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    Getting Pre-Signed URLs

    Last updated: 2024-02-02 14:36:36
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      Overview

      This document provides an overview of SDK code samples related to generating pre-signed object URLs.
      Note:
      You are advised to use a temporary key to generate a pre-signed URL for the security of your requests such as uploads and downloads. When you apply for a temporary key, follow the Principle of Least Privilege to avoid leaking resources besides your buckets and objects.
      If you need to use a permanent key to generate a pre-signed URL, you are advised to limit the permission of the permanent key to uploads and downloads only to avoid risks.
      For more information about how to get a temporary key, please see Generating and Using Temporary Keys.

      Generating a Pre-Signed Object URL

      Sample code 1. Generate a pre-signed URL

      try
      {
        PreSignatureStruct preSignatureStruct = new PreSignatureStruct();
        // For details about how to get the APPID, visit https://console.tencentcloud.com/developer.
        preSignatureStruct.appid = "1250000000";
        // Bucket region. For the abbreviations of COS regions, visit https://www.tencentcloud.com/zh/document/product/436/6224.
        preSignatureStruct.region = "COS_REGION"; 
        // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.tencentcloud.com/developer.
        preSignatureStruct.bucket = "examplebucket-1250000000";
        preSignatureStruct.key = "exampleobject"; // Object key
        preSignatureStruct.httpMethod = "GET"; // HTTP request method
        preSignatureStruct.isHttps = true; // Generate an HTTPS request URL
        preSignatureStruct.signDurationSecond = 600; // Request signature duration is 600s
        preSignatureStruct.headers = null;// Header in the signature that needs to be verified
        preSignatureStruct.queryParameters = null; // URL request parameters in the signature that need to be verified
      
        string requestSignURL = cosXml.GenerateSignURL(preSignatureStruct); 
      
        // Pre-signed URL for download request (signed URL calculated with the permanent key method)
        string localDir = System.IO.Path.GetTempPath();// Local file directory
        string localFileName = "my-local-temp-file"; // Filename of the local file
        GetObjectRequest request = new GetObjectRequest(null, null, localDir, localFileName);
        // Set the pre-signed URL for download requests
        request.RequestURLWithSign = requestSignURL;
        // Set the progress callback
        request.SetCosProgressCallback(delegate (long completed, long total)
        {
          Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
        });
        // Execute the request
        GetObjectResult result = cosXml.GetObject(request);
        // Request succeeded
        Console.WriteLine(result.GetResultInfo());
      }
      catch (COSXML.CosException.CosClientException clientEx)
      {
        // Request failed
        Console.WriteLine("CosClientException: " + clientEx);
      }
      catch (COSXML.CosException.CosServerException serverEx)
      {
        // Request failed
        Console.WriteLine("CosServerException: " + serverEx.GetInfo());
      }
      Note:
      For the complete sample, go to GitHub.

      Sample code 2. Generate a pre-signed upload URL

      try
      {
        PreSignatureStruct preSignatureStruct = new PreSignatureStruct();
        // For details about how to get the APPID, visit https://console.tencentcloud.com/developer.
        preSignatureStruct.appid = "1250000000";
        // Bucket region. For the abbreviations of COS regions, visit https://www.tencentcloud.com/zh/document/product/436/6224.
        preSignatureStruct.region = "COS_REGION";
        // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.tencentcloud.com/developer.
        preSignatureStruct.bucket = "examplebucket-1250000000";
        preSignatureStruct.key = "exampleobject"; // Object key
        preSignatureStruct.httpMethod = "PUT"; // HTTP request method
        preSignatureStruct.isHttps = true; // Generate an HTTPS request URL
        preSignatureStruct.signDurationSecond = 600; // Request signature duration is 600s
        preSignatureStruct.headers = null;// Header in the signature that needs to be verified
        preSignatureStruct.queryParameters = null; // URL request parameters in the signature that need to be verified
      
        // Pre-signed URL for upload (signed URL calculated with the permanent key method)
        string requestSignURL = cosXml.GenerateSignURL(preSignatureStruct);
      
        string srcPath = @"temp-source-file";// Absolute path of the local file
        PutObjectRequest request = new PutObjectRequest(null, null, srcPath);
        // Set the pre-signed URL for the upload request
        request.RequestURLWithSign = requestSignURL;
        // Set the progress callback
        request.SetCosProgressCallback(delegate (long completed, long total)
        {
          Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
        });
        // Execute the request
        PutObjectResult result = cosXml.PutObject(request);
        // Request succeeded
        Console.WriteLine(result.GetResultInfo());
      }
      catch (COSXML.CosException.CosClientException clientEx)
      {
        // Request failed
        Console.WriteLine("CosClientException: " + clientEx);
      }
      catch (COSXML.CosException.CosServerException serverEx)
      {
        // Request failed
        Console.WriteLine("CosServerException: " + serverEx.GetInfo());
      }
      Note:
      For the complete sample, go to GitHub.

      Sample code 3. Generate a pre-signed URL with Host in the signature

      try
      {
        PreSignatureStruct preSignatureStruct = new PreSignatureStruct();
        // For details about how to get the APPID, visit https://console.tencentcloud.com/developer.
        preSignatureStruct.appid = "1250000000";
        // Bucket region. For the abbreviations of COS regions, visit https://www.tencentcloud.com/zh/document/product/436/6224.
        preSignatureStruct.region = "COS_REGION"; 
        // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.tencentcloud.com/developer.
        preSignatureStruct.bucket = "examplebucket-1250000000";
        preSignatureStruct.key = "exampleobject"; // Object key
        preSignatureStruct.httpMethod = "GET"; // HTTP request method
        preSignatureStruct.isHttps = true; // Generate an HTTPS request URL
        preSignatureStruct.signDurationSecond = 600; // Request signature duration is 600s
        preSignatureStruct.signHost = true; // Whether to include `Host` in the request signature. It is recommended to include `Host` in the signature to avoid unauthorized requests. Note that if `Host` is included in the signature, the `Host` request header must also be carried in the actual request.
        preSignatureStruct.headers = null;// Header in the signature that needs to be verified
        preSignatureStruct.queryParameters = null; // URL request parameters in the signature that need to be verified
      
        string requestSignURL = cosXml.GenerateSignURL(preSignatureStruct); 
        Console.WriteLine("requestUrl is:" + requestSignURL);
      
        // Pre-signed URL for download request (signed URL calculated with the permanent key method)
        string localDir = System.IO.Path.GetTempPath();// Local file directory
        string localFileName = "my-local-temp-file"; // Filename of the local file
        GetObjectRequest request = new GetObjectRequest(null, null, localDir, localFileName);
        // Set the pre-signed URL for download requests
        request.RequestURLWithSign = requestSignURL;
        // Set the progress callback
        request.SetCosProgressCallback(delegate (long completed, long total)
        {
          Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
        });
        // Execute the request
        GetObjectResult result = cosXml.GetObject(request);
        // Request succeeded
        Console.WriteLine(result.GetResultInfo());
      }
      catch (COSXML.CosException.CosClientException clientEx)
      {
        // Request failed
        Console.WriteLine("CosClientException: " + clientEx);
      }
      catch (COSXML.CosException.CosServerException serverEx)
      {
        // Request failed
        Console.WriteLine("CosServerException: " + serverEx.GetInfo());
      }

      Sample code 4. Generate a pre-signed URL with request parameters in the signature

      try
      {
        PreSignatureStruct preSignatureStruct = new PreSignatureStruct();
        // For details about how to get the APPID, visit https://console.tencentcloud.com/developer.
        preSignatureStruct.appid = "1250000000";
        // Bucket region. For the abbreviations of COS regions, visit https://www.tencentcloud.com/zh/document/product/436/6224.
        preSignatureStruct.region = "COS_REGION"; 
        // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.tencentcloud.com/developer.
        preSignatureStruct.bucket = "examplebucket-1250000000";
        preSignatureStruct.key = "exampleobject"; // Object key
        preSignatureStruct.httpMethod = "GET"; // HTTP request method
        preSignatureStruct.isHttps = true; // Generate an HTTPS request URL
        preSignatureStruct.signDurationSecond = 600; // Request signature duration is 600s
        preSignatureStruct.signHost = true; // Whether to include `Host` in the request signature. It is recommended to include `Host` in the signature to avoid unauthorized requests. Note that if `Host` is included in the signature, the `Host` request header must also be carried in the actual request.
        preSignatureStruct.headers = null;// Headers in the signature that need to be verified
        string ci_params = "imageMogr2/thumbnail/!50p";
        preSignatureStruct.queryParameters = new Dictionary<string, string>(); // Request parameters in the URL in the signature that need to be verified. Take a CI image processing request as an example.
        preSignatureStruct.queryParameters.Add(ci_params, null);
      
        string requestSignURL = cosXml.GenerateSignURL(preSignatureStruct); 
        Console.WriteLine("requestUrl is:" + requestSignURL);
      
        // Pre-signed URL for download request (signed URL calculated with the permanent key method)
        string localDir = System.IO.Path.GetTempPath();// Local file directory
        string localFileName = "my-local-temp-file"; // Filename of the local file
        GetObjectRequest request = new GetObjectRequest(null, null, localDir, localFileName);
        // Set the pre-signed URL for download requests
        request.RequestURLWithSign = requestSignURL;
        // Set the progress callback
        request.SetCosProgressCallback(delegate (long completed, long total)
        {
          Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
        });
        // Execute the request
        GetObjectResult result = cosXml.GetObject(request);
        // Request succeeded
        Console.WriteLine(result.GetResultInfo());
      }
      catch (COSXML.CosException.CosClientException clientEx)
      {
        // Request failed
        Console.WriteLine("CosClientException: " + clientEx);
      }
      catch (COSXML.CosException.CosServerException serverEx)
      {
        // Request failed
        Console.WriteLine("CosServerException: " + serverEx.GetInfo());
      }
      
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