Ensure that we do not generate a NPE while reading response stream

2 files changed, 38 insertions, 13 deletions

diff --git a/main/src/cgeo/geocaching/connector/gc/RecaptchaHandler.java b/main/src/cgeo/geocaching/connector/gc/RecaptchaHandler.java
index db7b390..0a34928 100644
--- a/main/src/cgeo/geocaching/connector/gc/RecaptchaHandler.java
+++ b/main/src/cgeo/geocaching/connector/gc/RecaptchaHandler.java
@@ -92,20 +92,20 @@ public class RecaptchaHandler extends Handler {
                 Observable.defer(new Func0<Observable<? extends Bitmap>>() {
                     @Override
                     public Observable<? extends Bitmap> call() {
-                        InputStream is = null;
-                        try {
-                            final String url = "http://www.google.com/recaptcha/api/image?c=" + recaptchaReceiver.getChallenge();
-                            Log.d("Getting reCAPTCHA image from " + url);
-                            is = Network.getRequest(url).getEntity().getContent();
-                            final Bitmap img = BitmapFactory.decodeStream(is);
-                            IOUtils.closeQuietly(is);
-                            return Observable.from(img);
-                        } catch (final Exception e) {
-                            Log.e("RecaptchaHandler.getCaptcha", e);
-                            return Observable.error(e);
-                        } finally {
-                            IOUtils.closeQuietly(is);
+                        final String url = "http://www.google.com/recaptcha/api/image?c=" + recaptchaReceiver.getChallenge();
+                        final InputStream is = Network.getResponseStream(Network.getRequest(url));
+                        if (is != null) {
+                            try {
+                                final Bitmap img = BitmapFactory.decodeStream(is);
+                                return Observable.from(img);
+                            } catch (final Exception e) {
+                                Log.e("RecaptchaHandler.getCaptcha", e);
+                                return Observable.error(e);
+                            } finally {
+                                IOUtils.closeQuietly(is);
+                            }
                         }
+                        return Observable.empty();
                     }
                 }).subscribeOn(Schedulers.threadPoolForIO()));
     }
diff --git a/main/src/cgeo/geocaching/network/Network.java b/main/src/cgeo/geocaching/network/Network.java
index b737fd2..ffd58c3 100644
--- a/main/src/cgeo/geocaching/network/Network.java
+++ b/main/src/cgeo/geocaching/network/Network.java
@@ -47,6 +47,7 @@ import android.net.Uri;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
@@ -425,6 +426,30 @@ public abstract class Network {
         return null;
     }
 
+    /**
+     * Get the input stream corresponding to a HTTP response if it exists.
+     *
+     * @param response a HTTP response, which can be null
+     * @return the input stream if the HTTP request is successful, <code>null</code> otherwise
+     */
+    @Nullable
+    public static InputStream getResponseStream(@Nullable final HttpResponse response) {
+        if (!isSuccess(response)) {
+            return null;
+        }
+        assert(response != null);
+        final HttpEntity entity = response.getEntity();
+        if (entity == null) {
+            return null;
+        }
+        try {
+            return entity.getContent();
+        } catch (final IOException e) {
+            Log.e("Network.getResponseStream", e);
+            return null;
+        }
+    }
+
     @Nullable
     private static String getResponseDataNoError(final HttpResponse response, boolean replaceWhitespace) {
         try {