Java Requires Chilkat v11.5.0+

Box: Poll User Events and Save a Checkpoint

See more Box Examples

Poll the authenticated user event stream in bounded batches. The local JSON checkpoint keeps processed event IDs and the next stream position. This single-process demonstration logs events; a production worker should commit its business action, deduplication record, and cursor transactionally and prune old IDs.

See the Box API guide for setup and the complete workflow.

Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    //  Requires Chilkat 11.5.0 or later and a previously unlocked Chilkat bundle.
    //  See Global Unlock Sample.
    //  Guide: Box API Guide.

    success = false;

    //  Supply an unexpired token obtained with one of the Box authentication examples.
    //  A token represents a particular user or service account. IDs must be accessible to it.
    CkHttpCurl curl = new CkHttpCurl();
    curl.SetVar("access_token","BOX_ACCESS_TOKEN");

    CkJsonObject state = new CkJsonObject();
    CkFileAccess files = new CkFileAccess();
    String statePath = "qa_data/box_events_state.json";
    if (files.FileExists(statePath) == true) {
        success = state.LoadFile(statePath);
        if (success != true) {
            System.out.println(state.lastErrorText());
            return;
            }

        if (state.HasMember("position") != true) {
            System.out.println("Invalid checkpoint: position missing.");
            return;
            }

        }
    else {
        //  "now" starts a new subscription. It deliberately skips historical events.
        state.UpdateString("position","now");
        }

    curl.SetVar("position",state.stringOf("position"));
    CkJsonObject page = new CkJsonObject();
    CkStringBuilder seenPath = new CkStringBuilder();
    String eventId;
    String nextPosition;
    int batch = 0;
    int i;
    int count;
    boolean more = true;
    while ((more == true) && (batch < 20)) {
        curl.ClearTargetOutput("*");
        CkStringBuilder authorizedCommand1 = new CkStringBuilder();
        authorizedCommand1.SetString("curl -X GET \"https://api.box.com/2.0/events?stream_type=all&stream_position={{position}}&limit=100\" -H \"Authorization: Bearer {{access_token}}\"");
        int headerReplacement1 = authorizedCommand1.Replace("{{access_token}}",curl.getVar("access_token"));
        success = curl.DoYourThing(authorizedCommand1.getAsString());
        if ((success != true) || (curl.get_StatusCode() != 200)) {
            System.out.println("Box request failed. HTTP status: " + curl.get_StatusCode());
            System.out.println("Failure reason: " + curl.get_FailReason());
            System.out.println(curl.responseBodyStr());
            return;
            }

        success = curl.GetResponseJson(page);
        if (success != true) {
            System.out.println(curl.lastErrorText());
            return;
            }

        count = page.SizeOfArray("entries");
        i = 0;
        while (i < count) {
            page.put_I(i);
            eventId = page.stringOf("entries[i].event_id");
            if (eventId == "") {
                System.out.println("Event without an event_id; checkpoint not advanced.");
                return;
                }

            seenPath.Clear();
            seenPath.Append("seen.");
            seenPath.Append(eventId);
            if (state.HasMember(seenPath.getAsString()) == false) {
                //  Replace this logging with your idempotent business operation.
                //  Record success only after that operation succeeds.
                System.out.println(eventId + " " + page.stringOf("entries[i].event_type") + " " + page.stringOf("entries[i].source.id"));
                state.UpdateBool(seenPath.getAsString(),true);
                }

            i = i+1;
            }

        nextPosition = page.stringOf("next_stream_position");
        if (nextPosition == "") {
            System.out.println("Missing next_stream_position; checkpoint not advanced.");
            return;
            }

        more = (count > 0) && (nextPosition != curl.getVar("position"));
        state.UpdateString("position",nextPosition);
        success = state.WriteFile(statePath);
        if (success != true) {
            System.out.println(state.lastErrorText());
            return;
            }

        curl.SetVar("position",nextPosition);
        batch = batch+1;
        }

    System.out.println("Checkpoint saved. Run again later to continue polling.");
  }
}