Help Center/ Object Storage Service/ SDK Reference/ .NET/ Temporarily Authorized Access/ Using a Temporary URL for Authorized Access
Updated on 2023-12-25 GMT+08:00

Using a Temporary URL for Authorized Access

If you have any questions during the development, post them on the Issues page of GitHub. For details about parameters and usage of each API, see the API Reference.

ObsClient allows you to create a URL whose Query parameters are carried with authentication information by specifying the AK and SK, HTTP method, and request parameters. You can provide other users with this URL for temporary access. When generating a URL, you need to specify the validity period of the URL to restrict the access duration of visitors.

If you want to grant other users the permission to perform other operations on buckets or objects (for example, upload or download objects), generate a URL with the corresponding request (for example, to upload an object using the URL that generates the PUT request) and provide the URL for other users.

The following table lists operations can be performed through a signed URL.

Operation

HTTP Request Method (Value in OBS .NET SDK)

Sub-resource (Value in OBS .NET SDK)

Bucket Name Required

Object Name Required

PUT Bucket

HttpVerb.PUT

N/A

Yes

No

GET Buckets

HttpVerb.GET

N/A

No

No

DELETE Bucket

HttpVerb.DELETE

N/A

Yes

No

GET Objects

HttpVerb.GET

N/A

Yes

No

GET Object versions

HttpVerb.GET

SubResourceEnum.Versions

Yes

No

List Multipart uploads

HttpVerb.GET

SubResourceEnum.Uploads

Yes

No

Obtain Bucket Metadata

HttpVerb.HEAD

N/A

Yes

No

GET Bucket location

HttpVerb.GET

SubResourceEnum.Location

Yes

No

GET Bucket storageinfo

HttpVerb.GET

SubResourceEnum.StorageInfo

Yes

No

PUT Bucket quota

HttpVerb.PUT

SubResourceEnum.Quota

Yes

No

GET Bucket quota

HttpVerb.GET

SubResourceEnum.Quota

Yes

No

PUT Bucket storagePolicy

HttpVerb.PUT

SubResourceEnum.StoragePolicy

Yes

No

GET Bucket storagePolicy

HttpVerb.GET

SubResourceEnum.StoragePolicy

Yes

No

PUT Bucket acl

HttpVerb.PUT

SubResourceEnum.Acl

Yes

No

GET Bucket acl

HttpVerb.GET

SubResourceEnum.Acl

Yes

No

PUT Bucket logging

HttpVerb.PUT

SubResourceEnum.Logging

Yes

No

GET Bucket logging

HttpVerb.GET

SubResourceEnum.Logging

Yes

No

PUT Bucket policy

HttpVerb.PUT

SubResourceEnum.Policy

Yes

No

GET Bucket policy

HttpVerb.GET

SubResourceEnum.Policy

Yes

No

DELETE Bucket policy

HttpVerb.DELETE

SubResourceEnum.Policy

Yes

No

PUT Bucket lifecycle

HttpVerb.PUT

SubResourceEnum.Lifecycle

Yes

No

GET Bucket lifecycle

HttpVerb.GET

SubResourceEnum.Lifecycle

Yes

No

DELETE Bucket lifecycle

HttpVerb.DELETE

SubResourceEnum.Lifecycle

Yes

No

PUT Bucket website

HttpVerb.PUT

SubResourceEnum.Website

Yes

No

GET Bucket website

HttpVerb.GET

SubResourceEnum.Website

Yes

No

DELETE Bucket website

HttpVerb.DELETE

SubResourceEnum.Website

Yes

No

PUT Bucket versioning

HttpVerb.PUT

SubResourceEnum.Versioning

Yes

No

GET Bucket versioning

HttpVerb.GET

SubResourceEnum.Versioning

Yes

No

PUT Bucket cors

HttpVerb.PUT

SubResourceEnum.Cors

Yes

No

GET Bucket cors

HttpVerb.GET

SubResourceEnum.Cors

Yes

No

DELETE Bucket cors

HttpVerb.DELETE

SubResourceEnum.Cors

Yes

No

PUT Bucket tagging

HttpVerb.PUT

SubResourceEnum.Tagging

Yes

No

GET Bucket tagging

HttpVerb.GET

SubResourceEnum.Tagging

Yes

No

DELETE Bucket tagging

HttpVerb.DELETE

SubResourceEnum.Tagging

Yes

No

PUT Object

HttpVerb.PUT

N/A

Yes

Yes

Append Object

HttpVerb.POST

SubResourceEnum.Append

Yes

Yes

GET Object

HttpVerb.GET

N/A

Yes

Yes

PUT Object - Copy

HttpVerb.PUT

N/A

Yes

Yes

DELETE Object

HttpVerb.DELETE

N/A

Yes

Yes

DELETE Objects

HttpVerb.POST

SubResourceEnum.Delete

Yes

Yes

Obtain Object Metadata

HttpVerb.HEAD

N/A

Yes

Yes

PUT Object acl

HttpVerb.PUT

SubResourceEnum.Acl

Yes

Yes

GET Object acl

HttpVerb.GET

SubResourceEnum.Acl

Yes

Yes

Initiate Multipart Upload

HttpVerb.POST

SubResourceEnum.Uploads

Yes

Yes

Upload Part

HttpVerb.PUT

N/A

Yes

Yes

Upload Part - Copy

HttpVerb.PUT

N/A

Yes

Yes

List Parts

HttpVerb.GET

N/A

Yes

Yes

Complete Multipart Upload

HttpVerb.POST

N/A

Yes

Yes

Abort Multipart Upload

HttpVerb.DELETE

N/A

Yes

Yes

POST Object restore

HttpVerb.POST

SubResourceEnum.Restore

Yes

Yes

To access OBS using a temporary URL generated by the OBS .NET SDK, perform the following steps:

  1. Call ObsClient.CreateTemporarySignature to generate a signed URL.
  2. Use any HTTP library to make an HTTP/HTTPS request to OBS.

If a CORS or signature mismatch error occurs, refer to the following steps to troubleshoot the issue:

  1. If CORS is not configured, you need to configure CORS rules on OBS Console. For details, see Configuring CORS.
  2. If the signatures do not match, check whether signature parameters are correct by referring to Authentication of Signature in a URL. For example, during an object upload, the backend uses Content-Type to calculate the signature and generate an authorized URL, but if Content-Type is not set or is set to an incorrect value when the frontend uses the authorized URL, a CORS error occurs. To avoid this issue, ensure that Content-Type fields at both the frontend and backend are kept consistent.

The following content provides examples of accessing OBS using a temporary URL, including bucket creation, as well as object upload, download, listing, and deletion.

Creating a Bucket

// Initialize configuration parameters.
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// Create an ObsClient instance.
ObsClient client = new ObsClient(accessKey, secretKey, config);

// Specify the validity period of the URL to 3600 seconds.
long exipreSeconds = 3600;

CreateTemporarySignatureRequest request = new CreateTemporarySignatureRequest();
request.BucketName = "bucketname";
request.Method = HttpVerb.PUT;
request.Expires = exipreSeconds;

CreateTemporarySignatureResponse response = client.CreateTemporarySignature(request);
Console.WriteLine("Creating bucket using temporary signature url:");
Console.WriteLine("\t" + response.SignUrl);

// Use a PUT request to create a bucket.
HttpWebRequest webRequest = WebRequest.Create(response.SignUrl) as HttpWebRequest;
webRequest.Method = "PUT";


foreach (KeyValuePair<string, string> header in response.ActualSignedRequestHeaders)
{
    if (!header.Key.Equals("host", StringComparison.OrdinalIgnoreCase))
    {
        webRequest.Headers.Add(header.Key, header.Value);
    }
}

string location = "your bucket location";
            
webRequest.SendChunked = true;
webRequest.AllowWriteStreamBuffering = false;
using (Stream requestStream = webRequest.GetRequestStream())
{
    byte[] buffer = Encoding.UTF8.GetBytes("<CreateBucketConfiguration><LocationConstraint>" + location + "</LocationConstraint></CreateBucketConfiguration>");
    requestStream.Write(buffer, 0, buffer.Length);
}

HttpWebResponse webResponse = null;
try
{
    webResponse = webRequest.GetResponse() as HttpWebResponse;
}
catch (WebException ex)
{
    webResponse = ex.Response as HttpWebResponse;
}
Console.WriteLine("Response Status:" + Convert.ToInt32(webResponse.StatusCode));
using (MemoryStream dest = new MemoryStream())
{
    using (Stream stream = webResponse.GetResponseStream())
    {
        byte[] buffer = new byte[8192];
        int bytesRead;
        while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
        {
            dest.Write(buffer, 0, bytesRead);
        }

    }
    Console.WriteLine("Response Content:");
    Console.WriteLine(Encoding.UTF8.GetString(dest.ToArray()));
}

Uploading an Object

// Initialize configuration parameters.
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// Create an ObsClient instance.
ObsClient client = new ObsClient(accessKey, secretKey, config);

// Specify the validity period of the URL to 3600 seconds.
long exipreSeconds = 3600;

CreateTemporarySignatureRequest request = new CreateTemporarySignatureRequest();
request.BucketName = "bucketname";
request.ObjectKey = "objectkey";         
request.Method = HttpVerb.PUT;
request.Expires = exipreSeconds;

CreateTemporarySignatureResponse response = client.CreateTemporarySignature(request);
Console.WriteLine("Creating object using temporary signature url:");
Console.WriteLine("\t" + response.SignUrl);

// Use a PUT request to upload an object.
HttpWebRequest webRequest = WebRequest.Create(response.SignUrl) as HttpWebRequest;
webRequest.Method = "PUT";


foreach (KeyValuePair<string, string> header in response.ActualSignedRequestHeaders)
{
    if (!header.Key.Equals("host", StringComparison.OrdinalIgnoreCase))
    {
        webRequest.Headers.Add(header.Key, header.Value);
    }
}
            
webRequest.SendChunked = true;
webRequest.AllowWriteStreamBuffering = false;
using (Stream requestStream = webRequest.GetRequestStream())
{
    byte[] buffer = Encoding.UTF8.GetBytes("Hello OBS");
    requestStream.Write(buffer, 0, buffer.Length);
}

HttpWebResponse webResponse = null;
try
{
    webResponse = webRequest.GetResponse() as HttpWebResponse;
}
catch (WebException ex)
{
    webResponse = ex.Response as HttpWebResponse;
}
Console.WriteLine("Response Status:" + Convert.ToInt32(webResponse.StatusCode));
using (MemoryStream dest = new MemoryStream())
{
    using (Stream stream = webResponse.GetResponseStream())
    {
        byte[] buffer = new byte[8192];
        int bytesRead;
        while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
        {
            dest.Write(buffer, 0, bytesRead);
        }

    }
    Console.WriteLine("Response Content:");
    Console.WriteLine(Encoding.UTF8.GetString(dest.ToArray()));
}

Downloading an Object

// Initialize configuration parameters.
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// Create an ObsClient instance.
ObsClient client = new ObsClient(accessKey, secretKey, config);

// Specify the validity period of the URL to 3600 seconds.
long exipreSeconds = 3600;

CreateTemporarySignatureRequest request = new CreateTemporarySignatureRequest();
request.BucketName = "bucketname";
request.ObjectKey = "objectkey";         
request.Method = HttpVerb.GET;
request.Expires = exipreSeconds;

CreateTemporarySignatureResponse response = client.CreateTemporarySignature(request);
Console.WriteLine("Getting object using temporary signature url:");
Console.WriteLine("\t" + response.SignUrl);

// Make a GET request to download an object.
HttpWebRequest webRequest = WebRequest.Create(response.SignUrl) as HttpWebRequest;
webRequest.Method = "GET";


foreach (KeyValuePair<string, string> header in response.ActualSignedRequestHeaders)
{
    if (!header.Key.Equals("host", StringComparison.OrdinalIgnoreCase))
    {
        webRequest.Headers.Add(header.Key, header.Value);
    }
}
            
HttpWebResponse webResponse = null;
try
{
    webResponse = webRequest.GetResponse() as HttpWebResponse;
}
catch (WebException ex)
{
    webResponse = ex.Response as HttpWebResponse;
}
Console.WriteLine("Response Status:" + Convert.ToInt32(webResponse.StatusCode));
using (MemoryStream dest = new MemoryStream())
{
    using (Stream stream = webResponse.GetResponseStream())
    {
        byte[] buffer = new byte[8192];
        int bytesRead;
        while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
        {
            dest.Write(buffer, 0, bytesRead);
        }

    }
    Console.WriteLine("Response Content:");
    Console.WriteLine(Encoding.UTF8.GetString(dest.ToArray()));
}

Listing Objects

// Initialize configuration parameters.
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// Create an ObsClient instance.
ObsClient client = new ObsClient(accessKey, secretKey, config);

// Specify the validity period of the URL to 3600 seconds.
long exipreSeconds = 3600;

CreateTemporarySignatureRequest request = new CreateTemporarySignatureRequest();
request.BucketName = "bucketname";
request.Method = HttpVerb.GET;
request.Expires = exipreSeconds;

CreateTemporarySignatureResponse response = client.CreateTemporarySignature(request);
Console.WriteLine("Getting object list using temporary signature url:");
Console.WriteLine("\t" + response.SignUrl);

// Use a GET request to obtain the object list.
HttpWebRequest webRequest = WebRequest.Create(response.SignUrl) as HttpWebRequest;
webRequest.Method = "GET";


foreach (KeyValuePair<string, string> header in response.ActualSignedRequestHeaders)
{
    if (!header.Key.Equals("host", StringComparison.OrdinalIgnoreCase))
    {
        webRequest.Headers.Add(header.Key, header.Value);
    }
}
            
HttpWebResponse webResponse = null;
try
{
    webResponse = webRequest.GetResponse() as HttpWebResponse;
}
catch (WebException ex)
{
    webResponse = ex.Response as HttpWebResponse;
}
Console.WriteLine("Response Status:" + Convert.ToInt32(webResponse.StatusCode));
using (MemoryStream dest = new MemoryStream())
{
    using (Stream stream = webResponse.GetResponseStream())
    {
        byte[] buffer = new byte[8192];
        int bytesRead;
        while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
        {
            dest.Write(buffer, 0, bytesRead);
        }

    }
    Console.WriteLine("Response Content:");
    Console.WriteLine(Encoding.UTF8.GetString(dest.ToArray()));
}

Deleting an Object

// Initialize configuration parameters.
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// Hard-coded or plaintext AK/SK are risky. For security purposes, encrypt your AK/SK and store them in the configuration file or environment variables. In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, configure environment variables AccessKeyID and SecretAccessKey.
// Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// Create an ObsClient instance.
ObsClient client = new ObsClient(accessKey, secretKey, config);

// Specify the validity period of the URL to 3600 seconds.
long exipreSeconds = 3600;

CreateTemporarySignatureRequest request = new CreateTemporarySignatureRequest();
request.BucketName = "bucketname";
request.ObjectKey = "objectkey";
request.Method = HttpVerb.DELETE;
request.Expires = exipreSeconds;

CreateTemporarySignatureResponse response = client.CreateTemporarySignature(request);
Console.WriteLine("Deleting object using temporary signature url:");
Console.WriteLine("\t" + response.SignUrl);

// Use a DELETE request to delete an object.
HttpWebRequest webRequest = WebRequest.Create(response.SignUrl) as HttpWebRequest;
webRequest.Method = "DELETE";


foreach (KeyValuePair<string, string> header in response.ActualSignedRequestHeaders)
{
    if (!header.Key.Equals("host", StringComparison.OrdinalIgnoreCase))
    {
        webRequest.Headers.Add(header.Key, header.Value);
    }
}
            
HttpWebResponse webResponse = null;
try
{
    webResponse = webRequest.GetResponse() as HttpWebResponse;
}
catch (WebException ex)
{
    webResponse = ex.Response as HttpWebResponse;
}
Console.WriteLine("Response Status:" + Convert.ToInt32(webResponse.StatusCode));
using (MemoryStream dest = new MemoryStream())
{
    using (Stream stream = webResponse.GetResponseStream())
    {
        byte[] buffer = new byte[8192];
        int bytesRead;
        while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0)
        {
            dest.Write(buffer, 0, bytesRead);
        }

    }
    Console.WriteLine("Response Content:");
    Console.WriteLine(Encoding.UTF8.GetString(dest.ToArray()));
}

HttpVerb is an enumeration type defined in OBS .NET SDK, whose value indicates the request method types.