Fixed NPE in OAuth1 implementation when one of the parameters has no value (#1877)

Author: Asapin

client/src/main/java/org/asynchttpclient/oauth/OAuthSignatureCalculatorInstance.java

@@ -156,6 +156,9 @@ private String encodedParams(ConsumerKey consumerAuth, RequestToken userAuth, lo
     }
 
     private static String percentEncodeAlreadyFormUrlEncoded(String s) {
+        if (s == null) {
+            return "";
+        }
         s = STAR_CHAR_PATTERN.matcher(s).replaceAll("%2A");
         s = PLUS_CHAR_PATTERN.matcher(s).replaceAll("%20");
         s = ENCODED_TILDE_PATTERN.matcher(s).replaceAll("~");

client/src/test/java/org/asynchttpclient/oauth/OAuthSignatureCalculatorTest.java

@@ -20,6 +20,7 @@
 import org.asynchttpclient.Request;
 import org.asynchttpclient.RequestBuilder;
 import org.asynchttpclient.util.Utf8UrlEncoder;
+import org.junit.jupiter.api.Test;
 
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
@@ -132,6 +133,20 @@ public void testSignatureBaseStringWithRawUri() throws NoSuchAlgorithmException
         testSignatureBaseStringWithEncodableOAuthToken(request);
     }
 
+    @Test
+    public void testSignatureBaseStringWithNoValueQueryParameter() throws NoSuchAlgorithmException {
+        // Query parameter with no value in OAuth1 should be treated the same as query parameter with an empty value.
+        // i.e."http://example.com/request?b5" == "http://example.com/request?b5="
+        // Tested with http://lti.tools/oauth/
+        Request request = post("http://example.com/request?b5=%3D%253D&a3=a&c%40&a2=r%20b")
+                .addFormParam("c2", "")
+                .addFormParam("a3", "2 q")
+                .build();
+
+        testSignatureBaseString(request);
+        testSignatureBaseStringWithEncodableOAuthToken(request);
+    }
+
     // based on the reference test case from
     // http://oauth.pbwiki.com/TestCases
     @RepeatedIfExceptionsTest(repeats = 5)