout after the instance has been used. You have to pass in a CancellationToken instead. There … Read more

C# – Newtonsoft extension methods for HttpClient

System.Net.Http.Json provides extension methods that simplify getting and sending JSON with HttpClient. Internally, it uses System.Text.Json for serialization. What if you want to use Newtonsoft instead of System.Text.Json? You can use the following extension methods for that: These are modeled off of the extension methods in System.Net.Http.Json. You can pass in a JsonSerializerSettings object to … Read more

C# – Get and send JSON with HttpClient

The simplest way to get and send JSON with HttpClient is to use the GetFromJsonAsync() and PostAsJsonAsync() extension methods found in System.Net.Http.Json, like this: Note: You have to install the System.Net.Http.Json nuget package if you’re using a framework version before .NET 5. These extension methods use System.Text.Json for serialization. They simplify things by abstracting away … Read more