How to manage symbolic links for files by using Swift SDK - Object Storage Service

The symbolic link feature provides easy access to frequently used files in a bucket. After you create a symbolic link, you can use it to open a file, which is similar to using a shortcut in Windows. This topic describes how to use the OSS Swift SDK to create and retrieve symbolic links.

Precautions

The sample code in this topic uses the China (Hangzhou) region ID cn-hangzhou as an example. The code uses a public endpoint by default. To access OSS from other Alibaba Cloud products in the same region, use an internal endpoint. For more information about the mappings between OSS-supported regions and endpoints, see Regions and endpoints.
To create a symbolic link, you must have the oss:PutObject permission. To retrieve a symbolic link, you must have the oss:GetObject permission. For more information, see Grant custom permissions to a RAM user.

Sample code

Create a symbolic link

You can use the following code to create a symbolic link.

import AlibabaCloudOSS
import Foundation

@main
struct Main {
    static func main() async {
        do {
            // Specify the region where the bucket is located. Example: China (Hangzhou) is cn-hangzhou.
            let region = "cn-hangzhou"
            // Specify the bucket name.
            let bucket = "yourBucketName"
            // Optional. Specify the domain name to access OSS. For example, for the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
            let endpoint: String? = nil
            // Specify the name of the symbolic link to create, for example, symlink.txt.
            let key = "yourSymlinkName"
            // Specify the path of the target object for the symbolic link, for example, /path/to/target.txt.
            let symlinkTarget = "yourTargetObjectPath"

            // Initialize the credential provider. The OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are used.
            let credentialsProvider = EnvironmentCredentialsProvider()

            // Configure the parameters for the OSS client.
            let config = Configuration.default()
                .withRegion(region)        // Set the region where the bucket is located.
                .withCredentialsProvider(credentialsProvider)  // Set the access credentials.
                
            // Set the endpoint.
            if let endpoint = endpoint {
                config.withEndpoint(endpoint)
            }

            // Create an OSS client instance.
            let client = Client(config)

            // Create the symbolic link.
            let result = try await client.putSymlink(
                PutSymlinkRequest(
                    bucket: bucket,
                    key: key,
                    symlinkTarget: symlinkTarget
                )
            )
            print("result:\n\(result)")

        } catch {
            // Print the error message and continue.
            print("error: \(error)")
        }
    }
}

Get a symbolic link

You can use the following code to retrieve a symbolic link and the name of its target object.

import AlibabaCloudOSS
import Foundation

@main
struct Main {
    static func main() async {

        do {
            // Specify the region where the bucket is located. Example: China (Hangzhou) is cn-hangzhou.
            let region = "cn-hangzhou" // Replace with the actual region ID.
            // Specify the bucket name.
            let bucket = "yourBucketName" // Replace with the actual bucket name.
            // Optional. Specify the domain name to access OSS. For example, for the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
            let endpoint: String? = nil
            // Specify the name of the symbolic link. Example: document.txt.
            let key = "yourObjectName" // Replace with the actual name of the symbolic link.

            // Initialize the credential provider. The OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are used.
            let credentialsProvider = EnvironmentCredentialsProvider()

            // Configure the parameters for the OSS client.
            let config = Configuration.default()
                .withRegion(region)        // Set the region where the bucket is located.
                .withCredentialsProvider(credentialsProvider)  // Set the access credentials.
                
            // Set the endpoint.
            if let endpoint = endpoint {
                config.withEndpoint(endpoint)
            }
            
            // Create an OSS client instance.
            let client = Client(config)

            // Get the symbolic link.
            let result = try await client.getSymlink(
                GetSymlinkRequest(
                    bucket: bucket,
                    key: key
                )
            )
            print("result:\n\(result)")

        } catch {
            // Print the error message and continue.
            print("error: \(error)")
        }
    }
}

References

For the complete sample code for symbolic links, see the GitHub examples put_symlink and get_symlink.
For more information about operations on symbolic links, see Symbolic links.
For more information about the API operation to create a symbolic link, see PutSymlink.
For more information about the API operation to retrieve a symbolic link, see GetSymlink.