Handle HTTP request to find top most similar items

[EmadAghaei]

A user may compare a browsed item with other similar items, generating an HTTP request to find similar items with a browsed item. The handler should search among the items in the store that their name includes the name of the browsed item, if similar items are more than 20 items, The handler only returns top 20 items that have rating more than 3 stars (ex: there exist 35 similar items, The handler should only return the 20 items rated more than 3 stars), if the handler could not find any similar item it returns empty collection. The user already logged in the system and tried to comparing items, the handler should store a log from the items that the user have seen, this can be useful for future item recommendations. The handler may make use of a 3rd party persistence library. finally, the handler should also check the validity of input arguments, the handler should check the information of the user, information of the item to not be empty or null, if it is invalid a 400 response should be returned with a description.

Important notes: The endpoint address is "/fetchTopMostSimilarItems", the URL query parameters are: "userId" , "itemName".