Object Storage Service:IMG by using OSS SDK for Go

You can encapsulate multiple IMG parameters within a style and then use the style to process an image. For more information, see Image styles. The following sample code provides an example on how to use an image style to process an image:

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 the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Create an OSSClient instance. 
	// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint. 
	// Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to cn-hangzhou. Specify the actual region.
	clientOptions := []oss.ClientOption{oss.SetCredentialsProvider(&provider)}
	clientOptions = append(clientOptions, oss.Region("yourRegion"))
	// Specify the version of the signature algorithm.
	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 in which the source image is stored. Example: examplebucket. 
	bucketName := "examplebucket"
	bucket, err := client.Bucket(bucketName)
	if err != nil {
		HandleError(err)
	}
	// Specify the name of the source image. If the source image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: example/example.jpg. 
	sourceImageName := "example/example.jpg"
	// Save the processed image as newexample.jpg to your local computer. 
	targetImageName := "D:\\localpath\\newexample.jpg"
	// Use an image style to process the image. Set yourCustomStyleName to the name of the image style that you created in the OSS console. 
	style := "style/yourCustomStyleName"
	// Save the processed image to your local computer. 
	err = bucket.GetObjectToFile(sourceImageName, targetImageName, oss.Process(style))
	if err != nil {
		HandleError(err)
	}
}

You can call the ImgSaveAs operation to save processed images to a specific 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 the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
    provider, err := oss.NewEnvironmentVariableCredentialsProvider()
    if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
    }

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

    // Specify the name of the bucket in which the source image is stored. Example: srcbucket. 
    bucketName := "SourceBucketName"
    bucket, err := client.Bucket(bucketName)
    if err != nil {
    HandleError(err)
    }
    // Specify the name of the source image. If the source image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: example/example.jpg. 
    sourceImageName := "yourObjectName"
    // Specify the name of the bucket to which you want to store the processed image. The bucket must be located in the same region as the bucket in which the source image is stored. 
    targetBucketName := "TargetBucketName"
    // Specify the name of the processed image. If the processed image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg. 
    targetImageName := "TargetObjectName"
    // Resize the image to 100 x 100 pixels and save the image to a specific 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 URL of a private object is signed. IMG parameters cannot be directly added to the end of a signed URL. If you want to process a private object, add IMG parameters to the signature. The following sample code provides an example on how to add IMG parameters to a signature:

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 the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
    provider, err := oss.NewEnvironmentVariableCredentialsProvider()
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }

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

    // Specify the name of the bucket in which the source image is stored. 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 stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg. 
    ossImageName := "exampledir/example.jpg"
    // Generate a signed URL that includes IMG parameters. Set the validity period of the signed URL to 600 seconds. (The maximum validity period is 32400 seconds.)
    signedURL, err := bucket.SignURL(ossImageName, oss.HTTPGet, 600, oss.Process("image/format,png"))
    if err != nil {
    HandleError(err)
    } else {
    fmt.Println(signedURL)
    }
}