Message Persistence API for Python-Asyncio 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)

History

Requires Message Persistence

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

This function fetches historical messages of a channel.

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

Search from the newest end of the timeline (default: reverse = False).
Search 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 timeline by providing both a start and end timetoken.
Limit the number of messages using the count parameter.

Start & End parameter usage clarity

If you specify only start (without end), you receive messages older than and up to that start timetoken. If you specify only end (without start), you receive messages that match that end timetoken and newer. If you specify both start and end, you receive messages between those timetokens (inclusive of end). You still receive up to 100 messages even if more match. Make iterative calls to history, adjusting start, to page through the full result set.

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	Specifies `channel` to return history messages from.
`include_meta` Type: Boolean	Specifies whether or not the message's meta information should be returned.
`reverse` Type: Boolean	Whether to traverse the timeline in reverse starting with the oldest message first.
`include_timetoken` Type: Boolean	Whether event dates timetokens should be included in the response.
`start` Type: Int	Timetoken delimiting the start of time slice (exclusive) to pull messages from.
`end` Type: Int	Timetoken delimiting the end of time slice (inclusive) to pull messages from.
`count` Type: Int	Number of historical messages to return.

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

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 properties:

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

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 Python-asyncio SDK.

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

* required

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

Sample code

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)​

Using the reverse parameter

Sample code​

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)​

Sample code​

Other examples​

Delete specific message from history​

History

Method(s)

Sample 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

Include timetoken in history response

Delete messages from history

Method(s)

Sample code

Other examples

Delete specific message from history