# Configuring Event Notification for a Bucket

#### Functions

This operation notifies users of their operations on buckets, allowing users know events happened on buckets in a timely manner.

By default, the notification function of a bucket is not enabled, and the NotificationConfiguration element is null. If you want to disable the function, set the NotificationConfiguration element to null.

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    <NotificationConfiguration>
    </NotificationConfiguration>

After receiving a request for configuring event notification, OBS verifies whether the specified SMN topic exists and whether the topic is authorized to OBS. If the topic exists and is authorized to OBS, OBS sends a test notification to the topic subscriber.

To perform this operation, you must have the PutBucketNotification permission. By default, the permission is granted to the bucket owner only. However, it can be granted to other users by configuring the bucket policy.

#### Request Syntax

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    PUT /?notification HTTP/1.1
    Host: bucketname.obs.region.example.com
    Date: date
    Authorization: authorization string

    <NotificationConfiguration>
        <TopicConfiguration>
            <Id>ConfigurationId</Id>
            <Filter>
                <Object>
                    <FilterRule>
                        <Name>prefix</Name>
                        <Value>prefix-value</Value>
                    </FilterRule>
                    <FilterRule>
                        <Name>suffix</Name>
                        <Value>suffix-value</Value>
                    </FilterRule>
               </Object>
            </Filter>
            <Topic>TopicARN</Topic>
            <Event>event-type</Event>
            <Event>event-type</Event>
            ...
        </TopicConfiguration>
        ...
    </NotificationConfiguration>

#### Request Parameters

This request contains no parameter.

#### Request Headers

This request uses common headers. For details, see Table 3.

#### Request Elements

This request contains elements to specify the notification configuration for the bucket in XML format. For details about the configuration elements, see Table 1.

Table 1 Request elements for notification function configuration
Element | Description | Mandatory
--- | --- | ---
NotificationConfiguration | Root element for configuring the event notification function of a bucket. If the sub element is null, the function is disabled. Type: element Ancestor: none Children: no or multiple TopicConfigurations | Yes
TopicConfiguration | Element for configuring the event notification topic. Type: element Ancestor: NotificationConfiguration Children: Id, Filter, Topic, Event, or Events | No

Topic

URN of the event notification topic. When OBS detects a specific event in the bucket, it publishes a notification message to the topic. The topic value can be found in SMN topics.

Type: string

Ancestor: TopicConfiguration

Template:

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    <Topic>urn:smn:region:project_id:smn_topic</Topic>

Example:

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    <Topic>urn:smn:exampleRegion:d745b885f14941369b2d2138e7a65bef:obs_test</Topic>

Required if TopicConfiguration is added

Id | Unique ID of each event notification. If the user does not specify an ID, the system assigns an ID automatically. Type: string Ancestor: TopicConfiguration | No
Filter | Element used to store rules of filtering object names. Type: element Ancestor: TopicConfiguration Children: Object | No
Object | Element that defines the filtering rule. The rule filters objects based on the prefixes and suffixes of object names. Type: element Ancestor: Filter Children: one or more FilterRules | No
FilterRule | Element that defines key-value pairs of the filtering rule Type: element Ancestor: Object Children: Name, Value | No
Name | Prefix or suffix of object names for filtering Type: string Ancestor: FilterRule Value options: prefix, suffix | No
Value | Key word of object names. Based on the prefix or suffix defined by Name, enter the key word for filtering objects. A longer string of characters delivers a more accurate filtering result. A maximum of 1024 characters are supported. Type: string Ancestor: FilterRule | No

Event

Type of events that need to be notified

NOTE:

Multiple event types can be added in one TopicConfiguration item.

Type: string

Value options:

The following values can be used to upload an object:

- ObjectCreated:Put
- ObjectCreated:Post
- ObjectCreated:Copy
- ObjectCreated:CompleteMultipartUpload

Or use wildcard characters to support all upload operations:

- ObjectCreated:*

The following values can be used to delete an object:

- ObjectRemoved:Delete
- ObjectRemoved:DeleteMarkerCreated

Or use wildcard characters to support all delete operations:

- ObjectRemoved:*

Ancestor:

TopicConfiguration

Required if TopicConfiguration is added

#### Response Syntax

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    HTTP/1.1 status_code
    Date: date
    Content-Length: length
    Content-Type: type

#### Response Headers

The response to the request uses common headers. For details, see Table 1.

#### Response Elements

This response involves no elements.

#### Error Responses

When this operation is being called, the system checks whether the NotificationConfiguration element is valid and whether the configuration is valid. The following table lists the common errors and possible causes of this operation.

Table 2 Error codes and possible causes
Error Code | Description | HTTP Status Code
--- | --- | ---

InvalidArgument

Possible causes of this error are:

- The specified event is not supported.
- The specified URN does not exist or is incorrect.
- The specified region in the URN is different as the region where the bucket resides.
- The specified filtering rules overlap.

400 Bad Request

AccessDenied | The operator is not the bucket owner and not granted with the PutBucketNotification permission. | 403 Forbidden

#### Sample Request

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    PUT /?notification HTTP/1.1
    User-Agent: curl/7.29.0
    Host: examplebucket.obs.region.example.com
    Accept: */*
    Date: WED, 01 Jul 2015 03:15:45 GMT
    Authorization: OBS H4IPJX0TQTHTHEBQQCEC:uRTt8YTkAqJCUfWfYkveEcIGAC0=
    Content-Length: 538

    <NotificationConfiguration>
      <TopicConfiguration>
        <Id>ConfigurationId</Id>
        <Filter>
          <Object>
            <FilterRule>
              <Name>prefix</Name>
              <Value>object</Value>
            </FilterRule>
            <FilterRule>
              <Name>suffix</Name>
              <Value>txt</Value>
            </FilterRule>
          </Object>
        </Filter>
        <Topic>urn:smn:region:4b29a3cb5bd64581bda5714566814bb7:tet555</Topic>
        <Event>ObjectCreated:Put</Event>
      </TopicConfiguration>
    </NotificationConfiguration>

#### Sample Response

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    HTTP/1.1 200 OK
    Server: OBS
    x-obs-request-id: 9046000001643C8E80C19FAC4D8068E3
    x-obs-id-2: 32AAAQAAEAABSAAkgAIAABAAAQAAEAABCTFAxJPTib3GkcQ7nVVs4C8Z6NNcfVDu
    Date: WED, 01 Jul 2015 03:15:46 GMT
    Content-Length: 0

Parent topic: Advanced Bucket Settings