[[docs-get]]
== Get API

The get API allows to get a typed JSON document from the index based on
its id. The following example gets a JSON document from an index called
twitter, under a type called tweet, with id valued 0:

[source,js]
--------------------------------------------------
GET twitter/tweet/0
--------------------------------------------------
// CONSOLE
// TEST[setup:twitter]

The result of the above get operation is:

[source,js]
--------------------------------------------------
{
    "_index" : "twitter",
    "_type" : "tweet",
    "_id" : "0",
    "_version" : 1,
    "found": true,
    "_source" : {
        "user" : "kimchy",
        "date" : "2009-11-15T14:12:12",
        "likes": 0,
        "message" : "trying out Elasticsearch"
    }
}
--------------------------------------------------
// TESTRESPONSE

The above result includes the `_index`, `_type`, `_id` and `_version`
of the document we wish to retrieve, including the actual `_source`
of the document if it could be found (as indicated by the `found`
field in the response).

The API also allows to check for the existence of a document using
`HEAD`, for example:

[source,js]
--------------------------------------------------
HEAD twitter/tweet/0
--------------------------------------------------
// CONSOLE
// TEST[setup:twitter]

[float]
[[realtime]]
=== Realtime

By default, the get API is realtime, and is not affected by the refresh
rate of the index (when data will become visible for search). If a document
has been updated but is not yet refreshed, the get API will issue a refresh
call in-place to make the document visible. This will also make other documents
changed since the last refresh visible. In order to disable realtime GET,
one can set the `realtime` parameter to `false`.

[float]
[[type]]
=== Optional Type

The get API allows for `_type` to be optional. Set it to `_all` in order
to fetch the first document matching the id across all types.


[float]
[[get-source-filtering]]
=== Source filtering

By default, the get operation returns the contents of the `_source` field unless
you have used the `stored_fields` parameter or if the `_source` field is disabled.
You can turn off `_source` retrieval by using the `_source` parameter:

[source,js]
--------------------------------------------------
GET twitter/tweet/0?_source=false
--------------------------------------------------
// CONSOLE
// TEST[setup:twitter]

If you only need one or two fields from the complete `_source`, you can use the `_source_include`
& `_source_exclude` parameters to include or filter out that parts you need. This can be especially helpful
with large documents where partial retrieval can save on network overhead. Both parameters take a comma separated list
of fields or wildcard expressions. Example:

[source,js]
--------------------------------------------------
GET twitter/tweet/0?_source_include=*.id&_source_exclude=entities
--------------------------------------------------
// CONSOLE
// TEST[setup:twitter]

If you only want to specify includes, you can use a shorter notation:

[source,js]
--------------------------------------------------
GET twitter/tweet/0?_source=*.id,retweeted
--------------------------------------------------
// CONSOLE
// TEST[setup:twitter]

[float]
[[get-stored-fields]]
=== Stored Fields

The get operation allows specifying a set of stored fields that will be
returned by passing the `stored_fields` parameter.
If the requested fields are not stored, they will be ignored.
Consider for instance the following mapping:

[source,js]
--------------------------------------------------
PUT twitter
{
   "mappings": {
      "tweet": {
         "properties": {
            "counter": {
               "type": "integer",
               "store": false
            },
            "tags": {
               "type": "keyword",
               "store": true
            }
         }
      }
   }
}
--------------------------------------------------
// CONSOLE

Now we can add a document:

[source,js]
--------------------------------------------------
PUT twitter/tweet/1
{
    "counter" : 1,
    "tags" : ["red"]
}
--------------------------------------------------
// CONSOLE
// TEST[continued]

... and try to retrieve it:

[source,js]
--------------------------------------------------
GET twitter/tweet/1?stored_fields=tags,counter
--------------------------------------------------
// CONSOLE
// TEST[continued]

The result of the above get operation is:

[source,js]
--------------------------------------------------
{
   "_index": "twitter",
   "_type": "tweet",
   "_id": "1",
   "_version": 1,
   "found": true,
   "fields": {
      "tags": [
         "red"
      ]
   }
}
--------------------------------------------------
// TESTRESPONSE


Field values fetched from the document it self are always returned as an array.
Since the `counter` field is not stored the get request simply ignores it when trying to get the `stored_fields.`

It is also possible to retrieve metadata fields like `_routing` and `_parent` fields:

[source,js]
--------------------------------------------------
PUT twitter/tweet/2?routing=user1
{
    "counter" : 1,
    "tags" : ["white"]
}
--------------------------------------------------
// CONSOLE
// TEST[continued]

[source,js]
--------------------------------------------------
GET twitter/tweet/2?routing=user1&stored_fields=tags,counter
--------------------------------------------------
// CONSOLE
// TEST[continued]

The result of the above get operation is:

[source,js]
--------------------------------------------------
{
   "_index": "twitter",
   "_type": "tweet",
   "_id": "2",
   "_version": 1,
   "_routing": "user1",
   "found": true,
   "fields": {
      "tags": [
         "white"
      ]
   }
}
--------------------------------------------------
// TESTRESPONSE

Also only leaf fields can be returned via the `stored_field` option. So object fields can't be returned and such requests
will fail.

[float]
[[generated-fields]]
=== Generated fields
If no refresh occurred between indexing and refresh, GET will access the transaction log to fetch the document. However, some fields are generated only when indexing. 
If you try to access a field that is only generated when indexing, you will get an exception (default). You can choose to ignore field that are generated if the transaction log is accessed by setting `ignore_errors_on_generated_fields=true`.


[float]
[[_source]]
=== Getting the _source directly

Use the `/{index}/{type}/{id}/_source` endpoint to get
just the `_source` field of the document,
without any additional content around it. For example:

[source,js]
--------------------------------------------------
GET twitter/tweet/1/_source
--------------------------------------------------
// CONSOLE
// TEST[continued]

You can also use the same source filtering parameters to control which parts of the `_source` will be returned:

[source,js]
--------------------------------------------------
GET twitter/tweet/1/_source?_source_include=*.id&_source_exclude=entities'
--------------------------------------------------
// CONSOLE
// TEST[continued]

Note, there is also a HEAD variant for the _source endpoint to efficiently test for document _source existence.
An existing document will not have a _source if it is disabled in the <<mapping-source-field,mapping>>.

[source,js]
--------------------------------------------------
HEAD twitter/tweet/1/_source
--------------------------------------------------
// CONSOLE
// TEST[continued]

[float]
[[get-routing]]
=== Routing

When indexing using the ability to control the routing, in order to get
a document, the routing value should also be provided. For example:

[source,js]
--------------------------------------------------
GET twitter/tweet/2?routing=user1
--------------------------------------------------
// CONSOLE
// TEST[continued]

The above will get a tweet with id 2, but will be routed based on the
user. Note, issuing a get without the correct routing, will cause the
document not to be fetched.

[float]
[[preference]]
=== Preference

Controls a `preference` of which shard replicas to execute the get
request on. By default, the operation is randomized between the shard
replicas.

The `preference` can be set to:

`_primary`:: 
	The operation will go and be executed only on the primary
	shards.

`_local`:: 
	The operation will prefer to be executed on a local
	allocated shard if possible.

Custom (string) value:: 
	A custom value will be used to guarantee that
	the same shards will be used for the same custom value. This can help
	with "jumping values" when hitting different shards in different refresh
	states. A sample value can be something like the web session id, or the
	user name.

[float]
[[get-refresh]]
=== Refresh

The `refresh` parameter can be set to `true` in order to refresh the
relevant shard before the get operation and make it searchable. Setting
it to `true` should be done after careful thought and verification that
this does not cause a heavy load on the system (and slows down
indexing).

[float]
[[get-distributed]]
=== Distributed

The get operation gets hashed into a specific shard id. It then gets
redirected to one of the replicas within that shard id and returns the
result. The replicas are the primary shard and its replicas within that
shard id group. This means that the more replicas we will have, the
better GET scaling we will have.


[float]
[[get-versioning]]
=== Versioning support

You can use the `version` parameter to retrieve the document only if
its current version is equal to the specified one. This behavior is the same
for all version types with the exception of version type `FORCE` which always
retrieves the document. Note that `FORCE` version type is deprecated.

Internally, Elasticsearch has marked the old document as deleted and added an
entirely new document. The old version of the document doesn’t disappear
immediately, although you won’t be able to access it. Elasticsearch cleans up
deleted documents in the background as you continue to index more data.
