Files don't have URI nor href

Steps

1. Enable hal and rest modules.
2. Add a file to the page content type and create a node with a file in it.
3. Import the following REST configuration that gives access to nodes:

resources:
  'entity:node':
    GET:
      supported_formats:
        - hal_json
      supported_auth:
        - cookie

4. Open http://d8.local/node/1 with header "Accept: application/hal+json" (I normally use Dev HTTP client).

Expected

Within the HAL+JSON representation of the node we can see the file resource and the URL to the file.

Actual

File uri and href fields are empty.

Here is the full output of the node:

{
   "_links":{
      "self":{
         "href":"http:\/\/d8.local\/node\/2"
      },
      "type":{
         "href":"http:\/\/d8.local\/rest\/type\/node\/page"
      },
      "http:\/\/d8.local\/rest\/relation\/node\/page\/uid":[
         {
            "href":"http:\/\/d8.local\/user\/1",
            "lang":"en"
         }
      ],
      "http:\/\/d8.local\/rest\/relation\/node\/page\/revision_uid":[
         {
            "href":"http:\/\/d8.local\/user\/0"
         }
      ],
      "http:\/\/d8.local\/rest\/relation\/node\/page\/field_file":[
         {
            "href":""
         }
      ]
   },
   "uuid":[
      {
         "value":"a9d6d2bf-5d8f-4648-8c07-7b32754ce911"
      }
   ],
   "type":[
      {
         "target_id":"page"
      }
   ],
   "langcode":[
      {
         "value":"en"
      }
   ],
   "title":[
      {
         "value":"Tha title",
         "lang":"en"
      }
   ],
   "_embedded":{
      "http:\/\/d8.local\/rest\/relation\/node\/page\/uid":[
         {
            "_links":{
               "self":{
                  "href":"http:\/\/d8.local\/user\/1"
               },
               "type":{
                  "href":"http:\/\/d8.local\/rest\/type\/user\/user"
               }
            },
            "uuid":[
               {
                  "value":"37f20e01-027b-433e-a80b-111188403b70"
               }
            ],
            "lang":"en"
         }
      ],
      "http:\/\/d8.local\/rest\/relation\/node\/page\/revision_uid":[
         {
            "_links":{
               "self":{
                  "href":"http:\/\/d8.local\/user\/0"
               },
               "type":{
                  "href":"http:\/\/d8.local\/rest\/type\/user\/user"
               }
            },
            "uuid":[
               {
                  "value":"1e52d459-2904-4214-8960-96d25c08e787"
               }
            ]
         }
      ],
      "http:\/\/d8.local\/rest\/relation\/node\/page\/field_file":[
         {
            "_links":{
               "self":{
                  "href":""
               },
               "type":{
                  "href":"http:\/\/d8.local\/rest\/type\/file\/file"
               }
            },
            "uuid":[
               {
                  "value":"1e92c96f-f4b7-46ee-b926-38b68d186a0e"
               }
            ],
            "uri":[
               {
                  "value":"http:\/\/d8.local\/"
               }
            ]
         }
      ]
   },
   "status":[
      {
         "value":"1",
         "lang":"en"
      }
   ],
   "created":[
      {
         "value":"1401567395",
         "lang":"en"
      }
   ],
   "changed":[
      {
         "value":"1401567616",
         "lang":"en"
      }
   ],
   "promote":[
      {
         "value":"0",
         "lang":"en"
      }
   ],
   "sticky":[
      {
         "value":"0",
         "lang":"en"
      }
   ],
   "revision_timestamp":[
      {
         "value":"0"
      }
   ],
   "log":[
      {
         "value":"",
         "lang":"en"
      }
   ],
   "body":[
      {
         "value":"<p>tha body<\/p>\r\n",
         "format":"basic_html",
         "summary":""
      }
   ]
}