Enforce unique Rules (Old Urls)

[aniaw]

We assume that duplicate is a redirect rule with the same oldUrl unless this rule RedirectRuleType is set to Regex.

Old pattern	New pattern	Content Id	Redirect Rule Type	...	Created on	...
/en/alloy-plan	/en/new-alloy-plan	--	ExactMatch	--	28-05-2021 11:07:55	--
/en/alloy-plan	/en/new-alloy-plan	--	ExactMatch	--	27-05-2021 11:07:55	treat as a duplicate
/en/alloy-plan	/en/new-alloy	--	ExactMatch	--	26-05-2021 11:07:55	treat as a duplicate
/en/alloy-plan	--	1001	ExactMatch	--	25-05-2021 11:07:55	treat as a duplicate
/en/alloy-plan-123	/en/new-alloy-plan-123	--	ExactMatch	--	24-05-2021 11:07:55
/en/alloy-plan-123	/en/*	--	Regex	--	23-05-2021 11:07:55	don't treat as a duplicate

Update behavior

• During importing and adding redirect rules remove duplicate.
• When adding duplicate: first add a new redirect rule then remove duplicates if exist.

New feature

• Remove duplicates button - will remove all duplicates

[tomaszmadeyski]

I feel that at least what we should do here is to log error through ILogger - I know errors are ignored in every other method (ie Delete, ClearAll) but maybe we should fix that? What do you think @m-jedynak
(Even better solution is to return errror message to end user)

[tomaszmadeyski]

Since this method returns IQueryable<RedirectRule> (which I'm not 100% sure is required, since it is not used anywhere) I think to be on safe side we should check for null here so the last line:
return duplicates ?? Enumerable.Empty<RedirectRule>().AsQueryable();
so we do not hit NullReferenceException by accident

[tomaszmadeyski]

I'm not fluent with EpiServer store concept but I wonder if this is possible to have separate methods in controller (I believe it needs to be supported by JS side of EpiServer store): Delete(GuidId), ClearAll() and RemoveAllDuplicates() ?