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googleapis#3140 feature added to change hostname of generated Url
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praful committed Nov 14, 2018
1 parent 6d54796 commit 84d49e5
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Showing 2 changed files with 122 additions and 48 deletions.
64 changes: 64 additions & 0 deletions ...le-cloud-clients/google-cloud-storage/src/main/java/com/google/cloud/storage/Storage.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2119,6 +2119,70 @@ public static Builder newBuilder() {
*/
URL signUrl(BlobInfo blobInfo, long duration, TimeUnit unit, SignUrlOption... options);

/**
* Generates a signed URL for a blob. If you have a blob that you want to allow access to for a
* fixed amount of time, you can use this method to generate a URL that is only valid within a
* certain time period. This is particularly useful if you don't want publicly accessible blobs,
* but also don't want to require users to explicitly log in. Signing a URL requires
* a service account signer. If an instance of {@link com.google.auth.ServiceAccountSigner} was
* passed to {@link StorageOptions}' builder via {@code setCredentials(Credentials)} or the
* default credentials are being used and the environment variable
* {@code GOOGLE_APPLICATION_CREDENTIALS} is set or your application is running in App Engine,
* then {@code signUrl} will use that credentials to sign the URL. If the credentials passed to
* {@link StorageOptions} do not implement {@link ServiceAccountSigner} (this is the case, for
* instance, for Google Cloud SDK credentials) then {@code signUrl} will throw an
* {@link IllegalStateException} unless an implementation of {@link ServiceAccountSigner} is
* passed using the {@link SignUrlOption#signWith(ServiceAccountSigner)} option.
*
* <p>A service account signer is looked for in the following order:
* <ol>
* <li>The signer passed with the option {@link SignUrlOption#signWith(ServiceAccountSigner)}
* <li>The credentials passed to {@link StorageOptions}
* <li>The default credentials, if no credentials were passed to {@link StorageOptions}
* </ol>
*
* <p>Example of creating a signed URL that is valid for 2 weeks, using the default credentials
* for signing the URL.
* <pre> {@code
* String bucketName = "my_unique_bucket";
* String blobName = "my_blob_name";
* URL signedUrl = storage.signUrl(BlobInfo.newBuilder(bucketName, blobName).build(), 14,
* TimeUnit.DAYS);
* }</pre>
*
* <p>Example of creating a signed URL passing the
* {@link SignUrlOption#signWith(ServiceAccountSigner)} option, that will be used for signing the
* URL.
* <pre> {@code
* String bucketName = "my_unique_bucket";
* String blobName = "my_blob_name";
* String keyPath = "/path/to/key.json";
* URL signedUrl = storage.signUrl(BlobInfo.newBuilder(bucketName, blobName).build(),
* 14, TimeUnit.DAYS, SignUrlOption.signWith(
* ServiceAccountCredentials.fromStream(new FileInputStream(keyPath))));
* }</pre>
*
* <p>Note that the {@link ServiceAccountSigner} may require additional configuration to enable
* URL signing. See the documentation for the implementation for more details.</p>
*
* @param url can be customize
* @param blobInfo the blob associated with the signed URL
* @param duration time until the signed URL expires, expressed in {@code unit}. The finest
* granularity supported is 1 second, finer granularities will be truncated
* @param unit time unit of the {@code duration} parameter
* @param options optional URL signing options
* @throws IllegalStateException if {@link SignUrlOption#signWith(ServiceAccountSigner)} was not
* used and no implementation of {@link ServiceAccountSigner} was provided to
* {@link StorageOptions}
* @throws IllegalArgumentException if {@code SignUrlOption.withMd5()} option is used and
* {@code blobInfo.md5()} is {@code null}
* @throws IllegalArgumentException if {@code SignUrlOption.withContentType()} option is used and
* {@code blobInfo.contentType()} is {@code null}
* @throws SigningException if the attempt to sign the URL failed
* @see <a href="https://cloud.google.com/storage/docs/access-control#Signed-URLs">Signed-URLs</a>
*/
URL signUrl(String url, BlobInfo blobInfo, long duration, TimeUnit unit, SignUrlOption... options);

/**
* Gets the requested blobs. A batch request is used to perform this call.
*
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106 changes: 58 additions & 48 deletions ...loud-clients/google-cloud-storage/src/main/java/com/google/cloud/storage/StorageImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -84,6 +84,7 @@ final class StorageImpl extends BaseService<StorageOptions> implements Storage {
private static final String EMPTY_BYTE_ARRAY_MD5 = "1B2M2Y8AsgTpgAmY7PhCfg==";
private static final String EMPTY_BYTE_ARRAY_CRC32C = "AAAAAA==";
private static final String PATH_DELIMITER = "/";
private static final String DEFAULT_STORAGE_HOST = "https://storage.googleapis.com";

private static final Function<Tuple<Storage, Boolean>, Boolean> DELETE_FUNCTION =
new Function<Tuple<Storage, Boolean>, Boolean>() {
Expand Down Expand Up @@ -499,54 +500,63 @@ private BlobWriteChannel writer(BlobInfo blobInfo, BlobTargetOption... options)

@Override
public URL signUrl(BlobInfo blobInfo, long duration, TimeUnit unit, SignUrlOption... options) {
EnumMap<SignUrlOption.Option, Object> optionMap = Maps.newEnumMap(SignUrlOption.Option.class);
for (SignUrlOption option : options) {
optionMap.put(option.getOption(), option.getValue());
}
ServiceAccountSigner credentials =
(ServiceAccountSigner) optionMap.get(SignUrlOption.Option.SERVICE_ACCOUNT_CRED);
if (credentials == null) {
checkState(this.getOptions().getCredentials() instanceof ServiceAccountSigner,
"Signing key was not provided and could not be derived");
credentials = (ServiceAccountSigner) this.getOptions().getCredentials();
}

long expiration = TimeUnit.SECONDS.convert(
getOptions().getClock().millisTime() + unit.toMillis(duration), TimeUnit.MILLISECONDS);

StringBuilder stPath = new StringBuilder();
if (!blobInfo.getBucket().startsWith(PATH_DELIMITER)) {
stPath.append(PATH_DELIMITER);
}
stPath.append(blobInfo.getBucket());
if (!blobInfo.getBucket().endsWith(PATH_DELIMITER)) {
stPath.append(PATH_DELIMITER);
}
if (blobInfo.getName().startsWith(PATH_DELIMITER)) {
stPath.setLength(stPath.length() - 1);
}

String escapedName = UrlEscapers.urlFragmentEscaper().escape(blobInfo.getName());
stPath.append(escapedName.replace("?", "%3F"));

URI path = URI.create(stPath.toString());

try {
SignatureInfo signatureInfo = buildSignatureInfo(optionMap, blobInfo, expiration, path);
byte[] signatureBytes =
credentials.sign(signatureInfo.constructUnsignedPayload().getBytes(UTF_8));
StringBuilder stBuilder = new StringBuilder("https://storage.googleapis.com").append(path);
String signature =
URLEncoder.encode(BaseEncoding.base64().encode(signatureBytes), UTF_8.name());
stBuilder.append("?GoogleAccessId=").append(credentials.getAccount());
stBuilder.append("&Expires=").append(expiration);
stBuilder.append("&Signature=").append(signature);

return new URL(stBuilder.toString());

} catch (MalformedURLException | UnsupportedEncodingException ex) {
throw new IllegalStateException(ex);
}
return signUrlOptions(DEFAULT_STORAGE_HOST, blobInfo, duration, unit, options);
}

@Override
public URL signUrl(String url, BlobInfo blobInfo, long duration, TimeUnit unit, SignUrlOption... options) {
return signUrlOptions(url, blobInfo, duration, unit, options);
}

private URL signUrlOptions(String url, BlobInfo blobInfo, long duration, TimeUnit unit, SignUrlOption... options){
EnumMap<SignUrlOption.Option, Object> optionMap = Maps.newEnumMap(SignUrlOption.Option.class);
for (SignUrlOption option : options) {
optionMap.put(option.getOption(), option.getValue());
}
ServiceAccountSigner credentials =
(ServiceAccountSigner) optionMap.get(SignUrlOption.Option.SERVICE_ACCOUNT_CRED);
if (credentials == null) {
checkState(this.getOptions().getCredentials() instanceof ServiceAccountSigner,
"Signing key was not provided and could not be derived");
credentials = (ServiceAccountSigner) this.getOptions().getCredentials();
}

long expiration = TimeUnit.SECONDS.convert(
getOptions().getClock().millisTime() + unit.toMillis(duration), TimeUnit.MILLISECONDS);

StringBuilder stPath = new StringBuilder();
if (!blobInfo.getBucket().startsWith(PATH_DELIMITER)) {
stPath.append(PATH_DELIMITER);
}
stPath.append(blobInfo.getBucket());
if (!blobInfo.getBucket().endsWith(PATH_DELIMITER)) {
stPath.append(PATH_DELIMITER);
}
if (blobInfo.getName().startsWith(PATH_DELIMITER)) {
stPath.setLength(stPath.length() - 1);
}

String escapedName = UrlEscapers.urlFragmentEscaper().escape(blobInfo.getName());
stPath.append(escapedName.replace("?", "%3F"));

URI path = URI.create(stPath.toString());

try {
SignatureInfo signatureInfo = buildSignatureInfo(optionMap, blobInfo, expiration, path);
byte[] signatureBytes =
credentials.sign(signatureInfo.constructUnsignedPayload().getBytes(UTF_8));
StringBuilder stBuilder = new StringBuilder(url).append(path);
String signature =
URLEncoder.encode(BaseEncoding.base64().encode(signatureBytes), UTF_8.name());
stBuilder.append("?GoogleAccessId=").append(credentials.getAccount());
stBuilder.append("&Expires=").append(expiration);
stBuilder.append("&Signature=").append(signature);

return new URL(stBuilder.toString());

} catch (MalformedURLException | UnsupportedEncodingException ex) {
throw new IllegalStateException(ex);
}
}

/**
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