Emulate multipart copy

Fixes #56.

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

@@ -462,8 +462,13 @@ final class S3ProxyHandler extends AbstractHandler {
                 handleContainerCreate(request, response, blobStore, path[1]);
                 return;
             } else if (uploadId != null) {
-                handleUploadPart(request, response, blobStore, path[1],
-                        path[2], uploadId);
+                if (request.getHeader("x-amz-copy-source") != null) {
+                    handleCopyPart(request, response, blobStore, path[1],
+                            path[2], uploadId);
+                } else {
+                    handleUploadPart(request, response, blobStore, path[1],
+                            path[2], uploadId);
+                }
                 return;
             } else if (request.getHeader("x-amz-copy-source") != null) {
                 handleCopyBlob(request, response, blobStore, path[1], path[2]);
@@ -1510,16 +1515,135 @@ final class S3ProxyHandler extends AbstractHandler {
         }
     }
 
+    private void handleCopyPart(HttpServletRequest request,
+            HttpServletResponse response, BlobStore blobStore,
+            String containerName, String blobName, String uploadId)
+            throws IOException, S3Exception {
+        // TODO: duplicated from handlePutBlob
+        String copySourceHeader = request.getHeader("x-amz-copy-source");
+        copySourceHeader = URLDecoder.decode(copySourceHeader, "UTF-8");
+        if (copySourceHeader.startsWith("/")) {
+            // Some clients like boto do not include the leading slash
+            copySourceHeader = copySourceHeader.substring(1);
+        }
+        String[] path = copySourceHeader.split("/", 2);
+        if (path.length != 2) {
+            throw new S3Exception(S3ErrorCode.INVALID_REQUEST);
+        }
+        String sourceContainerName = path[0];
+        String sourceBlobName = path[1];
+
+        GetOptions options = new GetOptions();
+        String range = request.getHeader("x-amz-copy-source-range");
+        if (range != null && range.startsWith("bytes=") &&
+                // ignore multiple ranges
+                range.indexOf(',') == -1) {
+            range = range.substring("bytes=".length());
+            String[] ranges = range.split("-", 2);
+            if (ranges[0].isEmpty()) {
+                options.tail(Long.parseLong(ranges[1]));
+            } else if (ranges[1].isEmpty()) {
+                options.startAt(Long.parseLong(ranges[0]));
+            } else {
+                options.range(Long.parseLong(ranges[0]),
+                        Long.parseLong(ranges[1]));
+            }
+        }
+
+        String partNumberString = request.getParameter("partNumber");
+        if (partNumberString == null) {
+            throw new S3Exception(S3ErrorCode.INVALID_ARGUMENT);
+        }
+        int partNumber;
+        try {
+            partNumber = Integer.parseInt(partNumberString);
+        } catch (NumberFormatException nfe) {
+            throw new S3Exception(S3ErrorCode.INVALID_ARGUMENT,
+                    "Part number must be an integer between 1 and 10000" +
+                    ", inclusive", nfe, ImmutableMap.of(
+                            "ArgumentName", "partNumber",
+                            "ArgumentValue", partNumberString));
+        }
+        if (partNumber < 1 || partNumber > 10_000) {
+            throw new S3Exception(S3ErrorCode.INVALID_ARGUMENT,
+                    "Part number must be an integer between 1 and 10000" +
+                    ", inclusive", (Throwable) null, ImmutableMap.of(
+                            "ArgumentName", "partNumber",
+                            "ArgumentValue", partNumberString));
+        }
+
+        // TODO: how to reconstruct original mpu?
+        MultipartUpload mpu = MultipartUpload.create(containerName,
+                blobName, uploadId, createFakeBlobMetadata(blobStore));
+
+        Blob blob = blobStore.getBlob(sourceContainerName, sourceBlobName,
+                options);
+        if (blob == null) {
+            throw new S3Exception(S3ErrorCode.NO_SUCH_KEY);
+        }
+
+        BlobMetadata blobMetadata = blob.getMetadata();
+        long contentLength =
+                blobMetadata.getContentMetadata().getContentLength();
+        HashCode contentMD5 =
+                blobMetadata.getContentMetadata().getContentMD5AsHashCode();
+        String eTag;
+
+        try (InputStream is = blob.getPayload().openStream()) {
+            if (getBlobStoreType(blobStore).equals("azureblob")) {
+                // Azure has a maximum part size of 4 MB while S3 has a minimum
+                // part size of 5 MB and a maximum of 5 GB.  Split a single S3
+                // part multiple Azure parts.
+                long azureMaximumMultipartPartSize = 4 * 1024 * 1024;
+                HashingInputStream his = new HashingInputStream(Hashing.md5(),
+                        is);
+                for (int offset = 0, subPartNumber = 0; offset < contentLength;
+                        offset += azureMaximumMultipartPartSize,
+                        ++subPartNumber) {
+                    Payload payload = Payloads.newInputStreamPayload(
+                            ByteStreams.limit(his,
+                                    azureMaximumMultipartPartSize));
+                    payload.getContentMetadata().setContentLength(
+                            Math.min(azureMaximumMultipartPartSize,
+                                    contentLength - offset));
+                    blobStore.uploadMultipartPart(mpu,
+                            10_000 * partNumber + subPartNumber, payload);
+                }
+                eTag = BaseEncoding.base16().lowerCase().encode(
+                        his.hash().asBytes());
+            } else {
+                Payload payload = Payloads.newInputStreamPayload(is);
+                payload.getContentMetadata().setContentLength(contentLength);
+
+                MultipartPart part = blobStore.uploadMultipartPart(mpu,
+                        partNumber, payload);
+                eTag = part.partETag();
+            }
+        }
+
+        try (Writer writer = response.getWriter()) {
+            XMLStreamWriter xml = xmlOutputFactory.createXMLStreamWriter(
+                    writer);
+            xml.writeStartDocument();
+            xml.writeStartElement("CopyObjectResult");
+            xml.writeDefaultNamespace(AWS_XMLNS);
+
+            writeSimpleElement(xml, "LastModified",
+                    blobStore.getContext().utils().date()
+                            .iso8601DateFormat(blobMetadata.getLastModified()));
+            writeSimpleElement(xml, "ETag", maybeQuoteETag(eTag));
+
+            xml.writeEndElement();
+            xml.flush();
+        } catch (XMLStreamException xse) {
+            throw new IOException(xse);
+        }
+    }
+
     private void handleUploadPart(HttpServletRequest request,
             HttpServletResponse response, BlobStore blobStore,
             String containerName, String blobName, String uploadId)
             throws IOException, S3Exception {
-        // TODO: implement multipart copy
-        if (request.getHeader("x-amz-copy-source") != null ||
-                request.getHeader("x-amz-copy-source-range") != null) {
-            throw new S3Exception(S3ErrorCode.NOT_IMPLEMENTED);
-        }
-
         // TODO: duplicated from handlePutBlob
         String contentLengthString = null;
         String contentMD5String = null;

src/test/java/org/gaul/s3proxy/S3AwsSdkTest.java

@@ -189,15 +189,7 @@ public final class S3AwsSdkTest {
                 .withFirstByte(0L)
                 .withLastByte(BYTE_SOURCE.size() - 1)
                 .withPartNumber(1);
-        // TODO: S3Proxy lacks support for multipart copy
-        CopyPartResult copyPartResult = null;
-        try {
-            copyPartResult = client.copyPart(copyRequest);
-            Fail.failBecauseExceptionWasNotThrown(AmazonS3Exception.class);
-        } catch (AmazonS3Exception e) {
-            assertThat(e.getErrorCode()).isEqualTo("NotImplemented");
-            return;
-        }
+        CopyPartResult copyPartResult = client.copyPart(copyRequest);
 
         List<PartETag> partETags = new ArrayList<>();
         partETags.add(copyPartResult.getPartETag());