Elasticsearch NEST partial update of anonymous object with an empty nested object - elasticsearch

Question

Trying to "reset" a nested object in a document but it will not set it back to empty.
I have a POCO:
public class StreetAddress
{
public int HouseNumber { get; set; }
public string Street { get; set; }
}
public class FullAddress
{
public string City{ get; set; }
public string State { get; set; }
public StreetAddress StreetAddress { get; set; }
public int Zip { get; set; }
public List<string> Codes { get; set; }
}
So currently if I created this new document for FullAddress with the StreetAddress already set the document looks like this when queried:
"_source": {
"city": "Los Angeles",
"state": "California",
"zip": 90019,
"streetAddress": {
"houseNumber": 1,
"street": "Apple Street"
},
"codes" : [
{ "la-601" }
]
}
Now I want to call NEST client update to reset the StreetAddress nested object:
StreetAddress localStreetAddress = new StreetAddress();
var partialAddress = new
{
City = "NewCity",
Zip = 11111,
StreetAddress = localStreetAddress
};
this._client.Update<ElasticsearchProject, object>(update => update
.Id(1)
.Doc(partialAddress)
);
The final outcome I was hoping for when I query would be after the above update call:
"_source": {
"city": "NewCity",
"state": "California",
"zip": 11111,
"streetAddress": {}
}
However, the partial update does two things that is undesired:
It only updates the City and Zip fields and leaves the StreetAddress
as it was before and doesn't clear it out to empty or null.
It clears out the Codes list to empty since the partial update doesn't include the list.
I know I can set the StreetAddress to null and add the JSON property to include null like this:
[JsonProperty(NullValueHandling = NullValueHandling.Include)]
public StreetAddress StreetAddress { get; set; }
but all that would result is that the document update would set it to null and not empty and I am not sure if that is a desired result for the document:
"_source": {
"city": "NewCity",
"state": "California",
"zip": 11111,
"streetAddress": null
}
Not sure if there was a way to do a partial update without going down the script path to set the nested object back to empty.

Answer 1

Nested objects are actually mapped as separate hidden documents within Elasticsearch and as you have found, NEST by default is configured not to send through null values. the end result is that the nested type is not affected by your partial update to the top-level properties.
One way of handling this is to simply re-index the document again without the StreetAddress. An update is essentially a delete and insert behind the scenes anyway.
As an example
void Main()
{
var settings = new ConnectionSettings(new Uri("http://localhost:9200"), "address");
var client = new ElasticClient(settings);
// create the index
client.CreateIndex("address", c => c
.AddMapping<FullAddress>(m => m
.MapFromAttributes()
)
);
// index our document
client.Index(new FullAddress
{
City = "Los Angeles",
State = "California",
Zip = 90019,
Codes = new List<string>
{
"la-601"
},
StreetAddress = new StreetAddress
{
HouseNumber = 1,
Street = "Apple Street"
}
}, c => c.Id(1));
// Now at some later point, we need to update it,
// so get the current document
var response = client.Get<FullAddress>(1);
// make the changes to the current document
var address = response.Source;
address.StreetAddress = null;
// and re-index
client.Index<FullAddress>(address, c => c.Id(1));
}
public class StreetAddress
{
public int HouseNumber { get; set; }
public string Street { get; set; }
}
public class FullAddress
{
public string City { get; set; }
public string State { get; set; }
public StreetAddress StreetAddress { get; set; }
public int Zip { get; set; }
public List<string> Codes { get; set; }
}
The end result is as expected
{
"_index": "address",
"_type": "fulladdress",
"_id": "1",
"_version": 2,
"found": true,
"_source": {
"city": "Los Angeles",
"state": "California",
"zip": 90019,
"codes": [
"la-601"
]
}
}
You may also want to use optimistic concurrency control when doing this too, to handle any changes between the get and index.