PreloadDcdnObjectCaches-阿里云帮助中心

Operation description

Related operations: The refresh and prefetch operations include the RefreshDcdnObjectCaches refresh operation and the PreloadDcdnObjectCaches prefetch operation.
Request method: POST requests are supported. Parameters are displayed in a form.
Daily URL prefetch quota: By default, each account can submit up to 1,000 URL prefetch tasks per day. If the daily peak bandwidth of your account exceeds 200 Mbit/s, you can request a higher daily quota by Quota Management. Alibaba Cloud evaluates and configures the quota based on your actual business requirements.
You can submit up to 100 URL prefetch tasks at a time.
Prefetch queue rules: The prefetch queue for each account can contain up to 100,000 URLs. DCDN processes prefetch tasks in the order in which URLs are submitted. When the number of pending tasks in the prefetch queue reaches 100,000, DCDN uses a queuing mechanism. This means that the next URL prefetch task can be submitted only after the earliest URL prefetch task in the queue is completed.
Maximum invocation frequency per user: 15 times per second.

Before you begin

After a prefetch task is submitted and successfully executed, points of presence immediately fetch the required resources from the origin server through back-to-origin requests. Submitting a large number of prefetch tasks at a time generates many concurrent download tasks, which causes a surge in back-to-origin bandwidth and requests and increases the load on the origin server.
The time required to complete a prefetch task after submission depends on the size of the prefetched file. It takes approximately 5 to 30 minutes. The smaller the average file size, the faster the prefetch.
To use a Resource Access Management (RAM) user to perform refresh and prefetch operations, obtain the required authorization first. For more information, see Grant permissions to a RAM user for refresh and prefetch.

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Test

RAM authorization

The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.
API: The API that you can call to perform the action.
Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.
Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.
- For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.
- For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.
Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.
Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

Action

Access level

Resource type

Condition key

Dependent action

dcdn:PreloadDcdnObjectCaches

none

*domain

acs:dcdn:*:{#accountId}:domain/{#domainName}

None

Request parameters

Parameter	Type	Required	Description	Example
ObjectPath	string	Yes	The URLs to prefetch. The format is accelerated domain name/file to prefetch. Note Separate multiple URLs with line breaks. Each URL can be up to 1,024 characters in length.	example.com/examplefile.txt
Area	string	No	The prefetch region. Valid values: domestic: the Chinese mainland only. overseas: global (excluding the Chinese mainland). If you do not specify this parameter, the prefetch region defaults to the DCDN acceleration region configured for your domain name: If the acceleration region of the domain name is Chinese Mainland Only, the prefetch region is the Chinese mainland only. If the acceleration region of the domain name is Global, the prefetch region is global. If the acceleration region of the domain name is Global (Excluding the Chinese Mainland), the prefetch region is global (excluding the Chinese mainland).	domestic
L2Preload	boolean	No	Specifies whether to prefetch content directly to L2 nodes. Valid values: true: The prefetch node hierarchy must include L2 nodes. false (default): Only origin-layer nodes are prefetched. Origin-layer nodes can be L2 nodes or L3 nodes.	true
WithHeader	string	No	The custom prefetch headers. Specify the value in JSON format.	{ "Accept-Encoding": [ "gzip" ] }
QueryHashkey	boolean	No	This parameter is used when certain rules (such as URL rewrite or parameter filtering) are configured. It specifies whether to enable hashkey query mode when executing prefetch tasks. Valid values: false: default mode. This mode is used when this parameter is not specified. The submitted URL is directly used as the hashkey of the prefetched file. true: queries the actual hashkey used by the prefetch URL based on the domain name configuration.	true

Response elements

Element	Type	Description	Example
	object
PreloadTaskId	string	The IDs of the prefetch tasks. Multiple task IDs are separated by commas (,). The returned task IDs are merged based on the following rules: Prefetch tasks (at URL granularity) submitted for the same domain name within the same second are merged into a single RushTaskId. If more than 500 prefetch tasks (at URL granularity) are submitted for the same domain name within the same second, the tasks are merged into RushTaskIds in batches of 500.	95248880
RequestId	string	The request ID.	E5BD4B50-7A02-493A-AE0B-97B9024B4135

Examples

Success response

JSON format

{
  "PreloadTaskId": "95248880",
  "RequestId": "E5BD4B50-7A02-493A-AE0B-97B9024B4135"
}

Error codes

HTTP status code	Error code	Error message	Description
400	SingleRequest.OverLimit	A maximum of 1000 URLs are supported for each request.
400	QuotaExceeded.Preload	Your refresh attempts have exceeded the daily limit.	The maximum number of refresh and prefetch requests on the current day has been reached.
400	InvalidObjectPath.Malformed	The specified ObjectPath is invalid.	The ObjectPath parameter is set to an invalid value. Specify a valid value and try again.
400	InvalidExtensiveDomain.ValueNotSupported	The specified ExtensiveDomain is not supported.	Wildcard domain names are not supported.
400	PreloadQueueFull	The warming queue is full; please try again later.	The maximum number of URLs of the objects that are being prefetched has been reached. Try again later.
400	InvalidObjectPath.ExceedsMaximum	The maximum number of urls is exceeded.	The number of submitted URLs exceeds the maximum limit.

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.