Message Persistence API for Go SDK

Message Persistence gives you real-time access to the history of messages published to PubNub. Each message is timestamped to the nearest 10 nanoseconds and stored across multiple availability zones in several geographic locations. You can encrypt stored messages with AES-256 so they are not readable on PubNub’s network. For details, see Message Persistence.

You control how long messages are stored through your account’s retention policy. Options include: 1 day, 7 days, 30 days, 3 months, 6 months, 1 year, or Unlimited.

You can retrieve the following:

  • Messages
  • Message reactions
  • Files (using the File Sharing API)

Fetch history​

Requires Message Persistence

Enable Message Persistence for your key in the Admin Portal. See how to enable add-on features.

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

You can control how messages are returned and in what order:

  • If you specify only the start parameter (without end), you receive messages older than the start timetoken.
  • If you specify only the end parameter (without start), you receive messages from that end timetoken and newer.
  • If you specify both start and end, you retrieve messages between those timetokens (inclusive of the end value).

You can receive up to 100 messages for a single channel, or 25 messages per channel when querying multiple channels (up to 500 channels). If more messages match the time range, make iterative calls and adjust the start timetoken to page through the results.

Method(s)​

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

pn.Fetch().
    Channels(channels).
    Count(count).
    Start(start).
    End(end).
    IncludeMeta(bool).
    IncludeMessageType(bool).
    IncludeUUID(bool).
    IncludeMessageActions(bool).
    IncludeCustomMessageType(bool).
    Reverse(reverse).
    QueryParam(queryParam).
    Execute()
* required
ParameterDescription
Channels *
Type: string
Default:
n/a
Specifies channelsto return history messages. Maximum of 500 channels are allowed.
Count
Type: int
Default:
100 or 25
Specifies 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.
Start
Type: int64
Default:
n/a
Timetoken delimiting the start of time slice (exclusive) to pull messages from.
End
Type: int64
Default:
n/a
Timetoken delimiting the end of time slice (inclusive) to pull messages from.
IncludeMeta
Type: bool
Default:
false
Whether meta (passed when Publishing the message) should be included in response or not.
IncludeMessageType
Type: bool
Default:
true
Pass true to receive the message type with each history message.
IncludeUUID
Type: bool
Default:
true
Pass true to receive the publisher uuid with each history message.
IncludeMessageActions
Type: bool
Default:
false
Whether MessageActions should be included in response or not. If true, the method is limited to one channel and 25 messages only.
IncludeCustomMessageType
Type: bool
Default:
n/a
Indicates whether to retrieve messages with the custom message type.

For more information, refer to Retrieving Messages.
Reverse
Type: bool
Default:
false
Setting to true will traverse the time line in reverse starting with the oldest message first.
QueryParam
Type: map[string]string
Default:
nil
QueryParam 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 message actions, the response may be truncated when internal limits are reached. If truncated, a more property is returned with additional parameters. Make iterative calls to history, adjusting the parameters to fetch more messages.

Sample code​

Reference code
This example is a self-contained code snippet ready to be run. It includes necessary imports and executes methods with console logging. Use it as a reference when working with other examples in this document.

Retrieve the last messages on a channel:

package main

import (
	"fmt"
	"log"

	pubnub "github.com/pubnub/go/v7"
)

func main() {
	// Configure the PubNub instance with demo keys
	config := pubnub.NewConfigWithUserId("myUniqueUserId")
	config.SubscribeKey = "demo"
	config.PublishKey = "demo"

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Returns​

MethodDescription
Message
Type: interface
Message from history.
Timetoken
Type: string
Timetoken of the message.
Meta
Type: interface
The meta data (if sent with the message).
MessageType
Type: number
Returns 4 for file messages.
CustomMessageType
Type: string
The custom message type.
Uuid
Type: string
Publisher uuid of the message.
MessageActions
Type: map[string]PNHistoryMessageActionsTypeMap
Message actions associated with the message. Details of type PNHistoryMessageActionsTypeMap are described below

PNHistoryMessageActionsTypeMap​

Property NameTypeDescription
ActionsTypeValues
map[string][]PNHistoryMessageActionTypeVal
Details of type PNHistoryMessageActionTypeVal are described below

PNHistoryMessageActionTypeVal​

Property NameTypeDescription
UUID
string
The UUID of the publisher.
ActionTimetoken
string
The publish timetoken of the action.

Response​

Method
Error
Type: error
Category
Type: StatusCategory
Operation
Type: OperationType
StatusCode
Type: int
TLSEnabled
Type: bool
UUID
Type: string
AuthKey
Type: string
Origin
Type: string
OriginalResponse
Type: string
Request
Type: string
AffectedChannels
Type: []string
AffectedChannelGroups
Type: []string

Delete messages from history​

Requires Message Persistence

Enable Message Persistence for your key in the Admin Portal. See how to enable add-on features.

Remove messages from the history of a specific channel.

Required setting

To accept delete-from-history requests, enable the Delete-From-History setting for your key in the Admin Portal and initialize the SDK with a secret key.

Method(s)​

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

pn.DeleteMessages().
    Channel(channel).
    Start(start).
    End(end).
    QueryParam(queryParam).
    Execute()
* required
ParameterDescription
Channel *
Type: string
Specifies channels to delete messages from.
Start
Type: int64
Timetoken delimiting the start of time slice (inclusive) to delete messages from.
End
Type: int64
Timetoken delimiting the end of time slice (exclusive) to delete messages from.
QueryParam
Type: map[string]string
QueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.

Sample code​

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

Response​

Method
Error
Type: error
Category
Type: StatusCategory
Operation
Type: OperationType
StatusCode
Type: int
TLSEnabled
Type: bool
UUID
Type: string
AuthKey
Type: string
Origin
Type: string
OriginalResponse
Type: string
Request
Type: string
AffectedChannels
Type: []string
AffectedChannelGroups
Type: []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(15526611838554309)).
        End(int64(15526611838554310)).
        Execute()

Message counts​

Requires Message Persistence

Enable Message Persistence for your key in the Admin Portal. See how to enable add-on features.

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

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 SDK:

pn.MessageCounts().
    Channels(channels).
    ChannelsTimetoken(channelsTimetoken).
    QueryParam(queryParam).
    Execute()
* required
ParameterDescription
Channels *
Type: []string
Default:
n/a
The channels to fetch the message count
ChannelsTimetoken *
Type: []int64
Default:
nil
Array 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 PNStatus with an error flag.
QueryParam
Type: map[string]string
Default:
nil
QueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.

Sample code​

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 properties:

MethodDescription
Channels
Type: map[string]int
Channel names with message counts. Channels without messages have a count of 0. Channels with 10,000 messages or more have a count of 10000.

Status response​

Method
Error
Type: error
Category
Type: StatusCategory
Operation
Type: OperationType
StatusCode
Type: int
TLSEnabled
Type: bool
UUID
Type: string
AuthKey
Type: string
Origin
Type: string
OriginalResponse
Type: string
Request
Type: string
AffectedChannels
Type: []string
AffectedChannelGroups
Type: []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

Enable Message Persistence for your key in the Admin Portal. See how to enable add-on features.

Alternative method

This method is deprecated. Use fetch history instead.

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 SDK:

pn.History().
    Channel(string).
    Reverse(bool).
    IncludeTimetoken(bool).
    IncludeMeta(bool).
    Start(int64).
    End(int64).
    Count(int).
    QueryParam(queryParam).
    Execute()
* required
ParameterDescription
Channel
Type: string
Default:
n/a
Specifies channel to return history messages from.
Reverse
Type: bool
Default:
false
Setting to true will traverse the time line in reverse starting with the oldest message first.
IncludeTimetoken
Type: bool
Default:
false
Whether event dates timetokens should be included in response or not.
IncludeMeta
Type: bool
Default:
false
Whether meta (passed when Publishing the message) should be included in response or not.
Start
Type: int64
Default:
n/a
Timetoken delimiting the start of time slice (exclusive) to pull messages from.
End
Type: int64
Default:
n/a
Timetoken delimiting the end of time slice (inclusive) to pull messages from.
Count
Type: int
Default:
100
Specifies the number of historical messages to return.
QueryParam
Type: map[string]string
Default:
nil
QueryParam accepts a map, the keys and values of the map are passed as the query string parameters of the URL called by the API.
tip
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.

Sample code​

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:

MethodDescription
Messages
Type: []HistoryResponseItem
array of messages of type PNHistoryItemResult. See PNHistoryItemResult for more details.
StartTimetoken
Type: int64
Start timetoken.
EndTimetoken
Type: int64
End timetoken.

PNHistoryItemResult​

MethodDescription
Timetoken
Type: int64
Timetoken of the message.
Message
Type: interface
The Message.
Meta
Type: interface
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)
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