CODEWITHSUNDEEP
javawebhooksslack
user5872256
user5872256

Reputation: 69

How to get the channel list from Slack API?

I'm using Slack's API with Java. I have already discovered how to create a simple code to send messages using incoming Webhooks, but now I am interested in receiving a list of the available channels in the getChannels function.

The problem is that I do not find examples in Java about this.

Now, my code is:

package slack;

import com.github.seratch.jslack.Slack;
import java.io.IOException;

import com.github.seratch.jslack.api.methods.SlackApiException;
import com.github.seratch.jslack.api.webhook.*;

public class SlackManager {

    private String token_="{myToken}";
    private Slack slack_ = Slack.getInstance();
    private String url_="{url}";

    public void sendMessage(String text, String channel, String name) throws IOException, SlackApiException {
        Payload payload = Payload.builder()
            .channel("#"+channel)
            .username(name)
            .iconEmoji(":smile_cat:")
            .text(text)
            .build();

        WebhookResponse response = slack_.send(url_, payload);
        System.out.println(response.getMessage().toString());
    }

    public void getChannels(){
        //I don't know how to get the channel list!!!
    }
}

I'm try this:

public void getChannels() throws IOException, SlackApiException{

    List<String> channels = slack_.methods().channelsList(ChannelsListRequest.builder().token(token_).build())
            .getChannels().stream()
            .map(c -> c.getId()).collect(Collectors.toList());

    for (String string : channels) {
        System.out.println(string);
    }
}

but the result was a 'javaNullPointException'. Must the token be String?

Upvotes: 3

Views: 1178

Answers (1)

Adil B
Adil B

Reputation: 16778

Slack's incoming webhooks won't be able to provide this functionality - you'll need to use Slack's Web API to get what you need.

Using the Web API, try following this example from the jslack library you're using:

List<String> channels = slack.methods().channelsList(ChannelsListRequest.builder().token(token).build())
        .getChannels().stream()     
        .map(c -> c.getId()).collect(toList());

Upvotes: 1

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