ASP.NET Core 2.2 - SignalR Breaking changes

After a seamlessly flawless upgrade to ASP.NET Core, we got into trouble when using SignalR hubs.

In our code we were rather lazy and had allowed CORS for everything:

In ASP.NET Core 2.2 it is no longer allowed to combine AllowAnyOrigin and AllowCredentials. When you try to use the two together, you‘ll see the following warning in the output window:

warn: Microsoft.AspNetCore.Cors.Infrastructure.CorsService

The CORS protocol does not allow specifying a wildcard (any) origin and credentials at the same time. Configure the policy by listing individual origins if credentials needs to be supported.

Problem is that this warning breaks the preflight OPTIONS check of SignalR and the client can no longer connect to the hubs.

To fix this, you have to remove the AllowAnyOrigin method and instead specify the origins explicitly(like it should be in the first place):

Azure DevOps/ GitHub emoji

I’m really bad at remembering emoji’s. So here is cheat sheet with all emoji’s that can be used in tools that support the github emoji markdown markup: All credits go to rcaviers who created this list.

Kubernetes–Limit your environmental impact

Reducing the carbon footprint and CO2 emission of our (cloud) workloads, is a responsibility of all of us. If you are running a Kubernetes cluster, have a look at Kube-Green . kube-green is a simple Kubernetes operator that automatically shuts down (some of) your pods when you don't need them. A single pod produces about 11 Kg CO2eq per year( here the calculation). Reason enough to give it a try! Installing kube-green in your cluster The easiest way to install the operator in your cluster is through kubectl. We first need to install a cert-manager: kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.14.5/cert-manager.yaml Remark: Wait a minute before you continue as it can take some time before the cert-manager is up & running inside your cluster. Now we can install the kube-green operator: kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml Now in the namespace where we want t

DevToys–A swiss army knife for developers

As a developer there are a lot of small tasks you need to do as part of your coding, debugging and testing activities. DevToys is an offline windows app that tries to help you with these tasks. Instead of using different websites you get a fully offline experience offering help for a large list of tasks. Many tools are available. Here is the current list: Converters JSON <> YAML Timestamp Number Base Cron Parser Encoders / Decoders HTML URL Base64 Text & Image GZip JWT Decoder Formatters JSON SQL XML Generators Hash (MD5, SHA1, SHA256, SHA512) UUID 1 and 4 Lorem Ipsum Checksum Text Escape / Unescape Inspector & Case Converter Regex Tester Text Comparer XML Validator Markdown Preview Graphic Color B

The art of simplicity

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