AWS Lambda Twitter Search Bot... uses S3 for persistence and SNS to send out messages.

aws-twitter-search-bot.js

var querystring = require('querystring');
var https = require('https');
var aws = require('aws-sdk');

var s3 = new aws.S3();
var sns = new aws.SNS({
    region: 'us-east-1'
}); 

var query = '#SEARCH TERM HERE';

var twitter_consumer_key = 'CONSUMER_KEY_HERE';
var twitter_consumer_secret = 'CONSUMER_SECRET_HERE';

var s3_bucket = 'S3_BUCKET_HERE';
var s3_key = 'FOLDER_NAME/tweet-ids.json';
 
var ids = [];
var access_token = access_token || '';

exports.handler = function(event, context) {
    checkTweets(context);
};

function checkTweets(context) {

    console.log('Starting process...');

    getIds(function() {

        getAuth(function(){

            getTweets(function(tweets){

                processTweets(tweets, function(){

                    console.log('Process complete. \n');
                    context.succeed('Process complete');

                });

            });

        });

    });

}


function getIds(fn) {

    console.log('Getting Ids');

    s3.getObject({
        Bucket: s3_bucket,
        Key: s3_key
    }, function(err, data) {
        if (err) {
            console.log(err);
        } else {
            ids = JSON.parse(data.Body.toString());
        }
        fn();
    });

}

function saveIds(fn) {

    console.log('Saving Ids');

    var body = new Buffer(JSON.stringify(ids));
    s3.putObject({
        Bucket: s3_bucket,
        Key: s3_key,
        Body: body
    }, function(err, data) {
        if (err) {
            console.log(err);
        } else {
            console.log('Saved new data', data);
        }
        fn();
    });
}

function sendMessage(message) {

    console.log('Sending message', new Date(), message);

    var params = {
        Subject: 'New Twitter Message for ' + query,
        Message: '\n\n' + message + '\n\n\n\n\n\n\n',
        TopicArn: 'arn:aws:sns:us-east-1:665844865211:TwitterSearchBotNotifications'
    };

    sns.publish(params, function(err, data) {
        if (err) {
            console.log('sns error', err)
        } else {
            console.log('Message sent', data)
        }
    });

}


function getAuth(fn) {

    if(access_token){
        fn();
        return;
    }

    console.log('Getting auth_token');

    var b64Credentials = new Buffer(twitter_consumer_key + ':' + twitter_consumer_secret).toString('base64');

    var post_data = 'grant_type=client_credentials';

    var options = {
        host: 'api.twitter.com',
        port: '443',
        path: '/oauth2/token',
        method: 'POST',
        headers: {
            'Authorization': 'Basic ' + b64Credentials,
            'Content-Type': 'application/x-www-form-urlencoded;charset=UTF-8',
            'Content-Length': Buffer.byteLength(post_data)
        },
    };

    var req = https.request(options, function(res) {
        var str = '';
        res.on('data', function(body) {
            str += body;
        });
        res.on('end', function() {
            var res_data = JSON.parse(str);
            access_token = res_data.access_token;
            fn();
        });
    });

    req.write(post_data);
    req.end();

}

function getTweets(fn) {

    console.log('Getting tweets');

    var options = {
        host: 'api.twitter.com',
        port: '443',
        path: '/1.1/search/tweets.json?result-type=recent&q=' + encodeURIComponent(query),
        method: 'GET',
        headers: {
            Authorization: 'Bearer ' + access_token
        }
    };

    var req = https.request(options, function(res) {
        var str = '';
        res.on('data', function(body) {
            str += body;
        });
        res.on('end', function() {
            var res_data = JSON.parse(str);
            fn(res_data);
        });
    });

    req.end();
}

function processTweets(tweets, fn) {

    console.log('Processing tweets');

    var save = false;

    var items = tweets.statuses;
    for (var x = 0; x < items.length; x++) {
        var id = items[x].id_str;
        if (ids.indexOf(id) == -1 && !items[x].retweeted_status) {
            var message = 'https://twitter.com/' + items[x].user.screen_name + '/status/' + id + '\n\n';
            message += '@' + items[x].user.screen_name + ' ' + items[x].text;
            if(items[x].entities.media){
                sendMessage(message);
            }
            ids.push(id);
            save = true;
        }
    }

    if (save) {
        saveIds(fn);
    } else {
        fn();
    }

}