news.js

const moment = require("moment");
const config = require("config");
const NewsAPI = require("newsapi");
const axios = require('axios');
const api_key = process.env.NEWS_API_KEY || config.get("news_api_key");
const newsapi = new NewsAPI(api_key);
const mongoose = require('mongoose');

mongoose.connect(process.env.MONGODB_URI || config.get("mongoDB"), {
  useNewUrlParser: true
});

const db = mongoose.connection;

db.on('connected', () => {console.log('mongo db successfully connected');});
db.on("disconnected", () => {console.log('mongo db successfully disconnected');});
db.on("error", () => {console.log('Error connecting to mongo db');});

// Use mongoose to save data to local database there by allowing an API
// that retrieves data from previous days

let fetch_date = null;
const searchNews = async term => {
    let results = {status:false,payload:[],error:{}};            
    let today = moment().format("YYYY-MM-DD");    
    // checking if results is already saved in redis if yes then use the results
    await newsapi.v2.everything({
        q: term,        
        from: today,    
        language: "en",
        sortBy: "relevancy",        
    }).then(response_json => {                           
        results.payload = [...response_json.articles];
        results.status = true;
    }).catch(error => {
        console.log(error.message);
        results.payload = [];
        results.error = {...error};
        results.status = false;
    });
    
    console.log('Results Returned from search news api',results.payload.length);

    return results.payload;
};


const articles_api = {	
	  entertainment: `https://newsapi.org/v2/top-headlines?country=za&category=entertainment&apiKey=${api_key}`,
	  sports: `https://newsapi.org/v2/top-headlines?country=za&category=sports&apiKey=${api_key}`,
    business: `https://newsapi.org/v2/top-headlines?country=za&category=business&apiKey=${api_key}`,
    tech: `https://newsapi.org/v2/top-headlines?country=za&category=technology&apiKey=${api_key}`,
    science: `https://newsapi.org/v2/top-headlines?country=za&category=science&apiKey=${api_key}`,
	  health: `https://newsapi.org/v2/top-headlines?country=za&category=health&apiKey=${api_key}`		
};    

const category_memory ={
    fetch_date : null,
    entertainment : [],
    sports : [],
    business : [],
    tech : [],
    science : [],
    health : [],
};    

async function get_blog_articles(category){
	let results = null;
    let apiRequest = null;
    const today = moment().format("YYYY-MM-DD");

    if ((fetch_date !== today) && (category_memory[category] && (category_memory[category].length < 1))){

     apiRequest = articles_api[category];
      await axios.get(apiRequest).then(result => {
          if (result.status === 200){
            return result.data;
          }else{
              throw new Error('there was an error fetching data');
          }

        }).then(json_articles => {
            results = json_articles.articles;
            category_memory[category] = results;
        }).catch(error => {
          console.log(error);
        });

      category_memory.fetch_date = today;
    } else {
      results = category_memory[category];
    }
    console.log('results returned from fetch blog articles',category);
	return results;
};

module.exports = {
  search: searchNews,
  refine: get_blog_articles,
};