Get ContentType name with select fields

Question

I have a problem with getting the ContentType name for a item.

when i use

http://sp2013dev/sites/mms/_api/web/lists/GetByTitle('List')/items(1)/?$expand=ContentType

I get as response all Fields from the ContentType, which is so far not bad, but if I use also select in the query the ContentType Fields are not included in the results it only returns

Result:

 ContentType: {
__deferred: {
uri: "http://site/_api/Web/Lists(guid'b911f75b-1988-4f44-bd88-39ab510562a4')/Items(1)/ContentType"
}-
}

Query:

http://site/_api/web/lists/GetByTitle('List')/items(1)/?$select=Id,Title,ContentType&$expand=ContentType

And the second problem is that when I use ?$expand=ContentType/Name (I only need the name of the ContentType) it is ignored completely and I get all Fields from the ContentType

Edit:

After trying

/_api/web/lists/GetByTitle('')/items()/?$select=Id,FileRef,ContentType/Id,ContentType/Name&$expand=ContentType

as recommend by Vadim i get the following response

{
  d: {
      __metadata: {
           id: "4b62e4e7-a023-4992-b689-e9cf49f3ef86"
           uri: "<url>/_api/Web/Lists(guid'b911f75b-1988-4f44-bd88-39ab510562a4')/Items(1)"
           etag: ""3""
           type: "SP.Data.AgendaElementsUsedListItem"
     }
     ContentType: {
           __deferred: {
               uri: "<url>/_api/Web/Lists(guid'b911f75b-1988-4f44-bd88-39ab510562a4')/Items(1)/ContentType"
           }
     }
     Id: 1
     ID: 1
     FileRef: "/sites/mms/Lists/AgendaElementsUsed/1_.000"
     }
}

Answer 1

Since $expand operator specifies which projected fields from a joined list are returned, the REST query:

/_api/web/lists/GetByTitle('<List Title>')/items(<Item Id>)/?$expand=ContentType

returns list item entity with content type entity.

In order to return the specific item properties along with Content Type properties, you should use $select and $expand operators as demonstrated below:

/_api/web/lists/GetByTitle('<List Title>')/items(<Item Id>)/?$select=Id,FileRef,ContentType/Id,ContentType/Name&$expand=ContentType

Answer 2

Add ContentTypeId to your select. In an on premise SP 2013 environment I found this is an important key. To return the ContentType Name, it is not enough to expand the content type. You also have to include ContentTypeId in the select. In other words, this will not achieve the desired result:

?$select=Id,ContentType/Name&$expand=ContentType

However, this will:

?$select=Id,ContentTypeId,ContentType/Name&$expand=ContentType