Adds media url provider

[rasmusjp]

fixes #4942

Breaking changes

• UrlProvider constructors now takes an IEnumerable<IMediaUrlProvider>
• UmbracoContextFactory constructor now takes a MediaUrlProviderCollection

Things to test

• media.Url returns the url for the umbracoFile property,
• media.UrlAbsolute() returns the absolute url for the umbracoFile property.
• media.GetCropUrl(200, 200) returns the crop url

Add a Umbraco.UploadField and a Umbraco.ImageCropper property to a content item and test the following both as invariant and variant

• content.MediaUrl('propertyAlias') returns the url for the media in the propertyAlias property
• content.MediaUrlAbsolute('propertyAlias') returns the absolute url for the media in the propertyAlias property
• content.MediaUrl('propertyAlias', "culture") returns the url for the media in the propertyAlias property in the specified culture
• content.MediaUrlAbsolute('propertyAlias', "culture") returns the absolute url for the media in the propertyAlias property in the specified culture
• content.GetCropUrl(200, 200 propertyAlias: "propertyAlias") returns the crop url

Crete a new implementation IMediaUrlProvider which always returns a full url and add it as the first one in the MediaUrlProviderCollection e.g.

public class CdnMediaUrlProvider : DefaultMediaUrlProvider
{
    public override UrlInfo GetMediaUrl(UmbracoContext umbracoContext, IPublishedContent content, string propertyAlias,
        UrlProviderMode mode, string culture, Uri current)
    {
        var mediaUrl = base.GetMediaUrl(umbracoContext, content, propertyAlias, UrlProviderMode.Relative, culture, current);
        if (mediaUrl == null)
            return null;

        if (mediaUrl.IsUrl == false)
            return mediaUrl;

        var cdnBaseUrl = "https://my.cdn";

        return UrlInfo.Url(cdnBaseUrl + mediaUrl.Text, culture);
    }
}

public class CdnComposer : IUserComposer
{
    public void Compose(Composition composition)
    {
        composition
            .MediaUrlProviders()
            .Insert<CdnMediaUrlProvider>();
    }
}

and test that all the above url's now is prefixed with https://my.cdn

[Shazwazza]

nice, haven't had time to fully look at this one but just wanted to ping @zpqrtbnk since he'll also have an interest in this one too.

[sitereactor]

What does this implementation mean for regular every day use of Umbraco?

1. Anything that needs to be done differently to get the media path/url through this provider?
2. Any scenarios that are not covered? Like content.GetPropertyValue("propertyAlias")

Just trying to get an idea of what would work and potentially what wouldn't when you have a CDN provider in place. Is there potential for getting media Urls without the CDN prefix.

[Shazwazza]

@sitereactor not sure if you've read all of the related issues? This is what this is fixing: #4942, this is the epic that contains it: https://github.com/umbraco/Umbraco.Private/issues/283, this is the spike with some research done #4943
... otherwise please keep asking questions :)

[sitereactor]

Okay, I will try to think of another way to ask my question so you will understand. From your reply I gather its not clear 😅

[sitereactor]

How about this:

Given all the tasks/subtasks mentioned in the #283 Epic are fully implemented. Will the use of getting a path/url to a media item be completely seemless to the user or is there anything that would require the developers to use different methods?

Say I'm on version 8.0.x and all the tasks from the Epic is implemented in 8.x and I upgrade to this version and configure a media provider to add a CDN to the site. Will everything Just Work™️ ?

[Shazwazza]

Yes.. it will 'just work', that's the whole premise for these changes, we don't want the user to have to do new/different things.

[sitereactor]

Great, thank you.

[rasmusjp]

For media .Url and .GetCropUrl() will use the url provider instead of just returning the umbracoFile property value, but if you have a upload/image cropper field on your content and uses content.Value() it will return the property value (either a string or ImageCropperValue) and it's not using the url providers, so you'll need to use content.MediaUrl() instead.

I guess we could make content.Value() work by changing the value converters for upload and image cropper, but not sure what would be the best approach here, maybe @zpqrtbnk has some input?

[sitereactor]

What about from a package developers perspective? Anything special they'd need to be aware of? Something around how to handle media paths within content.
Sorry about my lack of insight here. Just trying to understand.

[zpqrtbnk]

Not sure this does what we want. Calling ToAbsolute on an already absolute url is... going to do weird things? Looking into it.

[zpqrtbnk]

@rasmusjp I have pushed a commit that does some minor fixes, want to check I haven't done anything stupid?

Now running tests.

As for the behavior of Value() etc - see #5170 - we're going to refactor Url() and more generally the IPublishedContent interface in 8.1, so I think some of the methods defined in this PR will change again with #5170.

Ideally, Value() returns "the value" whatever that is, and Url() returns "the url". So I'd rather not use Value() to return a Url. And by default Url() should work with... umbracoFile if present, so ppl don't have to supply the property alias, by default. But can, if they want to override.

So in a view... <img src="@media.Url()" /> should "just" work - and if a dev replaces the media url provider, she can control what .Url() returns here.

Making sense?

[ronaldbarendse]

How do you get an absolute crop URL? GetCropUrl() should probably get an additional parameter to specify the UrlMode that is passed to MediaUrl for this, right?

Umbraco-CMS/src/Umbraco.Web/ImageCropperTemplateExtensions.cs

Line 133 in 3bfd9b7

var mediaItemUrl = mediaItem.MediaUrl(propertyAlias: propertyAlias);

[ronaldbarendse]

And all GetCropUrl() extension methods should probably also allow specifying a culture, so all MediaUrl() overloads are covered:

Umbraco-CMS/src/Umbraco.Web/PublishedElementExtensions.cs

Line 207 in 3bfd9b7

public static string MediaUrl(this IPublishedContent content, string culture = null, UrlMode mode = UrlMode.Default, string propertyAlias = Constants.Conventions.Media.File)

[ronaldbarendse]

BTW: adding support for culture variant media types will be required first: #4771.