Simple Slack API

This library allows an application to connect to Slack to receive and send messages from any channel as if it were a slack client.

The main purpose of this library is to build Slack bots able to react to channel events without having to configure any web hook.

With this library you should be able to connect to Slack and to send some messages in less than 20 lines (no one-liners).

Maven/Gradle

You can add this library as a dependency to your Maven or Gradle project through JitPack.

Released versions are also availables on the maven central repository :

group id: com.ullink.slack
artifact id: simpleslackapi

How to use it ?

You can find some samples of the most common use cases in the samples folder.

Sample code

SlackSession session = SlackSessionFactory.createWebSocketSlackSession("slack-bot-auth-token");
session.connect();
SlackChannel channel = session.findChannelByName("general"); //make sure bot is a member of the channel.
session.sendMessage(channel, "hi im a bot" );

Features

Supported Slack commands

All these commands can be sent through the library provided your bot has the rights to (IE : the bot has to be a member of the group or the channel to post some messages on it)

Post a message on a channel / private group / user
Post a typing indicator on a channel
Update a message
Delete a message
Join a channel
Leave a channel / a private group
Invite to a channel / a private group
Archive a channel
Open a direct message channel (since v0.5.0)
Open a multiparty direct message channel (since v0.5.0)
Get the presence status of a user
Add a reaction emoji to a message
Fetch the channel history (since v0.5.0) (needs full user credentials)
Invite a user to Slack (since v0.5.0)

On top of these built-in features, it is now possible to send not yet implemented API calls by using the postGenericSlackCommand method :

postGenericSlackCommand(Map<String, String> params, String command);

Supported Slack events

All these events can be listen provided your bot has the rights to (IE : the bot has to be a member of the group or a channel to gets the message events related to it)

message posted event
message deleted event
message updated event
channel created event
channel / private group deleted event
channel / private group archived event
channel / private group unarchived event
channel / private group renamed event
channel / private group joined event
reaction added to message event (since v0.5.0)
reaction removed from message event (since v0.5.0)
team joined event

Attention

From version 1.4.0 upward, channel members are not loaded in memory anymore in order for the api to start up faster. This should have no impact on the current behavior.