Absolute URL Methods Added to UrlHelper, Canonical URL Support and RequireHttpsAttribute Fix

[RehanSaeed]

UrlHelper

Following on from #1966 where a Link method was added to UrlHelper which requires a route name and route values. Having similar methods for 'Action' (controller and action name) and 'Content' (images and static content) would be really useful too. Here are some places where I find having 'Absolute Content' useful:

• Atom/RSS feeds require absolute URL's to image/audio/video (There is a way to specify a relative base URL but it's buggy in FireFox). See my ASP.NET MVC 6 Boilerplate example.
• Creating a dynamic OpenSearch.xml file which contains absolute URL links to images. See my ASP.NET MVC 6 Boilerplate example.
• Open Graph image/audio/video URL's are also required to be absolute.

I have these methods in my ASP.NET MVC 6 Boilerplate Framework NuGet package (Note that I add the word 'Absolute' at the beginning of the function. The current method is named 'Link' but it uses route names, so it could be named better at the very least).

Canonical URL's for Better Search Engine Optimization (SEO)

Support for canonical URL's with the RedirectToCanonicalUrlAttribute and NoTrailingSlashAttribute filters. Performing 301 permanent redirects to the canonical URL of a resource is the correct approach according to both Google and Bing. The RedirectToCanonicalUrlAttribute filter helps achieve this in conjunction with the RouteOptions (AppendTrailingSlash and LowercaseUrls). See my blog for full details.

[dnfclas]

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[dnfclas]

@RehanSaeed, Thanks for signing the contribution license agreement so quickly! Actual humans will now validate the agreement and then evaluate the PR.

Thanks, DNFBOT;

[dnfclas]

@RehanSaeed, Thanks for signing the contribution license agreement so quickly! Actual humans will now validate the agreement and then evaluate the PR.

Thanks, DNFBOT;

[davidfowl]

@RehanSaeed The team will evaluate these changes but here's some initial feedback:

• Split these unrelated changes into different PRs.
• Check out the coding guidelines, the style doesn't match what we expect.
• Add tests for each of the features implemented.

If you're just looking for initial feedback because this idea hasn't been cleared with the team then that should be reflected in either the title or description.

[RehanSaeed]

Will split this pull request. Thank you!