adding wrapper dsl query docs (#9939)

* adding wrapper dsl query docs

Signed-off-by: Anton Rubin <anton.rubin@eliatra.com>

* adding changes to the docs

Signed-off-by: Anton Rubin <anton.rubin@eliatra.com>

* addressing the PR comments

Signed-off-by: Anton Rubin <anton.rubin@eliatra.com>

* Apply suggestions from code review

Co-authored-by: kolchfa-aws <105444904+kolchfa-aws@users.noreply.github.com>
Signed-off-by: AntonEliatra <anton.rubin@eliatra.com>

* Update _query-dsl/specialized/wrapper.md

Signed-off-by: Nathan Bower <nbower@amazon.com>

---------

Signed-off-by: Anton Rubin <anton.rubin@eliatra.com>
Signed-off-by: AntonEliatra <anton.rubin@eliatra.com>
Signed-off-by: Nathan Bower <nbower@amazon.com>
Co-authored-by: kolchfa-aws <105444904+kolchfa-aws@users.noreply.github.com>
Co-authored-by: Nathan Bower <nbower@amazon.com>
(cherry picked from commit 5f2acf3)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: 3 people

_query-dsl/specialized/index.md

@@ -28,4 +28,4 @@ OpenSearch supports the following specialized queries:
 
 - [`script_score`]({{site.url}}{{site.baseurl}}/query-dsl/specialized/script-score/): Calculates a custom score for matching documents using a script.
 
-- `wrapper`: Accepts other queries as JSON or YAML strings.
+- [`wrapper`]({{site.url}}{{site.baseurl}}/query-dsl/specialized/wrapper/): Accepts other queries as JSON or YAML strings.

_query-dsl/specialized/wrapper.md

@@ -0,0 +1,96 @@
+---
+
+layout: default
+title: Wrapper
+parent: Specialized queries
+nav_order: 80
+---
+
+# Wrapper
+
+The `wrapper` query lets you submit a complete query in Base64-encoded JSON format. It is useful when the query must be embedded in contexts that only support string values.
+
+Use this query only when you need to manage system constraints. For readability and maintainability, it's better to use standard JSON-based queries when possible.
+
+## Example
+
+Create an index named `products` with the following mappings:
+
+```json
+PUT /products
+{
+  "mappings": {
+    "properties": {
+      "title": { "type": "text" }
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+Index sample documents:
+
+```json
+POST /products/_bulk
+{ "index": { "_id": 1 } }
+{ "title": "Wireless headphones with noise cancellation" }
+{ "index": { "_id": 2 } }
+{ "title": "Bluetooth speaker" }
+{ "index": { "_id": 3 } }
+{ "title": "Over-ear headphones with rich bass" }
+```
+{% include copy-curl.html %}
+
+Encode the following query in Base64 format:
+
+```bash
+echo -n '{ "match": { "title": "headphones" } }' | base64
+```
+{% include copy.html %}
+
+Execute the encoded query:
+
+```json
+POST /products/_search
+{
+  "query": {
+    "wrapper": {
+      "query": "eyAibWF0Y2giOiB7ICJ0aXRsZSI6ICJoZWFkcGhvbmVzIiB9IH0="
+    }
+  }
+}
+```
+{% include copy-curl.html %}
+
+The response contains the two matching documents:
+
+```json
+{
+  ...
+  "hits": {
+    "total": {
+      "value": 2,
+      "relation": "eq"
+    },
+    "max_score": 0.20098841,
+    "hits": [
+      {
+        "_index": "products",
+        "_id": "1",
+        "_score": 0.20098841,
+        "_source": {
+          "title": "Wireless headphones with noise cancellation"
+        }
+      },
+      {
+        "_index": "products",
+        "_id": "3",
+        "_score": 0.18459359,
+        "_source": {
+          "title": "Over-ear headphones with rich bass"
+        }
+      }
+    ]
+  }
+}
+```