Using a Temporary URL for Authorized Access

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:

Call ObsClient.CreateTemporarySignature to generate a signed URL.
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:

If CORS is not configured, you need to configure CORS rules on OBS Console. For details, see Configuring CORS.
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/eu/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/eu/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/eu/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/eu/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/eu/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()));
}