Object Storage Service:Document conversion

Prerequisites

• You have created a bucket in Object Storage Service (OSS), uploaded the source document to the bucket, and associated the bucket with an Intelligent Media Management (IMM) project. The IMM project must be in the same region as the bucket.

• You have the required permissions for IMM to process the document.

Convert documents

You can use an SDK to call the document conversion API and save the converted file to a specified bucket. Asynchronous processing for document conversion is supported only by the SDKs for Java, Python, and Go.

import com.aliyun.oss.ClientBuilderConfiguration;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.common.auth.CredentialsProviderFactory;
import com.aliyun.oss.common.auth.EnvironmentVariableCredentialsProvider;
import com.aliyun.oss.common.comm.SignVersion;
import com.aliyun.oss.model.AsyncProcessObjectRequest;
import com.aliyun.oss.model.AsyncProcessObjectResult;
import com.aliyuncs.exceptions.ClientException;

import java.util.Base64;

public class Demo1 {
    public static void main(String[] args) throws ClientException {
        // Set endpoint to the endpoint of the region where the bucket is located.
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Set region to the region ID, for example, cn-hangzhou.
        String region = "cn-hangzhou";
        // Obtain access credentials from environment variables. Before running this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the bucket name.
        String bucketName = "examplebucket";
        // Specify the name of the destination file.
        String targetKey = "dest.png";
        // Specify the name of the source document.
        String sourceKey = "src.docx";

        // Create an OSSClient instance.
        // When the OSSClient instance is no longer needed, call the shutdown method to release its resources.
        ClientBuilderConfiguration clientBuilderConfiguration = new ClientBuilderConfiguration();
        clientBuilderConfiguration.setSignatureVersion(SignVersion.V4);
        OSS ossClient = OSSClientBuilder.create()
                .endpoint(endpoint)
                .credentialsProvider(credentialsProvider)
                .clientConfiguration(clientBuilderConfiguration)
                .region(region)
                .build();

        try {
            // Build the string for document processing styles and conversion parameters.
            String style = String.format("doc/convert,target_png,source_docx");
            // Build the asynchronous processing instruction.
            String bucketEncoded = Base64.getUrlEncoder().withoutPadding().encodeToString(bucketName.getBytes());
            String targetEncoded = Base64.getUrlEncoder().withoutPadding().encodeToString(targetKey.getBytes());
            String process = String.format("%s|sys/saveas,b_%s,o_%s", style, bucketEncoded, targetEncoded);
            // Create an AsyncProcessObjectRequest object.
            AsyncProcessObjectRequest request = new AsyncProcessObjectRequest(bucketName, sourceKey, process);
            // Initiate the asynchronous task.
            AsyncProcessObjectResult response = ossClient.asyncProcessObject(request);
            System.out.println("EventId: " + response.getEventId());
            System.out.println("RequestId: " + response.getRequestId());
            System.out.println("TaskId: " + response.getTaskId());

        } finally {
            // Shut down the OSSClient instance.
            ossClient.shutdown();
        }
    }
}

# -*- coding: utf-8 -*-
import base64
import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider

def main():
    # Obtain access credentials from environment variables. Before running this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.
    auth = oss2.ProviderAuthV4(EnvironmentVariableCredentialsProvider())
    # Set endpoint to the endpoint of the region where the bucket is located. For example, for China (Hangzhou), set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
    endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'
    # Specify the general-purpose Alibaba Cloud region ID, for example, cn-hangzhou.
    region = 'cn-hangzhou'

    # Specify the bucket name, for example, examplebucket.
    bucket = oss2.Bucket(auth, endpoint, 'examplebucket', region=region)

    # Specify the name of the source document.
    source_key = 'src.docx'

    # Specify the name of the destination file.
    target_key = 'dest.png'

    # Build the string for document processing styles and conversion parameters.
    animation_style = 'doc/convert,target_png,source_docx'

    # Build the processing instruction, including the save path and the Base64-encoded bucket name and destination file name.
    bucket_name_encoded = base64.urlsafe_b64encode('examplebucket'.encode()).decode().rstrip('=')
    target_key_encoded = base64.urlsafe_b64encode(target_key.encode()).decode().rstrip('=')
    process = f"{animation_style}|sys/saveas,b_{bucket_name_encoded},o_{target_key_encoded}"

    try:
        # Initiate the asynchronous task.
        result = bucket.async_process_object(source_key, process)
        print(f"EventId: {result.event_id}")
        print(f"RequestId: {result.request_id}")
        print(f"TaskId: {result.task_id}")
    except Exception as e:
        print(f"Error: {e}")


if __name__ == "__main__":
    main()

package main

import (
    "encoding/base64"
    "fmt"
    "os"
    "github.com/aliyun/aliyun-oss-go-sdk/oss"
    "log"
)

func main() {
    // Obtain access credentials from environment variables. Before running this 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.
    // Set the endpoint to the one for your bucket's region. For the China (Hangzhou) region, for example, use https://oss-cn-hangzhou.aliyuncs.com. Set the endpoint based on your actual region.
    // Specify the general-purpose Alibaba Cloud region ID, for example, cn-hangzhou.
    client, err := oss.New("https://oss-cn-hangzhou.aliyuncs.com", "", "", oss.SetCredentialsProvider(&provider), oss.AuthVersion(oss.AuthV4), oss.Region("cn-hangzhou"))
    if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
    }
    // Specify the bucket name, for example, examplebucket.
    bucketName := "examplebucket"

    bucket, err := client.Bucket(bucketName)
    if err != nil {
    fmt.Println("Error:", err)
    os.Exit(-1)
    }

    // Specify the name of the source document.
    sourceKey := "src.docx"
    // Specify the name of the destination file.
    targetKey := "dest.png"

    // Build the string for document processing styles and conversion parameters.
    animationStyle := "doc/convert,target_png,source_docx"

    // Build the processing instruction, including the save path and the Base64-encoded bucket name and destination file name.
    bucketNameEncoded := base64.URLEncoding.EncodeToString([]byte(bucketName))
    targetKeyEncoded := base64.URLEncoding.EncodeToString([]byte(targetKey))
    process := fmt.Sprintf("%s|sys/saveas,b_%v,o_%v", animationStyle, bucketNameEncoded, targetKeyEncoded)

    // Initiate the asynchronous task.
    result, err := bucket.AsyncProcessObject(sourceKey, process)
    if err != nil {
    log.Fatalf("Failed to async process object: %s", err)
    }

    fmt.Printf("EventId: %s\n", result.EventId)
    fmt.Printf("RequestId: %s\n", result.RequestId)
    fmt.Printf("TaskId: %s\n", result.TaskId)
}

Convert documents

• Before conversion

  • Document format: DOCX

  • Document name: example.docx

• After conversion

  • File format: PNG

  • Storage path: oss://test-bucket/doc_images/{index}.png

    • b_dGVzdC1idWNrZXQ=: Saves the output to the bucket named test-bucket after transcoding is complete (dGVzdC1idWNrZXQ= is the Base64-encoded value of test-bucket).

    • o_ZG9jX2ltYWdlcy97aW5kZXh9LnBuZw==: Saves the object to the doc_images directory. The {index} variable is replaced with the page number of example.docx to form the image filename (ZG9jX2ltYWdlcy97aW5kZXh9LnBuZw== is the Base64-encoded value of doc_images/{index}.png).

  • Conversion completion notification: A message is sent to a Simple Message Queue (SMQ) (formerly MNS) topic named test-topic.

Sample request

// Convert the example.docx file to PNG images.
POST /example.docx?x-oss-async-process HTTP/1.1
Host: doc-demo.oss-cn-hangzhou.aliyuncs.com
Date: Fri, 28 Oct 2022 06:40:10 GMT
Authorization: SignatureValue

x-oss-async-process=doc/convert,target_png,source_docx|sys/saveas,b_dGVzdC1idWNrZXQ=,o_ZG9jX2ltYWdlcy97aW5kZXh9LnBuZw==/notify,topic_dGVzdC10b3BpYw

Convert a specific Excel worksheet

No. OSS document conversion converts all worksheets in an Excel workbook. To convert a specific worksheet, call the IMM CreateOfficeConversionTask operation and set the SheetIndex parameter.