Tutorial: RSS Module

index.js

var request = require('request'),
    FeedParser = require('feedparser'),
    _ = require('lodash');
module.exports = {
    run: function(step, dexter) {
        var url = step.input('url').first(),
            filter = step.input('filter').first(),
            self = this;
        if(!url) {
            this.log('No url provided, returing to App');
            //It's not really a critical failure to not have an url to work with, so we'll roll on.
            return this.complete();
        }
        //We've got an url, so let's use it
        this.fetchUrl(url, function(err, stream) {
            if(err) {
                //It IS a big deal if the url we're trying to contact isn't workable, so we'll fail here.
                return self.fail(err);
            }
            //Let the parser grab the data
            self.fetchItems(stream, function(err, items) {
                var response = [];
                if(err) {
                    return self.fail(err);
                }
                //Extract dexter-friendly data from the items
                _.each(items, function(item) {
                    response.push({
                        url: item.link,
                        title: item.title,
                        summary: item.summary,
                        author: item.author
                    });
                });
                if(filter) {
                    response = self.filterItems(response, filter);
                }
                return self.complete(response);
            });
        });
    },
    fetchUrl: function(url, callback) {
        var req = request(url);
        req.on('error', callback);
        req.on('response', function(resp) {
            if(resp.statusCode != 200) {
                return callback(new Error('Bad status code ' + resp.statusCode + ' for ' + url));
            }
            return callback(null, this);
        });
    }, 
    fetchItems: function(stream, callback) {
        var parser = new FeedParser()
            , items = [];
        parser.on('error', callback);
        parser.on('end', function(err) {
            if(err) {
                return callback(err);
            }
            return callback(null, items);
        });
        parser.on('readable', function() {
            var item;
            while((item = this.read())) {
                items.push(item);
            }
        });
        stream.pipe(parser);
    },
    filterItems: function(items, term) {
        var response = []
            , lcTerm = term.toLowerCase();
        _.each(items, function(item) {
            _.forIn(item, function(val) {
                if(val.toLowerCase().indexOf(lcTerm) >= 0) {
                    response.push(item);
                    return false;
                }
            });
        });
        return response;
    }
};

meta.json

{
    "inputs": [
        {
            "id": "url",
            "title":"Feed URL"
        }, {
            "id": "filter",
            "title": "Search term"
        }
    ],
    "outputs": [
        {
            "id": "url",
            "title":"Article URL"
        }, {
            "id": "title",
            "title":"Article title"
        }, {
            "id": "summary",
            "title":"Article summary"
        }, {
            "id": "author",
            "title":"Author"
        }
    ],
    "title": "Dexter Docs: RSS Filter"
}

package.json

{
  "name": "dexterdocs-rss-filter",
  "version": "0.0.1",
  "description": "",
  "main": "index.js",
  "author": "RunDexter Documentation",
  "license": "MIT",
  "private": true,
  "dependencies": {
    "feedparser": "^1.1.3",
    "lodash": "^3.9.3",
    "request": "^2.61.0"
  }
}