From 4d4102e8eef825e634640e7e44933f0bb4b836fd Mon Sep 17 00:00:00 2001
From: Vahagn Khachatryan <vkhachatrya5@bloomberg.net>
Date: Sun, 27 Jan 2019 23:52:00 +0000
Subject: [PATCH] Improving error handling.

---
 src/sidebar.js | 114 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 69 insertions(+), 45 deletions(-)

diff --git a/src/sidebar.js b/src/sidebar.js
index 84722d2..5d4cdf3 100644
--- a/src/sidebar.js
+++ b/src/sidebar.js
@@ -17,7 +17,7 @@ function getCurrentTab() {
             console.error(`Expected 1 active tab, received: ${tabs}`);
             throw 'Failed to get active tab.';
         }
-    }, onError);
+    });
 }
 
 function extractBookId(url){
@@ -52,28 +52,60 @@ class Book{
         this.page = page
     }
 
-    downloadResource(url){
-        console.info(`Downloading ${url}`)
+    downloadResource(url, retry=false){
+        if (retry){
+            console.warn(`Retry ${url}`)
+        } else {
+            console.info(`Downloading ${url}`)
+        }
         return fetch(url, {
                 credentials: 'include',
                 mode: "no-cors" // no-cors, cors, *same-origin
             })
             .catch((error)=>{
-                console.info(`Failed ${url} - ${error.message}`)
-                console.info(`Retry ${url}`)
-                // If failed to download, try second time.
-                return fetch(url, {
-                    credentials: 'include',
-                    mode: "no-cors" // no-cors, cors, *same-origin
-                })
+                if (!retry){
+                    console.warn(`Failed ${url} - ${error.message}`)
+                    return this.downloadResource(url, true)
+                } else {
+                    console.error(`Giving up on ${url} - ${error.message}`)
+                    throw `Failed second try on ${url} - ${error.message}`
+                }
+            })
+            .then((res)=>{
+                if (res.ok) {
+                    return res
+                } else if (!retry){
+                    console.warn(`Failed ${url} - ${res.status} - ${res.statusText}`)
+                    return this.downloadResource(url, true)
+                } else {
+                    console.error(`Giving up on ${url} - ${res.status} - ${res.statusText}`)
+                    throw `Failed second try on ${url} - ${res.status} - ${res.statusText}`
+                }
+            })
+    }
+
+    downloadAndReport(url, item_text=null){
+        let item_id = this.page.renderProgress(item_text ? item_text : url)
+        return this.downloadResource(url)
+            .then((res)=>{
+                if (item_id){
+                    this.page.renderDone(item_id)
+                }
+                return res
+            })
+            .catch((error)=>{
+                if (item_id){
+                    this.page.renderFail(item_id, error)
+                    throw error
+                }
             })
     }
 
     downloadJson(url){
-        return this.downloadResource(url)
+        return this.downloadAndReport(url)
             .then((res) => {
                 return res.json();
-            }, onError);
+            });
     }
 
     downloadBookInfo(){
@@ -82,7 +114,7 @@ class Book{
         return this.downloadJson(url)
             .then((book_info) => {
                 this.book_info = book_info;
-            }, onError);
+            });
     }
 
     downloadMetaContent(){
@@ -104,21 +136,17 @@ class Book{
             }))
         downloads.push(
             Promise.map(this.book_info.chapters, (chapter) => {
-                let item_id = this.page.renderProgress(`${chapter}`)
                 return this.downloadJson(chapter)
                         .then((json) => {
                             this.chapter_info[chapter] = json
                             return this.extractChapterAssets(json)
                         })
-                        .then(()=>{
-                            this.page.renderDone(item_id)
-                        })
-                        .catch((error)=>{
-                            this.page.renderFail(item_id, error)
-                        })
-            },{concurrency: concurrency}))
+            }, {concurrency: concurrency}))
 
         return Promise.all(downloads)
+                .catch((error)=>{
+                    throw `Failed to fetch meta data: "${error}"`
+                })
     }
 
 
@@ -146,8 +174,7 @@ class Book{
 
     downloadContent(){
         return Promise.map(Object.keys(this.book_files), (url) => {
-            let item_id = this.page.renderProgress(`${this.book_files[url].filename}`)
-            return this.downloadResource(url)
+                return this.downloadAndReport(url, this.book_files[url].filename)
                     .then((res) => {
                         if (res.ok){
                             this.book_files[url].headers = res.headers
@@ -157,14 +184,10 @@ class Book{
                             })
                         }
                     })
-                    .then((arrBuffer)=>{
-                        this.page.renderDone(item_id)
-                        return arrBuffer
-                    })
                     .catch((error)=>{
-                        this.page.renderFail(item_id, error)
+                        throw `Failed to download book content: "${error}"`
                     })
-        },{concurrency: concurrency})
+            },{concurrency: concurrency})
     }
 
     insertBookFile(url, filename){
@@ -198,6 +221,14 @@ class SidebarPage{
         $('#loading').hide();
     }
 
+    renderFailedTheBook(error) {
+        console.error(`Error: ${error}`);
+        $('#loading').hide();
+        $('#error-message').text(`Error: ${error}`);
+        $('#error-message').show();
+        // $('#book-info').hide();
+    }
+
     renderChapterList(book){
         // Add chapters to UI
         for (let chapter_idx in book.chapter_list) {
@@ -237,15 +268,6 @@ class SidebarPage{
     }
 }
 
-function onError(error) {
-    console.error(`Error: ${error}`);
-    $('#error-message').text(`Error: ${error}`);
-    $('#error-message').show();
-    $('#loading').hide();
-    $('#book-info').hide();
-}
-
-
 
 function fillMetadata(epub, book)
 {
@@ -363,11 +385,11 @@ function onDownloadBookClicked(){
     page = new SidebarPage()
 
     getCurrentTab()
-    .then(extractBookId, onError)
+    .then(extractBookId)
     .then((book_id) => {
         epub = new EpubWriter();
         book = new Book(book_id, page);
-        book.downloadBookInfo()
+        return book.downloadBookInfo()
         .then(() => { page.renderInfo(book); })
         // .then(() => { return book.downloadChapterList(); })
         // .then(() => { return page.renderChapterList(book); })
@@ -386,11 +408,13 @@ function onDownloadBookClicked(){
             let url = window.URL.createObjectURL(file)
             return browser.downloads.download({ "filename" : filename, url : url})
         })
-        .then(() =>{
-            page.renderDoneWithBook();
-        })
-
-    }, onError);
+    })
+    .then(() =>{
+        page.renderDoneWithBook();
+    })
+    .catch((error)=>{
+        page.renderFailedTheBook(error);
+    });
 }
 
 document.addEventListener('DOMContentLoaded', function() {