# ConnectAsViewer
<a name="ConnectAsViewer"></a>

Connects as a viewer to the signaling channel specified by the endpoint. Any WebSocket-compliant library can be used to connect to the secure websocket (WSS) endpoint obtained from the `GetSignalingChannelEndpoint` API call. The Amazon Resource Name (ARN) of the signaling channel and the client ID must be provided as query string parameters. There are separate endpoints for connecting as a master and as a viewer. If there is an existing connection with the same `ClientId` as specified in the request, the new connection takes precedence. The connection metadata is overwritten with the new information.

## Request
<a name="ConnectAsViewer-request"></a>

```
"X-Amz-ChannelARN": "string",
"X-Amz-ClientId": "string"
```
+ **X-Amz-ChannelARN** - ARN of the signaling channel.
  + Type: string
  + Length constraints: Minimum length of 1. Maximum length of 1024
  + Pattern: `arn:aws:kinesisvideo:[a-z0-9-]+:[0-9]+:[a-z]+/[a-zA-Z0-9_.-]+/[0-9]+`
  + Required: Yes
+ **X-Amz-ClientId** - A unique identifier for the client.
  + Type: string
  + Length constraints: Minimum length of 1. Maximum length of 256.
  + Pattern: `^(?!(?i)AWS_.*)[a-zA-Z0-9_.-]`
**Note**  
`X-Amz-ClientId` can't start with `AWS_`.
  + Required: Yes

## Response
<a name="ConnectAsViewer-response"></a>

200 OK HTTP status code with an empty body.

## Errors
<a name="ConnectAsViewer-errors"></a>
+ InvalidArgumentException

  A specified parameter exceeds its restrictions, is not supported, or cannot be used. For more information, see the returned message.

  HTTP Status Code: 400
+ AccessDeniedException

  The caller is not authorized to access the given channel or the token has expired.

  HTTP Status Code: 403
+ ResourceNotFoundException

  The channel doesn't exist.

  HTTP Status Code: 404
+ ClientLimitExceededException

  When the API is invoked at a rate that is too high or when there are more than the supported maximum number of viewers connected to the channel. For more information, see [Amazon Kinesis Video Streams with WebRTC service quotas](kvswebrtc-limits.md) and [Error Retries and Exponential Backoff in AWS](https://docs.aws.amazon.com/general/latest/gr/api-retries.html).

  HTTP Status Code: 400

## Limits/Throttling
<a name="ConnectAsViewer-limits"></a>

This API is throttled at an account level if the API is invoked at too high a rate or when there are more than the supported maximum number of viewers connected to the channel. An error returned when throttled with `ClientLimitExceededException`.

## Idempotent
<a name="ConnectAsViewer-idempotent"></a>

If a connection already exists for the specified `ClientId` and channel, the connection metadata is updated with the new information.

## Retry behavior
<a name="ConnectAsViewer-retry"></a>

This is counted as a new API call.

## Concurrent calls
<a name="ConnectAsViewer-concurrent"></a>

Concurrent calls are allowed, the connection metadata is updated for each call.