{
  "version": "2.0",
  "statement": [
    {
      "action": [
                //head operation 
                "name/cos:HeadObject",
                //Downloading operation
                "name/cos:GetObject",
      ],
      "effect": "allow",
      "resource": [
        "qcs::cos:ap-beijing:uid/1250000000:examplebucket-1250000000/doc/*"
      ]
    }
  ]
}

// Bucket name, which consists of bucketname-appid (appid must be included), can be viewed in the COS console. https://console.tencentcloud.com/cos5/bucket
let bucket = "examplebucket-1250000000";
//The location identifier of an object in a bucket, also known as the object key
let cosPath = "exampleobject.txt"; 
// Local file download path. If the file does not exist, the sdk will automatically create it.
let downliadPath = "Local file path"; 

let getRequest = new GetObjectRequest(bucket, cosPath, downliadPath);
let task: DownloadTask = CosXmlBaseService.default().download(getRequest);
// Download progress callback
task.onProgress = (progress: HttpProgress) => {
  // progress.complete indicates the currently downloaded size
  // progress.target is the total size
};
task.onResult = {
  // Download success callback
  onSuccess: (request, result: CosXmlDownloadTaskResult) => {
    // todo Logic after successful download
  },
  // Download failure callback
  onFail: (request, error: CosError) => {
    // todo Logic after download failure
  }
}
// Start download
task.start();
// Pause task
// task.pause();
// Resume task
// task.resume();
// Cancel task
// task.cancel();

// Anonymous download generates CosXmlBaseService without requiring key input
let noCredentialService = new CosXmlBaseService(
  context, new CosXmlServiceConfig("ap-guangzhou")
);

// Bucket name, which consists of bucketname-appid (appid must be included), can be viewed in the COS console. https://console.tencentcloud.com/cos5/bucket
let bucket = "examplebucket-1250000000";
//The location identifier of an object in a bucket, also known as the object key
let cosPath = "exampleobject.txt"; 
// Local file download path. If the file does not exist, the sdk will automatically create it.
let downliadPath = "Local file path"; 

let getRequest = new GetObjectRequest(bucket, cosPath, downliadPath);
let task: DownloadTask = noCredentialService.download(getRequest);
// Start download
task.start();

// Bucket name, which consists of bucketname-appid (appid must be included), can be viewed in the COS console. https://console.tencentcloud.com/cos5/bucket
let bucket = "examplebucket-1250000000";
//The location identifier of an object in a bucket, also known as the object key
let cosPath = "exampleobject.txt"; 
// Local file download path. If the file does not exist, the sdk will automatically create it.
let downliadPath = "Local file path"; 

let request = new GetObjectRequest(bucket, cosPath, downliadPath);
try {
  let result = await CosXmlBaseService.default().getObject(request)
  // The result includes http headers, etc.
} catch (e) {
  // Exception handling
}