Skip to main content

Blazor - Failed to find a valid digest in the 'integrity' attribute

After making a small change to a Blazor application, I redeployed it to an Azure App service. When I tried to open the updated Blazor application nothing happened.

When I opened up the browser console, I noticed a list of errors:

There are 2 errors important to explain what is going wrong:

Failed to find a valid digest in the 'integrity' attribute for resource 'https://cloudbreweshopweb.azurewebsites.net/_framework/dotnet.timezones.blat' with computed SHA-256 integrity '2NJf++ql6UnbRRdYWEir6MxH58bYGWDEqofII/z+Xmo='. The resource has been blocked.

Failed to find a valid digest in the 'integrity' attribute for resource 'https://cloudbreweshopweb.azurewebsites.net/_framework/dotnet.wasm' with computed SHA-256 integrity 'y0gwhQ7a6FTinj6R6HEA3SlRDb/iL70a56PEGpKbt/8='. The resource has been blocked.

This is related to the integrity checks executed by the browser.

Integrity checks

When Blazor WebAssembly downloads an app's startup files, it instructs the browser to perform integrity checks on the responses. Blazor sends SHA-256 hash values for DLL (.dll), WebAssembly (.wasm), and other files in the blazor.boot.json file, which isn't cached on clients. The file hashes of cached files are compared to the hashes in the blazor.boot.json file. For cached files with a matching hash, Blazor uses the cached files. Otherwise, files are requested from the server. After a file is downloaded, its hash is checked again for integrity validation. An error is generated by the browser if any downloaded file's integrity check fails.

There is a whole section in the Blazor documentation how you can troubleshoot this kind of error: https://learn.microsoft.com/en-us/aspnet/core/blazor/host-and-deploy/webassembly?view=aspnetcore-6.0#resolve-integrity-check-failures-1.

To get rid of this problem I did 2 things:

  1. I deleted the obj and bin folder for my Blazor app and recompiled the project afterwards.
  2. I reloaded the Blazor app using CTRL-F5 so that the browser cache is ignored.

That did the trick for me. Hope it helps…

Popular posts from this blog

.NET 8–Keyed/Named Services

A feature that a lot of IoC container libraries support but that was missing in the default DI container provided by Microsoft is the support for Keyed or Named Services. This feature allows you to register the same type multiple times using different names, allowing you to resolve a specific instance based on the circumstances. Although there is some controversy if supporting this feature is a good idea or not, it certainly can be handy. To support this feature a new interface IKeyedServiceProvider got introduced in .NET 8 providing 2 new methods on our ServiceProvider instance: object? GetKeyedService(Type serviceType, object? serviceKey); object GetRequiredKeyedService(Type serviceType, object? serviceKey); To use it, we need to register our service using one of the new extension methods: Resolving the service can be done either through the FromKeyedServices attribute: or by injecting the IKeyedServiceProvider interface and calling the GetRequiredKeyedServic...

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...