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Indexes: Converting to JSON and Accessing Metadata

Entities passed to an index can be converted to JSON using the AsJson method.
It is also possible to access metadata for a specified object using the MetadataFor method.

AsJson - Converting to JSON​

public class Products_AllProperties : AbstractIndexCreationTask<Product, Products_AllProperties.Result>
{
  public class Result
  {
      public string Query { get; set; }
  }

  public Products_AllProperties()
  {
      Map = products => from product in products
          select new
          {
              // convert product to JSON and select all properties from it
              Query = AsJson(product).Select(x => x.Value)
          };

      // mark 'Query' field as analyzed which enables full text search operations
      Index(x => x.Query, FieldIndexing.Search);
  }
}
IList<Product> results = session
.Query<Products_AllProperties.Result, Products_AllProperties>()
.Where(x => x.Query == "Chocolade")
.OfType<Product>()
.ToList();

MetadataFor - Accessing Metadata​

public class Products_WithMetadata : AbstractIndexCreationTask<Product>
{
public class Result
{
	public DateTime LastModified { get; set; }
}

public Products_WithMetadata()
{
	Map = products => from product in products
				let metadata = MetadataFor(product)
				select new
				{
					LastModified = metadata.Value<DateTime>("@last-modified")
				};
}
}
IList<Product> results = session
.Query<Products_WithMetadata.Result, Products_WithMetadata>()
.OrderByDescending(x => x.LastModified)
.OfType<Product>()
.ToList();