Add partial support for list objects v2

Not supporting fetch-owner until jclouds adds support for this.
Several applications like AWS CLI now require this RPC.  Fixes #168.

README.md

@@ -105,7 +105,6 @@ S3Proxy has broad compatibility with the S3 API, however, it does not support:
 * bucket logging
 * [CORS bucket operations](https://docs.aws.amazon.com/AmazonS3/latest/dev/cors.html#how-do-i-enable-cors) like getting or setting the CORS configuration for a bucket. S3Proxy only supports a static configuration (see below).
 * hosting static websites
-* list objects v2, see [#168](https://github.com/gaul/s3proxy/issues/168)
 * object server-side encryption
 * object tagging
 * object versioning, see [#74](https://github.com/gaul/s3proxy/issues/74)

src/main/java/org/gaul/s3proxy/S3ProxyHandler.java

@@ -143,7 +143,6 @@ public class S3ProxyHandler {
             "cors",
             "inventory",
             "lifecycle",
-            "list-type",
             "logging",
             "metrics",
             "notification",
@@ -1316,7 +1315,27 @@ public class S3ProxyHandler {
         if (prefix != null && !prefix.isEmpty()) {
             options.prefix(prefix);
         }
-        String marker = request.getParameter("marker");
+
+        boolean isListV2 = false;
+        String marker;
+        String listType = request.getParameter("list-type");
+        String continuationToken = request.getParameter("continuation-token");
+        String startAfter = request.getParameter("start-after");
+        if (listType == null) {
+            marker = request.getParameter("marker");
+        } else if (listType.equals("2")) {
+            isListV2 = true;
+            if (continuationToken != null && startAfter != null) {
+                throw new S3Exception(S3ErrorCode.INVALID_ARGUMENT);
+            }
+            if (continuationToken != null) {
+                marker = continuationToken;
+            } else {
+                marker = startAfter;
+            }
+        } else {
+            throw new S3Exception(S3ErrorCode.NOT_IMPLEMENTED);
+        }
         if (marker != null) {
             if (Quirks.OPAQUE_MARKERS.contains(blobStoreType)) {
                 String realMarker = lastKeyToMarker.getIfPresent(
@@ -1327,6 +1346,12 @@ public class S3ProxyHandler {
             }
             options.afterMarker(marker);
         }
+
+        String fetchOwner = request.getParameter("fetch-owner");
+        if (fetchOwner != null && !fetchOwner.equals("false")) {
+            throw new S3Exception(S3ErrorCode.NOT_IMPLEMENTED);
+        }
+
         int maxKeys = 1000;
         String maxKeysString = request.getParameter("max-keys");
         if (maxKeysString != null) {
@@ -1372,11 +1397,26 @@ public class S3ProxyHandler {
 
             writeSimpleElement(xml, "MaxKeys", String.valueOf(maxKeys));
 
-            if (marker == null) {
+            if (!isListV2) {
-                xml.writeEmptyElement("Marker");
+                if (marker == null) {
+                    xml.writeEmptyElement("Marker");
+                } else {
+                    writeSimpleElement(xml, "Marker", encodeBlob(
+                            encodingType, marker));
+                }
             } else {
-                writeSimpleElement(xml, "Marker", encodeBlob(
+                if (continuationToken == null) {
-                        encodingType, marker));
+                    xml.writeEmptyElement("ContinuationToken");
+                } else {
+                    writeSimpleElement(xml, "ContinuationToken", encodeBlob(
+                            encodingType, continuationToken));
+                }
+                if (startAfter == null) {
+                    xml.writeEmptyElement("StartAfter");
+                } else {
+                    writeSimpleElement(xml, "StartAfter", encodeBlob(
+                            encodingType, startAfter));
+                }
             }
 
             if (delimiter != null) {
@@ -1391,8 +1431,9 @@ public class S3ProxyHandler {
             String nextMarker = set.getNextMarker();
             if (nextMarker != null) {
                 writeSimpleElement(xml, "IsTruncated", "true");
-                writeSimpleElement(xml, "NextMarker", encodeBlob(
+                writeSimpleElement(xml,
-                        encodingType, nextMarker));
+                        isListV2 ? "NextContinuationToken" : "NextMarker",
+                        encodeBlob(encodingType, nextMarker));
                 if (Quirks.OPAQUE_MARKERS.contains(blobStoreType)) {
                     lastKeyToMarker.put(Maps.immutableEntry(containerName,
                             Iterables.getLast(set).getName()), nextMarker);

src/test/java/org/gaul/s3proxy/AwsSdkTest.java

@@ -70,6 +70,8 @@ import com.amazonaws.services.s3.model.InitiateMultipartUploadRequest;
 import com.amazonaws.services.s3.model.InitiateMultipartUploadResult;
 import com.amazonaws.services.s3.model.ListMultipartUploadsRequest;
 import com.amazonaws.services.s3.model.ListObjectsRequest;
+import com.amazonaws.services.s3.model.ListObjectsV2Request;
+import com.amazonaws.services.s3.model.ListObjectsV2Result;
 import com.amazonaws.services.s3.model.ListPartsRequest;
 import com.amazonaws.services.s3.model.MultipartUploadListing;
 import com.amazonaws.services.s3.model.ObjectListing;
@@ -904,6 +906,52 @@ public final class AwsSdkTest {
                 .isEqualTo("blob2");
     }
 
+    @Test
+    public void testBlobListV2() throws Exception {
+        ObjectMetadata metadata = new ObjectMetadata();
+        metadata.setContentLength(BYTE_SOURCE.size());
+        for (int i = 1; i < 5; ++i) {
+            client.putObject(containerName, String.valueOf(i),
+                    BYTE_SOURCE.openStream(), metadata);
+        }
+
+        ListObjectsV2Result result = client.listObjectsV2(
+                new ListObjectsV2Request()
+                .withBucketName(containerName)
+                .withMaxKeys(1)
+                .withStartAfter("1"));
+        assertThat(result.getContinuationToken()).isEmpty();
+        assertThat(result.getStartAfter()).isEqualTo("1");
+        assertThat(result.getNextContinuationToken()).isEqualTo("2");
+        assertThat(result.isTruncated()).isTrue();
+        assertThat(result.getObjectSummaries()).hasSize(1);
+        assertThat(result.getObjectSummaries().get(0).getKey()).isEqualTo("2");
+
+        result = client.listObjectsV2(
+                new ListObjectsV2Request()
+                .withBucketName(containerName)
+                .withMaxKeys(1)
+                .withContinuationToken(result.getNextContinuationToken()));
+        assertThat(result.getContinuationToken()).isEqualTo("2");
+        assertThat(result.getStartAfter()).isEmpty();
+        assertThat(result.getNextContinuationToken()).isEqualTo("3");
+        assertThat(result.isTruncated()).isTrue();
+        assertThat(result.getObjectSummaries()).hasSize(1);
+        assertThat(result.getObjectSummaries().get(0).getKey()).isEqualTo("3");
+
+        result = client.listObjectsV2(
+                new ListObjectsV2Request()
+                .withBucketName(containerName)
+                .withMaxKeys(1)
+                .withContinuationToken(result.getNextContinuationToken()));
+        assertThat(result.getContinuationToken()).isEqualTo("3");
+        assertThat(result.getStartAfter()).isEmpty();
+        assertThat(result.getNextContinuationToken()).isNull();
+        assertThat(result.isTruncated()).isFalse();
+        assertThat(result.getObjectSummaries()).hasSize(1);
+        assertThat(result.getObjectSummaries().get(0).getKey()).isEqualTo("4");
+    }
+
     @Test
     public void testBlobMetadata() throws Exception {
         String blobName = "blob";