.NET 6 Sizzling Reload and “Refused to hook up with ws: as a result of it violates the Content material Safety Coverage directive” as a result of Net Sockets

0
30



In case you’re enthusiastic about Sizzling Reload like me AND you additionally need an “A” grade from SecurityHeaders.com (actually, go do that now) then you’ll study in a short time about Content material-Safety-Coverage headers. You should spend a while studying and it’s possible you’ll find yourself with a considerably refined checklist of allowed issues, scripts, stylesheets, and so on.

In DasBlog Core (the cross platform weblog engine that runs this weblog) Mark Downie makes these configurable and makes use of the NWebSpec ASP.NET Middleware library so as to add the wanted headers.

if (SecurityStyleSources != null && SecurityScriptSources != null && DefaultSources != null)
{
app.UseCsp(choices => choices
.DefaultSources(s => s.Self()
.CustomSources(DefaultSources)
)
.StyleSources(s => s.Self()
.CustomSources(SecurityStyleSources)
.UnsafeInline()
)
.ScriptSources(s => s.Self()
.CustomSources(SecurityScriptSources)
.UnsafeInline()
.UnsafeEval()
)
);
}

Every of these variables comes out of a config file. Sure, it might be extra safety in the event that they got here out of a vault or had been even laborious coded.

DasBlog is a pretty big and funky app and we seen instantly upon Mark upgrading it to .NET 6 that we had been unable to make use of Sizzling Reload (by way of dotnet watch or from VS 2022). We are able to complain about it, or we will find out about the way it works and why it isn’t working for us!

Keep in mind: Nothing in your laptop is hidden from you.

Beginning with a easy “View Supply” we will see a JavaScript embrace on the very backside that’s positively not mine!

<script src="http://feeds.hanselman.com/_framework/aspnetcore-browser-refresh.js"></script>

Okay, this is sensible as we all know not solely does HotReload assist C# (code behinds) but in addition Markup by way of Razor Pages and altering CSS! It will positively want to speak “again residence” to the runner which is both “dotnet watch” or VS2022.

If I alter the ASPNETCORE_ENVIRONMENT to “Manufacturing” (both by way of launch.json, launchsettings, or an surroundings variable like this, I can see that further HotReload helper script is not there:

C:githubwshotreloadtest>dotnet run --environment="Manufacturing"
Constructing...
data: Microsoft.Internet hosting.Lifetime[14]
Now listening on: https://localhost:7216
data: Microsoft.Internet hosting.Lifetime[14]
Now listening on: http://localhost:5216

Keep in mind: You by no means need to use dotnet run in manufacturing! It is an SDK constructing command! You will need to use dotnet exec your.dll, dotnet your.dll, or better of all, in .NET 6 simply name the EXE immediately! .binDebugnet6.0wshotreloadtest.exe in my instance. Why? dotnet run will all the time assume it is in Improvement (you actually inform it to revive, construct, and exec in a single run command) should you run it. You will be aware that operating the precise EXE is all the time WAY quicker as nicely! Do not ship your .NET SDK to your webserver and do not recompile the entire thing on startup in manufacturing!

We are able to see that that aspnnetcore-browser-refresh.js is the shopper facet of Improvement-time HotReload. our browser console we see :

Refused to Connect because it violates a CSP Directive

Refused to hook up with 'wss://localhost:62486/' 
as a result of it violates the next Content material Safety Coverage
directive: "default-src 'self'".
Word that 'connect-src' was not explicitly set,
so 'default-src' is used as a fallback.

That is so much to consider. I began out my ASP.NET Net App’s center ware saying it was OK to speak “again to myself” however nowhere else.

app.UseCsp(choices => choices.DefaultSources(s => s.Self())); 

Hm, self appears cheap, why cannot the browser join BACK to the dotnet run’ed Kestrel Net Server? It is all localhost, proper? Properly, particularly it is http://localhost not ws://localhost, and even wss://localhost (that further s is for safe) so I have to explicitly enable ws: or wss: or each, however solely in Improvement.

Possibly like this (once more, I am utilizing NWebSpec, however these are simply HTTP Headers so you’ll be able to actually simply add them if you need, hardcoded.)

app.UseCsp(choices => choices.DefaultSources(s => s.Self())
.ConnectSources(s => s.CustomSources("wss://localhost:62895")));

However port numbers change, proper? Let’s do exactly wss:, solely in Improvement. Now, if I am utilizing each CSPs and WebSockets (ws:, wss:) in Manufacturing, I will have to be intentional about this.

What is the ethical?

In case you begin utilizing CSP Headers to tighten issues up, be aware and conscious of the headers you want for conveniences like Sizzling Reload in Improvement versus no matter issues it’s possible you’ll want in Manufacturing.

Hope this helps prevent a while!


Sponsor: At Rocket Mortgage® the work you do round right here will probably be 100% impactful however received’t take all of your free time, supplying you with the right work-life steadiness. Or as we name it, tech/life steadiness! Be taught extra.




About Scott

Scott Hanselman is a former professor, former Chief Architect in finance, now speaker, guide, father, diabetic, and Microsoft worker. He’s a failed stand-up comedian, a cornrower, and a ebook writer.

facebook
twitter
subscribe
About   E-newsletter

Internet hosting By
Hosted in an Azure App Service










LEAVE A REPLY

Please enter your comment!
Please enter your name here