feat: Adding custom checksum for upload part request

Author: Dhriti Chopra

google-cloud-storage/src/main/java/com/google/cloud/storage/MultipartUploadHttpRequestManager.java

@@ -166,7 +166,11 @@ UploadPartResponse sendUploadPartRequest(
     HttpRequest httpRequest =
         requestFactory.buildPutRequest(new GenericUrl(uploadUri), rewindableContent);
     httpRequest.getHeaders().putAll(headerProvider.getHeaders());
+   if (request.getCrc32c() != null) {
+    addChecksumHeader(request.getCrc32c(), httpRequest.getHeaders());
+  } else {
     addChecksumHeader(rewindableContent.getCrc32c(), httpRequest.getHeaders());
+  }
     httpRequest.setThrowExceptionOnExecuteError(true);
     return ChecksumResponseParser.parseUploadResponse(httpRequest.execute());
   }
@@ -199,6 +203,12 @@ private void addChecksumHeader(@Nullable Crc32cLengthKnown crc32c, HttpHeaders h
     }
   }
 
+  private void addChecksumHeader(@Nullable String crc32c, HttpHeaders headers) {
+    if (crc32c != null) {
+      headers.put("x-goog-hash", "crc32c=" + crc32c);
+    }
+  }
+
   private void addHeadersForCreateMultipartUpload(
       CreateMultipartUploadRequest request, HttpHeaders headers) {
     if (request.getCannedAcl() != null) {

google-cloud-storage/src/main/java/com/google/cloud/storage/multipartupload/model/UploadPartRequest.java

@@ -19,6 +19,7 @@
 import com.google.api.core.BetaApi;
 import com.google.common.base.MoreObjects;
 import java.util.Objects;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * An object to represent an upload part request. An upload part request is used to upload a single
@@ -33,12 +34,14 @@ public final class UploadPartRequest {
   private final String key;
   private final int partNumber;
   private final String uploadId;
+  @Nullable private final String crc32c;
 
   private UploadPartRequest(Builder builder) {
     this.bucket = builder.bucket;
     this.key = builder.key;
     this.partNumber = builder.partNumber;
     this.uploadId = builder.uploadId;
+    this.crc32c = builder.crc32c;
   }
 
   /**
@@ -85,6 +88,18 @@ public String uploadId() {
     return uploadId;
   }
 
+  /**
+   * Returns the CRC32C checksum of the part to upload.
+   *
+   * @return The CRC32C checksum of the part to upload.
+   * @since 2.60.0 This new api is in preview and is subject to breaking changes.
+   */
+  @BetaApi
+  @Nullable
+  public String getCrc32c() {
+    return crc32c;
+  }
+
   @Override
   public boolean equals(Object o) {
     if (this == o) {
@@ -97,12 +112,13 @@ public boolean equals(Object o) {
     return partNumber == that.partNumber
         && Objects.equals(bucket, that.bucket)
         && Objects.equals(key, that.key)
-        && Objects.equals(uploadId, that.uploadId);
+        && Objects.equals(uploadId, that.uploadId)
+        && Objects.equals(crc32c, that.crc32c);
   }
 
   @Override
   public int hashCode() {
-    return Objects.hash(bucket, key, partNumber, uploadId);
+    return Objects.hash(bucket, key, partNumber, uploadId, crc32c);
   }
 
   @Override
@@ -112,6 +128,7 @@ public String toString() {
         .add("key", key)
         .add("partNumber", partNumber)
         .add("uploadId", uploadId)
+        .add("crc32c", crc32c)
         .toString();
   }
 
@@ -137,6 +154,7 @@ public static class Builder {
     private String key;
     private int partNumber;
     private String uploadId;
+    @Nullable private String crc32c;
 
     private Builder() {}
 
@@ -192,6 +210,19 @@ public Builder uploadId(String uploadId) {
       return this;
     }
 
+    /**
+     * Sets the CRC32C checksum of the part to upload.
+     *
+     * @param crc32c The CRC32C checksum of the part to upload.
+     * @return This builder.
+     * @since 2.60.0 This new api is in preview and is subject to breaking changes.
+     */
+    @BetaApi
+    public Builder crc32c(@Nullable String crc32c) {
+      this.crc32c = crc32c;
+      return this;
+    }
+
     /**
      * Builds the {@link UploadPartRequest}.
      *

google-cloud-storage/src/test/java/com/google/cloud/storage/ITMultipartUploadHttpRequestManagerTest.java

@@ -25,6 +25,7 @@
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 import com.google.api.client.http.HttpResponseException;
 import com.google.cloud.NoCredentials;
+import com.google.cloud.storage.Crc32cValue.Crc32cLengthKnown;
 import com.google.cloud.storage.FakeHttpServer.HttpRequestHandler;
 import com.google.cloud.storage.it.runner.StorageITRunner;
 import com.google.cloud.storage.it.runner.annotations.Backend;
@@ -813,6 +814,48 @@ public void sendUploadPartRequest_withChecksums() throws Exception {
     }
   }
 
+  @Test
+  public void sendUploadPartRequest_withCustomChecksum() throws Exception {
+    String etag = "\"af1ed31420542285653c803a34aa839a\"";
+    String content = "hello world";
+    byte[] contentBytes = content.getBytes(StandardCharsets.UTF_8);
+
+    String customCrc32cString = "CustomCrc32";
+
+    HttpRequestHandler handler =
+        req -> {
+          assertThat(req.headers().get("x-goog-hash")).isEqualTo("crc32c=" + customCrc32cString);
+          FullHttpRequest fullReq = (FullHttpRequest) req;
+          ByteBuf requestContent = fullReq.content();
+          byte[] receivedBytes = new byte[requestContent.readableBytes()];
+          requestContent.readBytes(receivedBytes);
+          assertThat(receivedBytes).isEqualTo(contentBytes);
+
+          DefaultFullHttpResponse resp = new DefaultFullHttpResponse(req.protocolVersion(), OK);
+          resp.headers().set("ETag", etag);
+          return resp;
+        };
+
+    try (FakeHttpServer fakeHttpServer = FakeHttpServer.of(handler)) {
+      URI endpoint = URI.create(fakeHttpServer.getEndpoint() + "/");
+      UploadPartRequest request =
+          UploadPartRequest.builder()
+              .bucket("test-bucket")
+              .key("test-key")
+              .uploadId("test-upload-id")
+              .partNumber(1)
+              .crc32c(customCrc32cString)
+              .build();
+
+      UploadPartResponse response =
+          multipartUploadHttpRequestManager.sendUploadPartRequest(
+              endpoint, request, RewindableContent.of(ByteBuffer.wrap(contentBytes)));
+
+      assertThat(response).isNotNull();
+      assertThat(response.eTag()).isEqualTo(etag);
+    }
+  }
+
   @Test
   public void sendUploadPartRequest_error() throws Exception {
     HttpRequestHandler handler =