packages/slack/post.js

// Licensed to the Apache Software Foundation (ASF) under one or more contributor
// license agreements; and to You under the Apache License, Version 2.0.

var request = require('request');

/**
 * Action to post to slack
 *  @param {string} url - Slack webhook url
 *  @param {string} channel - (optional) Slack channel to post the message to
 *  @param {string} username - name to post the message as
 *  @param {string} text - message to post
 *  @param {string} icon_emoji - (optional) emoji to use as the icon for the message
 *  @param {boolean} as_user - (optional) when the token belongs to a bot, whether to post as the bot itself
 *  @param {object} attachments - (optional) message attachments (see Slack documentation for format)
 *  @return {object} Promise
 */
function main(params) {
    let errorMsg = checkParams(params);
    if (errorMsg) {
        return { error: errorMsg };
    }

    var body = {
        channel: params.channel,
        username: params.username || 'Simple Message Bot'
    };

    if (params.icon_emoji) {
        // guard against sending icon_emoji: undefined
        body.icon_emoji = params.icon_emoji;
    }

    if (params.as_user === true) {
        body.as_user = true;
    }

    if (params.text) {
        body.text = params.text;
    }

    if (params.attachments) {
        body.attachments = JSON.stringify(params.attachments);
    }

    if (params.token) {
        //
        // this allows us to support /api/chat.postMessage
        // e.g. users can pass params.url = https://slack.com/api/chat.postMessage
        //                 and params.token = <their auth token>
        //
        body.token = params.token;
    } else {
        //
        // the webhook api expects a nested payload
        //
        // notice that we need to stringify; this is due to limitations
        // of the formData npm: it does not handle nested objects
        //
        body = {
            payload: JSON.stringify(body)
        };
    }

    var promise = new Promise(function (resolve, reject) {
        request.post({
            url: params.url,
            formData: body
        }, function (err, res, body) {
            if (err) {
                console.log('error: ', err, body);
                reject(err);
            } else {
                console.log('success: ', params.text, 'successfully sent');
                resolve();
            }
        });
    });

    return promise;
}

/**
 *  Checks if all required params are set.
 */
function checkParams(params) {
    if (params.text === undefined && params.attachments === undefined) {
        return ('No text provided');
    }
    else if (params.url === undefined) {
        return 'No Webhook URL provided';
    }
    else {
        return undefined;
    }
}