channels.history

Fetches history of messages and events from a channel.

Facts

This method returns a portion of message events from the specified public channel.

To read the entire history for a channel, call the method with no latest or oldest arguments, and then continue paging using the instructions below.

To retrieve a single message, set latest to the message’s ts value, inclusive to true, and dial your count down to 1.

Arguments

Present arguments as parameters in application/x-www-form-urlencoded querystring or POST body. This method does not currently accept application/json.

Response

{
    "ok": true,
    "messages": [
        {
            "type": "message",
            "ts": "1358546515.000008",
            "user": "U2147483896",
            "text": "Hello"
        },
        {
            "type": "message",
            "ts": "1358546515.000007",
            "user": "U2147483896",
            "text": "World",
            "is_starred": true,
            "reactions": [
                {
                    "name": "space_invader",
                    "count": 3,
                    "users": [
                        "U1",
                        "U2",
                        "U3"
                    ]
                },
                {
                    "name": "sweet_potato",
                    "count": 5,
                    "users": [
                        "U1",
                        "U2",
                        "U3",
                        "U4",
                        "U5"
                    ]
                }
            ]
        },
        {
            "type": "something_else",
            "ts": "1358546515.000007"
        },
        {
            "text": "Containment unit is 98% full",
            "username": "ecto1138",
            "bot_id": "B19LU7CSY",
            "attachments": [
                {
                    "text": "Don't get too attached",
                    "id": 1,
                    "fallback": "This is an attachment fallback"
                }
            ],
            "type": "message",
            "subtype": "bot_message",
            "ts": "1503435956.000247"
        }
    ],
    "has_more": false
}

{
    "ok": true,
    "latest": "1512085950.000216",
    "messages": [
        {
            "type": "message",
            "user": "U012AB3CDE",
            "text": "I find you punny and would like to smell your nose letter",
            "ts": "1512085950.000216"
        }
    ],
    "has_more": false
}

{
    "ok": false,
    "error": "channel_not_found"
}

Navigating through collections of messages

The messages array contains up to 100 messages between latest and oldest. If there were more than 100 messages between those two points, then has_more will be true.

Provide timestamps in latest and oldest to specify the period in channel’s history you want to cover. If a message has the same timestamp as latest or oldest it will not be included in the list, unless inclusive is true. The inclusive parameter is ignored when latest or oldest is not specified.

If the response includes has_more then the client can make another call, using the ts value of the final messages as the latest param to get the next page of messages.

If there are more than 100 messages between the two timestamps then the messages returned are the ones closest to latest. In most cases an application will want the most recent messages and will page backward from there. If oldest is provided but not latest then the messages returned are those closest to oldest, allowing you to page forward through history if desired.

Retrieving a single message

channels.history can also be used to pluck a single message from the archive.

You'll need a message's ts value, uniquely identifying it within a channel. You'll also need that channel's ID.

Provide another message's ts value as the latest parameter. Specify true for the inclusive parameter and set the count to 1. If it exists, you'll receive the queried message in return.

GET /api/channels.history?token=TOKEN_WITH_CHANNELS_HISTORY_SCOPE&channel=C2EB2QT8A&latest=1476909142.000007&inclusive=true&count=1

Easily generate a permalink URL for any specific message using chat.getPermalink.

Message types

Messages of type "message" are user-entered text messages sent to the channel, while other types are events that happened within the channel. All messages have both a type and a sortable ts, but the other fields depend on the type. For a list of all possible events, see the channel messages documentation.

Messages that have been reacted to by team members will have a reactions array delightfully included.

If a message has been starred by the calling user, the is_starred property will be present and true. This property is only added for starred items, so is not present in the majority of messages.

The is_limited boolean property is only included for free teams that have reached the free message limit. If true, there are messages before the current result set, but they are beyond the message limit.

Errors

This table lists the expected errors that this method could return. However, other errors can be returned in the case where the service is down or other unexpected factors affect processing. Callers should always check the value of the ok params in the response.

Warnings

This table lists the expected warnings that this method will return. However, other warnings can be returned in the case where the service is experiencing unexpected trouble.