Month: August 2021

How to get raw query generated by Elasticsearch NEST library for debugging purpose

Source: https://stackoverflow.com/questions/28939022/get-raw-query-from-nest-client/50023531#50023531

For NEST / Elasticsearch.NET v6.0.2, use the ApiCall property of the IResponse object. You can write a handy extension method like this:

public static string ToJson(this IResponse response)
{
    return Encoding.UTF8.GetString(response.ApiCall.RequestBodyInBytes);
}

Or, if you want to log all requests made to Elastic, you can intercept responses with the connection object:

var node = new Uri("https://localhost:9200");
var pool = new SingleNodeConnectionPool(node);
var connectionSettings = new ConnectionSettings(pool, new HttpConnection());
connectionSettings.OnRequestCompleted(call =>
{
    Debug.Write(Encoding.UTF8.GetString(call.RequestBodyInBytes));
});

You need to call on the ES client connection setting object to allow reading request JSON. This is best done on DEBUG mode.

connectionSettings.DisableDirectStreaming(true)

Filtering by multiple conditions with nested queries in Elasticsearch

All bool queries are evaluated on a single document.

So if you have an index like this

Products= {

Fields: { Name: string; Value: int; }[];

}

And you want to find products with field “Price” between 10 and 20, and field “Discount” between 0 and 5, you can use the following query

bool: {

must: [

{nested: { //nested query to find products with price from 10 to 20},

{nested: { //nested query to find products with Discount from 0 to 5}

]

}

It looks quite hard to follow.