Elasticsearch bulk insert with index name in URL

es_bulk1

$ cat req
{ "index" : { "_type" : "type1", "_id" : "1" } }
{ "field1" : "value1" }
{ "index" : { "_type" : "type1", "_id" : "2" } }
{ "field1" : "value2" }
$ curl -XPOST  localhost:9200/testing/_bulk?pretty=true --data-binary @req
{
  "took" : 5,
  "items" : [ {
    "index" : {
      "_index" : "testing",
      "_type" : "type1",
      "_id" : "1",
      "_version" : 2,
      "ok" : true
    }
  }, {
    "index" : {
      "_index" : "testing",
      "_type" : "type1",
      "_id" : "2",
      "_version" : 2,
      "ok" : true
    }
  } ]
}

es_bulk2

#note how the index in the file overrides the one in the URL

$ cat req
{ "index" : { "_index": "override", "_type" : "type1", "_id" : "1" } }
{ "field1" : "value1" }
{ "index" : { "_index": "override", "_type" : "type1", "_id" : "2" } }
{ "field1" : "value2" }
$ curl -XPOST  localhost:9200/testing/_bulk?pretty=true --data-binary @req
{
  "took" : 234,
  "items" : [ {
    "index" : {
      "_index" : "override",
      "_type" : "type1",
      "_id" : "1",
      "_version" : 1,
      "ok" : true
    }
  }, {
    "index" : {
      "_index" : "override",
      "_type" : "type1",
      "_id" : "2",
      "_version" : 1,
      "ok" : true
    }
  } ]
}