/src/com/foursquare/examples/push/PushHandler.java

 1package com.foursquare.examples.push;
 2
 3import java.io.IOException;
 4import java.util.List;
 5import java.util.logging.Logger;
 6
 7import javax.jdo.PersistenceManager;
 8import javax.servlet.http.HttpServlet;
 9import javax.servlet.http.HttpServletRequest;
10import javax.servlet.http.HttpServletResponse;
11
12import org.json.JSONException;
13import org.json.JSONObject;
14
15import com.foursquare.examples.push.models.ChannelRecord;
16import com.foursquare.examples.push.util.Common;
17
18/**
19 * The landing point for pushes from foursquare. Ensures that the push secret value is correct,
20 * then parses the JSON and pushes the results out to the approrpiate clients.
21 */
22@SuppressWarnings("serial")
23public class PushHandler extends HttpServlet {
24  private static final Logger log = Logger.getLogger(PushHandler.class.getName());
25  
26  public void doPost(HttpServletRequest req, HttpServletResponse resp)
27      throws IOException {
28    String pushSecret = req.getParameter("secret");
29    String pushBody = req.getParameter("checkin");
30    log.info("Push received: " + pushBody);
31    if (pushSecret != null && pushBody != null && pushSecret.equals(Common.PUSH_SECRET)) {
32      try {
33        handlePush(pushBody);
34      } catch (JSONException e) {
35        log.warning("Had a terrible run-in with invalid JSON!\n" + e.getMessage()
36                    + "\n" + pushBody);
37      }
38    }
39  }
40  
41  // Parse the json and send the messages.
42  private void handlePush(String pushBody) throws JSONException {
43    JSONObject pushJson = new JSONObject(pushBody);
44    
45    // Read out the isMayor flag. This is so complicated since it could be not present if false.
46    // If it isn't present, a JSON exception is thrown. So, we catch that and make it false.
47    boolean isMayor = false;
48    try {
49      Boolean mayorness = pushJson.getBoolean("isMayor");
50      isMayor = (mayorness != null && mayorness);
51    } catch (JSONException e) { isMayor = false; }
52    
53    // Load in the required information. These will throw an exception if missing, which is OK
54    // since we couldn't continue if any of them aren't there.
55    String vid = pushJson.getJSONObject("venue").getString("id");
56    JSONObject user = pushJson.getJSONObject("user");
57    String name = user.getString("firstName");
58    String photo = user.getString("photo");
59    photo.replace("_thumbs", "");
60    
61    if (vid != null && name != null) {
62      PersistenceManager pm = Common.getPM();
63      try {
64        List<String> targetClients = ChannelRecord.loadOrCreate(pm, vid).clientIds();
65        Common.sendUpdate(targetClients, Common.checkinToJson(name, photo, isMayor));
66      } finally {
67        pm.close();
68      }
69    }
70  }
71}