Creating a Signed URL for Downloading a Processed Image (SDK for Java)
Function
This API processes images in a stable, secure, efficient, easy, and cost-effective manner. You can pass the parameters for clipping, resizing, watermarking, converting the format of, or performing other operations on images to generate a signed URL.
If you have any questions during development, post them on the Issues page of GitHub.
Restrictions
- To download an object, you must be the bucket owner or have the required permission (obs:object:GetObject in IAM or GetObject in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
- The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.
- All image processing operations do not affect the original image.
- Archive storage does not support image processing.
- The processed image is directly returned to the browser for display. It is not stored in OBS, does not occupy storage space, and does not incur storage charges.
Method
obsClient.createTemporarySignature(TemporarySignatureRequest request)
Request Parameters
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
request |
Yes |
Explanation: Request parameters for creating a signed URL. For details, see Table 2. |
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
bucketName |
String |
No |
Explanation: Bucket name. Restrictions:
Default value: None |
objectKey |
String |
No |
Explanation: Object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None |
specialParam |
No |
Explanation: Special parameters that may be used in the request. For details, see Table 3. |
|
method |
Yes |
Explanation: HTTP method. For details, see Table 3. |
|
headers |
Map<String, String> |
No |
Explanation: HTTP response header list, composed of tuples. In a tuple, the String key and value indicate the name and value of the header respectively. Default value: None |
queryParams |
Map<String, Object> |
No |
Explanation: Query parameters in the request. In Map<String, Object>, String indicates the key of query parameter in the request, and Object indicates the value of the query parameter. Default value: None |
expires |
long |
Yes |
Explanation: Expiration time of the object. The calculation starts from the time when the object was last modified. Once the object expires, it is automatically deleted. Restrictions: This parameter can be configured only when uploading the object. It cannot be modified by calling a metadata modification API. Value range: An integer greater than 0, in days. Default value: None |
requestDate |
Date |
Yes |
Explanation: Time when a request is initiated. Default value: None |
Operation |
HTTP Request Method (Value in OBS SDK for Java) |
Special Operator (Value in OBS SDK for Java) |
Bucket Name Required (Yes/No) |
Object Name Required (Yes/No) |
---|---|---|---|---|
Create Bucket |
HttpMethodEnum.PUT |
N/A |
Yes |
No |
List Buckets |
HttpMethodEnum.GET |
N/A |
No |
No |
Delete Bucket |
HttpMethodEnum.DELETE |
N/A |
Yes |
No |
List Objects |
HttpMethodEnum.GET |
N/A |
Yes |
No |
List Object Versions |
HttpMethodEnum.GET |
SpecialParamEnum.VERSIONS |
Yes |
No |
List Multipart Uploads |
HttpMethodEnum.GET |
SpecialParamEnum.UPLOADS |
Yes |
No |
Get Bucket Metadata |
HttpMethodEnum.HEAD |
N/A |
Yes |
No |
Get Bucket Location |
HttpMethodEnum.GET |
SpecialParamEnum.LOCATION |
Yes |
No |
Get Bucket Storageinfo |
HttpMethodEnum.GET |
SpecialParamEnum.STORAGEINFO |
Yes |
No |
Set Bucket Quota |
HttpMethodEnum.PUT |
SpecialParamEnum.QUOTA |
Yes |
No |
Get Bucket Quota |
HttpMethodEnum.GET |
SpecialParamEnum.QUOTA |
Yes |
No |
Set Bucket Storage Policy |
HttpMethodEnum.PUT |
SpecialParamEnum.STORAGEPOLICY |
Yes |
No |
Get Bucket Storage Policy |
HttpMethodEnum.GET |
SpecialParamEnum.STORAGEPOLICY |
Yes |
No |
Set Bucket ACL |
HttpMethodEnum.PUT |
SpecialParamEnum.ACL |
Yes |
No |
Get Bucket ACL |
HttpMethodEnum.GET |
SpecialParamEnum.ACL |
Yes |
No |
Set Bucket Logging |
HttpMethodEnum.PUT |
SpecialParamEnum.LOGGING |
Yes |
No |
Get Bucket Logging |
HttpMethodEnum.GET |
SpecialParamEnum.LOGGING |
Yes |
No |
Set Bucket Policy |
HttpMethodEnum.PUT |
SpecialParamEnum.POLICY |
Yes |
No |
Get Bucket Policy |
HttpMethodEnum.GET |
SpecialParamEnum.POLICY |
Yes |
No |
Delete Bucket Policy |
HttpMethodEnum.DELETE |
SpecialParamEnum.POLICY |
Yes |
No |
Set Lifecycle Rule |
HttpMethodEnum.PUT |
SpecialParamEnum.LIFECYCLE |
Yes |
No |
Get Lifecycle Rule |
HttpMethodEnum.GET |
SpecialParamEnum.LIFECYCLE |
Yes |
No |
Delete Lifecycle Rule |
HttpMethodEnum.DELETE |
SpecialParamEnum.LIFECYCLE |
Yes |
No |
Set Website Hosting |
HttpMethodEnum.PUT |
SpecialParamEnum.WEBSITE |
Yes |
No |
Get Website Hosting |
HttpMethodEnum.GET |
SpecialParamEnum.WEBSITE |
Yes |
No |
Delete Website Hosting |
HttpMethodEnum.DELETE |
SpecialParamEnum.WEBSITE |
Yes |
No |
Set Bucket Versioning |
HttpMethodEnum.PUT |
SpecialParamEnum.VERSIONING |
Yes |
No |
Get Bucket Versioning |
HttpMethodEnum.GET |
SpecialParamEnum.VERSIONING |
Yes |
No |
Set CORS Rule |
HttpMethodEnum.PUT |
SpecialParamEnum.CORS |
Yes |
No |
Get CORS Rule |
HttpMethodEnum.GET |
SpecialParamEnum.CORS |
Yes |
No |
Delete CORS Rule |
HttpMethodEnum.DELETE |
SpecialParamEnum.CORS |
Yes |
No |
Set Bucket Tagging |
HttpMethodEnum.PUT |
SpecialParamEnum.TAGGING |
Yes |
No |
Get Bucket Tagging |
HttpMethodEnum.GET |
SpecialParamEnum.TAGGING |
Yes |
No |
Delete Bucket Tagging |
HttpMethodEnum.DELETE |
SpecialParamEnum.TAGGING |
Yes |
No |
Upload Object |
HttpMethodEnum.PUT |
N/A |
Yes |
Yes |
Append Object |
HttpMethodEnum.POST |
SpecialParamEnum.APPEND |
Yes |
Yes |
Get Object |
HttpMethodEnum.GET |
N/A |
Yes |
Yes |
Copy Object |
HttpMethodEnum.PUT |
N/A |
Yes |
Yes |
Delete Object |
HttpMethodEnum.DELETE |
N/A |
Yes |
Yes |
Delete Objects |
HttpMethodEnum.POST |
SpecialParamEnum.DELETE |
Yes |
Yes |
Get Object Metadata |
HttpMethodEnum.HEAD |
N/A |
Yes |
Yes |
Set Object ACL |
HttpMethodEnum.PUT |
SpecialParamEnum.ACL |
Yes |
Yes |
Get Object ACL |
HttpMethodEnum.GET |
SpecialParamEnum.ACL |
Yes |
Yes |
Initiate Multipart Upload |
HttpMethodEnum.POST |
SpecialParamEnum.UPLOADS |
Yes |
Yes |
Upload Part |
HttpMethodEnum.PUT |
N/A |
Yes |
Yes |
Copy Part |
HttpMethodEnum.PUT |
N/A |
Yes |
Yes |
List Parts |
HttpMethodEnum.GET |
N/A |
Yes |
Yes |
Assemble Parts |
HttpMethodEnum.POST |
N/A |
Yes |
Yes |
Delete Multipart Upload |
HttpMethodEnum.DELETE |
N/A |
Yes |
Yes |
Restore Archive Object |
HttpMethodEnum.POST |
SpecialParamEnum.RESTORE |
Yes |
Yes |
Responses
Parameter |
Type |
Description |
---|---|---|
signedUrl |
String |
Explanation: The signed URL. Default value: None |
actualSignedRequestHeaders |
Map<String, String> |
Explanation: Actual headers in the request initiated using the signed URL. Default value: None |
Code Examples
This example creates a signed URL for downloading a resized and rotated image objectname.jpg from bucket examplebucket.
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import com.obs.services.ObsClient; import com.obs.services.exception.ObsException; import com.obs.services.model.HttpMethodEnum; import com.obs.services.model.TemporarySignatureRequest; import com.obs.services.model.TemporarySignatureResponse; import java.util.HashMap; import java.util.Map; public class GetObject009 { public static void main(String[] args) { // Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage. // Obtain an AK/SK pair on the management console. String ak = System.getenv("ACCESS_KEY_ID"); String sk = System.getenv("SECRET_ACCESS_KEY_ID"); // (Optional) If you are using a temporary AK/SK pair and a security token to access OBS, you are advised not to use hard coding, which may result in information leakage. // Obtain an AK/SK pair and a security token using environment variables or import them in other ways. // String securityToken = System.getenv("SECURITY_TOKEN"); // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one in your actual situation. String endPoint = "https://obs.ap-southeast-1.myhuaweicloud.com"; // Obtain an endpoint using environment variables or import it in other ways. //String endPoint = System.getenv("ENDPOINT"); // Create an ObsClient instance. // Use the permanent AK/SK pair to initialize the client. ObsClient obsClient = new ObsClient(ak, sk,endPoint); // Use the temporary AK/SK pair and security token to initialize the client. // ObsClient obsClient = new ObsClient(ak, sk, securityToken, endPoint); try { // Create a signed URL for downloading a processed image. long expireSeconds = 3600L; TemporarySignatureRequest request = new TemporarySignatureRequest(HttpMethodEnum.GET, expireSeconds); request.setBucketName("examplebucket"); request.setObjectKey("objectname.jpg"); // Set image processing parameters to resize and rotate the images in the predefined sequence. Map<String, Object> queryParams = new HashMap<String, Object>(); queryParams.put("x-image-process", "image/resize,m_fixed,w_100,h_100/rotate,90"); request.setQueryParams(queryParams); // Generate the signed URL. TemporarySignatureResponse response = obsClient.createTemporarySignature(request); System.out.println("getSignedUrl successfully"); System.out.println(response.getSignedUrl()); } catch (ObsException e) { System.out.println("getSignedUrl failed"); // Request failed. Print the HTTP status code. System.out.println("HTTP Code:" + e.getResponseCode()); // Request failed. Print the server-side error code. System.out.println("Error Code:" + e.getErrorCode()); // Request failed. Print the error details. System.out.println("Error Message:" + e.getErrorMessage()); // Request failed. Print the request ID. System.out.println("Request ID:" + e.getErrorRequestId()); System.out.println("Host ID:" + e.getErrorHostId()); e.printStackTrace(); } catch (Exception e) { System.out.println("getSignedUrl failed"); // Print other error information. e.printStackTrace(); } } } |
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