Object Storage Service:Image processing (Go SDK V1)

You can encapsulate multiple image processing parameters into a style and then use the style to process images in batches. For more information, see Image styles. The following code shows how to process an image using a style:

package main

import (
	"fmt"
	"os"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
	fmt.Println("Error:", err)
	os.Exit(-1)
}

func main() {
	// Obtain access credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Create an OSSClient instance.
	// Set yourEndpoint to the Endpoint of the bucket. For example, for a bucket in the China (Hangzhou) region, set the Endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, use the actual Endpoint.
	// Set yourRegion to the region where the bucket is located. For example, for a bucket in the China (Hangzhou) region, set the region to cn-hangzhou. For other regions, use the actual region.
	clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
	clientOptions = append(clientOptions, oss.Region("yourRegion"))
	// Set the signature version.
	clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
	client, err := oss.New("yourEndpoint", "", "", clientOptions...)
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}

	// Specify the name of the bucket where the source image is stored, for example, examplebucket.
	bucketName := "examplebucket"
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		HandleError(err)
	}
	// Specify the name of the source image. If the image is not in the root directory of the bucket, include the full path of the file, such as example/example.jpg.
	sourceImageName := "example/example.jpg"
	// Name the processed image newexample.jpg and save it locally.
	targetImageName := "D:\\localpath\\newexample.jpg"
	// Process the image using a style. Set yourCustomStyleName to the name of the image style that you created in the OSS console.
	style := "style/yourCustomStyleName"
	// Save the processed image locally.
	err = bucket.GetObjectToFile(sourceImageName, targetImageName, oss.Process(style))
	if err != nil {
		HandleError(err)
	}
}

You can use the ImgSaveAs operation to save the processed image to a specified bucket.

package main

import (
	"encoding/base64"
	"fmt"
	"os"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
	fmt.Println("Error:", err)
	os.Exit(-1)
}

func main() {
	// Obtain access credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}

	// Create an OSSClient instance.
	// Set yourEndpoint to the Endpoint of the bucket. For example, for a bucket in the China (Hangzhou) region, set the Endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, use the actual Endpoint.
	// Set yourRegion to the region where the bucket is located. For example, for a bucket in the China (Hangzhou) region, set the region to cn-hangzhou. For other regions, use the actual region.
	clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
	clientOptions = append(clientOptions, oss.Region("yourRegion"))
	// Set the signature version.
	clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
	client, err := oss.New("yourEndpoint", "", "", clientOptions...)
	if err != nil {
		HandleError(err)
	}

	// Specify the name of the bucket where the source image is stored, for example, srcbucket.
	bucketName := "SourceBucketName"
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		HandleError(err)
	}
	// Specify the name of the source image. If the image is not in the root directory of the bucket, include the full path of the file, such as example/example.jpg.
	sourceImageName := "yourObjectName"
	// Specify the name of the bucket to store the processed image. This bucket must be in the same region as the source bucket.
	targetBucketName := "TargetBucketName"
	// Specify the name for the processed image. If the image is not in the root directory of the bucket, include the full access path of the file, such as exampledir/example.jpg.
	targetImageName := "TargetObjectName"
	// Resize the image to a fixed width and height of 100 px and save it to the specified bucket.
	style := "image/resize,m_fixed,w_100,h_100"
	process := fmt.Sprintf("%s|sys/saveas,o_%v,b_%v", style, base64.URLEncoding.EncodeToString([]byte(targetImageName)), base64.URLEncoding.EncodeToString([]byte(targetBucketName)))
	result, err := bucket.ProcessObject(sourceImageName, process)
	if err != nil {
		HandleError(err)
	} else {
		fmt.Println(result)
	}
}

The access URL for a private file contains a signature. OSS does not support appending image processing parameters directly to a signed URL. To process a private file, you must add the image processing parameters to the signature. The following code provides an example:

package main

import (
	"fmt"
	"os"

	"github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
	fmt.Println("Error:", err)
	os.Exit(-1)
}

func main() {
	// Obtain access credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set.
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}

	// Create an OSSClient instance.
	// Set yourEndpoint to the Endpoint of the bucket. For example, for a bucket in the China (Hangzhou) region, set the Endpoint to https://oss-cn-hangzhou.aliyuncs.com. For other regions, use the actual Endpoint.
	// Set yourRegion to the region where the bucket is located. For example, for a bucket in the China (Hangzhou) region, set the region to cn-hangzhou. For other regions, use the actual region.
	clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
	clientOptions = append(clientOptions, oss.Region("yourRegion"))
	// Set the signature version.
	clientOptions = append(clientOptions, oss.AuthVersion(oss.AuthV4))
	client, err := oss.New("yourEndpoint", "", "", clientOptions...)
	if err != nil {
		HandleError(err)
	}

	// Specify the name of the bucket where the image is stored, for example, examplebucket.
	bucketName := "examplebucket"
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		HandleError(err)
	}
	// Specify the name of the image. If the image is not in the root directory of the bucket, include the full path of the file, such as exampledir/example.jpg.
	ossImageName := "exampledir/example.jpg"
	// Generate a signed URL that expires in 600 seconds. The maximum validity period is 32,400 seconds.
	signedURL, err := bucket.SignURL(ossImageName, oss.HTTPGet, 600, oss.Process("image/format,png"))
	if err != nil {
		HandleError(err)
	} else {
		fmt.Println(signedURL)
	}
}