ai.nitro.bot4j.integration.slack.receive.webhook.impl.SlackEventWebhookImpl.java Source code

Introduction

Here is the source code for ai.nitro.bot4j.integration.slack.receive.webhook.impl.SlackEventWebhookImpl.java

Source

/*
 * Copyright (C) 2016, nitro.ai
 * All rights reserved.
 *
 * This software may be modified and distributed under the terms
 * of the BSD 3-clause license. See the LICENSE file for details.
 */

package ai.nitro.bot4j.integration.slack.receive.webhook.impl;

import java.io.IOException;

import javax.inject.Inject;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import com.google.common.io.CharStreams;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

import ai.nitro.bot4j.integration.slack.receive.SlackReceiveHandler;
import ai.nitro.bot4j.integration.slack.receive.webhook.SlackEventWebhook;

public class SlackEventWebhookImpl implements SlackEventWebhook {

    private static final String BOT_ID = "bot_id";

    private static final String BOT_MESSAGE = "bot_message";

    private static final String CHALLENGE = "challenge";

    private static final String EVENT = "event";

    private static final String EVENT_CALLBACK = "event_callback";

    private final static Logger LOG = LogManager.getLogger(SlackEventWebhookImpl.class);

    private static final String MESSAGE = "message";

    private static final String SUBTYPE = "subtype";

    private static final String TYPE = "type";

    private static final String URL_VERIFICATION = "url_verification";

    @Inject
    protected SlackReceiveHandler slackReceiveHandler;

    protected void handleEvent(final JsonObject jsonReq, final HttpServletResponse res) {
        final JsonObject eventJsonObject = jsonReq.get(EVENT).getAsJsonObject();

        if (!eventJsonObject.has(TYPE)) {
            LOG.warn("no type in event JSON");
        } else if (!MESSAGE.equals(eventJsonObject.get(TYPE).getAsString())) {
            LOG.warn("no message in event JSON");
        } else if (eventJsonObject.has(BOT_ID)) {
            LOG.info("ignoring bot message");
        } else if (eventJsonObject.has(SUBTYPE) && BOT_MESSAGE.equals(eventJsonObject.get(SUBTYPE).getAsString())) {
            LOG.info("ignoring bot message");
        } else {
            slackReceiveHandler.handleEvent(eventJsonObject, (long) 0);
        }
    }

    protected void handleException(final Exception e) {
        LOG.error(e.getMessage(), e);
    }

    protected String handleUrlVerification(final JsonObject jsonReq, final HttpServletResponse res)
            throws IOException {
        res.setContentType("application/x-www-form-urlencoded");

        final JsonElement jsonElementChallenge = jsonReq.get(CHALLENGE);
        final String challenge = jsonElementChallenge.getAsString();

        LOG.info("Responding challenge {}", challenge);

        return challenge;
    }

    @Override
    public String post(final HttpServletRequest req, final HttpServletResponse res) {
        String result = "";

        try {
            final String body = CharStreams.toString(req.getReader());
            final JsonParser jsonParser = new JsonParser();
            final JsonObject jsonReq = jsonParser.parse(body).getAsJsonObject();

            if (!jsonReq.has(TYPE)) {
                LOG.warn("no type in JSON");
            } else {
                final JsonElement typeJsonElement = jsonReq.get(TYPE);
                final String type = typeJsonElement.getAsString();

                switch (type) {
                case URL_VERIFICATION:
                    result = handleUrlVerification(jsonReq, res);
                    break;
                case EVENT_CALLBACK:
                    handleEvent(jsonReq, res);
                    break;
                default:
                    LOG.info("unknown type {}", type);
                    break;
                }
            }
        } catch (final Exception e) {
            handleException(e);
        }

        return result;
    }
}