Types

The Ably REST client library defines both data types and option types. Data types are used to represent object such as messages; Option types are used in method arguments.

Where client libraries support both Realtime and REST APIs, the types are shared between both clients.

All types are always classes or their respective equivalent for each language implementation. Options on the other hand, may often support both typed option classes or more flexible key value objects such as a Hash or plain JavaScript object.

If you are interested in finding out more about the exact types and options definitions in each language, we recommend you download our open source libraries and review the code.

REST Data types

ChannelDetails

ChannelDetails is an object returned when requesting or receiving channel metadata. It contains information on the channel itself, along with the current state of the channel in the ChannelStatus object.

ParameterDescriptionType
channelIdThe required name of the channel including any qualifier, if anystring
regionIn events relating to the activity of a channel in a specific region, this optionally identifies the regionstring
isGlobalMasterIn events relating to the activity of a channel in a specific region, this optionally identifies whether or not that region is responsible for global coordination of the channelboolean
statusAn optional ChannelStatus instanceChannelStatus

The following is an example of a ChannelDetails JSON object:

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  {
    "channelId": "foo",
    "status": {
      "isActive": true,
      "occupancy": {
        "metrics": {
          "connections": 1,
          "publishers": 1,
          "subscribers": 1,
          "presenceConnections": 1,
          "presenceMembers": 0,
          "presenceSubscribers": 1,
          "objectPublishers": 1,
          "objectSubscribers": 1
        }
      }
    }
  }

ChannelDetails.ChannelStatus

ChannelStatus is contained within the ChannelDetails object, and optionally contains an Occupancy object.

ParameterDescriptionType
isActiveA required boolean value indicating whether the channel that is the subject of the event is active. For events indicating regional activity of a channel this indicates activity in that region, not global activityboolean
occupancyAn optional Occupancy instance indicating the occupancy of the channel. For events indicating regional activity of a channel this indicates activity in that region, not global activityOccupancy

ChannelDetails.ChannelStatus.Occupancy

Occupancy is optionally contained within the ChannelStatus object, and contains metadata relating to the occupants of the channel. This is usually contained within the occupancy attribute of the ChannelStatus object.

The occupancy attribute contains the metrics attribute, which contains the following members:

ParameterDescriptionType
connectionsThe number of connectionsinteger
publishersThe number of connections attached to the channel that are authorised to publishinteger
subscribersThe number of connections attached that are authorised to subscribe to messagesinteger
presenceSubscribersThe number of connections that are authorised to subscribe to presence messagesinteger
presenceConnectionsThe number of connections that are authorised to enter members into the presence channelinteger
presenceMembersThe number of members currently entered into the presence channelinteger
objectPublishersThe number of connections that are authorised to publish updates to objects on the channelinteger
objectSubscribersThe number of connections that are authorised to subscribe to objects on the channelinteger

ErrorInfo

An ErrorInfo is a type encapsulating error information containing an Ably-specific error code and generic status code.

Properties

ParameterDescriptionType
codeAbly error code (see ably-common/protocol/errors.json)Integer
statusCodeHTTP Status Code corresponding to this error, where applicableInteger
messageAdditional message information, where availableString
causeInformation pertaining to what caused the error where availableErrorInfo
hrefAbly may additionally include a URL to get more help on this errorString

Error nesting

ErrorInfo objects can contain nested errors through the cause property, allowing you to trace the root cause of failures. When an operation fails due to underlying system errors, the main ErrorInfo provides the high-level failure reason while the nested cause contains more specific details about what went wrong.

One example of ErrorInfo nesting is 80019: Auth server rejecting request where the main error indicates token renewal failed, while the nested cause contains the specific HTTP error from the auth server.

The following example demonstrates how to handle nested errors:

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function handleError(error) {
    console.log(`Main error: ${error.code} - ${error.message}`);

    // Check for nested error
    if (error.cause) {
        console.log(`Root cause: ${error.cause.code} - ${error.cause.message}`);

        // Handle further nesting if needed
        if (error.cause.cause) {
            console.log(`Deeper cause: ${error.cause.cause.code} - ${error.cause.cause.message}`);
        }
    }
}

Message

A Message represents an individual message that is sent to or received from Ably.

name

The event name, if provided.
Type: String

data

The message payload, if provided.
Type: String, StringBuffer, JSON Object

extras

Metadata and/or ancillary payloads, if provided. Valid payloads include push, headers (a map of strings to strings for arbitrary customer-supplied metadata), ephemeral, and privileged objects.
Type: JSON Object

id

A Unique ID assigned by Ably to this message.
Type: String

clientId

The client ID of the publisher of this message.
Type: String

connectionId

The connection ID of the publisher of this message.
Type: String

connectionKey

A connection key, which can optionally be included for a REST publish as part of the publishing on behalf of a realtime client functionality.
Type: String

timestamp

Timestamp when the message was first received by the Ably, as milliseconds since the epoch.
Type: Integer

encoding

This will typically be empty as all messages received from Ably are automatically decoded client-side using this value. However, if the message encoding cannot be processed, this attribute will contain the remaining transformations not applied to the data payload.
Type: String

action

The action type of the message, one of the MessageAction enum values.
Type: int enum { MESSAGE_CREATE, MESSAGE_UPDATE, MESSAGE_DELETE, META, MESSAGE_SUMMARY }

serial

A server-assigned identifier that will be the same in all future updates of this message. It can be used to add annotations to a message. Serial will only be set if you enable annotations in channel rules.
Type: String

annotations

An object containing information about annotations that have been made to the object.
Type: MessageAnnotations

Message constructors

Message.fromEncoded

Message.fromEncoded(Object encodedMsg, ChannelOptions channelOptions?) -> Message

A static factory method to create a Message from a deserialized Message-like object encoded using Ably's wire protocol.

Parameters
ParameterDescriptionType
encodedMsgA Message-like deserialized objectObject
channelOptionsAn optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the dataObject
Returns

A Message object

Message.fromEncodedArray

Message.fromEncodedArray(Object[] encodedMsgs, ChannelOptions channelOptions?) -> Message[]

A static factory method to create an array of Messages from an array of deserialized Message-like object encoded using Ably's wire protocol.

Parameters
ParameterDescriptionType
encodedMsgsAn array of Message-like deserialized objectsArray
channelOptionsAn optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the dataObject
Returns

An Array of Message objects

PresenceMessage

A PresenceMessage represents an individual presence update that is sent to or received from Ably.

Properties

ParameterDescriptionType
actionThe event signified by a PresenceMessage. See Presence actionint enum { ABSENT, PRESENT, ENTER, LEAVE, UPDATE }
dataThe presence update payload, if providedString, StringBuffer, JSON Object
extrasMetadata and/or ancillary payloads, if provided. The only currently valid payloads for extras are the push, ref and privileged objectsJSON Object
idUnique ID assigned by Ably to this presence updateString
clientIdThe client ID of the publisher of this presence updateString
connectionIdThe connection ID of the publisher of this presence updateString
timestampTimestamp when the presence update was received by Ably, as milliseconds since the epochInteger
encodingThis will typically be empty as all presence updates received from Ably are automatically decoded client-side using this value. However, if the message encoding cannot be processed, this attribute will contain the remaining transformations not applied to the data payloadString

PresenceMessage constructors

PresenceMessage.fromEncoded

PresenceMessage.fromEncoded(Object encodedPresMsg, ChannelOptions channelOptions?) -> PresenceMessage

A static factory method to create a PresenceMessage from a deserialized PresenceMessage-like object encoded using Ably's wire protocol.

Parameters
ParameterDescriptionType
encodedPresMsgA PresenceMessage-like deserialized objectObject
channelOptionsAn optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the dataObject
Returns

A PresenceMessage object

PresenceMessage.fromEncodedArray

PresenceMessage.fromEncodedArray(Object[] encodedPresMsgs, ChannelOptions channelOptions?) -> PresenceMessage[]

A static factory method to create an array of PresenceMessages from an array of deserialized PresenceMessage-like object encoded using Ably's wire protocol.

Parameters
ParameterDescriptionType
encodedPresMsgsAn array of PresenceMessage-like deserialized objectsArray
channelOptionsAn optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the dataObject
Returns

An Array of PresenceMessage objects

Presence action

Presence action is a String with a value matching any of the Realtime Presence states & events.

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  var PresenceActions = [
    'absent', // (reserved for internal use)
    'present',
    'enter',
    'leave',
    'update'
  ]

PaginatedResult

A PaginatedResult is a type that represents a page of results for all message and presence history, stats and REST presence requests. The response from a Ably REST API paginated query is accompanied by metadata that indicates the relative queries available to the PaginatedResult object.

Properties

ParameterDescriptionType
itemsContains the current page of results (for example an Array of Message or PresenceMessage objects for a channel history request)Array

Methods

first

first(): Promise<PaginatedResult>

Returns a promise. On success, the promise is fulfilled with a new PaginatedResult for the first page of results. On failure, the promise is rejected with an ErrorInfo object that details the reason why it was rejected.

hasNext

Boolean hasNext()

Returns true if there are more pages available by calling next and returns false if this page is the last page available.

isLast

Boolean isLast()

Returns true if this page is the last page and returns false if there are more pages available by calling next available.

next

next(): Promise<PaginatedResult | null>

Returns a promise. On success, the promise is fulfilled with a new PaginatedResult loaded with the next page of results. If there are no further pages, then null is returned. On failure, the promise is rejected with an ErrorInfo object that details the reason why it was rejected.

current

current(): Promise<[PaginatedResult](#paginated-result>)

Returns a promise. On success, the promise is fulfilled with a new PaginatedResult loaded with the current page of results. On failure, the promise is rejected with an ErrorInfo object that details the reason why it was rejected.

Example

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const paginatedResult = await channel.history();
console.log('Page 0 item 0:' + paginatedResult.items[0].data);
const nextPage = await paginatedResult.next();
console.log('Page 1 item 1: ' + nextPage.items[1].data);
console.log('Last page?: ' + nextPage.isLast());

HttpPaginatedResponse

An HttpPaginatedResponse is a superset of PaginatedResult, which is a type that represents a page of results plus metadata indicating the relative queries available to it. HttpPaginatedResponse additionally carries information about the response to an HTTP request. It is used when making custom HTTP requests.

Properties

ParameterDescriptionType
statusCodeThe HTTP status code of the responseNumber
successWhether the HTTP status code indicates success. This is equivalent to 200 <= statusCode < 300Boolean
headersThe headers of the responseObject
errorCodeThe error code if the X-Ably-Errorcode HTTP header is sent in the responseNumber
errorMessageThe error message if the X-Ably-Errormessage HTTP header is sent in the responseString

Methods

first

first(): Promise<HttpPaginatedResponse>

Returns a promise. On success, the promise is fulfilled with a new HttpPaginatedResponse for the first page of results. On failure, the promise is rejected with an ErrorInfo object that details the reason why it was rejected.

hasNext

Boolean hasNext()

Returns true if there are more pages available by calling next and returns false if this page is the last page available.

isLast

Boolean isLast()

Returns true if this page is the last page and returns false if there are more pages available by calling next available.

next

next(): Promise<HttpPaginatedResponse>

Returns a promise. On success, the promise is fulfilled with a new HttpPaginatedResponse loaded with the next page of results. If there are no further pages, then null is returned. On failure, the promise is rejected with an ErrorInfo object that details the reason why it was rejected.

current

current(): Promise<HttpPaginatedResponse>

Returns a promise. On success, the promise is fulfilled with a new HttpPaginatedResponse loaded with the current page of results. On failure, the promise is rejected with an ErrorInfo object that details the reason why it was rejected.

Example

The HttpPaginatedResponse interface is a superset of PaginatedResult, see the PaginatedResult example

TokenDetails

TokenDetails is a type providing details of Ably Token string and its associated metadata.

Properties

ParameterDescriptionType
tokenThe Ably Token itself. A typical Ably Token string may appear like {{TOKEN}}String
expiresThe time (in milliseconds since the epoch) at which this token expiresInteger
issuedThe time (in milliseconds since the epoch) at which this token was issuedInteger
capabilityThe capability associated with this Ably Token. The capability is a a JSON stringified canonicalized representation of the resource paths and associated operations. Read more about authentication and capabilitiesString
clientIdThe client ID, if any, bound to this Ably Token. If a client ID is included, then the Ably Token authenticates its bearer as that client ID, and the Ably Token may only be used to perform operations on behalf of that client ID. The client is then considered to be an identified clientString

TokenDetails constructors

TokenDetails.fromJson

TokenDetails.fromJson(String json) -> TokenDetails

A static factory method to create a TokenDetails from a deserialized TokenDetails-like object or a JSON stringified TokenDetails. This method is provided to minimize bugs as a result of differing types by platform for fields such as timestamp or ttl. For example, in Ruby ttl in the TokenDetails object is exposed in seconds as that is idiomatic for the language, yet when serialized to JSON using to_json it is automatically converted to the Ably standard which is milliseconds. By using the fromJson method when constructing a TokenDetails, Ably ensures that all fields are consistently serialized and deserialized across platforms.

Parameters
ParameterDescriptionType
jsonA TokenDetails-like deserialized object or JSON stringified TokenDetails.Object, String
Returns

A TokenDetails object

TokenRequest

TokenRequest is a type containing parameters for an Ably TokenRequest. Ably Tokens are requested using Auth#requestToken

Properties

ParameterDescriptionType
keyNameThe key name of the key against which this request is made. The key name is public, whereas the key secret is privateString
ttlRequested time to live for the Ably Token in milliseconds. If the Ably TokenRequest is successful, the TTL of the returned Ably Token will be less than or equal to this value depending on application settings and the attributes of the issuing key.Integer
timestampThe timestamp of this request in millisecondsInteger
capabilityCapability of the requested Ably Token. If the Ably TokenRequest is successful, the capability of the returned Ably Token will be the intersection of this capability with the capability of the issuing key. The capability is a JSON stringified canonicalized representation of the resource paths and associated operations. Read more about authentication and capabilitiesString
clientIdThe client ID to associate with the requested Ably Token. When provided, the Ably Token may only be used to perform operations on behalf of that client IDString
nonceAn opaque nonce string of at least 16 charactersString
macThe Message Authentication Code for this requestString

TokenRequest constructors

TokenRequest.fromJson

TokenRequest.fromJson(String json) -> TokenRequest

A static factory method to create a TokenRequest from a deserialized TokenRequest-like object or a JSON stringified TokenRequest. This method is provided to minimize bugs as a result of differing types by platform for fields such as timestamp or ttl. For example, in Ruby ttl in the TokenRequest object is exposed in seconds as that is idiomatic for the language, yet when serialized to JSON using to_json it is automatically converted to the Ably standard which is milliseconds. By using the fromJson method when constructing a TokenRequest, Ably ensures that all fields are consistently serialized and deserialized across platforms.

Parameters
ParameterDescriptionType
jsonA TokenRequest-like deserialized object or JSON stringified TokenRequest.Object, String
Returns

A TokenRequest object

Stats object

A Stats object represents an application's statistics for the specified interval and time period. Ably aggregates statistics globally for all accounts and applications, and makes these available both through our statistics API as well as your application dashboard.

Properties
ParameterDescriptionType
appIdThe ID of the Ably application the statistics relate to.String
entriesThe statistics for the requested time interval and time period. The schema property provides further informationPartial<Record<String, Number>>
inProgressOptional. For entries that are still in progress, such as the current month, the last sub-interval included in the stats entry. In the format yyyy-mm-dd:hh:mm:ssString
intervalIdThe UTC time period that the stats coverage begins at. If unit was requested as minute this will be in the format YYYY-mm-dd:HH:MM, if hour it will be YYYY-mm-dd:HH, if day it will be YYYY-mm-dd:00 and if month it will be YYYY-mm-01:00String
schemaThe URL of a JSON schema describing the structure of the Stats objectString

StatsIntervalGranularity

StatsIntervalGranularity is an enum specifying the granularity of a Stats interval.

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  const StatsIntervalGranularity = [
      'minute',
      'hour',
      'day',
      'month'
  ]

BatchPublishSpec

A BatchPublishSpec describes the messages that should be published by a batch publish operation, and the channels to which they should be published.

Properties

ParameterDescriptionType
channelsThe names of the channels to publish the messages toString[]
messagesAn array of Message objectsMessage[]

BatchResult

A BatchResult contains information about the results of a batch operation.

Properties

ParameterDescriptionType
successCountThe number of successful operations in the requestNumber
failureCountThe number of unsuccessful operations in the requestNumber
messagesAn array of results for the batch operation (for example, an array of BatchPublishSuccessResult or BatchPublishFailureResult for a channel batch publish request)Object[]

BatchPublishSuccessResult

A BatchPublishSuccessResult contains information about the result of successful publishes to a channel requested by a single BatchPublishSpec.

Properties

ParameterDescriptionType
channelThe name of the channel the message(s) was published toString
messageIdA unique ID prefixed to the Message.id of each published messageString

BatchPublishFailureResult

A BatchPublishFailureResult contains information about the result of unsuccessful publishes to a channel requested by a single BatchPublishSpec.

Properties

ParameterDescriptionType
channelThe name of the channel the message(s) failed to be published toString
errorDescribes the reason for which the message(s) failed to publish to the channel as an ErrorInfo objectErrorInfo

BatchPresenceSuccessResult

A BatchPresenceSuccessResult contains information about the result of a successful batch presence request for a single channel.

Properties

ParameterDescriptionType
channelThe channel name the presence state was retrieved forString
presenceAn array of PresenceMessage describing members present on the channelPresenceMessage[]

BatchPresenceFailureResult

A BatchPresenceFailureResult contains information about the result of an unsuccessful batch presence request for a single channel.

Properties

ParameterDescriptionType
channelThe channel name the presence state failed to be retrieved forString
errorDescribes the reason for which presence state could not be retrieved for the channel as an ErrorInfo objectErrorInfo

TokenRevocationSuccessResult

A TokenRevocationSuccessResult contains information about the result of a successful token revocation request for a single target specifier.

Properties

ParameterDescriptionType
targetThe target specifierString
appliesAtThe time at which the token revocation will take effect, as a Unix timestamp in millisecondsNumber
issuedBeforeA Unix timestamp in milliseconds. Only tokens issued earlier than this time will be revokedNumber

TokenRevocationFailureResult

A TokenRevocationFailureResult contains information about the result of an unsuccessful token revocation request for a single target specifier.

Properties

ParameterDescriptionType
targetThe target specifierString
errorDescribes the reason for which token revocation failed for the given target as an ErrorInfo objectErrorInfo

REST Other types

AuthOptions Object

AuthOptions is a plain JavaScript object and is used when making authentication requests. If passed in, an authOptions object will be used instead of (as opposed to supplementing or being merged with) the default values given when the library was instantiated. The following attributes are supported:

Properties

ParameterDescriptionType
authCallbackA functionfunction with the form function(tokenParams, callback(err, tokenOrTokenRequest)) which is called when a new token is required. The role of the callback is to obtain a fresh token, one of: an Ably Token string (in plain text format); a signed TokenRequest; a TokenDetails (in JSON format); an Ably JWT. See our authentication documentation for details of the Ably TokenRequest format and associated API calls.Callable
authUrlA URL that the library may use to obtain a fresh token, one of: an Ably Token string (in plain text format); a signed TokenRequest; a TokenDetails (in JSON format); an Ably JWT. For example, this can be used by a client to obtain signed Ably TokenRequests from an application server.String
authMethodThe HTTP verb to use for the request, either GET or POST. The default is GET.String
authHeadersA set of key value pair headers to be added to any request made to the authUrl. Useful when an application requires these to be added to validate the request or implement the response. If the authHeaders object contains an authorization key, then withCredentials will be set on the xhr request.Object
authParamsA set of key value pair params to be added to any request made to the authUrl. When the authMethod is GET, query params are added to the URL, whereas when authMethod is POST, the params are sent as URL encoded form data. Useful when an application require these to be added to validate the request or implement the response.Object
tokenDetailsAn authenticated TokenDetails object (most commonly obtained from an Ably Token Request response). This option is mostly useful for testing: since tokens are short-lived, in production you almost always want to use an authentication method that allows the client library to renew the token automatically when the previous one expires, such as authUrl or authCallback. Use this option if you wish to use Token authentication. Read more about Token authenticationTokenDetails
keyOptionally the API key to use can be specified as a full key string; if not, the API key passed into ClientOptions when instancing the Realtime or REST library is usedString
queryTimeIf true, the library will query the Ably servers for the current time when issuing TokenRequests instead of relying on a locally-available time of day. Knowing the time accurately is needed to create valid signed Ably TokenRequests, so this option is useful for library instances on auth servers where for some reason the server clock cannot be kept synchronized through normal means, such as an NTP daemon. The server is queried for the current time once per client library instance (which stores the offset from the local clock), so if using this option you should avoid instancing a new version of the library for each request. The default is false.Boolean
tokenAn authenticated token. This can either be a TokenDetails object, a TokenRequest object, or token string (obtained from the token property of a TokenDetails component of an Ably TokenRequest response, or a JSON Web Token satisfying the Ably requirements for JWTs). This option is mostly useful for testing: since tokens are short-lived, in production you almost always want to use an authentication method that allows the client library to renew the token automatically when the previous one expires, such as authUrl or authCallback. Read more about Token authenticationString, TokenDetails or TokenRequest

ClientOptions Object

ClientOptions is a plain JavaScript object and is used in the Ably.Rest constructor's options argument. The following attributes can be defined on the object:

Properties

ParameterDescriptionType
keyThe full key string, as obtained from the application dashboard. Use this option if you wish to use Basic authentication, or wish to be able to issue Ably Tokens without needing to defer to a separate entity to sign Ably TokenRequests. Read more about Basic authenticationString
tokenAn authenticated token. This can either be a TokenDetails object, a TokenRequest object, or token string (obtained from the token property of a TokenDetails component of an Ably TokenRequest response, or a JSON Web Token satisfying the Ably requirements for JWTs). This option is mostly useful for testing: since tokens are short-lived, in production you almost always want to use an authentication method that allows the client library to renew the token automatically when the previous one expires, such as authUrl or authCallback. Read more about Token authenticationString, TokenDetails or TokenRequest
authCallbackA functionfunction with the form function(tokenParams, callback(err, tokenOrTokenRequest)) which is called when a new token is required. The role of the callback is to obtain a fresh token, one of: an Ably Token string (in plain text format); a signed TokenRequest; a TokenDetails (in JSON format); an Ably JWT. See our authentication documentation for details of the Ably TokenRequest format and associated API calls.Callable
authUrlA URL that the library may use to obtain a fresh token, one of: an Ably Token string (in plain text format); a signed TokenRequest; a TokenDetails (in JSON format); an Ably JWT. For example, this can be used by a client to obtain signed Ably TokenRequests from an application server.String
authMethodThe HTTP verb to use for the request, either GET or POST. The default is GET.String
authHeadersA set of key value pair headers to be added to any request made to the authUrl. Useful when an application requires these to be added to validate the request or implement the response. If the authHeaders object contains an authorization key, then withCredentials will be set on the xhr request.Object
authParamsA set of key value pair params to be added to any request made to the authUrl. When the authMethod is GET, query params are added to the URL, whereas when authMethod is POST, the params are sent as URL encoded form data. Useful when an application require these to be added to validate the request or implement the response.Object
tokenDetailsAn authenticated TokenDetails object (most commonly obtained from an Ably Token Request response). This option is mostly useful for testing: since tokens are short-lived, in production you almost always want to use an authentication method that allows the client library to renew the token automatically when the previous one expires, such as authUrl or authCallback. Use this option if you wish to use Token authentication. Read more about Token authenticationTokenDetails
tlsA boolean value, indicating whether or not a TLS ("SSL") secure connection should be used. An insecure connection cannot be used with Basic authentication as it would lead to a possible compromise of the private API key while in transit. Find out more about TLS. The default is true.Boolean
clientIdA client ID, used for identifying this client when publishing messages or for presence purposes. The clientId can be any non-empty string. This option is primarily intended to be used in situations where the library is instantiated with a key; note that a clientId may also be implicit in a token used to instantiate the library; an error will be raised if a clientId specified here conflicts with the clientId implicit in the token. Find out more about client identitiesString
useTokenAuthWhen true, forces Token authentication to be used by the library. Please note that if a clientId is not specified in the ClientOptions or TokenParams, then the Ably Token issued will be anonymous. The default is false.Boolean
endpointEnables enterprise customers to use their own custom endpoints, which support dedicated, isolated clusters and regional message routing and storage constraints. See our platform customization guide for more details. The default is null.String
environmentDeprecated, use endpoint. Enables enterprise customers to use their own custom environments, which support dedicated, isolated clusters and regional message routing and storage constraints. See our platform customization guide for more details. The default is null.String
idempotentRestPublishingWhen true, enables idempotent publishing by assigning a unique message ID client-side, allowing the Ably servers to discard automatic publish retries following a failure such as a network fault. We recommend you enable this by default. In version 1.2 onwards, idempotent publishing for retries will be enabled by default. The default is false.Boolean
fallbackHostsAn array of fallback hosts to be used in the case of an error necessitating the use of an alternative host. When a custom environment is specified, the fallback host functionality is disabled. If your customer success manager has provided you with a set of custom fallback hosts, please specify them here. The default is [a.ably-realtime.com, b.ably-realtime.com, c.ably-realtime.com, d.ably-realtime.com, e.ably-realtime.com].String []
transportParamsOptional. Can be used to pass in arbitrary connection parameters, such as heartbeatInterval and remainPresentForObject
logLevelA number controlling the verbosity of the log output of the library. Valid values are: 0 (no logs), 1 (errors only), 2 (errors plus connection and channel state changes), 3 (high-level debug output), and 4 (full debug output).Integer
logHandlerA function to handle each line of the library's log output. If logHandler is not specified, console.log is used.Callable
transportsAn optional array of transports to use, in descending order of preference. In the browser environment the available transports are: web_socket, xhr_polling.String []
useBinaryProtocolIf set to true, will enable the binary protocol (MessagePack) if it is supported. It's disabled by default on browsers for performance considerations (browsers are optimized for decoding JSON). The default is false. Find out more about the benefits of binary encodingBoolean
queryTimeIf true, the library will query the Ably servers for the current time when issuing TokenRequests instead of relying on a locally-available time of day. Knowing the time accurately is needed to create valid signed Ably TokenRequests, so this option is useful for library instances on auth servers where for some reason the server clock cannot be kept synchronized through normal means, such as an NTP daemon. The server is queried for the current time once per client library instance (which stores the offset from the local clock), so if using this option you should avoid instancing a new version of the library for each request. The default is false.Boolean
defaultTokenParamsWhen a TokenParams object is provided, it will override the client library defaults when issuing new Ably Tokens or Ably TokenRequestsTokenParams

ClientOptions Object

Channel options are used for setting channel parameters and configuring encryption.

ChannelOptions, a plain JavaScript object, may optionally be specified when instancing a Channel, and this may be used to specify channel-specific options. The following attributes can be defined on the object:

Properties

ParameterDescriptionType
paramsOptional parameters which specify behaviour of the channel.JSON Object
cipherRequests encryption for this channel when not null, and specifies encryption-related parameters (such as algorithm, chaining mode, key length and key). See an exampleCipherParams or an options object containing at a minimum a key

CipherParams

A CipherParams contains configuration options for a channel cipher, including algorithm, mode, key length and key. Ably client libraries currently support AES with CBC, PKCS#7 with a default key length of 256 bits. All implementations also support AES128.

Individual client libraries may support either instancing a CipherParams directly, using Crypto.getDefaultParams(), or generating one automatically when initializing a channel, as in this example.

Properties

ParameterDescriptionType
keyA binary (ArrayBuffer or Uint8Array) or base64-encoded String containing the secret key used for encryption and decryption
algorithmThe name of the algorithm in the default system provider, or the lower-cased version of it; eg "aes" or "AES". The default is AES.String
keyLengthThe key length in bits of the cipher, either 128 or 256. The default is 256.Integer
modeThe cipher mode. The default is CBC.String

TokenParams Object

TokenParams is a plain JavaScript object and is used in the parameters of token authentication requests, corresponding to the desired attributes of the Ably Token. The following attributes can be defined on the object:

Properties

ParameterDescriptionType
capabilityJSON stringified capability of the Ably Token. If the Ably Token request is successful, the capability of the returned Ably Token will be the intersection of this capability with the capability of the issuing key. Find our more about how to use capabilities to manage access privileges for clients.String
clientIdA client ID, used for identifying this client when publishing messages or for presence purposes. The clientId can be any non-empty string. This option is primarily intended to be used in situations where the library is instantiated with a key; note that a clientId may also be implicit in a token used to instantiate the library; an error will be raised if a clientId specified here conflicts with the clientId implicit in the token. Find out more about client identitiesString
nonceAn optional opaque nonce string of at least 16 characters to ensure uniqueness of this request. Any subsequent request using the same nonce will be rejected.String
timestampThe timestamp (in milliseconds since the epoch) of this request. timestamp, in conjunction with the nonce, is used to prevent requests for Ably Token from being replayed.Integer
ttlRequested time to live for the Ably Token being created in milliseconds When omitted, the Ably REST API default of 60 minutes is applied by Ably. The default is 1 hour.Integer (milliseconds)

TokenRevocationTargetSpecifier

A TokenRevocationTargetSpecifier describes which tokens should be affected by a token revocation request.

Properties

ParameterDescriptionType
typeThe type of token revocation target specifier. Valid values include clientId, revocationKey and channelString
valueThe value of the token revocation target specifierString

TokenRevocationOptions

A TokenRevocationOptions describes the additional options accepted by revoke tokens request.

Properties

ParameterDescriptionType
issuedBeforeAn optional Unix timestamp in milliseconds where only tokens issued before this time are revoked. The default is the current time. Requests with an issuedBefore in the future, or more than an hour in the past, will be rejectedNumber
allowReauthMarginIf true, permits a token renewal cycle to take place without needing established connections to be dropped, by postponing enforcement to 30 seconds in the future, and sending any existing connections a hint to obtain (and upgrade the connection to use) a new token. The default is false, meaning that the effect is near-immediate.Boolean
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