4b. introduce summarizer ; use summarizer for top news reading

backend/helpers/externalSource.js

@@ -1,5 +1,7 @@
 let request = require ('request');
 let Parser = require ('rss-parser');
+let summarizer = require ('node-summary');
+const constants = require ('../config/constants');
 
 let parser = new Parser ();
 
@@ -9,44 +11,88 @@ getDataFromRSSFeed = function (url) {
   //feed.items.forEach(item => {
   //  console.log(item.title + ':' + item.link)
   //});
-}
+};
 
 getDataFromWPJSON = function (sourceUrl, page = 1, maxPosts = 10) {
   return new Promise ((resolve, reject) => {
     var options = {
       method: 'GET',
       url: `${sourceUrl}/wp-json/wp/v2/posts`,
-      qs:{
-          page:page,
-          per_page:maxPosts
-      }
+      qs: {
+        page: page,
+        per_page: maxPosts,
+      },
     };
 
-    request (options, (error, response, body)=> {
+    request (options, (error, response, body) => {
       if (error) {
         reject (error);
       } else {
-        resolve(JSON.parse (body));
+        resolve (JSON.parse (body));
       }
     });
   });
-}
+};
+
+summarizeText = function (title, text) {
+  return new Promise ((resolve, reject) => {
+    summarizer.summarize (title, text, (err, summary) => {
+      if (err) {
+        reject (err);
+      } else {
+        resolve (summary);
+      }
+    });
+  });
+};
 
 module.exports = {
-  getAnswerFromWP : function (sourceUrl){
+  getAnswerFromWP: function (sourceUrl) {
     //This function will extract needed data from JSON, which we got from getDataFromWPJSON
     //At the moment, it's taking titles and creates answer
-    return new Promise((resolve,reject)=>{
-      getDataFromWPJSON(sourceUrl).then(rawData=>{
-        let result='';
-        rawData.forEach(post=>{
-          result += post.title.rendered + '<break time="300ms"/> '
+    return new Promise ((resolve, reject) => {
+      getDataFromWPJSON (sourceUrl)
+        .then (rawData => {
+          let result = '';
+          rawData.forEach (post => {
+            result += post.title.rendered + `<break time="${constants.voiceResponseTimings.PAUSE_BETWEEN_TITLES}ms"/> `;
+          });
+          resolve (result);
+        })
+        .catch (err => {
+          reject (constants.voiceResponseString.ERROR_FETCHING_CONTENT);
         });
-        resolve(result);
-      }).catch(err=>{
-        reject('Failed to get answer');
-      });
     });
-  }
-}
+  },
 
+  getLatestNewsFromWP: function (sourceUrl, postCount = 10, includeTitle = false) {
+    return new Promise ((resolve, reject) => {
+      getDataFromWPJSON (sourceUrl, 1, postCount)
+        .then (rawData => {
+          let result = '';
+          let summarizers = [];
+          rawData.forEach (post => {
+            summarizers.push (
+              summarizeText (post.title.rendered, post.content.rendered).then(summary=>{
+                result += (includeTitle) ? post.title.rendered : '';
+                result += (includeTitle) ? `<break time="${constants.voiceResponseTimings.PAUSE_BETWEEN_TITLE_AND_CONTENT}ms"/>` : '';
+                result += summary;
+                result += `<break time="${constants.voiceResponseTimings.PAUSE_BETWEEN_NEWS}ms"/>`; 
+              }).catch(err=>{
+                result += constants.voiceResponseString.ERROR_SUMMARIZING_CONTENT;
+                result += `<break time="${constants.voiceResponseTimings.PAUSE_BETWEEN_NEWS}ms"/>`;
+              })
+            );
+          });
+          Promise.all(summarizers).then(()=>{
+            resolve(result);
+          }).catch(()=>{
+            reject(result);
+          });
+        })
+        .catch (err => {
+          reject (constants.voiceResponseString.ERROR_FETCHING_CONTENT);
+        });
+    });
+  },
+};