Message Persistence API for PubNub Python SDK

The message persistence service 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, 3, 5, 7, 15, or 30 days, and Forever.

You can retrieve the following:

  • Messages
  • Message actions
  • Files (using Files API)

Fetch History

Requires Message Persistence add-on

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

Description

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

Method(s)

To run Fetch History, you can use the following method(s) in the Python V4 SDK:

pubnub.fetch_messages()
.channels(List)
.maximum_per_channel(Int)
.start(Int)
.end(Int)
.include_message_actions(Boolean)
.include_meta(Boolean)
ParameterTypeRequiredDefaultDescription
channelsList<string>Yesn/aSpecifies the channels for which to return history. Maximum of 500 channels are allowed.
startIntNon/aTimetoken delimiting the exclusive start of the time slice from which to pull messages
endIntNon/aTimetoken delimiting the inclusive end of the time slice from which to pull messages
maximum_per_channelIntNo25 or 100Specifies the number of historical messages to return. If include_message_actions is True, 25 is the default (and maximum) value; otherwise, default and maximum is 100 for a single channel, or 25 for multiple channels.
include_message_actionsBooleanNoFalseSet to True to retrieve history messages with their associated message actions. If you include message actions, the fetch_messages() method is limited to one channel only.
include_metaBooleanNoFalseWhether to include message metadata within response or not
include_message_typeBooleanNon/aWhether to include message type
include_uuidBooleanNon/aWhether to include UUID of the sender

Basic Usage

Retrieve the last message on a channel:

def my_fetch_messages_callback(envelope, status):
if not status.is_error():
# Messages successfully retrieved from the specified channel.

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)

for action_type in message.actions:
print("\nMessage Action type: " + action_type)
for action_value in message.actions[action_type]:
print("Message Action value: %s" % action_value)
for action in message.actions[action_type][action_value]:
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Returns

The response is of the type PNFetchMessagesResult.

MethodTypeDescription
channelsDictDictionary of PNFetchMessageItem
start_timetokenIntStart timetoken
end_timetokenIntEnd timetoken

PNFetchMessageItem is defined as follows:

MethodTypeDescription
messageStringThe message
metaAnyMeta value
message_typeAnyType of the message
uuidStringUUID of the sender
timetokenIntTimetoken of the message
actionsListA 3-dimensional List of message actions, grouped by action type and value

Delete Messages from History

Requires Message Persistence add-on

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

Description

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 V4 SDK.

pubnub.delete_messages().channel(String).start(Int).end(Int).sync()
ParameterTypeRequiredDefaultDescription
channelStringYesSpecifies channels to delete messages from.
startIntOptionalTimetoken delimiting the start of time slice (inclusive) to delete messages from.
endIntOptionalTimetoken delimiting the end of time slice (exclusive) to delete messages from.

Basic Usage

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

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.

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

Message Counts

Requires Message Persistence add-on

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

Description

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 channel_timetokensparameter.

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 V4 SDK:

pn.message_counts().channel(String).channel_timetokens(List)
ParameterTypeRequiredDefaultDescription
channelStringYesThe channels to fetch the message count. Single channel or multiple channels, separated by comma are accepted.
channel_timetokensListYesnullA list of timetokens ordered the same way as channels. Timetokens can be str or int type.

Basic Usage

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

Other Examples

Retrieve count of messages using different timetokens for each channel

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

History (deprecated)

Requires Message Persistence add-on

This method requires that the Message Persistence add-on 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.

Description

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(Int).end(Int).count(Int)
ParameterTypeRequiredDefaultDescription
channelStringYesSpecifies channel to return history messages from.
include_metaBooleanNoFalseSpecifies whether or not the message's meta information should be returned.
reverseBooleanOptionalFalseSetting to True will traverse the time line in reverse starting with the oldest message first.
include_timetokenBooleanOptionalFalseWhether event dates timetokens should be included in response or not.
startIntOptionalTimetoken delimiting the start of time slice (exclusive) to pull messages from.
endIntOptionalTimetoken delimiting the end of time slice (inclusive) to pull messages from.
countIntOptionalSpecifies the 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.

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:

MethodTypeDescription
messagesListList of messages of type PNHistoryItemResult. See PNHistoryItemResult for more details.
start_timetokenIntStart timetoken.
end_timetokenIntEnd timetoken.

PNHistoryItemResult

MethodTypeDescription
timetokenIntTimetoken of the message.
entryObjectMessage.

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
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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
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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)

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Include timetoken in history response

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