Added support for empty parameters in signature

signpost-core/src/main/java/oauth/signpost/AbstractOAuthConsumer.java

@@ -115,11 +115,52 @@ public synchronized HttpRequest sign(HttpRequest request) throws OAuthMessageSig
         return request;
     }
 
+    public synchronized HttpRequest sign(HttpRequest request, boolean addEmptyParameters) throws OAuthMessageSignerException,
+        OAuthExpectationFailedException, OAuthCommunicationException {
+        if (consumerKey == null) {
+            throw new OAuthExpectationFailedException("consumer key not set");
+        }
+        if (consumerSecret == null) {
+            throw new OAuthExpectationFailedException("consumer secret not set");
+        }
+
+        requestParameters = new HttpParameters();
+        try {
+            if (additionalParameters != null) {
+                requestParameters.putAll(additionalParameters, false);
+            }
+            collectHeaderParameters(request, requestParameters);
+            collectQueryParameters(request, requestParameters, addEmptyParameters);
+            collectBodyParameters(request, requestParameters);
+
+            // add any OAuth params that haven't already been set
+            completeOAuthParameters(requestParameters);
+
+            requestParameters.remove(OAuth.OAUTH_SIGNATURE);
+
+        } catch (IOException e) {
+            throw new OAuthCommunicationException(e);
+        }
+
+        String signature = messageSigner.sign(request, requestParameters);
+        OAuth.debugOut("signature", signature);
+
+        signingStrategy.writeSignature(signature, request, requestParameters);
+        OAuth.debugOut("Request URL", request.getRequestUrl());
+
+        return request;
+    }
+
     public synchronized HttpRequest sign(Object request) throws OAuthMessageSignerException,
             OAuthExpectationFailedException, OAuthCommunicationException {
         return sign(wrap(request));
     }
 
+    public synchronized HttpRequest sign(Object request, boolean addEmptyParameters) throws OAuthMessageSignerException,
+        OAuthExpectationFailedException, OAuthCommunicationException {
+        return sign(wrap(request), addEmptyParameters);
+    }
+
     public synchronized String sign(String url) throws OAuthMessageSignerException,
             OAuthExpectationFailedException, OAuthCommunicationException {
         HttpRequest request = new UrlStringRequestAdapter(url);
@@ -252,6 +293,16 @@ protected void collectQueryParameters(HttpRequest request, HttpParameters out) {
         }
     }
 
+    protected void collectQueryParameters(HttpRequest request, HttpParameters out, boolean addEmptyParameters) {
+
+        String url = request.getRequestUrl();
+        int q = url.indexOf('?');
+        if (q >= 0) {
+            // Combine the URL query string with the other parameters:
+            out.putAll(OAuth.decodeForm(url.substring(q + 1), addEmptyParameters), true);
+        }
+    }
+
     protected String generateTimestamp() {
         return Long.toString(System.currentTimeMillis() / 1000L);
     }

signpost-core/src/main/java/oauth/signpost/OAuth.java

@@ -146,6 +146,29 @@ public static HttpParameters decodeForm(String form) {
                 name = percentDecode(nvp.substring(0, equals));
                 value = percentDecode(nvp.substring(equals + 1));
             }
+            params.put(name, value);
+        }
+        return params;
+    }
+
+    /** Parse a form-urlencoded document. */
+    public static HttpParameters decodeForm(String form, boolean addEmptyParameters) {
+        HttpParameters params = new HttpParameters();
+        if (isEmpty(form)) {
+            return params;
+        }
+
+        for (String nvp : form.split("\\&")) {
+            int equals = nvp.indexOf('=');
+            String name;
+            String value;
+            if (equals < 0) {
+                name = percentDecode(nvp);
+                value = (addEmptyParameters) ? "" : null;
+            } else {
+                name = percentDecode(nvp.substring(0, equals));
+                value = percentDecode(nvp.substring(equals + 1));
+            }
 
             params.put(name, value);
         }