Message Persistence API for PubNub Java SDK

Breaking changes in v9.0.0

PubNub Java SDK version 9.0.0 unifies the codebases for Java and Kotlin SDKs, introduces a new way of instantiating the PubNub client, and changes asynchronous API callbacks and emitted status events. These changes can impact applications built with previous versions (< 9.0.0) of the Java SDK.

For more details about what has changed, refer to Java/Kotlin SDK migration guide.

Message Persistence provides real-time access to the history of 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 locations. Stored messages can be encrypted with AES-256 message encryption, ensuring that they are not readable while stored on PubNub's network. For more information, refer to Message Persistence.

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 day, 7 days, 30 days, 3 months, 6 months, 1 year, or Unlimited.

You can retrieve the following:

Messages
Message reactions
File Sharing (using File Sharing API)

Fetch History

Requires Message Persistence

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

This function fetches historical messages from one or multiple channels. The includeMessageActions flag also allows you to fetch message reactions 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 Message Persistence.

Method(s)

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

this.pubnub.fetchMessages()
    .channels(List<String>)
    .maximumPerChannel(Integer)
    .start(Long)
    .end(Long)
    .includeMessageActions(Boolean)
    .includeMeta(Boolean)
    .includeMessageType(Boolean)
    .includeCustomMessageType(Boolean)
    .includeUUID(Boolean)

Parameter	Type	Required	Default	Description
`channels`	List`<String>`	Yes		Specifies `channels` to return history messages from. Maximum of 500 channels are allowed.
`maximumPerChannel`	Integer	Optional	`100` or `25`	Specifies the number of historical messages to return per channel. Maximum value is 100 for a single channel, or 25 for multiple channels. If `includeMessageActions` is `true`, then `25` is the default (and maximum) value.
`start`	Long	Optional		Timetoken delimiting the `start` of time slice (exclusive) to pull messages from.
`end`	Long	Optional		Timetoken delimiting the `end` of time slice (inclusive) to pull messages from.
`includeMessageActions`	Boolean	Optional	`false`	The flag denoting to retrieve history messages with message reactions. If `true`, the method is limited to one channel and 25 messages only.
`includeMeta`	Boolean	Optional	`false`	Whether to include message metadata within response or not.
`includeMessageType`	Boolean	Optional	`true`	The flag denoting to retrieve history messages with message type.
`includeCustomMessageType`	Boolean	No	`false`	Indicates whether to retrieve messages with the custom message type. For more information, refer to Retrieving Messages.
`includeUUID`	Boolean	Optional	`true`	The flag denoting to retrieve history messages with UUID of a publisher.
`async`	`Consumer<Result>`	Yes		`Consumer` of a `Result` of type `PNFetchMessagesResult`.

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:

pubnub.fetchMessages()
        .channels(Arrays.asList("my_channel"))
        .maximumPerChannel(25)
        .includeMessageActions(true)
        .includeMeta(true)
        .includeMessageType(true)
        .includeCustomMessageType(true)
        .includeUUID(true)
        .async(result -> {
            result.onSuccess(res -> {
                Map<String, List<PNFetchMessageItem>> channels = res.getChannels();
                for (PNFetchMessageItem messageItem : channels.get("my_channel")) {
                    System.out.println(messageItem.getMessage());
                    System.out.println(messageItem.getMeta());
                    System.out.println(messageItem.getTimetoken());
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Returns

The fetchMessages() operation returns a list of PNFetchMessagesResult objects, each containing the following operations:

Method	Type	Description
`getMessage()`	JsonElement	Message content.
`getMeta()`	JsonElement	Message metadata if any, and if requested via `includeMeta(true)`.
`getTimetoken()`	Long	Publish timetoken.
`getActionTimetoken()`	Long	Timestamp when the message reaction was created.
`getActions()`	HashMap	Actions data of the message, if any, and if requested via `includeMessageActions(true)`.
`getMessageType()`	Integer	Message type `0` - message, `1` - signal, `2` - object, `3` - message reaction, `4` - files
`getCustomMessageType()`	String	The custom message type.
`getUuid()`	String	UUID of the publisher

Other Examples

Paging History Responses

package com.we.pubnubtest.utils;

import com.pubnub.api.models.consumer.history.PNFetchMessagesResult;

public abstract class CallbackSkeleton {

    public CallbackSkeleton() {
    }

    public abstract void handleResponse(PNFetchMessagesResult result);

    public abstract void finish();

}

package com.we.pubnubtest.utils;

import com.pubnub.api.java.PubNub;
import com.pubnub.api.java.callbacks.PNCallback;
import com.pubnub.api.models.consumer.PNStatus;
import com.pubnub.api.models.consumer.history.PNFetchMessagesResult;
import com.pubnub.api.models.consumer.pubsub.PNMessageResult;

import java.util.Arrays;
import java.util.List;
import java.util.concurrent.CountDownLatch;

public class PubnubRecursiveHistoryFetcher {
    private PubNub pubNub;
    private String channels;
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Delete Messages from History

Requires Message Persistence

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

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 Java SDK.

this.pubnub.deleteMessages()
    .channels(Array)
    .start(Long)
    .end(Long)

Parameter	Type	Required	Description
`channels`	Array	Yes	Specifies `channels` to delete messages from.
`start`	Long	Optional	Timetoken delimiting the `start` of time slice (inclusive) to delete messages from.
`end`	Long	Optional	Timetoken delimiting the `end` of time slice (exclusive) to delete messages from.
`async`	`Consumer<Result>`	Yes	`Consumer` of a `Result` of type `PNDeleteMessagesResult`.

Basic Usage

pubnub.deleteMessages()
    .channels(Arrays.asList("channel_1", "channel_2"))
    .start(1460693607379L)
    .end(1460893617271L)
    .async(result -> { /* check result */ });

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.

pubnub.deleteMessages()
    .channels(Arrays.asList("channel_1"))
    .start(15526611838554309L)
    .end(15526611838554310L)
    .async(result -> { /* check result */ });

Message Counts

Requires Message Persistence

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

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 Java SDK:

this.pubnub.messageCounts()
    .channels(Array)
    .channelsTimetoken(Array)

Parameter	Type	Required	Description
`channels`	Array	Yes	The `channels` to fetch the message count
`channelsTimetoken`	Array	Yes	List 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.
`async`	`Consumer<Result>`	Yes	`Consumer` of a `Result` of type `PNMessageCountResult`.

Basic Usage

Long lastHourTimetoken = (Calendar.getInstance().getTimeInMillis() - TimeUnit.HOURS.toMillis(1)) * 10000L;

pubnub.messageCounts()
    .channels(Arrays.asList("news"))
    .channelsTimetoken(Arrays.asList(lastHourTimetoken))
    .async(result -> {
        result.onSuccess(res -> {
            for (Map.Entry<String, Long> messageCountEntry : res.getChannels().entrySet()) {
                messageCountEntry.getKey(); // the channel name
                messageCountEntry.getValue(); // number of messages for that channel
            }
        }).onFailure(exception -> {
            exception.printStackTrace();
        });
    });

Returns

The operation returns a PNMessageCountResult which contains the following operations

Method	Type	Description
`getChannels()`	Map`<String, Long>`	A map with values of `Long` for each channel. `Channels` without messages have a count of 0. `Channels` with 10,000 messages or more have a count of 10000.

Other Examples

Retrieve count of messages using different timetokens for each channel

Long lastHourTimetoken = (Calendar.getInstance().getTimeInMillis() - TimeUnit.HOURS.toMillis(1)) * 10000L;
Long lastDayTimetoken = (Calendar.getInstance().getTimeInMillis() - TimeUnit.DAYS.toMillis(1)) * 10000L;

pubnub.messageCounts()
    .channels(Arrays.asList("news", "info"))
    .channelsTimetoken(Arrays.asList(lastHourTimetoken, lastDayTimetoken))
    .async(result -> {
        result.onSuccess(res -> {
            for (Map.Entry<String, Long> messageCountEntry : res.getChannels().entrySet()) {
                messageCountEntry.getKey(); // the channel name
                messageCountEntry.getValue(); // number of messages for that channel
            }
        }).onFailure(exception -> {
            exception.printStackTrace();
        });
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History (deprecated)

Requires Message Persistence

This method requires that Message Persistence 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.

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 Java SDK:

this.pubnub.history()
    .channel(String)
    .reverse(Boolean)
    .includeTimetoken(Boolean)
    .includeMeta(Boolean)
    .start(Long)
    .end(Long)
    .count(Integer);

Parameter	Type	Required	Default	Description
`channel`	String	Yes		Specifies `channel`to return history messages from.
`reverse`	Boolean	Optional	`false`	Setting to `true` traverses the time line in reverse, starting with the oldest message first.
`includeTimetoken`	Boolean	Optional	`false`	Whether event dates `timetokens` should be included in response or not.
`includeMeta`	Boolean	Optional	`false`	Whether to include message metadata within response or not.
`start`	Long	Optional		Timetoken delimiting the `start` of time slice (exclusive) to pull messages from.
`end`	Long	Optional		Timetoken delimiting the `end` of time slice (inclusive) to pull messages from.
`count`	Int	Optional	`100`	Specifies the number of historical messages to return.
`async`	`Consumer<Result>`	Yes		`Consumer` of a `Result` of type `PNHistoryResult`.

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.

Basic Usage

Retrieve the last 100 messages on a channel:

pubnub.history()
    .channel("history_channel") // where to fetch history from
    .count(100) // how many items to fetch
    .async(result -> { /* check result */ });

Returns

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

Method	Type	Description
`getMessages()`	List`<PNHistoryItemResult>`	List of messages of type `PNHistoryItemResult`. See PNHistoryItemResult for more details.
`getStartTimetoken()`	Long	Start `timetoken`.
`getEndTimetoken()`	Long	End `timetoken`.

PNHistoryItemResult

Method	Type	Description
`getTimetoken()`	Long	`Timetoken` of the message.
`getEntry()`	JsonElement	Message.

Other Examples

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

pubnub.history()
    .channel("my_channel") // where to fetch history from
    .count(3) // how many items to fetch
    .reverse(true) // should go in reverse?
    .async(result -> { /* check result */ });

Response

result.onSuccess(res -> {
    for (PNHistoryItemResult pnHistoryItemResult: res.getMessages()) {
        pnHistoryItemResult.getEntry(); // 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)

pubnub.history()
    .channel("my_channel") // where to fetch history from
    .start(13847168620721752L) // first timestamp
    .reverse(true) // should go in reverse?
    .async(result -> { /* check result */ });

Response

result.onSuccess(res -> {
    for (PNHistoryItemResult pnHistoryItemResult: res.getMessages()) {
        pnHistoryItemResult.getEntry(); // 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)

pubnub.history()
    .channel("my_channel") // where to fetch history from
    .count(100) // how many items to fetch
    .start(-1) // first timestamp
    .end(13847168819178600L) // last timestamp
    .reverse(true) // should go in reverse?
    .async(result -> { /* check result */ });

Response

[
    ["Pub3","Pub4","Pub5"],
    13406746780720711,
    13406746845892666
]

History Paging Example

Usage

You can call the method by passing 0 or a valid timetoken as the argument.

package com.pubnub.api;

import com.pubnub.api.java.v2.PNConfiguration;
import com.pubnub.api.java.PubNub;
import com.pubnub.api.java.callbacks.PNCallback;
import com.pubnub.api.models.consumer.PNStatus;
import com.pubnub.api.models.consumer.history.PNHistoryItemResult;
import com.pubnub.api.models.consumer.history.PNHistoryResult;

public class PubNubRecursiveHistoryFetcher {

    private PubNub pubnub;

    private static abstract class CallbackSkeleton {
        public abstract void handleResponse(PNHistoryResult result);
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Include timetoken in history response

pubnub.history()
    .channel("history_channel") // where to fetch history from
    .count(100) // how many items to fetch
    .includeTimetoken(true) // include timetoken with each entry
    .async(result -> { /* check result */ });

Breaking changes in v9.0.0

Fetch History​

Requires Message Persistence

Method(s)​

Truncated response

Basic Usage​

Returns​

Other Examples​

Paging History Responses​

Delete Messages from History​

Requires Message Persistence

Required setting

Method(s)​

Basic Usage​

Other Examples​

Delete specific message from history​

Message Counts​

Requires Message Persistence

Unlimited message retention

Method(s)​

Basic Usage​

Returns​

Other Examples​

Retrieve count of messages using different timetokens for each channel​

History (deprecated)​

Requires Message Persistence

Alternative method

Start & End parameter usage clarity

Method(s)​

tip

Basic Usage​

Returns​

PNHistoryItemResult​

Other Examples​

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

Response​

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)​

Response​

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)​

Response​

History Paging Example​

Usage

Include timetoken in history response​

Fetch History

Method(s)

Basic Usage

Returns

Other Examples

Paging History Responses

Delete Messages from History

Method(s)

Basic Usage

Other Examples

Delete specific message from history

Message Counts

Method(s)

Basic Usage

Returns

Other Examples

Retrieve count of messages using different timetokens for each channel

History (deprecated)

Method(s)

Basic Usage

Returns

PNHistoryItemResult

Other Examples

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

Response

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)

Response

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)

Response

History Paging Example

Include timetoken in history response