So you need to add the ingest attachment plugin
Click on Settings and Plugins:
Add the plugin. And don't forget to save the changes.
After the cluster has been updated, you will be able to use the Elasticsearch endpoint to call the _simulate API. See Simulate pipeline API | Elasticsearch Reference [7.11] | Elastic
If you mix that with the plugin documentation, you should be able to execute something like:
# Create the pipeline
PUT _ingest/pipeline/attachment
{
"description" : "Extract attachment information",
"processors" : [
{
"attachment" : {
"field" : "data"
}
}
]
}
Use the simulate endpoint
POST /_ingest/pipeline/attachment/_simulate
{
"docs": [
{
"_index": "index",
"_id": "id",
"_source": {
"data": "e1xydGYxXGFuc2kNCkxvcmVtIGlwc3VtIGRvbG9yIHNpdCBhbWV0DQpccGFyIH0="
}
}
]
}
This will give you an output. Use that content to build your own JSON and send that to AppSearch.
Note that e1xydGYxXGFuc2kNCkxvcmVtIGlwc3VtIGRvbG9yIHNpdCBhbWV0DQpccGFyIH0= is a BASE64 encoding of a binary file. (A text file here).