Message Persistence API for Python 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)

Request execution and return values

You can decide whether to perform the Python SDK operations synchronously or asynchronously.

• .sync() returns an Envelope object, which has two fields: Envelope.result, whose type differs for each API, and Envelope.status of type PnStatus.

  pubnub.publish() \
      .channel("myChannel") \
      .message("Hello from PubNub Python SDK") \
      .sync()

• .pn_async(callback) returns None and passes the values of Envelope.result and Envelope.status to a callback you must define beforehand.

  def my_callback_function(result, status):
      print(f'TT: {result.timetoken}, status: {status.category.name}')
  
  pubnub.publish() \
      .channel("myChannel") \
      .message("Hello from PubNub Python SDK") \
      .pn_async(my_callback_function)

Fetch History

Requires Message Persistence

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

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 Python SDK:

pubnub.fetch_messages() \
    .channels(List) \
    .maximum_per_channel(Integer) \
    .start(Integer) \
    .end(Integer) \
    .include_message_actions(Boolean) \
    .include_meta(Boolean)
    .include_message_type(Boolean) \
    .include_custom_message_type(Boolean) \
    .include_uuid(Boolean) \

* required

Parameter	Description
channels * Type: List<string> Default: n/a	Specifies the channels for which to return history. Maximum of 500 channels are allowed.
maximum_per_channel Type: Integer Default: 25 or 100	Specifies the number of historical messages to return. If include_message_actions is True, method is limited to single channel and 25 is the default (and maximum) value; otherwise, default and maximum is 100 for a single channel, or 25 for multiple channels.
start Type: Integer Default: n/a	Timetoken delimiting the exclusive start of the time slice from which to pull messages.
end Type: Integer Default: n/a	Timetoken delimiting the inclusive end of the time slice from which to pull messages.
include_message_actions Type: Boolean Default: False	Set to True to retrieve history messages with their associated message reactions. If you include message reactions, the fetch_messages() method is limited to one channel only.
include_meta Type: Boolean Default: False	Whether to include message metadata within response or not.
include_message_type Type: Boolean Default: n/a	Indicates whether to retrieve messages with PubNub message type. For more information, refer to Retrieving Messages.
include_custom_message_type Type: Boolean Default: n/a	Indicates whether to retrieve messages with the custom message type. For more information, refer to Retrieving Messages.
include_uuid Type: Boolean Default: n/a	Whether to include UUID of the sender

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 message on a channel:

Builder Pattern

import os
from pubnub.pnconfiguration import PNConfiguration
from pubnub.pubnub import PubNub


def my_fetch_messages_callback(envelope, status):
    if status.is_error():
        print(f"Something went wrong. Error: {status.error_data}")
        return

    print("Fetch Messages Result:\n")
    for message in envelope.channels["my_channel"]:
        print("Message: %s" % message.message)
        print("Meta: %s" % message.meta)
        print("Timetoken: %s" % message.timetoken)

show all 48 lines

Named Arguments

message_envelope = pubnub.fetch_messages(channels=["my_channel"], maximum_per_channel=1, include_message_actions=True,
    include_meta=True, include_message_type=True, include_custom_message_type=True, include_uuid=True).sync()

if message_envelope.status.is_error():
    print(f"Something went wrong. Error: {status.error_data}")
else:
        print("Fetch Messages Result:\n")
    for message in message_envelope.result.channels["my_channel"]:
        print(f"Message: {message.message}")
        print(f"Meta: {message.meta}")
        print(f"Timetoken: {message.timetoken}")

        for action_type in message.actions:
            print(f"Message Reaction type: {action_type}")
            for action_value in message.actions[action_type]:

show all 20 lines

Returns

The fetch_messages() operation returns an Envelope which contains the following fields:

Field	Type	Description
result	PNFetchMessagesResult	A detailed object containing the result of the operation.
status	PNStatus	A status object with additional information.

PNFetchMessagesResult

Method	Description
channels Type: Dictionary	Dictionary of PNFetchMessageItem
start_timetoken Type: Int	Start timetoken
end_timetoken Type: Int	End timetoken

PNFetchMessageItem

Method	Description
message Type: String	The message
meta Type: Any	Meta value
message_type Type: Any	Type of the message
custom_message_type Type: Any	Custom type of the message
uuid Type: String	UUID of the sender
timetoken Type: Int	Timetoken of the message
actions Type: List	A 3-dimensional List of message reactions, grouped by action type and value

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 SDK.

pubnub.delete_messages() \
    .channel(String) \
    .start(Integer) \
    .end(Integer) \
    .sync()

* required

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

Basic Usage

Builder Pattern

envelope = PubNub(pnconf).delete_messages() \
    .channel("my-ch") \
    .start(123) \
    .end(456) \
    .sync()

Named Arguments

envelope = pubnub.delete_messages(channels=["my_channel"], start=123, end=456).sync()

Returns

The delete_messages() operation doesn't have a return value.

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.

Builder Pattern

envelope = PubNub(pnconf).delete_messages() \
    .channel("my-ch") \
    .start(15526611838554309) \
    .end(15526611838554310) \
    .sync()

Named Arguments

envelope = pubnub.delete_messages(channels="my-ch", start=15526611838554309, end=15526611838554310).sync()

Message Counts

Requires Message Persistence

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

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 the passed value in the channel_timetokens parameter.

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 Python SDK:

pn.message_counts() \
    .channel(String) \
    .channel_timetokens(List)

* required

Parameter	Description
channel * Type: String Default: n/a	The channels to fetch the message count. Single channel or multiple channels, separated by comma are accepted.
channel_timetokens * Type: List Default: null	A list of timetokens ordered the same way as channels. Timetokens can be str or int type.

Basic Usage

Builder Pattern

envelope = pn.message_counts() \
    .channel('unique_1') \
    .channel_timetokens([15510391957007182]) \
    .sync() \
print(envelope.result.channels['unique_1'])

Named Arguments

envelope = pubnub.message_counts(channels="my-ch", channel_timetokens=[15510391957007182]).sync()

Returns

The message_counts() operation returns an Envelope which contains the following fields:

Field	Type	Description
result	PNMessageCountResult	A detailed object containing the result of the operation.
status	PNStatus	A status object with additional information.

PNMessageCountResult

Field	Type	Description
channels	Dictionary	A dictionary with the number of missed messages for each channel.

Other Examples

Retrieve count of messages using different timetokens for each channel

Builder Pattern

envelope = pn.message_counts() \
    .channel('unique_1,unique_100') \
    .channel_timetokens([15510391957007182, 15510391957007184]) \
    .sync()
print(envelope.result.channels)

Named Arguments

envelope = pubnub.message_counts(channels="unique_1,unique_100",
    channel_timetokens=[15510391957007182, 15510391957007184]).sync()

History (deprecated)

Requires Message Persistence

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

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 Python SDK:

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

* 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: Integer Default: n/a	Timetoken delimiting the start of time slice (exclusive) to pull messages from.
end Type: Integer Default: n/a	Timetoken delimiting the end of time slice (inclusive) to pull messages from.
count Type: Integer 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

Retrieve the last 100 messages on a channel:

envelope = pubnub.history() \
    .channel("history_channel") \
    .count(100) \
    .sync()

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: Integer	Start timetoken.
end_timetoken Type: Integer	End timetoken.

PNHistoryItemResult

Method	Description
timetoken Type: Integer	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 = pubnub.history() \
    .channel("my_channel") \
    .count(3) \
    .reverse(True) \
    .sync()

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

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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")\
    .start(13847168620721752)\
    .reverse(True)\
    .sync()

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)

pubnub.history()\
    .channel("my_channel")\
    .count(100)\
    .start(-1)\
    .end(13847168819178600)\
    .reverse(True)\
    .sync()

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.

def get_all_messages(start_tt):
    def history_callback(result, status):
        msgs = result.messages
        start = result.start_timetoken
        end = result.end_timetoken
        count = len(msgs)

        if count > 0:
            print("%d" % count)
            print("start %d" % start)
            print("end %d" % end)

        if count == 100:
            get_all_messages(start)

show all 22 lines

Include timetoken in history response

pubnub.history()\
    .channel("my_channel")\
    .count(100)\
    .include_timetoken()
    .sync()