# 使用临时URL进行授权访问
![](https://support.huaweicloud.com/sdk-dotnet-devg-obs/public_sys-resources/notice_3.0-zh-cn.png)
开发过程中，您有任何问题可以在github上[提交issue](https://github.com/huaweicloud/huaweicloud-sdk-dotnet-obs/issues)，或者在[华为云对象存储服务论坛](https://bbs.huaweicloud.com/forum/forum-620-1.html)中发帖求助。[接口参考文档](https://obssdk.obs.cn-north-1.myhuaweicloud.com/apidoc/cn/dotnet/html/G_OBS.htm)详细介绍了每个接口的参数和使用方法。
OBS客户端支持通过访问密钥、请求方法类型、请求参数等信息生成一个在Query参数中携带鉴权信息的URL，可将该URL提供给其他用户进行临时访问。在生成URL时，您需要指定URL的有效期来限制访客用户的访问时长。
如果您想授予其他用户对桶或对象临时进行其他操作的权限（例如上传或下载对象），则需要生成带对应请求的URL后（例如使用生成PUT请求的URL上传对象），将该URL提供给其他用户。
通过该方式可支持的操作以及相关信息见下表：
| **操作名**   | **HTTP请求方法（OBS .NET SDK对应值）** | **子资源（OBS .NET SDK对应值）**      | **是否需要桶名** | **是否需要对象名** |
|:---|:---|:---|:---|:---|
| 创建桶       | HttpVerb.PUT                  | N/A                           | 是          | 否           |
| 获取桶列表     | HttpVerb.GET                  | N/A                           | 否          | 否           |
| 删除桶       | HttpVerb.DELETE               | N/A                           | 是          | 否           |
| 列举桶内对象    | HttpVerb.GET                  | N/A                           | 是          | 否           |
| 列举桶内多版本对象 | HttpVerb.GET                  | SubResourceEnum.Versions      | 是          | 否           |
| 列举分段上传任务  | HttpVerb.GET                  | SubResourceEnum.Uploads       | 是          | 否           |
| 获取桶元数据    | HttpVerb.HEAD                 | N/A                           | 是          | 否           |
| 获取桶区域位置   | HttpVerb.GET                  | SubResourceEnum.Location      | 是          | 否           |
| 获取桶存量信息   | HttpVerb.GET                  | SubResourceEnum.StorageInfo   | 是          | 否           |
| 设置桶配额     | HttpVerb.PUT                  | SubResourceEnum.Quota         | 是          | 否           |
| 获取桶配额     | HttpVerb.GET                  | SubResourceEnum.Quota         | 是          | 否           |
| 设置桶存储类型   | HttpVerb.PUT                  | SubResourceEnum.StoragePolicy | 是          | 否           |
| 获取桶存储类型   | HttpVerb.GET                  | SubResourceEnum.StoragePolicy | 是          | 否           |
| 桶ACL      | HttpVerb.PUT                  | SubResourceEnum.Acl           | 是          | 否           |
| 获取桶ACL    | HttpVerb.GET                  | SubResourceEnum.Acl           | 是          | 否           |
| 开启/关闭桶日志  | HttpVerb.PUT                  | SubResourceEnum.Logging       | 是          | 否           |
| 查看桶日志     | HttpVerb.GET                  | SubResourceEnum.Logging       | 是          | 否           |
| 设置桶策略     | HttpVerb.PUT                  | SubResourceEnum.Policy        | 是          | 否           |
| 查看桶策略     | HttpVerb.GET                  | SubResourceEnum.Policy        | 是          | 否           |
| 删除桶策略     | HttpVerb.DELETE               | SubResourceEnum.Policy        | 是          | 否           |
| 设置生命周期规则  | HttpVerb.PUT                  | SubResourceEnum.Lifecycle     | 是          | 否           |
| 查看生命周期规则  | HttpVerb.GET                  | SubResourceEnum.Lifecycle     | 是          | 否           |
| 删除生命周期规则  | HttpVerb.DELETE               | SubResourceEnum.Lifecycle     | 是          | 否           |
| 设置托管配置    | HttpVerb.PUT                  | SubResourceEnum.Website       | 是          | 否           |
| 查看托管配置    | HttpVerb.GET                  | SubResourceEnum.Website       | 是          | 否           |
| 清除托管配置    | HttpVerb.DELETE               | SubResourceEnum.Website       | 是          | 否           |
| 设置桶多版本状态  | HttpVerb.PUT                  | SubResourceEnum.Versioning    | 是          | 否           |
| 查看桶多版本状态  | HttpVerb.GET                  | SubResourceEnum.Versioning    | 是          | 否           |
| 设置跨域规则    | HttpVerb.PUT                  | SubResourceEnum.Cors          | 是          | 否           |
| 查看跨域规则    | HttpVerb.GET                  | SubResourceEnum.Cors          | 是          | 否           |
| 删除跨域规则    | HttpVerb.DELETE               | SubResourceEnum.Cors          | 是          | 否           |
| 设置桶标签     | HttpVerb.PUT                  | SubResourceEnum.Tagging       | 是          | 否           |
| 查看桶标签     | HttpVerb.GET                  | SubResourceEnum.Tagging       | 是          | 否           |
| 删除桶标签     | HttpVerb.DELETE               | SubResourceEnum.Tagging       | 是          | 否           |
| 上传对象      | HttpVerb.PUT                  | N/A                           | 是          | 是           |
| 追加上传      | HttpVerb.POST                 | SubResourceEnum.Append        | 是          | 是           |
| 下载对象      | HttpVerb.GET                  | N/A                           | 是          | 是           |
| 复制对象      | HttpVerb.PUT                  | N/A                           | 是          | 是           |
| 删除对象      | HttpVerb.DELETE               | N/A                           | 是          | 是           |
| 批量删除对象    | HttpVerb.POST                 | SubResourceEnum.Delete        | 是          | 是           |
| 获取对象属性    | HttpVerb.HEAD                 | N/A                           | 是          | 是           |
| 设置对象ACL   | HttpVerb.PUT                  | SubResourceEnum.Acl           | 是          | 是           |
| 查看对象ACL   | HttpVerb.GET                  | SubResourceEnum.Acl           | 是          | 是           |
| 初始化分段上传任务 | HttpVerb.POST                 | SubResourceEnum.Uploads       | 是          | 是           |
| 上传段       | HttpVerb.PUT                  | N/A                           | 是          | 是           |
| 复制段       | HttpVerb.PUT                  | N/A                           | 是          | 是           |
| 列举已上传的段   | HttpVerb.GET                  | N/A                           | 是          | 是           |
| 合并段       | HttpVerb.POST                 | N/A                           | 是          | 是           |
| 取消分段上传任务  | HttpVerb.DELETE               | N/A                           | 是          | 是           |
| 恢复归档存储对象  | HttpVerb.POST                 | SubResourceEnum.Restore       | 是          | 是           |
   
通过OBS .NET SDK生成临时URL访问OBS的步骤如下：
1. 通过ObsClient.CreateTemporarySignature生成带签名信息的URL。
2. 使用任意HTTP库发送HTTP/HTTPS请求，访问OBS服务。
![](https://support.huaweicloud.com/sdk-dotnet-devg-obs/public_sys-resources/caution_3.0-zh-cn.png)
如果遇到跨域报错、签名不匹配问题，请参考以下步骤排查问题：
1. 未配置跨域，需要在控制台配置CORS规则，请参考[配置桶允许跨域请求](https://support.huaweicloud.com/sdk-browserjs-devg-obs/obs_24_0107.html)。
2. 签名计算问题，请参考[URL中携带签名](https://support.huaweicloud.com/api-obs/obs_04_0011.html)排查签名参数是否正确；比如上传对象功能，后端将Content-Type参与计算签名生成授权URL，但是前端使用授权URL时没有设置Content-Type字段或者传入错误的值，此时会出现跨域错误。解决方案为：Content-Type字段前后端保持一致。
 
以下代码展示了如何使用临时URL进行授权访问，包括：创建桶、上传对象、下载对象、列举对象、删除对象。
#### 创建桶
```
// 初始化配置参数
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全；本示例以ak和sk保存在环境变量中为例，运行本示例前请先在本地环境中设置环境变量AccessKeyID和SecretAccessKey。
// 您可以登录访问管理控制台获取访问密钥AK/SK，获取方式请参见https://support.huaweicloud.com/usermanual-ca/ca_01_0003.html
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// 创建ObsClient实例
ObsClient client = new ObsClient(accessKey, secretKey, config);
// URL有效期，3600秒
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);
// 使用PUT请求创建桶
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()));
}
```
#### 上传对象
```
// 初始化配置参数
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全；本示例以ak和sk保存在环境变量中为例，运行本示例前请先在本地环境中设置环境变量AccessKeyID和SecretAccessKey。
// 您可以登录访问管理控制台获取访问密钥AK/SK，获取方式请参见https://support.huaweicloud.com/usermanual-ca/ca_01_0003.html
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// 创建ObsClient实例
ObsClient client = new ObsClient(accessKey, secretKey, config);
// URL有效期，3600秒
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);
// 使用PUT请求上传对象
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()));
}
```
#### 下载对象
```
// 初始化配置参数
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全；本示例以ak和sk保存在环境变量中为例，运行本示例前请先在本地环境中设置环境变量AccessKeyID和SecretAccessKey。
// 您可以登录访问管理控制台获取访问密钥AK/SK，获取方式请参见https://support.huaweicloud.com/usermanual-ca/ca_01_0003.html
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// 创建ObsClient实例
ObsClient client = new ObsClient(accessKey, secretKey, config);
// URL有效期，3600秒
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);
// 使用GET请求下载对象
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()));
}
```
#### 列举对象
```
// 初始化配置参数
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全；本示例以ak和sk保存在环境变量中为例，运行本示例前请先在本地环境中设置环境变量AccessKeyID和SecretAccessKey。
// 您可以登录访问管理控制台获取访问密钥AK/SK，获取方式请参见https://support.huaweicloud.com/usermanual-ca/ca_01_0003.html
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// 创建ObsClient实例
ObsClient client = new ObsClient(accessKey, secretKey, config);
// URL有效期，3600秒
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);
// 使用GET请求获取对象列表
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()));
}
```
#### 删除对象
```
// 初始化配置参数
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全；本示例以ak和sk保存在环境变量中为例，运行本示例前请先在本地环境中设置环境变量AccessKeyID和SecretAccessKey。
// 您可以登录访问管理控制台获取访问密钥AK/SK，获取方式请参见https://support.huaweicloud.com/usermanual-ca/ca_01_0003.html
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// 创建ObsClient实例
ObsClient client = new ObsClient(accessKey, secretKey, config);
// URL有效期，3600秒
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);
// 使用DELETE请求删除对象
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()));
}
```
#### 初始化分段上传任务
```
// 初始化配置参数
ObsConfig config = new ObsConfig();
config.Endpoint = "https://your-endpoint";
// 认证用的ak和sk硬编码到代码中或者明文存储都有很大的安全风险，建议在配置文件或者环境变量中密文存放，使用时解密，确保安全；本示例以ak和sk保存在环境变量中为例，运行本示例前请先在本地环境中设置环境变量AccessKeyID和SecretAccessKey。
// 您可以登录访问管理控制台获取访问密钥AK/SK，获取方式请参见https://support.huaweicloud.com/usermanual-ca/ca_01_0003.html
string accessKey= Environment.GetEnvironmentVariable("AccessKeyID", EnvironmentVariableTarget.Machine);
string secretKey= Environment.GetEnvironmentVariable("SecretAccessKey", EnvironmentVariableTarget.Machine);
// 创建ObsClient实例
ObsClient client = new ObsClient(accessKey, secretKey, config);
// URL有效期，3600秒
long exipreSeconds = 3600;
CreateTemporarySignatureRequest request = new CreateTemporarySignatureRequest();
request.BucketName = "bucketname";
request.ObjectKey = "objectkey";         
request.Method = HttpVerb.POST;
request.Expires = exipreSeconds;
request.SubResource = SubResourceEnum.Uploads;
CreateTemporarySignatureResponse response = client.CreateTemporarySignature(request);
Console.WriteLine("Creating mission using temporary signature url:");
Console.WriteLine("\t" + response.SignUrl);
// 使用POST请求创建多段任务
HttpWebRequest webRequest = WebRequest.Create(response.SignUrl) as HttpWebRequest;
webRequest.Method = "POST";
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()));
}
```
![](https://support.huaweicloud.com/sdk-dotnet-devg-obs/public_sys-resources/note_3.0-zh-cn.png)
HttpVerb是OBS .NET SDK定义的枚举类型，代表请求方法类型。