AddIndexer.ps1

$AzureCognitiveSearchURL = "https://sharepointsearchinstance.search.windows.net"
$AzureCognitiveSearchAdminKey = "Wt1mZ0sjkKoXW913d2eJ8xXYJk4JHThk1UK8H0wZoIAzSeDjYTmC"

$Header = @{"api-key"  = "$AzureCognitiveSearchAdminKey"
"content-type" = "application/json"

}



$Body = @"
{
    "name" : "sharepoint-indexer",
    "dataSourceName" : "sharepoint-datasource",
    "targetIndexName" : "sharepoint-index",
    "parameters": {
    "batchSize": null,
    "maxFailedItems": null,
    "maxFailedItemsPerBatch": null,
    "base64EncodeKeys": null,
    "configuration": {
        "indexedFileNameExtensions" : ".pdf, .docx",
        "excludedFileNameExtensions" : ".png, .jpg",
        "dataToExtract": "contentAndMetadata"
      }
    },
    "schedule" : { },
    "fieldMappings" : [
        { 
          "sourceFieldName" : "metadata_spo_site_library_item_id", 
          "targetFieldName" : "id", 
          "mappingFunction" : { 
            "name" : "base64Encode" 
          } 
         }
    ]
}

"@

$uri = "$AzureCognitiveSearchURL/indexers?api-version=2020-06-30"
invoke-restmethod -Method POST -Uri $uri -Body $body  -Headers $Header