Rename PhysicalFileSystemProvider to WebRootImageProvider

[ronaldbarendse]

The current PhysicalFileSystemProvider uses the IFileProvider abstraction from environment.WebRootFileProvider, which doesn't have to be a physical file system (it's just that ASP.NET Core does use PhysicalFileProvider by default).

I would suggest adding a (base?) class that accepts any IFileProvider implementation (e.g. FileProviderImageProvider[Base]) and rename the current implementation to WebRootImageProvider.

The same is true for PhysicalFileSystemResolver, which uses the IFileInfo abstraction: this could be renamed to FileInfoImageResolver (and be re-used by any of the provider implementations).

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It's a bit different for PhysicalFileSystemCache, as that does use System.IO.File (as it needs write access, which the IFileProvider API doesn't provide). So this name makes perfect sense, but it's also using the PhysicalFileProvider/IFileProvider abstraction (and therefore also requires a dependency on Microsoft.Extensions.FileProviders.Physical)! I would suggest removing this and use direct file paths instead...

@JimBobSquarePants Let me know what you think about these (breaking) changes. I'll be happy to create a PR for this 😃

[JimBobSquarePants]

Yeah.... The current implementation isn't pretty and we should fix it while we can.

I actually think we should do the opposite and simply mirror the PhysicalFileSystemCache. We can provide options containing a ProviderRootPath property and default to the IWebHostEnvironment.WebRootPath if not set. (I'd probably rename PhysicalFileSystemCacheOptions.CacheRoot to CacheRootPath also.)

I'm loath to introduce additional base classes. It's an additional opportunity for me to miss something important which makes them unusable.

[deanmarcussen]

I agree on that @JimBobSquarePants @ronaldbarendse

Would actually suggest, since we're at it, that PhysicalFileSystemCache should also take a ProviderRootPath, and default to WebRootPath

I didn't do that last time, but we've had a couple of requests to move it outside of the webroot, for users that are securing images, and others that can see a use for a cache folder per tenant (makes managing cache sizes/quotas a little more practical).

Not sure about the base classes, we have our own custom implementation, and it wouldn't benefit from them, it's not a lot on the interface to implement.

[JimBobSquarePants]

PhysicalFileSystemCache already has that but it's called CacheRoot

ImageSharp.Web/src/ImageSharp.Web/Caching/PhysicalFileSystemCacheOptions.cs

Lines 16 to 28 in 7c2b496

	/// <summary>
	/// Gets or sets the optional cache root folder.
	/// <para>
	/// This value can be <see langword="null"/>, a fully qualified absolute path,
	/// or a path relative to the directory that contains the application
	/// content files.
	/// </para>
	/// <para>
	/// If not set, this will default to the directory that contains the web-servable
	/// application content files; commonly 'wwwroot'.
	/// </para>
	/// </summary>
	public string CacheRoot { get; set; }