Simple upload - Object Storage Service - Alibaba Cloud Documentation Center

Simple upload is an upload method that you can use to upload an object by calling the PutObject operation. You can use simple upload to upload a string or local file to Object Storage Service (OSS) in synchronous or asynchronous mode. You can also perform MD5 verification to ensure data integrity in simple upload.

Usage notes

In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS by using other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about the regions and endpoints supported by OSS, see Regions and endpoints.
In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient instance by using custom domain names or Security Token Service (STS), see Initialization.
By default, an Alibaba Cloud account has the permissions to perform simple upload. To perform simple upload by using a RAM user or Security Token Service (STS), you must have the oss:PutObject permission. For more information, see Attach a custom policy to a RAM user.

Upload a string

The following sample code provides an example on how to upload a string to an object named exampleobject.txt in a bucket named examplebucket:

using System.Text;
using Aliyun.OSS;

// 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. 
var endpoint = "yourEndpoint";
// 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. 
var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
// Specify the name of the bucket. Example: examplebucket. 
var bucketName = "examplebucket";
// Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
var objectName = "exampledir/exampleobject.txt";
// Specify the string that you want to upload. 
var objectContent = "More than just cloud.";

// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    byte[] binaryData = Encoding.ASCII.GetBytes(objectContent);
    MemoryStream requestContent = new MemoryStream(binaryData);
    // Upload the object. 
    client.PutObject(bucketName, objectName, requestContent);
    Console.WriteLine("Put object succeeded");
}
catch (Exception ex)
{
    Console.WriteLine("Put object failed, {0}", ex.Message);
}

Upload a local file

The following sample code provides an example on how to upload a local file named examplefile.txt to a bucket named examplebucket. The uploaded file is stored as an object named exampleobject.txt in OSS.

using Aliyun.OSS;

// 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. 
var endpoint = "yourEndpoint";
// 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. 
var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
// Specify the name of the bucket. Example: examplebucket. 
var bucketName = "examplebucket";
// Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
var objectName = "exampledir/exampleobject.txt";
// Specify the full path of the local file that you want to upload. By default, if you do not specify the full path of a local file, the local file is uploaded from the path of the project to which the sample program belongs. 
var localFilename = "D:\\localpath\\examplefile.txt";

// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    // Upload the local file. 
    client.PutObject(bucketName, objectName, localFilename);
    Console.WriteLine("Put object succeeded");
}
catch (Exception ex)
{
    Console.WriteLine("Put object failed, {0}", ex.Message);
}

Upload a local file and perform MD5 verification

To ensure that the data sent by the client is the same as that received by the OSS server, you can add the Content-MD5 header to the request as an metadata item of the object. The OSS server uses the value of this header to perform MD5 verification.

Important

Take note that MD5 verification has a negative impact on OSS performance.

The following sample code provides an example on how to perform MD5 verification when you upload a local file:

using System;
using System.IO;

using Aliyun.OSS;
using Aliyun.OSS.Util;
// 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. 
var endpoint = "yourEndpoint";
// 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. 
var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
// Specify the name of the bucket. Example: examplebucket. 
var bucketName = "examplebucket";
// Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
var objectName = "exampledir/exampleobject.txt";
// Specify the full path of the local file. Example: D:\\localpath\\examplefile.txt. By default, if you do not specify the full path of a local file, the local file is uploaded from the path of the project to which the sample program belongs. 
var localFilename = "D:\\localpath\\examplefile.txt";

// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    // Calculate the MD5 hash. 
    string md5;
    using (var fs = File.Open(localFilename, FileMode.Open))
    {
        md5 = OssUtils.ComputeContentMd5(fs, fs.Length);
    }
    var objectMeta = new ObjectMetadata
    {
        ContentMd5 = md5
    };
    // Upload the local file. 
    client.PutObject(bucketName, objectName, localFilename, objectMeta);
    Console.WriteLine("Put object succeeded");
}
catch (Exception ex)
{
    Console.WriteLine("Put object failed, {0}", ex.Message);
}

Upload a local file in asynchronous mode

The following sample code provides an example on how to upload a local file named examplefile.txt to a bucket named examplebucket in asynchronous mode. The uploaded file is stored as an object named exampleobject.txt in OSS. When you upload a local file in asynchronous mode, you must implement a function to process callback information.

using System;
using System.IO;
using System.Threading;

using Aliyun.OSS;
using Aliyun.OSS.Common;

// Upload a local file in asynchronous mode. 
namespace AsyncPutObject
{
    class Program
    {
        // 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. 
        static string endpoint = "yourEndpoint";
        // 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. 
        var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
        var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
        // Specify the name of the bucket. Example: examplebucket. 
        static string bucketName = "examplebucket";
        // Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
        static string objectName = "exampledir/exampleobject.txt";
        // Specify the full path of the local file. Example: D:\\localpath\\examplefile.txt. By default, if you do not specify the full path of a local file, the local file is uploaded from the path of the project to which the sample program belongs. 
        static string localFilename = "D:\\localpath\\examplefile.txt";

        static AutoResetEvent _event = new AutoResetEvent(false);

        // Create an OSSClient instance. 
        static OssClient client = new OssClient(endpoint, accessKeyId, accessKeySecret);

        private static void PutObjectCallback(IAsyncResult ar)
        {
            try
            {
                client.EndPutObject(ar);
                Console.WriteLine(ar.AsyncState as string);
                Console.WriteLine("Put object succeeded");
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
            finally
            {
                _event.Set();
            }
        }

        public static void AsyncPutObject()
        {
            try
            {
                using (var fs = File.Open(localFilename, FileMode.Open))
                {
                    var metadata = new ObjectMetadata();
                    // Add user metadata. 
                    metadata.UserMetadata.Add("mykey1", "myval1");
                    metadata.UserMetadata.Add("mykey2", "myval2");
                    metadata.CacheControl = "No-Cache";
                    metadata.ContentType = "text/txt";
                    string result = "Notice user: put object finish";

                    // Upload the local file in asynchronous mode. 
                    client.BeginPutObject(bucketName, objectName, fs, metadata, PutObjectCallback, result.ToCharArray());

                    _event.WaitOne();
                }
            }
            catch (OssException ex)
            {
                Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
                    ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Failed with error info: {0}", ex.Message);
            }
        }

        static void Main(string[] args)
        {
            Program.AsyncPutObject();
        }
    }
}

References

For the complete sample code that is used to perform simple upload, visit GitHub.
For more information about the API operation that you can call to perform simple upload, see PutObject.