Creates a subscription to a topic.
Authorization
By default, only Alibaba Cloud accounts can call this operation. RAM users can call this operation only after these RAM users are granted related permissions. The following table describes the authorization information of this operation. For more information, see Permission policies and examples.
Item | Value |
---|---|
API operation | Subscribe |
Action | mns:Subscribe |
Resource | acs:mns:$region:$accountid:/topics/$topicName/subscriptions/$subscriptionName |
Description
- A subscription name can be up to 255 characters in length and contain letters, digits, and hyphens (-). It must start with a letter or digit.
- You must specify an endpoint when you create a subscription. Otherwise, the subscription is invalid.
Request
A request consists of the following parts:
- Request line
PUT /topics/$TopicName/subscriptions/$SubscriptionName HTTP/1.1
- Operation-specific request headers
None.
- Request body
The request body is in the XML format. The request body includes the following parameters.
Parameter Type Required Example Description Endpoint String Yes http://example.com The endpoint that the subscriber uses to receive messages. Syntax: acs:mns:{REGION}:{AccountID}:queues/{QueueName}. FilterTag String No important The tag that is used to filter messages. Only the messages that have the same tag can be pushed. A tag is a string that can be up to 16 characters in length.
By default, no tag is specified to filter messages.
NotifyStrategy Boolean No BACKOFF_RETRY The retry policy that is applied if an error occurs when MNS pushes messages to the endpoint. Valid values:- BACKOFF_RETRY: retries with a fixed backoff interval.
- EXPONENTIAL_DECAY_RETRY: retries with exponential backoff.
Default value: BACKOFF_RETRY.
NotifyContentFormat Boolean No SIMPLIFIED The format of the message that is pushed to the endpoint. Valid values:- XML
- JSON
- SIMPLIFIED
Default value: XML.
Response
A response consists of the following parts:
- HTTP status code
HTTP/1.1 201
In a topic, each subscription name must be unique. If you create a subscription that already exists, errors may occur. For example, if the parameters of two subscriptions are the same, the HTTP status code 204 is returned. If the parameters of the two subscriptions are different, the HTTP status code 409 is returned.
- Operation-specific response headers
Parameter Type Example Description Location String http://$AccountId.mns.cn-hangzhou.aliyuncs.com/topics/$TopicName/subscriptions/$SubscriptionName The URL of the subscription that is created. Syntax: http://$AccountId.mns.cn-hangzhou.aliyuncs.com/topics/$TopicName/subscriptions/$SubscriptionName. For more information about common response headers, see Common parameters.
- Response body
None.
Examples
Sample requests
PUT /topics/$TopicName/subscriptions/$SubscriptionName HTTP/1.1
Host: $AccountId.mns.cn-hangzhou.aliyuncs.com
Date: Tue, 08 Dec 2015 06:06:46 GMT
Authorization:MNS 15B4D3461F177624206A:xQE0diMbLRepdf3YB+FIEXA*****
x-mns-version: 2015-06-06
<?xml version="1.0" encoding="utf-8"?>
<Subscription xmlns="http://mns.aliyuncs.com/doc/v1/">
<Endpoint>http://example.com</Endpoint>
<NotifyStrategy>BACKOFF_RETRY</NotifyStrategy>
<NotifyContentFormat>SIMPLIFIED</NotifyContentFormat>
<FilterTag>important</FilterTag>
</Subscription>
Sample success responses
HTTP/1.1 201
x-mns-request-id:56667376B2B71C9C1600****
x-mns-version: 2015-06-06
Location: http://$AccountId.mns.cn-hangzhou.aliyuncs.com/topics/$TopicName/subscriptions/$SubscriptionName
Error codes
Error code | Error message | HTTP status code | Description |
---|---|---|---|
SubscriptionNameLengthError | Subscription name length is out of range, should be between 1 and 255. | 400 | The error message returned because the subscription name is invalid. Modify the name as suggested. |
SubscriptionNameInvalid | The subscription you provided is invalid. SubscriptionName should start with alpha or digit, and contain only alpha, digit or -. | 400 | The error message returned because the subscription name is invalid. Modify the name as suggested. |
SubscriptionAlreadyExist | The subscription you want to create already exists. | 409 | The error message returned because the specified subscription has the same name as an existing subscription, but has different parameters from the existing subscription. |
EndpointInvalid | The endpoint you provided is invalid. | 400 | The error message returned because the specified endpoint is invalid. For more information, see Endpoint. |
InvalidArgument | The length of filter tag should be between 1 and 16. | 400 | The error message returned because the length of the tag is invalid. Modify the tag. |