Simple Slack API
This library allows an aplication 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.
Short example
Slack connection :
The connection is made through the SlackSessionFactory class :
Direct connection :
SlackSession session = SlackSessionFactory.
createWebSocketSlackSession("authenticationtoken");
session.connect();
Through a proxy :
SlackSession session = SlackSessionFactory.
createWebSocketSlackSession("authenticationtoken", Proxy.Type.HTTP, "myproxy", 1234);
session.connect();
Listening to messages :
Slack messages can be retrieved by attaching a SlackMessageListener to the session provided by the factory :
session.addMessagePostedListener(new SlackMessagePostedListener()
{
@Override
public void onEvent(SlackMessagePosted event, SlackSession session)
{
session.sendMessageOverWebSocket(session.findChannelByName("general"), "Message sent : " + event.getMessageContent(), null);
}
});
(Since v0.4.0, lambda friendly version)
session.addMessagePostedListener((e, s)
-> s.sendMessageOverWebSocket(s.findChannelByName("general"), "Message sent : " + e.getMessageContent(), null));
Message operation :
The SlackSession interface provides various methods to send/modify and delete messages on a given channel :
SlackMessageHandle sendMessage(SlackChannel channel, String message, SlackAttachment attachment);
SlackMessageHandle sendMessage(SlackChannel channel, String message, SlackAttachment attachment, SlackChatConfiguration chatConfiguration);
SlackMessageHandle updateMessage(String timeStamp, SlackChannel channel, String message);
SlackMessageHandle deleteMessage(String timeStamp, SlackChannel channel)
(Since v0.4.3, emoji reactions on channel messages)
The SlackSession interface provides a method to add an emoji reaction to a message on a given channel :
SlackMessageHandle addReactionToMessage(SlackChannel channel, String messageTimeStamp, String emojiCode);
Full example :
Here's a full example with an echoing bot using this library :
public class Example
{
public static void main(String[] args) throws Exception
{
final SlackSession session = SlackSessionFactory.
createWebSocketSlackSession("authenticationtoken", Proxy.Type.HTTP, "myproxy", 1234, true);
session.addMessagePostedListener(new SlackMessagePostedListener()
{
@Override
public void onEvent(SlackMessagePosted event, SlackSession session)
{
//let's send a message
SlackMessageHandle handle = session.sendMessage(session.getChannel(),
event.getMessageContent(), null);
try
{
Thread.sleep(2000);
} catch (InterruptedException e)
{
e.printStackTrace();
}
//2 secs later, let's update the message (I can only update my own messages)
session.updateMessage(handle.getSlackReply().getTimestamp(),session.getChannel(),
event.getMessageContent()+" UPDATED");
try
{
Thread.sleep(2000);
} catch (InterruptedException e)
{
e.printStackTrace();
}
//2 secs later, let's now delete the message (I can only delete my own messages)
session.deleteMessage(handle.getSlackReply().getTimestamp(),session.getChannel())
}
});
session.connect();
while (true)
{
Thread.sleep(1000);
}
}
}
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
- 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)
Thanks
Many thanks to everyone who has contributed to this library :
- Christian Sprecher
- Jan Vidar Krey
- David Seebacher
- Wouter Vernaillen
- Claudio Comandini
- Maxim Gurkin
- Ole Kozaczenko
- Georges Gomes
- François Valdy
- Harry Fox
(Let me know if I forgot someone, I'll fix that ASAP ;) )
License
This library is licensed under the Creative Commons CC0 1.0 Universal license with no warranty (expressed or implied) for any purpose.