From a96386b344a49391588762301ad71f1d39c11ca7 Mon Sep 17 00:00:00 2001
From: gmungoc <g.m.carstairs@dundee.ac.uk>
Date: Mon, 18 Jul 2016 16:39:34 +0100
Subject: [PATCH] JAL-2105 check content of Ensembl REST ping response

---
 src/jalview/ext/ensembl/EnsemblInfo.java       |    2 +-
 src/jalview/ext/ensembl/EnsemblRestClient.java |   28 ++++++++++++++++--------
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/jalview/ext/ensembl/EnsemblInfo.java b/src/jalview/ext/ensembl/EnsemblInfo.java
index 950b658..88b5ac4 100644
--- a/src/jalview/ext/ensembl/EnsemblInfo.java
+++ b/src/jalview/ext/ensembl/EnsemblInfo.java
@@ -33,7 +33,7 @@ class EnsemblInfo
 
   /*
    * true when http://rest.ensembl.org/info/ping/?content-type=application/json
-   * returns response code 200
+   * returns response code 200 and not {"error":"Database is unavailable"}
    */
   boolean restAvailable;
 
diff --git a/src/jalview/ext/ensembl/EnsemblRestClient.java b/src/jalview/ext/ensembl/EnsemblRestClient.java
index e651ddf..f9cfe05 100644
--- a/src/jalview/ext/ensembl/EnsemblRestClient.java
+++ b/src/jalview/ext/ensembl/EnsemblRestClient.java
@@ -155,30 +155,40 @@ abstract class EnsemblRestClient extends EnsemblSequenceFetcher
   protected abstract String getResponseMimeType();
 
   /**
-   * Tries to connect to Ensembl's REST 'ping' endpoint, and returns true if
-   * successful, else false
+   * Checks Ensembl's REST 'ping' endpoint, and returns true if response
+   * indicates available, else false
    * 
+   * @see http://rest.ensembl.org/documentation/info/ping
    * @return
    */
   private boolean checkEnsembl()
   {
+    HttpURLConnection conn = null;
     try
     {
       // note this format works for both ensembl and ensemblgenomes
       // info/ping.json works for ensembl only (March 2016)
       URL ping = new URL(getDomain()
               + "/info/ping?content-type=application/json");
-      HttpURLConnection conn = (HttpURLConnection) ping.openConnection();
-      int rc = conn.getResponseCode();
-      conn.disconnect();
-      if (rc >= 200 && rc < 300)
-      {
-        return true;
-      }
+
+      /*
+       * expect {"ping":1} if ok
+       */
+      BufferedReader br = getHttpResponse(ping, null);
+      JSONParser jp = new JSONParser();
+      JSONObject val = (JSONObject) jp.parse(br);
+      String pingString = val.get("ping").toString();
+      return pingString != null;
     } catch (Throwable t)
     {
       System.err.println("Error connecting to " + PING_URL + ": "
               + t.getMessage());
+    } finally
+    {
+      if (conn != null)
+      {
+        conn.disconnect();
+      }
     }
     return false;
   }
-- 
1.7.10.2