CODEWITHSUNDEEP
c#.net-coreasp.net-core-2.2
Konrad Viltersten
Konrad Viltersten

Reputation: 39210

Why does order between UseStaticFiles and UseDefaultFiles matter?

I understand that the order of registration for middleware may matter. However, it's not given that it's necessarily the case.

I noticed that UseDefaultFiles() needs to precede UseStaticFiles() (which can neatly be circumvented by UseFileServer()).

What I don't understand is why. How do they collide?!

I've googled the issue but got zero motivation on why the order is significant in this particular case. Only that it is of importance...

Upvotes: 17

Views: 9916

Answers (3)

rickvdbosch
rickvdbosch

Reputation: 15621

Taken from the documentation on Static files in ASP.NET Core (under Serve a default document, there's an important note).

UseDefaultFiles must be called before UseStaticFiles to serve the default file. UseDefaultFiles is a URL rewriter that doesn't actually serve the file. Enable Static File Middleware via UseStaticFiles to serve the file.

Based on this, it's important to first setup the URL rewriter (UseDefaultFiles) before serving the actual file (UseStaticFiles).
If you don't, the UseStaticFiles middleware will kick in first, but a request to the root of the application won't tell the middleware which 'file' to serve. When you make sure the rewrite is in place first, a request to the root of the application will have been rewritten to be a request for (one of the) default file(s).

Upvotes: 20

Manoj Choudhari
Manoj Choudhari

Reputation: 5634

UseDefaultFiles() should always be before UseStaticFiles().

This is because UseDefaultFiles rewrite the URLs. Use Static files only serves the URLs.

If serving of document happens earlier than URL rewrite, then you may not get default document served.

Refernece:https://learn.microsoft.com/en-us/aspnet/core/fundamentals/static-files?view=aspnetcore-2.2#serve-a-default-document

Upvotes: 3

DavidG
DavidG

Reputation: 119056

From the docs:

UseDefaultFiles must be called before UseStaticFiles to serve the default file. UseDefaultFiles is a URL rewriter that doesn't actually serve the file. Enable Static File Middleware via UseStaticFiles to serve the file.

The order of middleware does matter, this is why, for example, UseStaticFiles has to come before UseMvc as the MVC engine will handle all of the requests. In this case, UseDefaultFiles is simply rewriting the URL and passing it on to the UseStaticFiles middleware to serve.

Upvotes: 7

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