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Cloud Object Storage
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    Getting Started

    Last updated: 2025-01-09 14:26:04
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      Download and Installation

      Relevant resources

      Download COS XML C++ SDK source code below: Linux/Windows/macOS: XML Linux C++ SDK
      Download XML C++ SDK.
      Download the demo here
      For the SDK changelog, see Changelog.
      Note:
      If you encounter errors such as non-existent functions or methods when using the XML version of the SDK, please update the SDK to the latest version and try again.

      Manual Compilation

      Compilation options

      You can configure the following compilation options using the CMakeLists.txt file in the root directory:
      option(BUILD_UNITTEST "Build unittest" OFF) # Configure unit testing compilation.
      option(BUILD_DEMO "Build demo" ON) # Configure demo testable code compilation.
      option(BUILD_SHARED_LIB "Build shared library" OFF) # Configure dynamic library compilation.

      Dependent libraries

      Shared libraries: POCO, OpenSSL
      The following third-party dependent libraries can be found in the Third-party directory:
      third_party/lib/linux/poco/ # Linux-dependent POCO dynamic library. The POCO library is compiled based on OpenSSL v1.0.2. If your compilation environment uses a different OpenSSL version, you need to compile the POCO library again.
      third_party/lib/Win32/openssl/ # Win32-dependent OpenSSL library
      third_party/lib/Win32/poco/ # Win32-dependent POCO library
      third_party/lib/x64/openssl/ # Win64-dependent OpenSSL library
      third_party/lib/x64/poco/ # Win64-dependent POCO library
      third_party/lib/macOS/poco/ # macOS-dependent POCO library
      Note:
      Copy the dependent libraries that suit your OS to your project.

      Compiling Linux SDK

      1. Install the compiler and dependent libraries.
      yum install -y gcc gcc-c++ make cmake openssl
      # The CMake version should be later than 2.8.
      2. Compile the SDK. Download the XML C++ SDK source code to your development environment and run the following command:
      cd ${cos-cpp-sdk} 
      mkdir -p build 
      cd build 
      cmake .. 
      make
      3. Install the POCO libraries.
      cd ${cos-cpp-sdk} 
      sh install-libpoco.sh
      Note:
      This script installs the POCO dynamic library to the /usr/lib64 directory and creates a soft link. To use a COS SDK in the production environment, install the POCO library to the production environment as well.
      4. Run the demo.
      Note:
      You can skip this step if you don’t need to test the demo.
      cd ${cos-cpp-sdk} 
      vim demo/cos_demo.cpp  # Modify the bucket name and testable code in the demo.
      vim CMakeLists.txt # Set "BUILD_DEMO" to "ON" in "CMakeLists.txt" in the root directory to start compiling the demo.
      cd build && make # Compile the demo.
      ls bin/cos_demo # The generated executable file is in the "bin" directory.
      vim bin/config.json # Modify the key and the region.
      cd bin && ./cos_demo # Run the demo.
      5. Use the SDK. The compiled libraries can be found in the build/lib directory. The static library name is libcossdk.a and the dynamic library name is libcossdk-shared.so. During actual use, copy the libraries to your project and copy the include directory to the include directory of your project.

      Compiling Windows SDK

      1. Install Visual Studio 2017. Install the Visual Studio 2017 development environment.
      2. Install CMake. Download the Windows version of the CMake compiler from the CMake official website, and configure ${CMake installation path}\\bin in the Path environment variable.
      3. Compile the SDK.
      3.1 Download XML C++ SDK source code to your development environment.
      3.2 Open the Windows command-line tool, cd to the directory of the C++ SDK source code, and run the following command:
      mkdir build
      cd build
      cmake .. # Generate the Win32 Makefile.
      cmake -G "Visual Studio 15 Win64" .. # Generate the Win64 Makefile.
      Note:
      cmake -G parameters are related to the actual Windows environment and cmake version. If using other versions of Visual Studio, use other parameters (different cmake versions may specify different build tool parameters. The command listed below is for cmake version 3.23.0. Run the cmake -h command to see the supported build tool versions and usage in the Generators section of the output. If not included, please upgrade cmake).
      Parameter list:
      Visual Studio Version
      CMake Command
      Visual Studio 2022
      cmake -G "Visual Studio 17 2022" ..
      You can specify the architecture with the -A parameter, such as cmake -G "Visual Studio 17 2022" -A x64 ..
      Visual Studio 2019
      cmake -G "Visual Studio 16 2019" .. (you can specify the architecture with the -A parameter, refer to the 2022 example)
      Visual Studio 2017
      cmake -G "Visual Studio 15 2017 Win64" ..
      Visual Studio 2015
      cmake -G "Visual Studio 14 2015 Win64" ..
      Visual Studio 2013
      cmake -G "Visual Studio 12 2013 Win64" ..
      Visual Studio 2012
      cmake -G "Visual Studio 11 2012 Win64" ..
      
      3.3 Use Visual Studio 2017 to open the solution file and compile.
      4. Test the demo.
      Note:
      You can skip this step if you don’t need to test the demo.
      Modify the demo code and compile it. The generated cos_demo.exe file is in the bin directory. You can modify bin/config.json to run cos_demo.exe.
      5. Use the SDK. The compiled libraries can be found in the build/Release directory. The static library is named cossdk.lib. During actual use, copy the library to your project and copy the include directory to the include directory of your project.

      Compiling Mac SDK

      1. Install the compiler and dependent libraries.
      brew install gcc make cmake openssl
      2. Compile the SDK. Download the XML C++ SDK source code to your development environment and run the following command:
      cd ${cos-cpp-sdk} 
      mkdir -p build 
      cd build 
      cmake .. 
      make
      3. Install the POCO libraries. The POCO libraries are in the third_party/lib/macOS/poco directory. You can install them by yourself.
      4. Run the demo.
      Note:
      You can skip this step if you don’t need to test the demo.
      Modify the demo code and compile it. The generated cos_demo is in the bin directory. Copy cos-cpp-sdk-v5/demo/config.json to the bin directory and modify bin/config.json. Then you can run cos_demo.
      5. Use the SDK. The compiled libraries can be found in the build/lib directory. The static library is named libcossdk.a, and the dynamic library is named libcossdk-shared.dylib. During actual use, copy the libraries to your project and copy the include directory to the include directory of your project.
      Note:
      If you encounter compilation problems, please refer to C++ SDK FAQ.

      Getting Started

      The section below describes how to use the COS C++ SDK to perform basic operations, such as initializing a client, creating a bucket, querying a bucket list, uploading an object, querying an object list, downloading an object, and deleting an object.
      Note:
      For the definition of terms such as SecretId, SecretKey, and Bucket, see COS Glossary.

      Initialization

      Note:
      We recommend you use a sub-account key and environment variables to call the SDK for security purposes. When authorizing a sub-account, follow the Notes on Principle of Least Privilege to avoid leaking resources besides your buckets and objects.
      If you must use a permanent key, we recommend you follow the Notes on Principle of Least Privilege to limit the scope of permission on the permanent key.

      Accessing COS using a temporary key

      To access COS using a temporary key, see the code below:
      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      int main(int argc, char *argv[]) {
          // Initialization can be done through parameter method or configuration file, you can choose different methods based on business selection.
          qcloud_cos::CosConfig config(appid, "secret_id", "secret_key", "region");
          // secret_id and secret_key of a temporary key are required. For details on how to generate and use a temporary key, visit https://www.tencentcloud.com/document/product/436/14048.
          config.SetTmpToken("xxx");
          qcloud_cos::CosAPI cos(config);
      }

      Accessing COS using a permanent key (not recommended)

      To access COS using a permanent key, see the code below:
      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      int main(int argc, char *argv[]) {
          qcloud_cos::CosConfig config("./config.json");  // Use the configuration file for initialization
          // Or use constructor parameters for initialization directly
          //qcloud_cos::CosConfig config(appid, "secret_id", "secret_key", "region");  // Permanent key
          qcloud_cos::CosAPI cos(config);
      }
      Fields in the configuration file are described as follows:
      {
      "SecretId":"********************************", // Replace `sercret_id` with your `SecretId`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
      "SecretKey":"*******************************", // Replace `sercret_key` with your `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
      "Region":"ap-guangzhou",                // Bucket region. Replace it with your bucket region, which can be viewed on the overview page in the COS console at https://console.tencentcloud.com/cos5/bucket/. For more information about regions, visit https://www.tencentcloud.com/document/product/436/6224?from_cn_redirect=1.
      "SignExpiredTime":360,              // Signature expiration time, in seconds
      "ConnectTimeoutInms":6000,          // Connection timeout, in milliseconds
      "ReceiveTimeoutInms":60000,         // Receive timeout, in milliseconds
      "UploadPartSize":10485760,          // Size of the part to upload, which can be 1 MB to 5 GB. Defaults to 10 MB.
      "UploadCopyPartSize":20971520,      // Size of the copied part for upload, which can be 5 MB to 5 GB. Defaults to 20 MB.
      "UploadThreadPoolSize":5,           // Size of the upload thread pool for a single multipart upload
      "DownloadSliceSize":4194304,        // Size of a part to download
      "DownloadThreadPoolSize":5,         // Size of the download thread pool for a single file
      "AsynThreadPoolSize":2,             // Async thread pool size for uploads/downloads
      "LogoutType":1,                     // Log output type. Valid values: 0 (no output), 1 (output to screen), 2 (output to syslog)
      "LogLevel":3,                       // Log level. Valid values: 1 (ERR), 2 (WARN), 3 (INFO), 4 (DBG)
      "IsDomainSameToHost":false,         // Whether there is a dedicated host
      "DestDomain":"",                    // Dedicated host
      "IsUseIntranet":false,              // Whether a specific IP and port number are used
      "IntranetAddr":""                   // IP and port number, such as "127.0.0.1:80"
      }

      Printing SDK internal logs to a custom log file

      To print SDK internal logs (especially for Windows OS) to a custom log file, see the code below:
      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      void TestLogCallback(const std::string& log) {
          std::ofstream ofs;
          ofs.open("test.log", std::ios_base::app);
          ofs << log;
          ofs.close();
      }
      int main(int argc, char** argv) {
          qcloud_cos::CosConfig config("./config.json");
          config.SetLogCallback(&TestLogCallback);
          qcloud_cos::CosAPI cos(config);
      }

      Creating a bucket

      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      
      int main(int argc, char *argv[]) {
          // 1. Specify the path to the configuration file and initialize CosConfig
          qcloud_cos::CosConfig config("./config.json");
          qcloud_cos::CosAPI cos(config);
      
          // 2. Construct the PUT Bucket request
          std::string bucket_name = "examplebucket-1250000000"; // Replace it with your bucket name, which is in the format of BucketName-APPID (APPID is required). It can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
          qcloud_cos::PutBucketReq req(bucket_name);
          qcloud_cos::PutBucketResp resp;
      
          // 3. Call the PUT Bucket API
          qcloud_cos::CosResult result = cos.PutBucket(req, &resp);
      
          // 4. Process the call result
          if (result.IsSucc()) {
              // Group created successfully
          } else {
              // Failed to create the bucket. You can call the CosResult member functions to output the error information such as the requestID.
              std::cout << "HttpStatus=" << result.GetHttpStatus() << std::endl;
              std::cout << "ErrorCode=" << result.GetErrorCode() << std::endl;
              std::cout << "ErrorMsg=" << result.GetErrorMsg() << std::endl;
              std::cout << "ResourceAddr=" << result.GetResourceAddr() << std::endl;
              std::cout << "XCosRequestId=" << result.GetXCosRequestId() << std::endl;
              std::cout << "XCosTraceId=" << result.GetXCosTraceId() << std::endl;
          }
      }
      

      Querying the bucket list

      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      
      int main(int argc, char *argv[]) {
          // 1. Specify the path to the configuration file and initialize CosConfig
          qcloud_cos::CosConfig config("./config.json");
          qcloud_cos::CosAPI cos(config);
      
          // 2. Construct a request to query the bucket list
          qcloud_cos::GetServiceReq req;
          qcloud_cos::GetServiceResp resp;
          qcloud_cos::CosResult result = cos.GetService(req, &resp);
      
          // 3. Get the response information
          const qcloud_cos::Owner& owner = resp.GetOwner();
          const std::vector<qcloud_cos::Bucket>& buckets = resp.GetBuckets();
          std::cout << "owner.m_id=" << owner.m_id << ", owner.display_name=" << owner.m_display_name << std::endl;
      
          for (std::vector<qcloud_cos::Bucket>::const_iterator itr = buckets.begin(); itr != buckets.end(); ++itr) {
              const qcloud_cos::Bucket& bucket = *itr;
              std::cout << "Bucket name=" << bucket.m_name << ", location="
                  << bucket.m_location << ", create_date=" << bucket.m_create_date << std::endl;
          }
      
          // 4. Process the call result
          if (result.IsSucc()) {
              // Queried the bucket list successfully
          } else {
              // Failed to query the bucket list. You can call the CosResult member functions to output the error information such as requestID.
              std::cout << "HttpStatus=" << result.GetHttpStatus() << std::endl;
              std::cout << "ErrorCode=" << result.GetErrorCode() << std::endl;
              std::cout << "ErrorMsg=" << result.GetErrorMsg() << std::endl;
              std::cout << "ResourceAddr=" << result.GetResourceAddr() << std::endl;
              std::cout << "XCosRequestId=" << result.GetXCosRequestId() << std::endl;
              std::cout << "XCosTraceId=" << result.GetXCosTraceId() << std::endl;
          }
      }

      Uploading an object

      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      
      int main(int argc, char *argv[]) {
          // 1. Specify the path to the configuration file and initialize CosConfig
          qcloud_cos::CosConfig config("./config.json");
          qcloud_cos::CosAPI cos(config);
      
          // 2. Construct a request to upload a file
          std::string bucket_name = "examplebucket-1250000000"; // Replace it with your bucket name, which is in the format of BucketName-APPID (APPID is required). It can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
          std::string object_name = "exampleobject"; // `exampleobject` is the ObjectKey (Key), the unique ID of an object in a bucket. For example, if the object's access domain name is `examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com/doc/pic.jpg`, the object key is `doc/pic.jpg`. Replace it with your object name.
          qcloud_cos::PutObjectByFileReq req(bucket_name, object_name, "/path/to/local/file"); // Replace the value with your file path.
          //req.SetXCosStorageClass("STANDARD_IA"); // `STANDARD_IA` is the default value. You can call the `Set` method to set the storage class.
          qcloud_cos::PutObjectByFileResp resp;
      
          // 3. Call the PUT Object API
          qcloud_cos::CosResult result = cos.PutObject(req, &resp);
      
          // 4. Process the call result
          if (result.IsSucc()) {
              // File uploaded successfully
          } else {
              // Failed to upload the file. You can call the `CosResult` member functions to output the error information such as the requestID.
              std::cout << "HttpStatus=" << result.GetHttpStatus() << std::endl;
              std::cout << "ErrorCode=" << result.GetErrorCode() << std::endl;
              std::cout << "ErrorMsg=" << result.GetErrorMsg() << std::endl;
              std::cout << "ResourceAddr=" << result.GetResourceAddr() << std::endl;
              std::cout << "XCosRequestId=" << result.GetXCosRequestId() << std::endl;
              std::cout << "XCosTraceId=" << result.GetXCosTraceId() << std::endl;
          }
      }

      Querying objects

      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      
      int main(int argc, char *argv[]) {
          // 1. Specify the path to the configuration file and initialize CosConfig
          qcloud_cos::CosConfig config("./config.json");
          qcloud_cos::CosAPI cos(config);
      
          // 2. Construct a request to query the object list
          std::string bucket_name = "examplebucket-1250000000"; // Replace it with your bucket name, which is in the format of BucketName-APPID (APPID is required). It can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
          qcloud_cos::GetBucketReq req(bucket_name);
          qcloud_cos::GetBucketResp resp;
          qcloud_cos::CosResult result = cos.GetBucket(req, &resp);   
      
          std::vector<qcloud_cos::Content> cotents = resp.GetContents();
          for (std::vector<qcloud_cos::Content>::const_iterator itr = cotents.begin(); itr != cotents.end(); ++itr) {
              const qcloud_cos::Content& content = *itr;
              std::cout << "key name=" << content.m_key << ", lastmodified ="
                  << content.m_last_modified << ", size=" << content.m_size << std::endl;
          }
      
          // 3. Process the call result
          if (result.IsSucc()) {
              // Queried the object list successfully
          } else {
              // Failed to query the object list. You can call the CosResult member functions to output the error information such as requestID.
              std::cout << "HttpStatus=" << result.GetHttpStatus() << std::endl;
              std::cout << "ErrorCode=" << result.GetErrorCode() << std::endl;
              std::cout << "ErrorMsg=" << result.GetErrorMsg() << std::endl;
              std::cout << "ResourceAddr=" << result.GetResourceAddr() << std::endl;
              std::cout << "XCosRequestId=" << result.GetXCosRequestId() << std::endl;
              std::cout << "XCosTraceId=" << result.GetXCosTraceId() << std::endl;
          }
      }

      Downloading an object

      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      
      int main(int argc, char *argv[]) {
          // 1. Specify the path to the configuration file and initialize CosConfig
          qcloud_cos::CosConfig config("./config.json");
          qcloud_cos::CosAPI cos(config);
      
          // 2. Construct a request to download the object
          std::string bucket_name = "examplebucket-1250000000"; // Replace it with your bucket name, which is in the format of BucketName-APPID (APPID is required). It can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
          std::string object_name = "exampleobject"; // `exampleobject` is the ObjectKey (Key), the unique ID of an object in a bucket. For example, if the object's access domain name is `examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com/doc/pic.jpg`, the object key is `doc/pic.jpg`. Replace it with your object name.
          std::string local_path = "/tmp/exampleobject";
          // appid, bucketname, object, and a local path (including filename) are required for the request.
          qcloud_cos::GetObjectByFileReq req(bucket_name, object_name, local_path);
          qcloud_cos::GetObjectByFileResp resp;
      
          // 3. Call the object download API
          qcloud_cos::CosResult result = cos.GetObject(req, &resp);
      
          // 4. Process the call result
          if (result.IsSucc()) {
              // File downloaded successfully
          } else {
              // Failed to download the file. You can call the CosResult member functions to output the error information such as the requestID.
              std::cout << "HttpStatus=" << result.GetHttpStatus() << std::endl;
              std::cout << "ErrorCode=" << result.GetErrorCode() << std::endl;
              std::cout << "ErrorMsg=" << result.GetErrorMsg() << std::endl;
              std::cout << "ResourceAddr=" << result.GetResourceAddr() << std::endl;
              std::cout << "XCosRequestId=" << result.GetXCosRequestId() << std::endl;
              std::cout << "XCosTraceId=" << result.GetXCosTraceId() << std::endl;
          }
      }

      Deleting an object

      #include "cos_api.h"
      #include "cos_sys_config.h"
      #include "cos_defines.h"
      
      int main(int argc, char *argv[]) {
          // 1. Specify the path to the configuration file and initialize CosConfig
          qcloud_cos::CosConfig config("./config.json");
          qcloud_cos::CosAPI cos(config);
      
          // 2. Construct a request to delete the object
          std::string bucket_name = "examplebucket-1250000000"; // Replace it with your bucket name, which is in the format of BucketName-APPID (APPID is required). It can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
          std::string object_name = "exampleobject"; // `exampleobject` is the ObjectKey (Key), the unique ID of an object in a bucket. For example, if the object's access domain name is `examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com/doc/pic.jpg`, the object key is `doc/pic.jpg`. Replace it with your object name.
          // 3. Call the object deleting API
          qcloud_cos::DeleteObjectReq req(bucket_name, object_name);
          qcloud_cos::DeleteObjectResp resp;
          qcloud_cos::CosResult result = cos.DeleteObject(req, &resp); 
      
          // 4. Process the call result
          if (result.IsSucc()) {
              // Deleted the object successfully
          } else {
              // Failed to delete the object. You can call the CosResult member functions to output the error information such as requestID.
              std::cout << "HttpStatus=" << result.GetHttpStatus() << std::endl;
              std::cout << "ErrorCode=" << result.GetErrorCode() << std::endl;
              std::cout << "ErrorMsg=" << result.GetErrorMsg() << std::endl;
              std::cout << "ResourceAddr=" << result.GetResourceAddr() << std::endl;
              std::cout << "XCosRequestId=" << result.GetXCosRequestId() << std::endl;
              std::cout << "XCosTraceId=" << result.GetXCosTraceId() << std::endl;
          }
      }
      
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