[[search-template]]
=== Search Template

Allows you to use the mustache language to pre render search requests.

[source,console]
------------------------------------------
GET _search/template
{
  "source" : {
    "query": { "match" : { "{{my_field}}" : "{{my_value}}" } },
    "size" : "{{my_size}}"
  },
  "params" : {
    "my_field" : "message",
    "my_value" : "foo",
    "my_size" : 5
  }
}
------------------------------------------
// TEST[setup:my_index]

[[search-template-api-request]]
==== {api-request-title}

`GET _search/template`


[[search-template-api-desc]]
==== {api-description-title}

The `/_search/template` endpoint allows you to use the mustache language to pre-
render search requests, before they are executed and fill existing templates
with template parameters.

For more information on how Mustache templating and what kind of templating you
can do with it check out the https://mustache.github.io/mustache.5.html[online
documentation of the mustache project].

NOTE: The mustache language is implemented in {es} as a sandboxed scripting
language, hence it obeys settings that may be used to enable or disable scripts
per type and context as described in the
<<allowed-script-types-setting, scripting docs>>.


[[search-template-api-path-params]]
==== {api-path-parms-title}

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=index]


[[search-template-api-query-params]]
==== {api-query-parms-title}

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=allow-no-indices]
+
Defaults to `true`.

`ccs_minimize_roundtrips`::
  (Optional, boolean) If `true`, network round-trips are minimized for
 cross-cluster search requests. Defaults to `true`.

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=expand-wildcards]

`explain`::
  (Optional, boolean) If `true`, the response includes additional details about
  score computation as part of a hit. Defaults to `false`.

`ignore_throttled`::
  (Optional, boolean) If `true`, specified concrete, expanded or aliased indices
  are not included in the response when throttled. Defaults to `true`.

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=index-ignore-unavailable]

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=preference]

`profile`::
  (Optional, boolean) If `true`, the query execution is profiled. Defaults
  to `false`.

`rest_total_hits_as_int`::
  (Optional, boolean) If `true`, `hits.total` are rendered as an integer in
  the response. Defaults to `false`.

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=routing]

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=scroll]

include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=search_type]

`typed_keys`::
  (Optional, boolean) If `true`, aggregation and suggester names are
  prefixed by their respective types in the response. Defaults to `false`.


[[search-template-api-request-body]]
==== {api-request-body-title}

The API request body must contain the search definition template and its parameters.


[[search-template-api-example]]
==== {api-response-codes-title}


[[pre-registered-templates]]
===== Store a search template

You can store a search template using the stored scripts API.

[source,console]
------------------------------------------
POST _scripts/<templateid>
{
  "script": {
    "lang": "mustache",
    "source": {
      "query": {
        "match": {
          "title": "{{query_string}}"
        }
      }
    }
  }
}
------------------------------------------
// TEST[continued]

//////////////////////////

The API returns the following result if the template has been successfully
created:

[source,console-result]
--------------------------------------------------
{
  "acknowledged" : true
}
--------------------------------------------------

//////////////////////////


The template can be retrieved by calling

[source,console]
------------------------------------------
GET _scripts/<templateid>
------------------------------------------
// TEST[continued]

The API returns the following result:

[source,console-result]
------------------------------------------
{
  "script" : {
    "lang" : "mustache",
    "source" : """{"query":{"match":{"title":"{{query_string}}"}}}""",
    "options": {
      "content_type" : "application/json; charset=UTF-8"
    }
  },
  "_id": "<templateid>",
  "found": true
}
------------------------------------------


This template can be deleted by calling

[source,console]
------------------------------------------
DELETE _scripts/<templateid>
------------------------------------------
// TEST[continued]


[[use-registered-templates]]
===== Using a stored search template

To use a stored template at search time send the following request:

[source,console]
------------------------------------------
GET _search/template
{
  "id": "<templateid>", <1>
  "params": {
    "query_string": "search for these words"
  }
}
------------------------------------------
// TEST[catch:missing]
<1> Name of the stored template script.


[[_validating_templates]]
==== Validating a search template

A template can be rendered in a response with given parameters by using the
following request:

[source,console]
------------------------------------------
GET _render/template
{
  "source": "{ \"query\": { \"terms\": {{#toJson}}statuses{{/toJson}} }}",
  "params": {
    "statuses" : {
        "status": [ "pending", "published" ]
    }
  }
}
------------------------------------------


The API returns the rendered template:

[source,console-result]
------------------------------------------
{
  "template_output": {
    "query": {
      "terms": {
        "status": [ <1>
          "pending",
          "published"
        ]
      }
    }
  }
}
------------------------------------------

<1> `status` array has been populated with values from the `params` object.


Stored templates can also be rendered by calling the following request:

[source,js]
------------------------------------------
GET _render/template/<template_name>
{
  "params": {
    "..."
  }
}
------------------------------------------
// NOTCONSOLE

[[search-template-explain-parameter]]
===== Using the explain parameter

You can use the `explain` parameter when running a template:

[source,console]
------------------------------------------
GET _search/template
{
  "id": "my_template",
  "params": {
    "status": [ "pending", "published" ]
  },
  "explain": true
}
------------------------------------------
// TEST[catch:missing]


[[search-template-profile-parameter]]
===== Profiling

You can use the `profile` parameter when running a template:

[source,console]
------------------------------------------
GET _search/template
{
  "id": "my_template",
  "params": {
    "status": [ "pending", "published" ]
  },
  "profile": true
}
------------------------------------------
// TEST[catch:missing]


[[search-template-query-string-single]]
===== Filling in a query string with a single value

[source,console]
------------------------------------------
GET _search/template
{
  "source": {
    "query": {
      "term": {
        "message": "{{query_string}}"
      }
    }
  },
  "params": {
    "query_string": "search for these words"
  }
}
------------------------------------------
// TEST[setup:my_index]

[[search-template-converting-to-json]]
===== Converting parameters to JSON

The `{{#toJson}}parameter{{/toJson}}` function can be used to convert parameters
like maps and array to their JSON representation:

[source,console]
------------------------------------------
GET _search/template
{
  "source": "{ \"query\": { \"terms\": {{#toJson}}statuses{{/toJson}} }}",
  "params": {
    "statuses" : {
        "status": [ "pending", "published" ]
    }
  }
}
------------------------------------------

which is rendered as:

[source,js]
------------------------------------------
{
  "query": {
    "terms": {
      "status": [
        "pending",
        "published"
      ]
    }
  }
}
------------------------------------------
// NOTCONSOLE

A more complex example substitutes an array of JSON objects:

[source,console]
------------------------------------------
GET _search/template
{
  "source": "{\"query\":{\"bool\":{\"must\": {{#toJson}}clauses{{/toJson}} }}}",
  "params": {
    "clauses": [
      { "term": { "user" : "foo" } },
      { "term": { "user" : "bar" } }
    ]
  }
}
------------------------------------------

which is rendered as:

[source,js]
------------------------------------------
{
  "query": {
    "bool": {
      "must": [
        {
          "term": {
            "user": "foo"
          }
        },
        {
          "term": {
            "user": "bar"
          }
        }
      ]
    }
  }
}
------------------------------------------
// NOTCONSOLE

[[search-template-concatenate-array]]
===== Concatenating array of values

The `{{#join}}array{{/join}}` function can be used to concatenate the
values of an array as a comma delimited string:

[source,console]
------------------------------------------
GET _search/template
{
  "source": {
    "query": {
      "match": {
        "emails": "{{#join}}emails{{/join}}"
      }
    }
  },
  "params": {
    "emails": [ "username@email.com", "lastname@email.com" ]
  }
}
------------------------------------------

which is rendered as:

[source,js]
------------------------------------------
{
  "query" : {
    "match" : {
      "emails" : "username@email.com,lastname@email.com"
    }
  }
}
------------------------------------------
// NOTCONSOLE

The function also accepts a custom delimiter:

[source,console]
------------------------------------------
GET _search/template
{
  "source": {
    "query": {
      "range": {
        "born": {
            "gte"   : "{{date.min}}",
            "lte"   : "{{date.max}}",
            "format": "{{#join delimiter='||'}}date.formats{{/join delimiter='||'}}"
	    }
      }
    }
  },
  "params": {
    "date": {
        "min": "2016",
        "max": "31/12/2017",
        "formats": ["dd/MM/yyyy", "yyyy"]
    }
  }
}
------------------------------------------

which is rendered as:

[source,js]
------------------------------------------
{
  "query": {
    "range": {
      "born": {
        "gte": "2016",
        "lte": "31/12/2017",
        "format": "dd/MM/yyyy||yyyy"
      }
    }
  }
}

------------------------------------------
// NOTCONSOLE

[[search-template-default-values]]
===== Default values

A default value is written as `{{var}}{{^var}}default{{/var}}` for instance:

[source,js]
------------------------------------------
{
  "source": {
    "query": {
      "range": {
        "line_no": {
          "gte": "{{start}}",
          "lte": "{{end}}{{^end}}20{{/end}}"
        }
      }
    }
  },
  "params": { ... }
}
------------------------------------------
// NOTCONSOLE

When `params` is `{ "start": 10, "end": 15 }` this query would be rendered as:

[source,js]
------------------------------------------
{
  "range": {
    "line_no": {
      "gte": "10",
      "lte": "15"
    }
  }
}
------------------------------------------
// NOTCONSOLE

But when `params` is `{ "start": 10 }` this query would use the default value
for `end`:

[source,js]
------------------------------------------
{
  "range": {
    "line_no": {
      "gte": "10",
      "lte": "20"
    }
  }
}
------------------------------------------
// NOTCONSOLE

[[search-template-conditional-clauses]]
===== Conditional clauses

Conditional clauses cannot be expressed using the JSON form of the template.
Instead, the template *must* be passed as a string.  For instance, let's say
we wanted to run a `match` query on the `line` field, and optionally wanted
to filter by line numbers, where `start` and `end` are optional.

The `params` would look like:

[source,js]
------------------------------------------
{
  "params": {
    "text": "words to search for",
    "line_no": {                      <1>
      "start": 10,
      "end": 20
    }
  }
}
------------------------------------------
// NOTCONSOLE
<1> The `line_no`, `start`, and `end` parameters are optional.

When written as a query, the template would include invalid JSON, such as
section markers like `{{#line_no}}`:

[source,js]
------------------------------------------
{
  "query": {
    "bool": {
      "must": {
        "match": {
          "line": "{{text}}" <1>
        }
      },
      "filter": {
        {{#line_no}} <2>
          "range": {
            "line_no": {
              {{#start}} <3>
                "gte": "{{start}}" <4>
                {{#end}},{{/end}} <5>
              {{/start}}
              {{#end}} <6>
                "lte": "{{end}}" <7>
              {{/end}}
            }
          }
        {{/line_no}}
      }
    }
  }
}
------------------------------------------
// NOTCONSOLE
<1> Fill in the value of param `text`
<2> Include the `range` filter only if `line_no` is specified
<3> Include the `gte` clause only if `line_no.start` is specified
<4> Fill in the value of param `line_no.start`
<5> Add a comma after the `gte` clause only if `line_no.start`
    AND `line_no.end` are specified
<6> Include the `lte` clause only if `line_no.end` is specified
<7> Fill in the value of param `line_no.end`

Because search templates cannot include invalid JSON, you can pass the same
query as a string instead:

[source,js]
--------------------
"source": "{\"query\":{\"bool\":{\"must\":{\"match\":{\"line\":\"{{text}}\"}},\"filter\":{{{#line_no}}\"range\":{\"line_no\":{{{#start}}\"gte\":\"{{start}}\"{{#end}},{{/end}}{{/start}}{{#end}}\"lte\":\"{{end}}\"{{/end}}}}{{/line_no}}}}}}"
--------------------
// NOTCONSOLE


[[search-template-encode-urls]]
===== Encoding URLs

The `{{#url}}value{{/url}}` function can be used to encode a string value
in a HTML encoding form as defined in by the
https://www.w3.org/TR/html4/[HTML specification].

As an example, it is useful to encode a URL:

[source,console]
------------------------------------------
GET _render/template
{
  "source": {
    "query": {
      "term": {
        "http_access_log": "{{#url}}{{host}}/{{page}}{{/url}}"
      }
    }
  },
  "params": {
    "host": "https://www.elastic.co/",
    "page": "learn"
  }
}
------------------------------------------


The previous query will be rendered as:

[source,console-result]
------------------------------------------
{
  "template_output": {
    "query": {
      "term": {
        "http_access_log": "https%3A%2F%2Fwww.elastic.co%2F%2Flearn"
      }
    }
  }
}
------------------------------------------


[[multi-search-template]]
=== Multi Search Template

Allows to execute several search template requests.

[[multi-search-template-api-request]]
==== {api-request-title}

`GET _msearch/template`


[[multi-search-template-api-desc]]
==== {api-description-title}

Allows to execute several search template requests within the same API using the
`_msearch/template` endpoint.

The format of the request is similar to the <<search-multi-search, Multi
Search API>> format:

[source,js]
--------------------------------------------------
header\n
body\n
header\n
body\n
--------------------------------------------------
// NOTCONSOLE

The header part supports the same `index`, `search_type`, `preference`, and
`routing` options as the Multi Search API.

The body includes a search template body request and supports inline, stored and
file templates.


[[multi-search-template-api-example]]
==== {api-examples-title}

[source,js]
--------------------------------------------------
$ cat requests
{"index": "test"}
{"source": {"query": {"match":  {"user" : "{{username}}" }}}, "params": {"username": "john"}} <1>
{"source": {"query": {"{{query_type}}": {"name": "{{name}}" }}}, "params": {"query_type": "match_phrase_prefix", "name": "Smith"}}
{"index": "_all"}
{"id": "template_1", "params": {"query_string": "search for these words" }} <2>

$ curl -H "Content-Type: application/x-ndjson" -XGET localhost:9200/_msearch/template --data-binary "@requests"; echo
--------------------------------------------------
// NOTCONSOLE
// Not converting to console because this shows how curl works
<1> Inline search template request

<2> Search template request based on a stored template

The response returns a `responses` array, which includes the search template
response for each search template request matching its order in the original
multi search template request. If there was a complete failure for that specific
search template request, an object with `error` message will be returned in
place of the actual search response.
