Message Persistence API for PubNub Go SDK

The PubNub Message Persistence Service provides real-time access to history for all messages published to PubNub. Each published message is timestamped to the nearest 10 nanoseconds, and is stored across multiple availability zones in several geographical data center locations. Stored messages can be encrypted with AES-256 message encryption, ensuring that they are not readable while stored on PubNub's network.

Messages can be stored for a configurable duration or forever, as controlled by the retention policy that is configured on your account. The following options are available: 1, 3, 5, 7, 15, or 30 days, and Forever.

Fetch History

Requires Message Persistence add-on

This method requires that the Message Persistence add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Description

This function fetches historical messages from one or multiple channels. The includeMessageActions flag also allows you to fetch message actions along with the messages.

It's possible to control how messages are returned and in what order.

  • if you specify only the start parameter (without end), you will receive messages that are older than the start timetoken
  • if you specify only the end parameter (without start), you will receive messages from that end timetoken and newer
  • if you specify values for both start and end parameters, you will retrieve messages between those timetokens (inclusive of the end value)

You will receive a maximum of 100 messages for a single channel or 25 messages for multiple channels (up to 500). If more messages meet the timetoken criteria, make iterative calls while adjusting the start timetoken to fetch the entire list of messages from storage.

Method(s)

To run Fetch History, you can use the following method(s) in the Go V4 SDK:

pn.Fetch().Channels(channels).Count(count).Start(start).End(end).IncludeMeta(bool).IncludeMessageType(bool).IncludeUUID(bool).IncludeMessageActions(bool).Reverse(reverse).QueryParam(queryParam).Execute()
ParameterTypeRequiredDefaultDescription
ChannelsstringYesSpecifies channelsto return history messages. Maximum of 500 channels are allowed.
CountintOptional100 or 25Specifies the number of historical messages to return. Default and maximum value is 100 for a single channel, 25 for multiple channels, and 25 when IncludeMessageActions is true.
Startint64OptionalTimetoken delimiting the start of time slice (exclusive) to pull messages from.
Endint64OptionalTimetoken delimiting the end of time slice (inclusive) to pull messages from.
IncludeMetaboolOptionalfalseWhether meta (passed when Publishing the message) should be included in response or not.
IncludeMessageTypeboolOptionaltruePass true to receive the message type with each history message.
IncludeUUIDboolOptionaltruePass true to receive the publisher uuid with each history message.
IncludeMessageActionsboolOptionalfalseWhether MessageActions should be included in response or not.
ReverseboolOptionalfalseSetting to true will traverse the time line in reverse starting with the oldest message first.
QueryParammap[string]stringOptionalnilQueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.
Truncated response

If you fetch messages with messages actions, the number of messages in the response may be truncated when internal limits are hit. If the response is truncated, a more property will be returned with additional parameters. Send iterative calls to history adjusting the parameters to fetch more messages.

Basic Usage

Retrieve the last message on a channel:

res, status, err := pn.Fetch().
Channels([]string{"ch1", "ch2"}).
Count(25).
Reverse(true).
Execute()

Returns

MethodTypeDescription
Messageinterface{}Message from History.
Timetokenstring{{Timetoken}} of the message.
Metainterface{}The meta data (if sent, when publishing the message)
MessageTypenumberReturns 4 for file messages.
UuidstringPublisher uuid of the message.
MessageActionsmap[string]PNHistoryMessageActionsTypeMapThe message actions associated with the message. Details of type PNHistoryMessageActionsTypeMap are here

PNHistoryMessageActionsTypeMap

Property NameTypeDescription
ActionsTypeValuesmap[string][]PNHistoryMessageActionTypeValDetails of type PNHistoryMessageActionTypeVal are here

PNHistoryMessageActionTypeVal

Property NameTypeDescription
UUIDstringThe UUID of the publisher.
ActionTimetokenstringThe publish timetoken of the action.

Response

MethodType
Errorerror
CategoryStatusCategory
OperationOperationType
StatusCodeint
TLSEnabledbool
UUIDstring
AuthKeystring
Originstring
OriginalResponsestring
Requeststring
AffectedChannels[]string
AffectedChannelGroups[]string

Delete Messages from History

Requires Message Persistence add-on

This method requires that the Message Persistence add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Description

Removes the messages from the history of a specific channel.

Required setting

There is a setting to accept delete from history requests for a key, which you must enable by checking the Enable Delete-From-History checkbox in the key settings for your key in the Admin Portal.

Requires Initialization with secret key.

Method(s)

To Delete Messages from History you can use the following method(s) in the Go V4 SDK.

pn.DeleteMessages().Channel(channel).Start(start).End(end).QueryParam(queryParam).Execute()
ParameterTypeRequiredDescription
ChannelstringYesSpecifies channels to delete messages from.
Startint64OptionalTimetoken delimiting the start of time slice (inclusive) to delete messages from.
Endint64OptionalTimetoken delimiting the end of time slice (exclusive) to delete messages from.
QueryParammap[string]stringOptionalQueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.

Basic Usage

res, status, err := pn.DeleteMessages().
Channel("ch").
Start(int64(15343325214676133)).
End(int64(15343325004275466)).
Execute()

Response

MethodType
Errorerror
CategoryStatusCategory
OperationOperationType
StatusCodeint
TLSEnabledbool
UUIDstring
AuthKeystring
Originstring
OriginalResponsestring
Requeststring
AffectedChannels[]string
AffectedChannelGroups[]string

Other Examples

Delete specific message from history

To delete a specific message, pass the publish timetoken (received from a successful publish) in the End parameter and timetoken +/- 1 in the Start parameter. For example, if 15526611838554310 is the publish timetoken, pass 15526611838554309 in Start and 15526611838554310 in End parameters respectively as shown in the following code snippet.

res, status, err := pn.DeleteMessages().
Channel("ch").
Start(int64(15526611838554310)).
End(int64(15526611838554309)).
Execute()

Message Counts

Requires Message Persistence add-on

This method requires that the Message Persistence add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Description

Returns the number of messages published on one or more channels since a given time. The count returned is the number of messages in history with a timetoken value greater than or equal to than the passed value in the ChannelsTimetokenparameter.

Unlimited message retention

For keys with unlimited message retention enabled, this method considers only messages published in the last 30 days.

Method(s)

You can use the following method(s) in the Go V4 SDK:

pn.MessageCounts().Channels(channels). ChannelsTimetoken(channelsTimetoken).QueryParam(queryParam).Execute()
ParameterTypeRequiredDefaultDescription
Channels[]stringYesThe channels to fetch the message count
ChannelsTimetoken[]int64YesnilArray of timetokens, in order of the channels list. Specify a single timetoken to apply it to all channels. Otherwise, the list of timetokens must be the same length as the list of channels, or the function returns a PNStatuswith an error flag.
QueryParammap[string]stringOptionalnilQueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.

Basic Usage

res, status, err := pn.MessageCounts().
Channels([]string{"ch1", "ch2"}).
ChannelsTimetoken([]int64{1551795013294}).
Execute()

Returns

The MessageCounts() operation returns a MessageCountsResponse object which contains the following operations:

MethodTypeDescription
Channelsmap[string]intA map of Channels with message count. Channels without messages have a count of 0. Channels with 10,000 messages or more have a count of 10000.

Status Response

MethodType
Errorerror
CategoryStatusCategory
OperationOperationType
StatusCodeint
TLSEnabledbool
UUIDstring
AuthKeystring
Originstring
OriginalResponsestring
Requeststring
AffectedChannels[]string
AffectedChannelGroups[]string

Other Examples

Retrieve count of messages using different timetokens for each channel

pn.MessageCounts().
Channels([]string{ch1, ch2}).
ChannelsTimetoken([]int64{1551795013294,155179501329433}).
Execute()

History (deprecated)

Requires Message Persistence add-on

This method requires that the Message Persistence add-on is enabled for your key in the Admin Portal. Read the support page on enabling add-on features on your keys.

Alternative method

This method is deprecated. Use fetch history instead.

Description

This function fetches historical messages of a channel.

It is possible to control how messages are returned and in what order, for example you can:

  • Search for messages starting on the newest end of the timeline (default behavior - Reverse = false)
  • Search for messages from the oldest end of the timeline by setting Reverse to true.
  • Page through results by providing a Start OR End timetoken.
  • Retrieve a slice of the time line by providing both a Start AND End timetoken.
  • Limit the number of messages to a specific quantity using the Count parameter.
Start & End parameter usage clarity

If only the Start parameter is specified (without End), you will receive messages that are older than and up to that Start timetoken value. If only the End parameter is specified (without Start) you will receive messages that match that End timetoken value and newer. Specifying values for both Start and End parameters will return messages between those timetoken values (inclusive on the End value). Keep in mind that you will still receive a maximum of 100 messages even if there are more messages that meet the timetoken values. Iterative calls to history adjusting the Start timetoken is necessary to page through the full set of results if more than 100 messages meet the timetoken values.

Method(s)

To run History you can use the following method(s) in the Go V4 SDK:

pn.History().Channel(string).Reverse(bool).IncludeTimetoken(bool).IncludeMeta(bool).Start(int64).End(int64).Count(int).QueryParam(queryParam).Execute()
ParameterTypeRequiredDefaultDescription
ChannelstringTrueSpecifies channel to return history messages from.
ReverseboolOptionalfalseSetting to true will traverse the time line in reverse starting with the oldest message first.
IncludeTimetokenboolOptionalfalseWhether event dates timetokens should be included in response or not.
IncludeMetaboolOptionalfalseWhether meta (passed when Publishing the message) should be included in response or not.
Startint64OptionalTimetoken delimiting the start of time slice (exclusive) to pull messages from.
Endint64OptionalTimetoken delimiting the end of time slice (inclusive) to pull messages from.
CountintOptional100Specifies the number of historical messages to return.
QueryParammap[string]stringOptionalnilQueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.
Using the reverse parameter

Messages are always returned sorted in ascending time direction from history regardless of Reverse. The Reverse direction matters when you have more than 100 (or Count, if it's set) messages in the time interval, in which case Reverse determines the end of the time interval from which it should start retrieving the messages.

Basic Usage

Retrieve the last 100 messages on a channel:

res, status, err := pn.History().
Channel("history_channel"). // where to fetch history from
Count(). // how many items to fetch
Execute()

fmt.Println(res, status, err)

Response

The History() operation returns a PNHistoryResult which contains the following operations:

MethodTypeDescription
Messages[]HistoryResponseItemarray of messages of type PNHistoryItemResult. See PNHistoryItemResult for more details.
StartTimetokenint64Start timetoken.
EndTimetokenint64End timetoken.

PNHistoryItemResult

MethodTypeDescription
Timetokenint64Timetoken of the message.
Messageinterface{}The Message.
Metainterface{}The meta data (if sent, when publishing the message).

Other Examples

Use History() to retrieve the three oldest messages by retrieving from the time line in reverse

res, status, err := pn.History().
Channel("my-ch"). // where to fetch history from
Count(3). // how many items to fetch
Reverse(true). // should go in reverse?
Execute()
Response
for _, v := range res.Messages {
fmt.Println(v.Entry) // custom JSON structure for message
}

Use History() to retrieve messages newer than a given timetoken by paging from oldest message to newest message starting at a single point in time (exclusive)

res, status, err := pn.History().
Channel("my-ch"). // where to fetch history from
Start(int64(13847168620721752)). // first timestamp
Reverse(true). // should go in reverse?
Execute()
Response
for _, v := range res.Messages {
fmt.Println(v.Entry) // custom JSON structure for message
}

Use History() to retrieve messages until a given timetoken by paging from newest message to oldest message until a specific end point in time (inclusive)

res, status, err := pn.History().
Channel("my-ch"). // where to fetch history from
Count(100).
Start(int64(-1)). // first timestamp
End(int64(13847168819178600)). // last timestamp
Reverse(true). // should go in reverse?
Execute()
Response
for _, v := range res.Messages {
fmt.Println(v.Entry) // custom JSON structure for message
}

History Paging Example

func getAllMessages(startTT int64) {
res, _, _ := pn.History().
Channel("history_channel").
Count(2).
Execute()

msgs := res.Messages
start := res.StartTimetoken
end := res.EndTimetoken

if len(msgs) > 0 {
fmt.Println(len(msgs))
fmt.Println("start " + strconv.Itoa(int(start)))
fmt.Println("end " + strconv.Itoa(int(end)))
}
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Include timetoken in history response

res, status, status := pn.History().
Channel("history_channel").
Count(100).
IncludeTimetoken(true).
Execute()

fmt.Println(res, status, err)