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fix: blob.reload() does not work as intuitively expected (#308)
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* fix: blob.reload() does not work as intuitively expected

* fix: blob.reload() does not work as intuitively expected

* fix: blob.reload() does not work as intuitively expected

* fix: blob.reload() does not work as intuitively expected

* fix: blob.reload() does not work as intuitively expected

* fix: blob.reload() does not work as intuitively expected
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@dmitry-fa
dmitry-fa committed May 13, 2020
1 parent 9201de5 commit a2bab58
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Showing 3 changed files with 73 additions and 19 deletions.
36 changes: 27 additions & 9 deletions google-cloud-storage/src/main/java/com/google/cloud/storage/Blob.java
View file
Expand Up @@ -525,24 +525,41 @@ public byte[] getContent(BlobSourceOption... options) {
}

/**
* Fetches current blob's latest information. Returns {@code null} if the blob does not exist.
* Fetches the latest blob properties. Returns {@code null} if the blob no longer exists.
*
* <p>Example of getting the blob's latest information, if its generation does not match the
* {@link Blob#getGeneration()} value, otherwise a {@link StorageException} is thrown.
* <p>{@code options} parameter can contain the preconditions. For example, the user might want to
* get the blob properties only if the content has not been updated externally. {@code
* StorageException} with the code {@code 412} is thrown if preconditions fail.
*
* <p>Example of retrieving the blob's latest information only if the content is not updated
* externally:
*
* <pre>{@code
* Blob latestBlob = blob.reload(BlobSourceOption.generationNotMatch());
* if (latestBlob == null) {
* // the blob was not found
* Blob blob = storage.get(BlobId.of(bucketName, blobName));
*
* doSomething();
*
* try {
* blob = blob.reload(Blob.BlobSourceOption.generationMatch());
* } catch (StorageException e) {
* if (e.getCode() == 412) {
* // the content was updated externally
* } else {
* throw e;
* }
* }
* }</pre>
*
* @param options blob read options
* @return a {@code Blob} object with latest information or {@code null} if not found
* @param options preconditions to use on reload, see <a
* href="https://cloud.google.com/storage/docs/json_api/v1/objects/get">https://cloud.google.com/storage/docs/json_api/v1/objects/get</a>
* for more information.
* @return a {@code Blob} object with latest information or {@code null} if no longer exists.
* @throws StorageException upon failure
*/
public Blob reload(BlobSourceOption... options) {
return storage.get(getBlobId(), toGetOptions(this, options));
// BlobId with generation unset is needed to retrieve the latest version of the Blob
BlobId idWithoutGeneration = BlobId.of(getBucket(), getName());
return storage.get(idWithoutGeneration, toGetOptions(this, options));
}

/**
Expand Down Expand Up @@ -730,6 +747,7 @@ public ReadChannel reader(BlobSourceOption... options) {
* } catch (IOException ex) {
* // handle exception
* }
* blob = blob.reload();
* }</pre>
*
* @param options target blob options
Expand Down
26 changes: 16 additions & 10 deletions google-cloud-storage/src/test/java/com/google/cloud/storage/BlobTest.java
View file
Expand Up @@ -129,7 +129,11 @@ public class BlobTest {
.setRetentionExpirationTime(RETENTION_EXPIRATION_TIME)
.build();
private static final BlobInfo BLOB_INFO =
BlobInfo.newBuilder("b", "n").setMetageneration(42L).build();
BlobInfo.newBuilder("b", "n", 12345678L).setMetageneration(42L).build();
private static final BlobInfo BLOB_INFO_NO_GENERATION =
BlobInfo.newBuilder(BLOB_INFO.getBucket(), BLOB_INFO.getName())
.setMetageneration(42L)
.build();
private static final BlobInfo DIRECTORY_INFO =
BlobInfo.newBuilder("b", "n/").setSize(0L).setIsDirectory(true).build();
private static final String BASE64_KEY = "JVzfVl8NLD9FjedFuStegjRfES5ll5zc59CIXw572OA=";
Expand Down Expand Up @@ -233,7 +237,7 @@ public void testReload() throws Exception {
initializeExpectedBlob(2);
Blob expectedReloadedBlob = expectedBlob.toBuilder().setCacheControl("c").build();
expect(storage.getOptions()).andReturn(mockOptions);
expect(storage.get(BLOB_INFO.getBlobId(), new Storage.BlobGetOption[0]))
expect(storage.get(BLOB_INFO_NO_GENERATION.getBlobId(), new Storage.BlobGetOption[0]))
.andReturn(expectedReloadedBlob);
replay(storage);
initializeBlob();
Expand All @@ -245,7 +249,8 @@ public void testReload() throws Exception {
public void testReloadNull() throws Exception {
initializeExpectedBlob(1);
expect(storage.getOptions()).andReturn(mockOptions);
expect(storage.get(BLOB_INFO.getBlobId(), new Storage.BlobGetOption[0])).andReturn(null);
expect(storage.get(BLOB_INFO_NO_GENERATION.getBlobId(), new Storage.BlobGetOption[0]))
.andReturn(null);
replay(storage);
initializeBlob();
Blob reloadedBlob = blob.reload();
Expand All @@ -258,7 +263,8 @@ public void testReloadWithOptions() throws Exception {
Blob expectedReloadedBlob = expectedBlob.toBuilder().setCacheControl("c").build();
Storage.BlobGetOption[] options = {Storage.BlobGetOption.metagenerationMatch(42L)};
expect(storage.getOptions()).andReturn(mockOptions);
expect(storage.get(BLOB_INFO.getBlobId(), options)).andReturn(expectedReloadedBlob);
expect(storage.get(BLOB_INFO_NO_GENERATION.getBlobId(), options))
.andReturn(expectedReloadedBlob);
replay(storage);
initializeBlob();
Blob updatedBlob = blob.reload(BlobSourceOption.metagenerationMatch());
Expand Down Expand Up @@ -301,8 +307,8 @@ public void testCopyToBucket() throws Exception {
initializeBlob();
CopyWriter returnedCopyWriter = blob.copyTo("bt");
assertEquals(copyWriter, returnedCopyWriter);
assertEquals(capturedCopyRequest.getValue().getSource(), blob.getBlobId());
assertEquals(capturedCopyRequest.getValue().getTarget(), target);
assertEquals(BLOB_INFO_NO_GENERATION.getBlobId(), capturedCopyRequest.getValue().getSource());
assertEquals(target, capturedCopyRequest.getValue().getTarget());
assertFalse(capturedCopyRequest.getValue().overrideInfo());
assertTrue(capturedCopyRequest.getValue().getSourceOptions().isEmpty());
assertTrue(capturedCopyRequest.getValue().getTargetOptions().isEmpty());
Expand All @@ -320,8 +326,8 @@ public void testCopyTo() throws Exception {
initializeBlob();
CopyWriter returnedCopyWriter = blob.copyTo("bt", "nt");
assertEquals(copyWriter, returnedCopyWriter);
assertEquals(capturedCopyRequest.getValue().getSource(), blob.getBlobId());
assertEquals(capturedCopyRequest.getValue().getTarget(), target);
assertEquals(BLOB_INFO_NO_GENERATION.getBlobId(), capturedCopyRequest.getValue().getSource());
assertEquals(target, capturedCopyRequest.getValue().getTarget());
assertFalse(capturedCopyRequest.getValue().overrideInfo());
assertTrue(capturedCopyRequest.getValue().getSourceOptions().isEmpty());
assertTrue(capturedCopyRequest.getValue().getTargetOptions().isEmpty());
Expand All @@ -340,8 +346,8 @@ public void testCopyToBlobId() throws Exception {
initializeBlob();
CopyWriter returnedCopyWriter = blob.copyTo(targetId);
assertEquals(copyWriter, returnedCopyWriter);
assertEquals(capturedCopyRequest.getValue().getSource(), blob.getBlobId());
assertEquals(capturedCopyRequest.getValue().getTarget(), target);
assertEquals(BLOB_INFO_NO_GENERATION.getBlobId(), capturedCopyRequest.getValue().getSource());
assertEquals(target, capturedCopyRequest.getValue().getTarget());
assertFalse(capturedCopyRequest.getValue().overrideInfo());
assertTrue(capturedCopyRequest.getValue().getSourceOptions().isEmpty());
assertTrue(capturedCopyRequest.getValue().getTargetOptions().isEmpty());
Expand Down
30 changes: 30 additions & 0 deletions google-cloud-storage/src/test/java/com/google/cloud/storage/it/ITStorageTest.java
View file
Expand Up @@ -21,6 +21,7 @@
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotEquals;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
Expand Down Expand Up @@ -3243,4 +3244,33 @@ public void testSignedPostPolicyV4() throws Exception {

assertEquals("hello world", new String(storage.get(BUCKET, "my-object").getContent()));
}

@Test
public void testBlobReload() throws Exception {
String blobName = "test-blob-reload";
BlobId blobId = BlobId.of(BUCKET, blobName);
BlobInfo blobInfo = BlobInfo.newBuilder(blobId).build();
Blob blob = storage.create(blobInfo, new byte[] {0, 1, 2});

Blob blobUnchanged = blob.reload();
assertEquals(blob, blobUnchanged);

blob.writer().close();
try {
blob.reload(Blob.BlobSourceOption.generationMatch());
fail("StorageException was expected");
} catch (StorageException e) {
assertEquals(412, e.getCode());
assertEquals("Precondition Failed", e.getMessage());
}

Blob updated = blob.reload();
assertEquals(blob.getBucket(), updated.getBucket());
assertEquals(blob.getName(), updated.getName());
assertNotEquals(blob.getGeneration(), updated.getGeneration());
assertEquals(new Long(0), updated.getSize());

updated.delete();
assertNull(updated.reload());
}
}

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