Azure Cognitive Search: How to index json custom metadata of a blob - azure

Question

I have a blob with a custom metadata property of jsonmd.
The custom metadata looks something like:
{
"ResourceName": "ipso factum...",
"ResourceVariations": [{
"Description": "ipso factum...",
"Name": "R4.mp4",
"Thumbnail": "R4.jpg",
"URL": ""
},
...
I was able to capture the full json in the index by including a filed in the index:
{
"name": "jsonmd",
"type": "Edm.String",
"facetable": true,
"filterable": true,
...
I want to capture the Thumbnail property and have added this field to the index:
{
"name": "Thumbnail",
"type": "Edm.String",
"facetable": true,
"filterable": true,
"key": false,
"retrievable": true,
"searchable": true,
"sortable": true,
"analyzer": "standard.lucene",
"indexAnalyzer": null,
"searchAnalyzer": null,
"synonymMaps": [],
"fields": []
}
I can't figure out how to use the custom metadata (jsonmd) to populate the Thumbnail property of the index?

Answer 1

You can define complex types in your index schema. Below is an example of how I collect metadata from PDF documents that we index. I extract the properties from the PDF using regular C# code, populate a Dictionary and then submit the objects using the Azure Cognitive Search SDK.
For more examples, see Model complex data types in Azure Cognitive Search.
{
"name": "Metadata",
"type": "Edm.ComplexType",
"analyzer": null,
"synonymMaps": [],
"fields": [
{
"name": "Properties",
"type": "Collection(Edm.ComplexType)",
"analyzer": null,
"synonymMaps": [],
"fields": [
{
"name": "Name",
"type": "Edm.String",
"facetable": true,
"filterable": true,
"key": false,
"retrievable": true,
"searchable": true,
"sortable": false,
"analyzer": "pattern",
"indexAnalyzer": null,
"searchAnalyzer": null,
"synonymMaps": [],
"fields": []
},
{
"name": "Values",
"type": "Collection(Edm.String)",
"facetable": true,
"filterable": true,
"retrievable": true,
"searchable": true,
"analyzer": "pattern",
"indexAnalyzer": null,
"searchAnalyzer": null,
"synonymMaps": [],
"fields": []
}
]
}
]
}