I am getting error in using a simple script. Can anybody take a look at what is wrong? I want to use doc['field_name'] but it is throwing error. I want to use doc['field_name'] in my code.

Error in Script

curl -XPOST localhost:9200/twitter/script -d '{"user" : 1}'
{"ok":true,"_index":"twitter","_type":"script","_id":"QdNvKdECReqKmJXz5XhJFw","_version":1}

curl -XGET 'localhost:9200/twitter/script/_search?pretty=true' -d '
{
   "query":
   {
      "custom_score":
      {
          "query":{"match_all":{}},
          "script" : " 1.0 + _source.user"
      }
   }
}'
{
  "took" : 5,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "failed" : 0
  },
  "hits" : {
    "total" : 1,
    "max_score" : 2.0,
    "hits" : [ {
      "_index" : "twitter",
      "_type" : "script",
      "_id" : "QdNvKdECReqKmJXz5XhJFw",
      "_score" : 2.0, "_source" : {"user" : 1}
    } ]
  }
}

curl -XGET 'localhost:9200/twitter/script/_search?pretty=true' -d '
{
   "query":
   {
      "custom_score":
      {
          "query":{"match_all":{}},
          "script" : " 1.0 + doc['user']"
      }
   }
}'
{
  "took" : 7,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 4,
    "failed" : 1,
    "failures" : [ {
      "index" : "twitter",
      "shard" : 4,
      "reason" : "QueryPhaseExecutionException[[twitter][4]: query[custom score (ConstantScore(*:*),function=org.elasticsearch.index.query.xcontent.CustomScoreQueryParser$ScriptScoreFunction@1dff935)],from[0],size[10]: Query Failed [Failed to execute main query]]; nested: CompileException[[Error: No field found for [org.elasticsearch.index.field.data.strings.StringDocFieldData@10a3029]]\n[Near : {... 1.0 + doc[user] ....}]\n             ^\n[Line: 1, Column: 1]]; nested: ElasticSearchIllegalArgumentException[No field found for [org.elasticsearch.index.field.data.strings.StringDocFieldData@10a3029]]; "
    } ]
  },
  "hits" : {
    "total" : 0,
    "max_score" : null,
    "hits" : [ ]
  }
}