### Install AsyncAws Sns Client

Source: https://github.com/async-aws/sns/blob/master/README.md

Use this command to install the AsyncAws Sns Client using Composer.

```cli
composer require async-aws/sns
```

--------------------------------

### Client Instantiation

Source: https://context7.com/async-aws/sns/llms.txt

Instantiate SnsClient with optional configuration, credential provider, and HTTP client. When no arguments are given, the client reads credentials from environment variables or the default AWS credential chain.

```APIDOC
## Client Instantiation

Instantiate `SnsClient` with optional configuration, credential provider, and HTTP client. When no arguments are given, the client reads credentials from environment variables or the default AWS credential chain.

```php
use AsyncAws\Sns\SnsClient;

// Default: credentials from environment / IAM role
$sns = new SnsClient(['region' => 'us-east-1']);

// Explicit credentials
$sns = new SnsClient([
    'region'  => 'eu-west-1',
    'accessKeyId'     => 'AKIAIOSFODNN7EXAMPLE',
    'accessKeySecret' => 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY',
]);

// FIPS endpoint
$sns = new SnsClient(['region' => 'fips-us-east-1']);
```
```

--------------------------------

### Instantiate SnsClient

Source: https://context7.com/async-aws/sns/llms.txt

Instantiate the SnsClient with optional configuration. By default, it reads credentials from environment variables or the AWS credential chain. Supports specifying region, access keys, and FIPS endpoints.

```php
use AsyncAws\Sns\SnsClient;

// Default: credentials from environment / IAM role
$sns = new SnsClient(['region' => 'us-east-1']);

// Explicit credentials
$sns = new SnsClient([
    'region'  => 'eu-west-1',
    'accessKeyId'     => 'AKIAIOSFODNN7EXAMPLE',
    'accessKeySecret' => 'wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY',
]);

// FIPS endpoint
$sns = new SnsClient(['region' => 'fips-us-east-1']);
```

--------------------------------

### List All SNS Topics (Paginated)

Source: https://context7.com/async-aws/sns/llms.txt

Retrieves a list of SNS topics, supporting automatic pagination for iterating through all topics. Throttled at 30 TPS.

```php
use AsyncAws\Sns\SnsClient;

$sns = new SnsClient(['region' => 'us-east-1']);

// --- Iterate all topics across all pages automatically ---
$result = $sns->listTopics();

foreach ($result as $topic) {
    echo "Topic ARN: " . $topic->getTopicArn() . "\n";
}

// --- Current page only (manual pagination) ---
$result = $sns->listTopics();
foreach ($result->getTopics(true) as $topic) {
    echo $topic->getTopicArn() . "\n";
}

$nextToken = $result->getNextToken();
if ($nextToken !== null) {
    $nextPage = $sns->listTopics(['NextToken' => $nextToken]);
    foreach ($nextPage->getTopics(true) as $topic) {
        echo $topic->getTopicArn() . "\n";
    }
}

```

--------------------------------

### List All Topics

Source: https://context7.com/async-aws/sns/llms.txt

Returns a paginated list of all topics. Supports auto-pagination for iterating through all topics across all pages.

```APIDOC
## `listTopics` — List All Topics (Paginated)

### Description
Returns up to 100 topics per page. The result implements `IteratorAggregate`, automatically fetching all pages when iterated without `$currentPageOnly = true`. Throttled at 30 TPS.

### Method
POST

### Endpoint
/

### Parameters
#### Query Parameters
- **NextToken** (string) - Optional - The token returned from a previous request to retrieve the next page of results.
- **MaxResults** (integer) - Optional - The maximum number of topics to return per page.

### Response
#### Success Response (200)
- **Topics** (array) - A list of topics. Each topic object contains:
  - **TopicArn** (string) - The ARN of the topic.
- **NextToken** (string) - The token to retrieve the next page of results, or null if there are no more pages.
```

--------------------------------

### createTopic

Source: https://context7.com/async-aws/sns/llms.txt

Creates a standard or FIFO SNS topic. The operation is idempotent: if a topic with the given name already exists its ARN is returned. FIFO topic names must end with `.fifo`.

```APIDOC
## `createTopic` — Create an SNS Topic

Creates a standard or FIFO SNS topic. The operation is idempotent: if a topic with the given name already exists its ARN is returned. FIFO topic names must end with `.fifo`.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\ValueObject\Tag;
use AsyncAws\Sns\Exception\TopicLimitExceededException;

$sns = new SnsClient(['region' => 'us-east-1']);

// Standard topic with display name and tags
try {
    $response = $sns->createTopic([
        'Name' => 'order-notifications',
        'Attributes' => [
            'DisplayName' => 'Order Notifications',
        ],
        'Tags' => [
            ['Key' => 'Environment', 'Value' => 'production'],
            ['Key' => 'Team',        'Value' => 'backend'],
        ],
    ]);

    $topicArn = $response->getTopicArn();
    // e.g. "arn:aws:sns:us-east-1:123456789012:order-notifications"
    echo "Topic ARN: $topicArn\n";
} catch (TopicLimitExceededException $e) {
    echo "Topic limit reached: " . $e->getMessage() . "\n";
}

// FIFO topic with content-based deduplication
$fifoResponse = $sns->createTopic([
    'Name' => 'inventory-updates.fifo',
    'Attributes' => [
        'FifoTopic'                 => 'true',
        'ContentBasedDeduplication' => 'true',
    ],
]);
echo "FIFO Topic ARN: " . $fifoResponse->getTopicArn() . "\n";
```
```

--------------------------------

### Create SNS Topic

Source: https://context7.com/async-aws/sns/llms.txt

Creates a standard or FIFO SNS topic. The operation is idempotent. FIFO topic names must end with '.fifo'. Supports setting display name, attributes like FifoTopic and ContentBasedDeduplication, and tags.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\ValueObject\Tag;
use AsyncAws\Sns\Exception\TopicLimitExceededException;

$sns = new SnsClient(['region' => 'us-east-1']);

// Standard topic with display name and tags
try {
    $response = $sns->createTopic([
        'Name' => 'order-notifications',
        'Attributes' => [
            'DisplayName' => 'Order Notifications',
        ],
        'Tags' => [
            ['Key' => 'Environment', 'Value' => 'production'],
            ['Key' => 'Team',        'Value' => 'backend'],
        ],
    ]);

    $topicArn = $response->getTopicArn();
    // e.g. "arn:aws:sns:us-east-1:123456789012:order-notifications"
    echo "Topic ARN: $topicArn\n";
} catch (TopicLimitExceededException $e) {
    echo "Topic limit reached: " . $e->getMessage() . "\n";
}

// FIFO topic with content-based deduplication
$fifoResponse = $sns->createTopic([
    'Name' => 'inventory-updates.fifo',
    'Attributes' => [
        'FifoTopic'                 => 'true',
        'ContentBasedDeduplication' => 'true',
    ],
]);
echo "FIFO Topic ARN: " . $fifoResponse->getTopicArn() . "\n";
```

--------------------------------

### createPlatformEndpoint

Source: https://context7.com/async-aws/sns/llms.txt

Registers a mobile device for push notifications on platforms like APNs or FCM. This operation is idempotent.

```APIDOC
## `createPlatformEndpoint` — Register a Mobile Device for Push Notifications

Creates an endpoint for a device and app on a push notification platform (APNs, FCM/GCM). Requires a `PlatformApplicationArn` from `CreatePlatformApplication`. The operation is idempotent — if an endpoint with the same token and attributes already exists, its ARN is returned.

### Method
POST

### Endpoint
/

### Parameters
#### Query Parameters
- **Action** (string) - Required - `CreatePlatformEndpoint`
- **Version** (string) - Required - `2010-03-31`

#### Request Body
- **PlatformApplicationArn** (string) - Required - The ARN of the platform application.
- **Token** (string) - Required - The identifier for the device token.
- **CustomUserData** (string) - Optional - Arbitrary user data to associate with the endpoint.
- **Attributes** (object) - Optional - A map of attributes to set on the endpoint.
  - **Enabled** (string) - Optional - Set to `true` to enable the endpoint, `false` to disable.

### Request Example
```json
{
  "PlatformApplicationArn": "arn:aws:sns:us-east-1:123456789012:app/GCM/MyAndroidApp",
  "Token": "APA91bHPRgkFzRisjVDSBQMmWEehy2zXx...",
  "CustomUserData": "{\"userId\": \"user-789\", \"deviceType\": \"android\"}",
  "Attributes": {
    "Enabled": "true"
  }
}
```

### Response
#### Success Response (200)
- **CreatePlatformEndpointResult** (object)
  - **EndpointArn** (string) - The ARN of the created endpoint.

#### Response Example
```json
{
  "CreatePlatformEndpointResult": {
    "EndpointArn": "arn:aws:sns:us-east-1:123456789012:endpoint/GCM/MyAndroidApp/abc123..."
  }
}
```
```

--------------------------------

### Create Platform Endpoint for Push Notifications

Source: https://context7.com/async-aws/sns/llms.txt

Registers a device for push notifications on platforms like APNs or FCM. The operation is idempotent. Ensure you have a `PlatformApplicationArn` from `CreatePlatformApplication`.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\Exception\InvalidParameterException;

$sns = new SnsClient(['region' => 'us-east-1']);

// Register an FCM (Firebase Cloud Messaging) device token
try {
    $response = $sns->createPlatformEndpoint([
        'PlatformApplicationArn' => 'arn:aws:sns:us-east-1:123456789012:app/GCM/MyAndroidApp',
        'Token'                  => 'APA91bHPRgkFzRisjVDSBQMmWEehy2zXx...',  // FCM registration token
        'CustomUserData'         => json_encode(['userId' => 'user-789', 'deviceType' => 'android']),
        'Attributes' => [
            'Enabled' => 'true',
        ],
    ]);

    $endpointArn = $response->getEndpointArn();
    // e.g. "arn:aws:sns:us-east-1:123456789012:endpoint/GCM/MyAndroidApp/abc123..."
    echo "Endpoint ARN: $endpointArn\n";

    // Use the endpoint ARN to send a direct push notification
    $pushResponse = $sns->publish([
        'TargetArn' => $endpointArn,
        'Message'   => json_encode([
            'GCM' => json_encode([
                'notification' => [
                    'title' => 'New message',
                    'body'  => 'You have 3 unread messages.',
                ],
            ]),
        ]),
        'MessageStructure' => 'json',
    ]);
    echo "Push MessageId: " . $pushResponse->getMessageId() . "\n";
} catch (InvalidParameterException $e) {
    echo "Invalid platform endpoint parameter: " . $e->getMessage() . "\n";
}
```

--------------------------------

### List SNS Subscriptions for a Topic (Paginated)

Source: https://context7.com/async-aws/sns/llms.txt

Lists subscriptions for a specific SNS topic, supporting auto-pagination. Each subscription object provides details like protocol, endpoint, and ARN.

```php
use AsyncAws\Sns\SnsClient;

$sns = new SnsClient(['region' => 'us-east-1']);

$topicArn = 'arn:aws:sns:us-east-1:123456789012:order-notifications';

// Auto-paginated iteration over all subscriptions
$result = $sns->listSubscriptionsByTopic(['TopicArn' => $topicArn]);

foreach ($result as $subscription) {
    printf(
        "Protocol: %-12s  Endpoint: %s\n",
        $subscription->getProtocol(),
        $subscription->getEndpoint()
    );
}

// Current page only, collecting into an array
$subscriptions = iterator_to_array(
    $sns->listSubscriptionsByTopic(['TopicArn' => $topicArn])->getSubscriptions(true)
);
echo "Subscriptions on first page: " . count($subscriptions) . "\n";

```

--------------------------------

### List Subscriptions for a Topic

Source: https://context7.com/async-aws/sns/llms.txt

Returns a paginated list of subscriptions for a specific topic. Supports auto-pagination for iterating through all subscriptions.

```APIDOC
## `listSubscriptionsByTopic` — List Subscriptions for a Topic (Paginated)

### Description
Returns up to 100 subscriptions per page for a specific topic. Supports auto-pagination via iterator. Each `Subscription` value object exposes `getSubscriptionArn()`, `getProtocol()`, `getEndpoint()`, `getOwner()`, and `getTopicArn()`.

### Method
POST

### Endpoint
/

### Parameters
#### Query Parameters
- **TopicArn** (string) - Required - The ARN of the topic for which to list subscriptions.
- **NextToken** (string) - Optional - The token returned from a previous request to retrieve the next page of results.
- **MaxResults** (integer) - Optional - The maximum number of subscriptions to return per page.

### Response
#### Success Response (200)
- **Subscriptions** (array) - A list of subscriptions. Each subscription object contains:
  - **SubscriptionArn** (string) - The ARN of the subscription.
  - **Protocol** (string) - The protocol of the subscription.
  - **Endpoint** (string) - The endpoint of the subscription.
  - **Owner** (string) - The owner of the subscription.
  - **TopicArn** (string) - The ARN of the topic.
- **NextToken** (string) - The token to retrieve the next page of results, or null if there are no more pages.
```

--------------------------------

### Publish Up to 10 Messages in a Single Request

Source: https://context7.com/async-aws/sns/llms.txt

Use this for sending multiple messages efficiently in one API call. Always check the `getFailed()` results for any messages that did not succeed, even if the overall HTTP status is 200.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\ValueObject\PublishBatchRequestEntry;
use AsyncAws\Sns\Exception\BatchRequestTooLongException;

$sns = new SnsClient(['region' => 'us-east-1']);

$entries = [
    new PublishBatchRequestEntry([
        'Id'      => 'msg-1',
        'Message' => json_encode(['event' => 'user.signup',   'userId' => 101]),
        'Subject' => 'User Signup',
    ]),
    new PublishBatchRequestEntry([
        'Id'      => 'msg-2',
        'Message' => json_encode(['event' => 'user.verified', 'userId' => 102]),
        'Subject' => 'User Verified',
    ]),
    new PublishBatchRequestEntry([
        'Id'      => 'msg-3',
        'Message' => json_encode(['event' => 'user.deleted',  'userId' => 103]),
        'Subject' => 'User Deleted',
    ]),
];

try {
    $response = $sns->publishBatch([
        'TopicArn'                   => 'arn:aws:sns:us-east-1:123456789012:user-events',
        'PublishBatchRequestEntries' => $entries,
    ]);

    foreach ($response->getSuccessful() as $success) {
        echo "Sent [{$success->getId()}] => MessageId: {$success->getMessageId()}\n";
    }

    foreach ($response->getFailed() as $failure) {
        echo "Failed [{$failure->getId()}] => {$failure->getCode()}: {$failure->getMessage()}\n";
    }
} catch (BatchRequestTooLongException $e) {
    echo "Batch payload too large: " . $e->getMessage() . "\n";
}
```

--------------------------------

### Subscribe an Endpoint to a Topic

Source: https://context7.com/async-aws/sns/llms.txt

Subscribes an endpoint (SQS queue, Lambda, HTTP/S URL, email address, SMS number, Firehose stream, or mobile app) to a topic. Supports filter policies to receive only a subset of messages. HTTP/S and email subscriptions require confirmation.

```APIDOC
## `subscribe` — Subscribe an Endpoint to a Topic

### Description
Subscribes an endpoint (SQS queue, Lambda, HTTP/S URL, email address, SMS number, Firehose stream, or mobile app) to a topic. HTTP/S and email subscriptions require the endpoint owner to confirm via `ConfirmSubscription`. Supports filter policies to receive only a subset of messages.

### Method
POST

### Endpoint
/

### Parameters
#### Query Parameters
- **TopicArn** (string) - Required - The ARN of the topic to subscribe to.
- **Protocol** (string) - Required - The protocol to use for the endpoint (e.g., 'sqs', 'lambda', 'email', 'sms').
- **Endpoint** (string) - Required - The endpoint to subscribe (e.g., SQS queue ARN, Lambda function ARN, email address).
- **Attributes** (map) - Optional - A map of attributes for the subscription, such as 'RawMessageDelivery' or 'FilterPolicy'.
- **ReturnSubscriptionArn** (boolean) - Optional - If true, returns the ARN of the newly created subscription.

### Request Example
```json
{
  "TopicArn": "arn:aws:sns:us-east-1:123456789012:order-notifications",
  "Protocol": "sqs",
  "Endpoint": "arn:aws:sqs:us-east-1:123456789012:order-processing-queue",
  "Attributes": {
    "RawMessageDelivery": "true"
  },
  "ReturnSubscriptionArn": true
}
```

### Response
#### Success Response (200)
- **SubscriptionArn** (string) - The ARN of the subscription. May be 'pending confirmation' for email/HTTP subscriptions until confirmed.
```

--------------------------------

### Publish Up to 10 Messages in a Single Request

Source: https://context7.com/async-aws/sns/llms.txt

Sends up to 10 messages in one API call. Each entry requires a unique `Id` within the batch. The response separates successful and failed entries — always check `getFailed()` even when the HTTP status is 200.

```APIDOC
## `publishBatch` — Publish Up to 10 Messages in a Single Request

### Description
Sends up to 10 messages in one API call. Each entry requires a unique `Id` within the batch. The response separates successful and failed entries — always check `getFailed()` even when the HTTP status is 200.

### Method
POST (implied by SDK usage)

### Endpoint
Not explicitly defined, SDK method call.

### Parameters
#### TopicArn
- **TopicArn** (string) - Required - The ARN of the topic to publish to.
#### PublishBatchRequestEntries
- **PublishBatchRequestEntries** (array) - Required - An array of message entries to publish.
  - **Id** (string) - Required - An identifier for the message within the batch.
  - **Message** (string) - Required - The message body.
  - **Subject** (string) - Optional - The subject of the message.
  - **MessageAttributes** (array) - Optional - A map of attributes to send with the message.
  - **MessageGroupId** (string) - Optional - The message group ID for FIFO topics.
  - **MessageDeduplicationId** (string) - Optional - The message deduplication ID for FIFO topics.

### Request Example
```php
$entries = [
    new PublishBatchRequestEntry([
        'Id'      => 'msg-1',
        'Message' => json_encode(['event' => 'user.signup',   'userId' => 101]),
        'Subject' => 'User Signup',
    ]),
    // ... other entries
];

$response = $sns->publishBatch([
    'TopicArn'                   => 'arn:aws:sns:us-east-1:123456789012:user-events',
    'PublishBatchRequestEntries' => $entries,
]);
```

### Response
#### Success Response
- **Successful** (array) - An array of successfully published messages.
  - **Id** (string) - The identifier of the message.
  - **MessageId** (string) - The ID of the published message.
  - **SequenceNumber** (string) - The sequence number for FIFO messages.
- **Failed** (array) - An array of failed messages.
  - **Id** (string) - The identifier of the message.
  - **Code** (string) - The error code.
  - **Message** (string) - The error message.

#### Response Example
```json
{
  "Successful": [
    {
      "Id": "msg-1",
      "MessageId": "example-message-id-1",
      "SequenceNumber": "1234567890"
    }
  ],
  "Failed": [
    {
      "Id": "msg-2",
      "Code": "InvalidParameter",
      "Message": "Invalid parameter provided."
    }
  ]
}
```

### Error Handling
- **BatchRequestTooLongException**: Thrown when the batch payload is too large.
```

--------------------------------

### Publish a Message to an SNS Topic

Source: https://context7.com/async-aws/sns/llms.txt

Use this for sending a single message to an SNS topic. It supports simple messages, messages with attributes for filtering, and per-protocol message formatting for different subscribers.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\ValueObject\MessageAttributeValue;
use AsyncAws\Sns\Exception\InvalidParameterException;

$sns = new SnsClient(['region' => 'us-east-1']);

// --- Simple topic publish ---
$response = $sns->publish([
    'TopicArn' => 'arn:aws:sns:us-east-1:123456789012:order-notifications',
    'Subject'  => 'New Order #42',
    'Message'  => 'Order #42 has been placed by customer John Doe.',
]);
echo "MessageId: " . $response->getMessageId() . "\n";

// --- Publish with message attributes (for subscription filter policies) ---
$response = $sns->publish([
    'TopicArn' => 'arn:aws:sns:us-east-1:123456789012:order-notifications',
    'Message'  => json_encode(['orderId' => 42, 'status' => 'shipped']),
    'MessageAttributes' => [
        'eventType' => new MessageAttributeValue([
            'DataType'    => 'String',
            'StringValue' => 'order.shipped',
        ]),
        'priority' => new MessageAttributeValue([
            'DataType'    => 'Number',
            'StringValue' => '1',
        ]),
    ],
]);
echo "MessageId: " . $response->getMessageId() . "\n";

// --- Per-protocol message (different body for email vs SQS) ---
$response = $sns->publish([
    'TopicArn'         => 'arn:aws:sns:us-east-1:123456789012:order-notifications',
    'MessageStructure' => 'json',
    'Message'          => json_encode([
        'default' => 'Order #42 shipped.',
        'email'   => "Dear customer,\n\nYour order #42 has been shipped.\n\nRegards,\nShop",
        'sqs'     => json_encode(['orderId' => 42, 'event' => 'shipped']),
    ]),
]);

// --- Direct SMS to a phone number ---
try {
    $response = $sns->publish([
        'PhoneNumber' => '+12025551234',
        'Message'     => 'Your verification code is 938271.',
    ]);
    echo "SMS MessageId: " . $response->getMessageId() . "\n";
} catch (InvalidParameterException $e) {
    echo "Invalid parameter: " . $e->getMessage() . "\n";
}

// --- FIFO topic publish ---
$response = $sns->publish([
    'TopicArn'             => 'arn:aws:sns:us-east-1:123456789012:inventory-updates.fifo',
    'Message'              => json_encode(['sku' => 'PROD-001', 'stock' => 150]),
    'MessageGroupId'       => 'warehouse-A',
    'MessageDeduplicationId' => 'inv-update-' . uniqid(),
]);
echo "FIFO SequenceNumber: " . $response->getSequenceNumber() . "\n";
```

--------------------------------

### Subscribe Endpoint to SNS Topic

Source: https://context7.com/async-aws/sns/llms.txt

Subscribes an endpoint to an SNS topic. Supports SQS, Lambda, email, and more. Email and HTTP/S subscriptions require confirmation. Filter policies can be applied for message filtering.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\Exception\SubscriptionLimitExceededException;

$sns = new SnsClient(['region' => 'us-east-1']);

$topicArn = 'arn:aws:sns:us-east-1:123456789012:order-notifications';

// --- SQS subscription with raw message delivery ---
$sqsResponse = $sns->subscribe([
    'TopicArn'  => $topicArn,
    'Protocol'  => 'sqs',
    'Endpoint'  => 'arn:aws:sqs:us-east-1:123456789012:order-processing-queue',
    'Attributes' => [
        'RawMessageDelivery' => 'true',
    ],
    'ReturnSubscriptionArn' => true,
]);
echo "SQS Subscription ARN: " . $sqsResponse->getSubscriptionArn() . "\n";

// --- Lambda subscription with attribute filter policy ---
$lambdaResponse = $sns->subscribe([
    'TopicArn' => $topicArn,
    'Protocol' => 'lambda',
    'Endpoint' => 'arn:aws:lambda:us-east-1:123456789012:function:processShippedOrders',
    'Attributes' => [
        'FilterPolicy'      => json_encode(['eventType' => ['order.shipped']]),
        'FilterPolicyScope' => 'MessageAttributes',
    ],
    'ReturnSubscriptionArn' => true,
]);
echo "Lambda Subscription ARN: " . $lambdaResponse->getSubscriptionArn() . "\n";

// --- Email subscription (requires confirmation by recipient) ---
try {
    $emailResponse = $sns->subscribe([
        'TopicArn' => $topicArn,
        'Protocol' => 'email',
        'Endpoint' => 'ops-team@example.com',
        'ReturnSubscriptionArn' => true,
    ]);
    // Returns "pending confirmation" until the recipient confirms
    echo "Email subscription: " . $emailResponse->getSubscriptionArn() . "\n";
} catch (SubscriptionLimitExceededException $e) {
    echo "Subscription limit reached: " . $e->getMessage() . "\n";
}

```

--------------------------------

### Publish a Message to a Topic or Endpoint

Source: https://context7.com/async-aws/sns/llms.txt

Sends a message to an SNS topic, a direct phone number (SMS), or a mobile platform endpoint. Supports per-protocol message formatting via `MessageStructure=json`, typed message attributes, and FIFO deduplication controls.

```APIDOC
## `publish` — Publish a Message to a Topic or Endpoint

### Description
Sends a message to an SNS topic, a direct phone number (SMS), or a mobile platform endpoint. Supports per-protocol message formatting via `MessageStructure=json`, typed message attributes, and FIFO deduplication controls.

### Method
POST (implied by SDK usage)

### Endpoint
Not explicitly defined, SDK method call.

### Parameters
#### TopicArn
- **TopicArn** (string) - Required - The ARN of the topic to publish to.
#### PhoneNumber
- **PhoneNumber** (string) - Required - The phone number to send the SMS message to.
#### Message
- **Message** (string) - Required - The message body.
#### Subject
- **Subject** (string) - Optional - The subject of the message.
#### MessageStructure
- **MessageStructure** (string) - Optional - Specifies whether the message is a JSON-formatted string containing per-protocol message bodies.
#### MessageAttributes
- **MessageAttributes** (array) - Optional - A map of attributes to send with the message.
#### MessageGroupId
- **MessageGroupId** (string) - Optional - The message group ID for FIFO topics.
#### MessageDeduplicationId
- **MessageDeduplicationId** (string) - Optional - The message deduplication ID for FIFO topics.

### Request Example
```php
$response = $sns->publish([
    'TopicArn' => 'arn:aws:sns:us-east-1:123456789012:order-notifications',
    'Subject'  => 'New Order #42',
    'Message'  => 'Order #42 has been placed by customer John Doe.',
]);
```

### Response
#### Success Response
- **MessageId** (string) - The ID of the published message.
- **SequenceNumber** (string) - The sequence number for FIFO messages.

#### Response Example
```json
{
  "MessageId": "example-message-id",
  "SequenceNumber": "1234567890"
}
```

### Error Handling
- **InvalidParameterException**: Thrown when a parameter is invalid.
```

--------------------------------

### deleteTopic

Source: https://context7.com/async-aws/sns/llms.txt

Deletes a topic and all its subscriptions. The operation is idempotent — deleting a non-existent topic does not throw an error.

```APIDOC
## `deleteTopic` — Delete an SNS Topic

Deletes a topic and all its subscriptions. The operation is idempotent — deleting a non-existent topic does not throw an error.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\Exception\NotFoundException;

$sns = new SnsClient(['region' => 'us-east-1']);

try {
    $result = $sns->deleteTopic([
        'TopicArn' => 'arn:aws:sns:us-east-1:123456789012:order-notifications',
    ]);

    // Trigger HTTP resolution (lazy by default)
    $result->resolve();
    echo "Topic deleted successfully.\n";
} catch (NotFoundException $e) {
    echo "Topic not found: " . $e->getMessage() . "\n";
}
```
```

--------------------------------

### Publish Message with Typed Attributes

Source: https://context7.com/async-aws/sns/llms.txt

Publishes a message to an SNS topic with typed metadata attributes. Supported data types are String, String.Array, Number, and Binary. These attributes are used for subscription filter policies.

```php
use AsyncAws\Sns\ValueObject\MessageAttributeValue;
use AsyncAws\Sns\SnsClient;

$sns = new SnsClient(['region' => 'us-east-1']);

$sns->publish([
    'TopicArn' => 'arn:aws:sns:us-east-1:123456789012:events',
    'Message'  => 'Payment received.',
    'MessageAttributes' => [
        // String attribute
        'transactionType' => new MessageAttributeValue([
            'DataType'    => 'String',
            'StringValue' => 'payment.received',
        ]),
        // Number attribute (stored as String per SNS API contract)
        'amount' => new MessageAttributeValue([
            'DataType'    => 'Number',
            'StringValue' => '99.95',
        ]),
        // String.Array attribute (JSON-encoded array)
        'tags' => new MessageAttributeValue([
            'DataType'    => 'String.Array',
            'StringValue' => '["billing","europe","priority"]',
        ]),
        // Binary attribute
        'checksum' => new MessageAttributeValue([
            'DataType'    => 'Binary',
            'BinaryValue' => hash('sha256', 'payload', true),  // raw binary
        ]),
    ],
]);
```

--------------------------------

### Delete Platform Endpoint

Source: https://context7.com/async-aws/sns/llms.txt

Deletes a previously created platform application endpoint. This operation is idempotent. Ensure the endpoint is unsubscribed from any topics before deletion.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\Exception\AuthorizationErrorException;

$sns = new SnsClient(['region' => 'us-east-1']);

try {
    $result = $sns->deleteEndpoint([
        'EndpointArn' => 'arn:aws:sns:us-east-1:123456789012:endpoint/GCM/MyAndroidApp/abc123...',
    ]);
    $result->resolve();
    echo "Endpoint deleted.\n";
} catch (AuthorizationErrorException $e) {
    echo "Authorization error: " . $e->getMessage() . "\n";
}
```

--------------------------------

### Delete SNS Topic

Source: https://context7.com/async-aws/sns/llms.txt

Deletes a topic and all its subscriptions. The operation is idempotent; deleting a non-existent topic does not throw an error. Use resolve() to trigger HTTP resolution for lazy responses.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\Exception\NotFoundException;

$sns = new SnsClient(['region' => 'us-east-1']);

try {
    $result = $sns->deleteTopic([
        'TopicArn' => 'arn:aws:sns:us-east-1:123456789012:order-notifications',
    ]);

    // Trigger HTTP resolution (lazy by default)
    $result->resolve();
    echo "Topic deleted successfully.\n";
} catch (NotFoundException $e) {
    echo "Topic not found: " . $e->getMessage() . "\n";
}
```

--------------------------------

### deleteEndpoint

Source: https://context7.com/async-aws/sns/llms.txt

Deletes a platform application endpoint. This operation is idempotent.

```APIDOC
## `deleteEndpoint` — Remove a Mobile Device Endpoint

Deletes a platform application endpoint. The operation is idempotent. If the endpoint is also subscribed to a topic, unsubscribe it separately first.

### Method
POST

### Endpoint
/

### Parameters
#### Query Parameters
- **Action** (string) - Required - `DeleteEndpoint`
- **Version** (string) - Required - `2010-03-31`

#### Request Body
- **EndpointArn** (string) - Required - The ARN of the endpoint to delete.

### Request Example
```json
{
  "EndpointArn": "arn:aws:sns:us-east-1:123456789012:endpoint/GCM/MyAndroidApp/abc123..."
}
```

### Response
#### Success Response (200)
An empty response indicates success.

#### Response Example
(No specific example provided, success is indicated by the absence of an error.)
```

--------------------------------

### Unsubscribe from a Topic

Source: https://context7.com/async-aws/sns/llms.txt

Removes a subscription by its ARN. Only the subscription owner or topic owner can call this operation if the subscription requires authentication for deletion.

```APIDOC
## `unsubscribe` — Remove a Subscription

### Description
Removes a subscription by its ARN. If the subscription requires authentication for deletion, only the subscription owner or topic owner can call this operation.

### Method
POST

### Endpoint
/

### Parameters
#### Query Parameters
- **SubscriptionArn** (string) - Required - The ARN of the subscription to remove.

### Request Example
```json
{
  "SubscriptionArn": "arn:aws:sns:us-east-1:123456789012:order-notifications:abc12345-6789-def0-1234-56789abcdef0"
}
```

### Response
#### Success Response (200)
- **Result** (boolean) - Indicates if the unsubscribe operation was successful.
```

--------------------------------

### Unsubscribe from SNS Topic

Source: https://context7.com/async-aws/sns/llms.txt

Removes a subscription from an SNS topic using its ARN. Requires authentication if the subscription is protected. Handles cases where the subscription is not found.

```php
use AsyncAws\Sns\SnsClient;
use AsyncAws\Sns\Exception\NotFoundException;

$sns = new SnsClient(['region' => 'us-east-1']);

try {
    $result = $sns->unsubscribe([
        'SubscriptionArn' => 'arn:aws:sns:us-east-1:123456789012:order-notifications:abc12345-6789-def0-1234-56789abcdef0',
    ]);
    $result->resolve();
    echo "Unsubscribed successfully.\n";
} catch (NotFoundException $e) {
    echo "Subscription not found: " . $e->getMessage() . "\n";
}

```

--------------------------------

### MessageAttributeValue

Source: https://context7.com/async-aws/sns/llms.txt

Represents a typed message attribute for use with subscription filter policies. Supports String, String.Array, Number, and Binary data types.

```APIDOC
## `MessageAttributeValue` — Typed Message Attribute

Attaches metadata to published messages for use by subscription filter policies. Supported `DataType` values are `String`, `String.Array`, `Number`, and `Binary`.

### Usage
This is a value object used within the `publish` operation's `MessageAttributes` parameter.

### Parameters
- **DataType** (string) - Required - The type of the attribute. Supported values: `String`, `String.Array`, `Number`, `Binary`.
- **StringValue** (string) - Required if `DataType` is `String`, `String.Array`, or `Number`. The string representation of the attribute value.
- **BinaryValue** (string) - Required if `DataType` is `Binary`. The base64-encoded binary value of the attribute.

### Example Usage in `publish` operation:
```php
use AsyncAws\Sns\ValueObject\MessageAttributeValue;

// ... within the publish call ...
'MessageAttributes' => [
    'transactionType' => new MessageAttributeValue([
        'DataType'    => 'String',
        'StringValue' => 'payment.received',
    ]),
    'amount' => new MessageAttributeValue([
        'DataType'    => 'Number',
        'StringValue' => '99.95',
    ]),
    'tags' => new MessageAttributeValue([
        'DataType'    => 'String.Array',
        'StringValue' => '["billing","europe","priority"]',
    ]),
    'checksum' => new MessageAttributeValue([
        'DataType'    => 'Binary',
        'BinaryValue' => hash('sha256', 'payload', true), // raw binary
    ]),
]
// ... 
```
```

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