Message Persistence API for Python-Asyncio SDK

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)

History

Requires Message Persistence

This method requires that Message Persistence is enabled for your key in the Admin Portal.

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 Python-asyncio SDK:

pubnub.history() \
    .channel(String) \
    .include_meta(True) \
    .reverse(Boolean) \
    .include_timetoken(Boolean) \
    .start(Int) \
    .end(Int) \
    .count(Int)

* required

Parameter	Description
`channel` * Type: String Default: n/a	Specifies `channel` to return history messages from.
`include_meta` Type: Boolean Default: `False`	Specifies whether or not the message's meta information should be returned.
`reverse` Type: Boolean Default: `False`	Setting to `True` will traverse the time line in reverse starting with the oldest message first.
`include_timetoken` Type: Boolean Default: `False`	Whether event dates timetokens should be included in response or not.
`start` Type: Int Default: n/a	Timetoken delimiting the start of time slice (exclusive) to pull messages from.
`end` Type: Int Default: n/a	Timetoken delimiting the end of time slice (inclusive) to pull messages from.
`count` Type: Int Default: n/a	Specifies the number of historical messages to return.

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

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 100 messages on a channel:

import asyncio
import os
from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub_asyncio import PubNubAsyncio
from pubnub.exceptions import PubNubException


async def get_history(pubnub: PubNubAsyncio):
    try:
        # Retrieve the last 100 messages on a channel
        envelope = await pubnub.history() \
            .channel('history_channel') \
            .count(100) \
            .future()

show all 42 lines

Returns

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

Method	Description
`messages` Type: List	List of messages of type `PNHistoryItemResult`. See PNHistoryItemResult for more details.
`start_timetoken` Type: Int	Start `timetoken`.
`end_timetoken` Type: Int	End `timetoken`.

PNHistoryItemResult

Method	Description
`timetoken` Type: Int	`Timetoken` of the message.
`entry` Type: Object	Message.

Other Examples

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

envelope = await pubnub.history() \
    .channel("my_channel") \
    .count(3) \
    .reverse(True) \
    .future()

Response

{
    end_timetoken: 13406746729185766,
    start_timetoken: 13406746780720711,
    messages: [{
        crypto: None,
        entry: 'Pub1',
        timetoken: None
    },{
        crypto: None,
        entry: 'Pub2',
        timetoken: None
    },{
        crypto: None,
        entry: 'Pub2',
        timetoken: None
show all 17 lines

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)

envelope = await pubnub.history()\
    .channel("my_channel")\
    .start(13847168620721752)\
    .reverse(true)\
    .future()

Response

{
    end_timetoken: 13406746729185766,
    start_timetoken: 13406746780720711,
    messages: [{
        crypto: None,
        entry: 'Pub4',
        timetoken: None
    },{
        crypto: None,
        entry: 'Pub5',
        timetoken: None
    },{
        crypto: None,
        entry: 'Pub6',
        timetoken: None
show all 17 lines

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)

envelope = await pubnub.history()\
    .channel("my_channel")\
    .count(100)\
    .start(-1)\
    .end(13847168819178600)\
    .reverse(True)\
    .future()

Response

{
    end_timetoken: 13406746729185766,
    start_timetoken: 13406746780720711,
    messages: [{
        crypto: None,
        entry: 'Pub4',
        timetoken: None
    },{
        crypto: None,
        entry: 'Pub5',
        timetoken: None
    },{
        crypto: None,
        entry: 'Pub6',
        timetoken: None
show all 17 lines

History Paging Example

Usage

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

async def get_all_messages(start_tt):
    envelope = await pubnub.history()\
        .channel('history_channel')\
        .count(100)\
        .start(start_tt)\
        .future()

    msgs = envelope.result.messages
    start = envelope.result.start_timetoken
    end = envelope.result.end_timetoken
    count = len(msgs)

    if count > 0:
        print("%d" % count)
        print("start %d" % start)
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Include timetoken in history response

envelope = await pubnub.history()\
    .channel("my_channel")\
    .count(100)\
    .include_tometoken()
    .future()

Delete Messages from History

Requires Message Persistence

This method requires that Message Persistence is enabled for your key in the Admin Portal.

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 Python-asyncio SDK.

pubnub.delete_messages() \
    .channel(String) \
    .start(Int) \
    .end(Int) \
    .future()

* required

Parameter	Description
`channel` * Type: String Default: n/a	Specifies `channels` to delete messages from.
`start` Type: Int Default: n/a	Timetoken delimiting the `start` of time slice (inclusive) to delete messages from.
`end` Type: Int Default: n/a	Timetoken delimiting the `end` of time slice (exclusive) to delete messages from.

Basic Usage

envelope = yield from pubnub.delete_messages()\
    .channel("my-ch")\
    .start(123)\
    .end(456)
    .future()

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 exmaple, if 15526611838554310 is the publish timetoken, pass 15526611838554309 in Start and 15526611838554310 in End parameters respectively as shown in the following code snippet.

envelope = yield from pubnub.delete_messages()\
    .channel("my-ch")\
    .start(15526611838554309)\
    .end(15526611838554310)
    .future()

History​

Requires Message Persistence

Start & End parameter usage clarity

Method(s)​

tip

Basic Usage​

Reference code

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​

Delete Messages from History​

Requires Message Persistence

Required setting

Method(s)​

Basic Usage​

Other Examples​

Delete specific message from history​

History

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

Delete Messages from History

Method(s)

Basic Usage

Other Examples

Delete specific message from history