Streaming large list of data as JSON format using Json.net
Assuming your final output is a JSON array and each "chunk" is one item in that array, you could try something like the following JsonStreamingResult
class. It uses a JsonTextWriter
to write the JSON to the output stream, and uses a JObject
as a means to serialize each item individually before writing it to the writer. You could pass the JsonStreamingResult
an IEnumerable
implementation which can read items individually from your data source so that you don't have them all in memory at once. I haven't tested this extensively, but it should get you going in the right direction.
public class JsonStreamingResult : ActionResult
{
private IEnumerable itemsToSerialize;
public JsonStreamingResult(IEnumerable itemsToSerialize)
{
this.itemsToSerialize = itemsToSerialize;
}
public override void ExecuteResult(ControllerContext context)
{
var response = context.HttpContext.Response;
response.ContentType = "application/json";
response.ContentEncoding = Encoding.UTF8;
JsonSerializer serializer = new JsonSerializer();
using (StreamWriter sw = new StreamWriter(response.OutputStream))
using (JsonTextWriter writer = new JsonTextWriter(sw))
{
writer.WriteStartArray();
foreach (object item in itemsToSerialize)
{
JObject obj = JObject.FromObject(item, serializer);
obj.WriteTo(writer);
writer.Flush();
}
writer.WriteEndArray();
}
}
}