History
Channel object
The Realtime Channel object exposes the following public method to obtain Message history.
Methods
history
Deferrable history(Hash option) → yields PaginatedResult<Message>
Gets a paginated set of historical messages for this channel.
Parameters
| Parameter | Description | Type |
|---|---|---|
| option | an optional set of key value pairs containing the query parameters | Hash |
| &block | yields a PaginatedResult<Message> object | Block |
options parameters
| Property | Description | Type |
|---|---|---|
| :start | Earliest Time or time in milliseconds since the epoch for any messages retrieved. Default: beginning of time | Int or Time |
| :end | Latest Time or time in milliseconds since the epoch for any messages retrieved. Default: current time | Int or Time |
| :direction | :forwards or :backwards. Default: :backwards | Symbol |
| :limit | Maximum number of messages to retrieve per page, up to 1,000. Default: 100 | Integer |
| :until_attach | when true, ensures message history is up until the point of the channel being attached. See continuous history for more info. Requires the direction to be backwards (the default). If the Channel is not attached, or if direction is set to forwards, this option will result in an error. Default: false | Boolean |
Returns
A Deferrable object is returned from the method.
On success, the registered success blocks for the Deferrable and any block provided to the method yield a PaginatedResult that encapsulates an array of Message objects corresponding to the current page of results. PaginatedResult supports pagination using next() and first() methods.
Failure to retrieve the message history will trigger the errback callbacks of the Deferrable with an ErrorInfo object with the failure reason.
Presence object
Realtime Presence object exposes the following public method to obtain presence event history such as enter, update and leave events. These events are represented as PresenceMessage objects.
Methods
history
Deferrable history(Hash option) → yields PaginatedResult<PresenceMessage>
Gets a paginated set of historical presence events for this channel.
Parameters
| Parameter | Description | Type |
|---|---|---|
| option | an optional set of key value pairs containing the query parameters | Hash |
| &block | yields a PaginatedResult<PresenceMessage> object | Block |
options parameters
| Property | Description | Type |
|---|---|---|
| :start | Earliest Time or time in milliseconds since the epoch for any presence events retrieved. Default: beginning of time | Int or Time |
| :end | Latest Time or time in milliseconds since the epoch for any presence events retrieved. Default: current time | Int or Time |
| :direction | :forwards or :backwards. Default: :backwards | Symbol |
| :limit | Maximum number of presence events to retrieve up to 1,000. Default: 100 | Integer |
| :until_attach | when true, ensures presence message history is up until the point of the channel being attached. See continuous history for more info. Requires the direction to be backwards (the default). If the Channel is not attached, or if direction is set to forwards, this option will result in an error. Default: false | Boolean |
Returns
A Deferrable object is returned from the method.
On success, the registered success blocks for the Deferrable and any block provided to the method yield a PaginatedResult that encapsulates an array of PresenceMessage objects corresponding to the current page of results. PaginatedResult supports pagination using next() and first() methods.
Failure to retrieve the presence event history will trigger the errback callbacks of the Deferrable with an ErrorInfo object with the failure reason.
Related types
Ably::Models::Message Enum
A Message represents an individual message that is sent to or received from Ably.
Properties
| Property | Description | Type |
|---|---|---|
| name | The event name, if provided. | String |
| data | The message payload, if provided. | String, Binary (ASCII-8BIT String), Hash, Array |
| 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. | Hash, Array |
| id | A Unique ID assigned by Ably to this message. | String |
| client_id | The client ID of the publisher of this message. | String |
| connection_id | The connection ID of the publisher of this message. | String |
| connection_key | A connection key, which can optionally be included for a REST publish as part of the publishing on behalf of a realtime client functionality. | String |
| timestamp | Timestamp when the message was first received by the Ably, as a Time object. | Time |
| 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. | String |
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
| Parameter | Description | Type |
|---|---|---|
| encodedMsg | a Message-like deserialized object. | Object |
| channelOptions | an optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the data. | Object |
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
| Parameter | Description | Type |
|---|---|---|
| encodedMsgs | an array of Message-like deserialized objects. | Array |
| channelOptions | an optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the data. | Object |
Returns
An Array of Message objects
Ably::Models::PresenceMessage Enum
A PresenceMessage represents an individual presence update that is sent to or received from Ably.
Properties
| Property | Description | Type |
|---|---|---|
| action | the event signified by a PresenceMessage. See PresenceMessage.action | enum { :absent, :present, :enter, :leave, :update } |
| data | The presence update payload, if provided | String, Binary (ASCII-8BIT String), Hash, Array |
| extras | Metadata and/or ancillary payloads, if provided. The only currently valid payloads for extras are the push, ref and privileged objects. | Hash, Array |
| id | Unique ID assigned by Ably to this presence update | String |
| client_id | The client ID of the publisher of this presence update | String |
| connection_id | The connection ID of the publisher of this presence update | String |
| timestamp | Timestamp when the presence update was received by Ably. | Time |
| encoding | This 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 payload | String |
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
| Parameter | Description | Type |
|---|---|---|
| encodedPresMsg | a PresenceMessage-like deserialized object. | Object |
| channelOptions | an optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the data. | Object |
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
| Parameter | Description | Type |
|---|---|---|
| encodedPresMsgs | an array of PresenceMessage-like deserialized objects. | Array |
| channelOptions | an optional ChannelOptions. If you have an encrypted channel, use this to allow the library to decrypt the data. | Object |
Returns
An Array of PresenceMessage objects
Ably::Models::PresenceMessage::ACTION
Ably::Models::PresenceMessage::ACTION is an enum-like value representing all the Realtime Presence states & events. ACTION can be represented interchangeably as either symbols or constants.
Symbol states
1
2
3
4
5
:absent # => 0 (reserved for internal use)
:present # => 1
:enter # => 2
:leave # => 3
:update # => 4Constant states
1
2
3
4
5
PresenceMessage::ACTION.Absent # => 0 (internal use)
PresenceMessage::ACTION.Present # => 1
PresenceMessage::ACTION.Enter # => 2
PresenceMessage::ACTION.Leave # => 3
PresenceMessage::ACTION.Update # => 4Example usage
1
2
3
4
5
6
7
8
# Example with symbols
presence.on(:attached) { ... }
# Example with constants
presence.on(Ably::Models::PresenceMessage::ACTION.Enter) { ... }
# Interchangeable
Ably::Models::PresenceMessage::ACTION.Enter == :enter # => trueAbly::Models::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
| Property | Description | Type |
|---|---|---|
| items | contains the current page of results (for example an Array of Message or PresenceMessage objects for a channel history request) | Array <Message, Presence, Stats> |
Methods
first
PaginatedResult first()
Returns a new PaginatedResult for the first page of results. When using the Realtime library, the first method returns a Deferrable and yields a PaginatedResult.
has_next?
Boolean has_next?
Returns true if there are more pages available by calling next and returns false if this page is the last page available.
last?
Boolean last?
Returns true if this page is the last page and returns false if there are more pages available by calling next available.
next
PaginatedResult next()
Returns a new PaginatedResult loaded with the next page of results. If there are no further pages, then null is returned. When using the Realtime library, the first method returns a Deferrable and yields a PaginatedResult.
Example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
# When using the REST sync library
first_page = channel.history
puts "Page 0 item 0: #{first_page.items[0].data}"
if first_page.has_next?
next_page = first_page.next
puts "Page 1 item 1: #{next_page.items[1].data}"
puts "Last page?: #{next_page.is_last?}"
end
# When using the Realtime EventMachine library
channel.history do |first_page|
puts "Page 0 item 0: #{first_page.items[0].data}"
if first_page.has_next?
first_page.next do |next_page|
puts "Page 1 item 1: #{next_page.items[1].data}"
puts "Last page?: #{next_page.is_last?}"
end
end
end