diff --git a/cps.py b/cps.py
index 180be500..523246b2 100755
--- a/cps.py
+++ b/cps.py
@@ -22,7 +22,7 @@ except ImportError:
 
 if __name__ == '__main__':
     if web.ub.DEVELOPMENT:
-        web.app.run(host="0.0.0.0", port=web.ub.config.config_port, debug=True)
+        web.app.run(port=web.ub.config.config_port, debug=True)
     else:
         if gevent_present:
             web.app.logger.info('Attempting to start gevent')
diff --git a/cps/helper.py b/cps/helper.py
index 7f561319..71cacd74 100755
--- a/cps/helper.py
+++ b/cps/helper.py
@@ -13,6 +13,7 @@ import os
 import traceback
 import re
 import unicodedata
+
 try:
     from StringIO import StringIO
     from email.MIMEBase import MIMEBase
diff --git a/cps/static/js/edit_books.js b/cps/static/js/edit_books.js
index 07d25148..810869a5 100644
--- a/cps/static/js/edit_books.js
+++ b/cps/static/js/edit_books.js
@@ -8,7 +8,7 @@
 Takes a prefix, query typeahead callback, Bloodhound typeahead adapter
  and returns the completions it gets from the bloodhound engine prefixed.
  */
-function prefixed_source(prefix, query, cb, bhAdapter) {
+function prefixedSource(prefix, query, cb, bhAdapter) {
     bhAdapter(query, function(retArray){
         var matches = [];
         for (var i = 0; i < retArray.length; i++) {
@@ -18,7 +18,7 @@ function prefixed_source(prefix, query, cb, bhAdapter) {
         cb(matches);
     });
 }
-function get_path(){
+function getPath(){
     var jsFileLocation = $("script[src*=edit_books]").attr("src");  // the js file path
     jsFileLocation = jsFileLocation.replace("/static/js/edit_books.js", '');   // the js folder path
     return jsFileLocation;
@@ -31,7 +31,7 @@ var authors = new Bloodhound({
     },
     queryTokenizer: Bloodhound.tokenizers.whitespace,
     remote: {
-        url: get_path()+"/get_authors_json?q=%QUERY"
+        url: getPath()+"/get_authors_json?q=%QUERY"
     }
 });
 
@@ -44,7 +44,7 @@ var series = new Bloodhound({
         return [query];
     },
     remote: {
-        url: get_path()+"/get_series_json?q=",
+        url: getPath()+"/get_series_json?q=",
         replace: function(url, query) {
             return url+encodeURIComponent(query);
         }
@@ -63,7 +63,7 @@ var tags = new Bloodhound({
         return tokens;
     },
     remote: {
-        url: get_path()+"/get_tags_json?q=%QUERY"
+        url: getPath()+"/get_tags_json?q=%QUERY"
     }
 });
 
@@ -76,10 +76,9 @@ var languages = new Bloodhound({
         return [query];
     },
     remote: {
-        url: get_path()+"/get_languages_json?q=",
+        url: getPath()+"/get_languages_json?q=",
         replace: function(url, query) {
-            url_query = url+encodeURIComponent(query);
-            return url_query;
+            return url+encodeURIComponent(query);
         }
     }
 });
@@ -101,7 +100,7 @@ function sourceSplit(query, cb, split, source) {
     for (var i = 0; i < tokens.length; i++) {
         prefix += tokens[i].trim() + newSplit;
     }
-    prefixed_source(prefix, currentSource, cb, bhAdapter);
+    prefixedSource(prefix, currentSource, cb, bhAdapter);
 }
 
 var promiseAuthors = authors.initialize();
@@ -130,7 +129,7 @@ var promiseSeries = series.initialize();
                 displayKey: "name",
                 source: series.ttAdapter()
             }
-    )
+    );
 });
 
 var promiseTags = tags.initialize();
@@ -165,7 +164,7 @@ var promiseLanguages = languages.initialize();
 
 $("form").on("change input typeahead:selected", function(data){
     var form = $("form").serialize();
-    $.getJSON( get_path()+"/get_matching_tags", form, function( data ) {
+    $.getJSON( getPath()+"/get_matching_tags", form, function( data ) {
       $(".tags_click").each(function() {
         if ($.inArray(parseInt($(this).children("input").first().val(), 10), data.tags) === -1 ) {
           if (!($(this).hasClass("active"))) {
diff --git a/cps/static/js/get_meta.js b/cps/static/js/get_meta.js
index 583abea2..316d2651 100644
--- a/cps/static/js/get_meta.js
+++ b/cps/static/js/get_meta.js
@@ -9,36 +9,95 @@ $(document).ready(function () {
     var msg = i18nMsg;
     var douban = "https://api.douban.com";
     var dbSearch = "/v2/book/search";
-    var db_get_info = "/v2/book/";
-    var db_get_info_by_isbn = "/v2/book/isbn/ ";
+    // var dbGetInfo = "/v2/book/";
+    // var db_get_info_by_isbn = "/v2/book/isbn/ ";
     var dbDone = false;
 
     var google = "https://www.googleapis.com/";
-    var gg_search = "/books/v1/volumes";
-    var gg_get_info = "/books/v1/volumes/";
-    var gg_done = false;
+    var ggSearch = "/books/v1/volumes";
+    // var gg_get_info = "/books/v1/volumes/";
+    var ggDone = false;
 
-    var db_results = [];
-    var gg_results = [];
-    var show_flag = 0;
-    String.prototype.replaceAll = function (s1, s2) {　　
+    var dbResults = [];
+    var ggResults = [];
+    var showFlag = 0;
+    String.prototype.replaceAll = function (s1, s2) {
         return this.replace(new RegExp(s1, "gm"), s2);
     };
 
-    function gg_search_book (title) {
+    function showResult () {
+        showFlag++;
+        if (showFlag === 1) {
+            $("#meta-info").html('<ul id="book-list" class="media-list"></ul>');
+        }
+        if (ggDone && dbDone) {
+            if (!ggResults && !dbResults) {
+                $("#meta-info").html('<p class="text-danger">'+ msg.no_result +"</p>");
+                return;
+            }
+        }
+        if (ggDone && ggResults.length > 0) {
+            for (var i = 0; i < ggResults.length; i++) {
+                var book = ggResults[i];
+                var bookCover;
+                if (book.volumeInfo.imageLinks) {
+                    bookCover = book.volumeInfo.imageLinks.thumbnail;
+                } else {
+                    bookCover = "/static/generic_cover.jpg";
+                }
+                var bookHtml = '<li class="media">' +
+                    '<img class="pull-left img-responsive" data-toggle="modal" data-target="#metaModal" src="' +
+                    bookCover + '" alt="Cover" style="width:100px;height:150px" onclick=\'javascript:get_meta("google",' +
+                    i + ')\'>' +
+                    '<div class="media-body">' +
+                    '<h4 class="media-heading"><a href="https://books.google.com/books?id=' +
+                    book.id + '"  target="_blank">' + book.volumeInfo.title + '</a></h4>' +
+                    "<p>"+ msg.author +"：" + book.volumeInfo.authors + "</p>" +
+                    "<p>"+ msg.publisher + "：" + book.volumeInfo.publisher + "</p>" +
+                    "<p>"+ msg.description + ":" + book.volumeInfo.description + "</p>" +
+                    "<p>"+ msg.source + ':<a href="https://books.google.com" target="_blank">Google Books</a></p>' +
+                    "</div>" +
+                    "</li>";
+                $("#book-list").append(bookHtml);
+            }
+            ggDone = false;
+        }
+        if (dbDone && dbResults.length > 0) {
+            for (var i = 0; i < dbResults.length; i++) {
+                var book = dbResults[i];
+                var bookHtml = '<li class="media">' +
+                    '<img class="pull-left img-responsive" data-toggle="modal" data-target="#metaModal" src="' +
+                    book.image + '" alt="Cover" style="width:100px;height: 150px" onclick=\'javascript:get_meta("douban",' +
+                    i + ')\'>' +
+                    '<div class="media-body">' +
+                    '<h4 class="media-heading"><a href="https://book.douban.com/subject/' +
+                    book.id + '"  target="_blank">' + book.title + "</a></h4>" +
+                    "<p>" + msg.author + "：" + book.author + "</p>" +
+                    "<p>" + msg.publisher + "：" + book.publisher + "</p>" +
+                    "<p>" + msg.description + ":" + book.summary + "</p>" +
+                    "<p>" + msg.source + ':<a href="https://book.douban.com" target="_blank">Douban Books</a></p>' +
+                    "</div>" +
+                    "</li>";
+                $("#book-list").append(bookHtml);
+            }
+            dbDone = false;
+        }
+    }
+
+    function ggSearchBook (title) {
         title = title.replaceAll(/\s+/, "+");
-        var url = google + gg_search + "?q=" + title;
+        var url = google + ggSearch + "?q=" + title;
         $.ajax({
             url,
             type: "GET",
             dataType: "jsonp",
             jsonp: "callback",
             success: function (data) {
-                gg_results = data.items;
+                ggResults = data.items;
             },
             complete: function () {
-                gg_done = true;
-                show_result();
+                ggDone = true;
+                showResult();
             }
         });
     }
@@ -47,7 +106,7 @@ $(document).ready(function () {
         var meta;
         var tags;
         if (source === "google") {
-            meta = gg_results[id];
+            meta = ggResults[id];
             $("#description").val(meta.volumeInfo.description);
             $("#bookAuthor").val(meta.volumeInfo.authors.join(" & "));
             $("#book_title").val(meta.volumeInfo.title);
@@ -61,13 +120,13 @@ $(document).ready(function () {
             return;
         }
         if (source === "douban") {
-            meta = db_results[id];
+            meta = dbResults[id];
             $("#description").val(meta.summary);
             $("#bookAuthor").val(meta.author.join(" & "));
             $("#book_title").val(meta.title);
-            tags = '';
+            tags = "";
             for (var i = 0; i < meta.tags.length; i++) {
-                tags = tags + meta.tags[i].title + ',';
+                tags = tags + meta.tags[i].title + ",";
             }
             $("#tags").val(tags);
             $("#rating").val(Math.round(meta.rating.average / 2));
@@ -75,91 +134,32 @@ $(document).ready(function () {
         }
     }
 
-    function do_search (keyword) {
-        show_flag = 0;
+    function doSearch (keyword) {
+        showFlag = 0;
         $("#meta-info").text(msg.loading);
-        var keyword = $("#keyword").val();
+        // var keyword = $("#keyword").val();
         if (keyword) {
-            db_search_book(keyword);
-            gg_search_book(keyword);
+            dbSearchBook(keyword);
+            ggSearchBook(keyword);
         }
     }
 
-    function show_result () {
-        show_flag++;
-        if (show_flag == 1) {
-            $('#meta-info').html('<ul id="book-list" class="media-list"></ul>');
-        }
-        if (gg_done && dbDone) {
-            if (!gg_results && !db_results) {
-                $('#meta-info').html('<p class="text-danger">'+ msg.no_result +'</p>');
-                return;
-            }
-        }
-        if (gg_done && gg_results.length > 0) {
-            for (var i = 0; i < gg_results.length; i++) {
-                var book = gg_results[i];
-                var book_cover;
-                if (book.volumeInfo.imageLinks) {
-                    book_cover = book.volumeInfo.imageLinks.thumbnail;
-                } else {
-                    book_cover = '/static/generic_cover.jpg';
-                }
-                var book_html = '<li class="media">' +
-                    '<img class="pull-left img-responsive" data-toggle="modal" data-target="#metaModal" src="' +
-                    book_cover + '" alt="Cover" style="width:100px;height:150px" onclick=\'javascript:get_meta("google",' +
-                    i + ')\'>' +
-                    '<div class="media-body">' +
-                    '<h4 class="media-heading"><a href="https://books.google.com/books?id=' +
-                    book.id + '"  target="_blank">' + book.volumeInfo.title + '</a></h4>' +
-                    '<p>'+ msg.author +'：' + book.volumeInfo.authors + '</p>' +
-                    '<p>'+ msg.publisher + '：' + book.volumeInfo.publisher + '</p>' +
-                    '<p>'+ msg.description + ':' + book.volumeInfo.description + '</p>' +
-                    '<p>'+ msg.source + ':<a href="https://books.google.com" target="_blank">Google Books</a></p>' +
-                    '</div>' +
-                    '</li>';
-                $("#book-list").append(book_html);
-            }
-            gg_done = false;
-        }
-        if (dbDone && db_results.length > 0) {
-            for (var i = 0; i < db_results.length; i++) {
-                var book = db_results[i];
-                var book_html = '<li class="media">' +
-                    '<img class="pull-left img-responsive" data-toggle="modal" data-target="#metaModal" src="' +
-                    book.image + '" alt="Cover" style="width:100px;height: 150px" onclick=\'javascript:get_meta("douban",' +
-                    i + ')\'>' +
-                    '<div class="media-body">' +
-                    '<h4 class="media-heading"><a href="https://book.douban.com/subject/' +
-                    book.id + '"  target="_blank">' + book.title + '</a></h4>' +
-                    '<p>' + msg.author + '：' + book.author + '</p>' +
-                    '<p>' + msg.publisher + '：' + book.publisher + '</p>' +
-                    '<p>' + msg.description + ':' + book.summary + '</p>' +
-                    '<p>' + msg.source + ':<a href="https://book.douban.com" target="_blank">Douban Books</a></p>' +
-                    '</div>' +
-                    "</li>";
-                $("#book-list").append(book_html);
-            }
-            dbDone = false;
-        }
-    }
-
-    db_search_book = function (title) {
-        var url = douban + dbSearch + '?q=' + title + '&fields=all&count=10';
+    function dbSearchBook (title) {
+        var url = douban + dbSearch + "?q=" + title + "&fields=all&count=10";
         $.ajax({
             url: url,
             type: "GET",
             dataType: "jsonp",
-            jsonp: 'callback',
+            jsonp: "callback",
             success: function (data) {
-                db_results = data.books;
+                dbResults = data.books;
             },
             error: function () {
-                $('#meta-info').html('<p class="text-danger">'+ msg.search_error+'!</p>');
+                $("#meta-info").html('<p class="text-danger">'+ msg.search_error+"!</p>");
             },
             complete: function () {
                 dbDone = true;
-                show_result();
+                showResult();
             }
         });
     }
@@ -167,15 +167,15 @@ $(document).ready(function () {
     $("#do-search").click(function () {
         var keyword = $("#keyword").val();
         if (keyword) {
-            do_search(keyword);
+            doSearch(keyword);
         }
     });
 
     $("#get_meta").click(function () {
-        var book_title = $("#book_title").val();
-        if (book_title) {
-            $("#keyword").val(book_title);
-            do_search(book_title);
+        var bookTitle = $("#book_title").val();
+        if (bookTitle) {
+            $("#keyword").val(bookTitle);
+            doSearch(bookTitle);
         }
     });
 
diff --git a/cps/static/js/main.js b/cps/static/js/main.js
index 8494973f..10e4dc08 100644
--- a/cps/static/js/main.js
+++ b/cps/static/js/main.js
@@ -49,13 +49,13 @@ $(function() {
         });
     });
     $("#check_for_update").click(function() {
-        var button_text = $("#check_for_update").html();
+        var buttonText = $("#check_for_update").html();
         $("#check_for_update").html("...");
         $.ajax({
             dataType: "json",
             url: window.location.pathname+"/../../get_update_status",
             success: function(data) {
-                $("#check_for_update").html(button_text);
+                $("#check_for_update").html(buttonText);
                 if (data.status === true) {
                     $("#check_for_update").addClass("hidden");
                     $("#perform_update").removeClass("hidden");
@@ -67,7 +67,7 @@ $(function() {
     });
     $("#restart_database").click(function() {
         $.ajax({
-            dataType: 'json',
+            dataType: "json",
             url: window.location.pathname+"/../../shutdown",
             data: {"parameter":2}
         });
@@ -76,7 +76,7 @@ $(function() {
         $("#spinner2").show();
         $.ajax({
         type: "POST",
-        dataType: 'json',
+        dataType: "json",
         data: { start: "True"},
         url: window.location.pathname+"/../../get_updater_status",
         success: function(data) {
@@ -94,10 +94,10 @@ $(function() {
 
     function updateTimer() {
         $.ajax({
-        dataType: 'json',
+        dataType: "json",
         url: window.location.pathname+"/../../get_updater_status",
         success: function(data) {
-            console.log(data.status);
+            // console.log(data.status);
             $("#UpdateprogressDialog #Updatecontent").html(updateText[data.status]);
             if (data.status >6){
                 clearInterval(updateTimerID);
diff --git a/cps/templates/book_edit.html b/cps/templates/book_edit.html
index 165512c7..b94ddbb2 100644
--- a/cps/templates/book_edit.html
+++ b/cps/templates/book_edit.html
@@ -106,7 +106,7 @@
     </div>
     <a href="#" id="get_meta" class="btn btn-default" data-toggle="modal" data-target="#metaModal">{{_('Get metadata')}}</a>
     <button type="submit" class="btn btn-default">{{_('Submit')}}</button>
-    <a href="{{ url_for('show_book',id=book.id) }}" class="btn btn-default">{{_('Back')}}</a>
+    <a href="{{ url_for('show_book', book_id=book.id) }}" class="btn btn-default">{{_('Back')}}</a>
   </form>
 </div>
 {% endif %}
diff --git a/cps/templates/detail.html b/cps/templates/detail.html
index e0a7ef01..44fc8f55 100644
--- a/cps/templates/detail.html
+++ b/cps/templates/detail.html
@@ -15,7 +15,7 @@
       <h2>{{entry.title}}</h2>
       <p class="author">
           {% for author in entry.authors %}
-            <a href="{{url_for('author', id=author.id ) }}">{{author.name}}</a>
+            <a href="{{url_for('author', book_id=author.id ) }}">{{author.name}}</a>
             {% if not loop.last %}
               &amp;
             {% endif %}
@@ -37,7 +37,7 @@
       {% endif %}
 
       {% if entry.series|length > 0 %}
-        <p>{{_('Book')}} {{entry.series_index}} {{_('of')}} <a href="{{url_for('series', id=entry.series[0].id)}}">{{entry.series[0].name}}</a></p>
+        <p>{{_('Book')}} {{entry.series_index}} {{_('of')}} <a href="{{url_for('series', book_id=entry.series[0].id)}}">{{entry.series[0].name}}</a></p>
       {% endif %}
 
       {% if entry.languages.__len__() > 0 %}
@@ -65,7 +65,7 @@
         <span class="glyphicon glyphicon-tags"></span>
         
         {% for tag in entry.tags %}
-          <a href="{{ url_for('category', id=tag.id) }}" class="btn btn-xs btn-info" role="button">{{tag.name}}</a>
+          <a href="{{ url_for('category', book_id=tag.id) }}" class="btn btn-xs btn-info" role="button">{{tag.name}}</a>
         {%endfor%}
       </div>
       </p>
@@ -110,7 +110,7 @@
       {% if not g.user.is_anonymous() %}
       <p>
         <div class="custom_columns" id="have_read_container">
-          <form id="have_read_form" action="{{ url_for('toggle_read', id=entry.id)}}" method="POST") >
+          <form id="have_read_form" action="{{ url_for('toggle_read', book_id=entry.id)}}" method="POST") >
             <input id="have_read_cb" type="checkbox" {% if have_read %}checked{% endif %} >
             <label for="have_read_cb">{{_('Read')}}</label>
           </form>
@@ -136,7 +136,7 @@
               </button>
               <ul class="dropdown-menu" aria-labelledby="btnGroupDrop1">
                 {% for format in entry.data %}
-                <li><a href="{{ url_for('get_download_link_ext', book_id=entry.id, format=format.format|lower, anyname=entry.id|string+'.'+format.format) }}">{{format.format}}</a></li>
+                <li><a href="{{ url_for('get_download_link_ext', book_id=entry.id, book_format=format.format|lower, anyname=entry.id|string+'.'+format.format) }}">{{format.format}}</a></li>
                 {%endfor%}
               </ul>
             </div>
@@ -154,7 +154,7 @@
                 <ul class="dropdown-menu" aria-labelledby="btnGroupDrop2">
                   {% for format in entry.data %}
                   {%if format.format|lower == 'epub' or format.format|lower == 'txt' or format.format|lower == 'pdf' or format.format|lower == 'cbr' or format.format|lower == 'cbt' or format.format|lower == 'cbz' %}
-                  <li><a target="_blank" href="{{ url_for('read_book', book_id=entry.id, format=format.format|lower) }}">{{format.format}}</a></li>
+                  <li><a target="_blank" href="{{ url_for('read_book', book_id=entry.id, book_format=format.format|lower) }}">{{format.format}}</a></li>
                   {% endif %}
                   {%endfor%}
                 </ul>
diff --git a/cps/templates/discover.html b/cps/templates/discover.html
index c340cfc0..32f89a47 100644
--- a/cps/templates/discover.html
+++ b/cps/templates/discover.html
@@ -8,14 +8,14 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
         {% if entry.has_cover is defined %}
-          <a href="{{ url_for('show_book', id=entry.id) }}">
+          <a href="{{ url_for('show_book', book_id=entry.id) }}">
             <img src="{{ url_for('get_cover', cover_path=entry.path.replace('\\','/')) }}" />
           </a>
         {% endif %}
       </div>
       <div class="meta">
         <p class="title">{{entry.title|shortentitle}}</p>
-        <p class="author"><a href="{{url_for('author', id=entry.authors[0].id) }}">{{entry.authors[0].name}}</a></p>
+        <p class="author"><a href="{{url_for('author', book_id=entry.authors[0].id) }}">{{entry.authors[0].name}}</a></p>
         {% if entry.ratings.__len__() > 0 %}
         <div class="rating">
           {% for number in range((entry.ratings[0].rating/2)|int(2)) %}
diff --git a/cps/templates/feed.xml b/cps/templates/feed.xml
index 8d57cfb3..65471fde 100644
--- a/cps/templates/feed.xml
+++ b/cps/templates/feed.xml
@@ -56,7 +56,7 @@
     <link type="image/jpeg" href="{{url_for('feed_get_cover', book_id=entry.id)}}" rel="http://opds-spec.org/image/thumbnail"/>
     {% endif %}
     {% for format in entry.data %}
-    <link rel="http://opds-spec.org/acquisition" href="{{ url_for('get_opds_download_link', book_id=entry.id, format=format.format|lower)}}"
+    <link rel="http://opds-spec.org/acquisition" href="{{ url_for('get_opds_download_link', book_id=entry.id, book_format=format.format|lower)}}"
           length="{{format.uncompressed_size}}" mtime="{{entry.timestamp}}" type="{{format.format|lower|mimetype}}"/>
     {% endfor %}
   </entry>
@@ -65,9 +65,9 @@
   {% for entry in listelements %}
   <entry>
     <title>{{entry.name}}</title>
-    <id>{{ url_for(folder, id=entry.id) }}</id>
-    <link type="application/atom+xml;profile=opds-catalog;type=feed;kind=acquisition" href="{{url_for(folder, id=entry.id)}}"/>
-    <link type="application/atom+xml" href="{{url_for(folder, id=entry.id)}}" rel="subsection"/>
+    <id>{{ url_for(folder, book_id=entry.id) }}</id>
+    <link type="application/atom+xml;profile=opds-catalog;type=feed;kind=acquisition" href="{{url_for(folder, book_id=entry.id)}}"/>
+    <link type="application/atom+xml" href="{{url_for(folder, book_id=entry.id)}}" rel="subsection"/>
   </entry>
   {% endfor %}
 </feed>
diff --git a/cps/templates/index.html b/cps/templates/index.html
index 744fea89..768c28bd 100755
--- a/cps/templates/index.html
+++ b/cps/templates/index.html
@@ -8,7 +8,7 @@
     {% for entry in random %}
     <div id="books_rand" class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
-          <a href="{{ url_for('show_book', id=entry.id) }}">
+          <a href="{{ url_for('show_book', book_id=entry.id) }}">
             {% if entry.has_cover %}
               <img src="{{ url_for('get_cover', cover_path=entry.path.replace('\\','/')) }}" />
             {% else %}
@@ -18,7 +18,7 @@
       </div>
       <div class="meta">
         <p class="title">{{entry.title|shortentitle}}</p>
-        <p class="author"><a href="{{url_for('author', id=entry.authors[0].id) }}">{{entry.authors[0].name}}</a></p>
+        <p class="author"><a href="{{url_for('author', book_id=entry.authors[0].id) }}">{{entry.authors[0].name}}</a></p>
         {% if entry.ratings.__len__() > 0 %}
         <div class="rating">
           {% for number in range((entry.ratings[0].rating/2)|int(2)) %}
@@ -44,7 +44,7 @@
     {% for entry in entries %}
     <div id="books" class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
-          <a href="{{ url_for('show_book', id=entry.id) }}">
+          <a href="{{ url_for('show_book', book_id=entry.id) }}">
             {% if entry.has_cover %}
               <img src="{{ url_for('get_cover', cover_path=entry.path.replace('\\','/')) }}" />
             {% else %}
@@ -56,7 +56,7 @@
         <p class="title">{{entry.title|shortentitle}}</p>
         <p class="author">
           {% for author in entry.authors %}
-            <a href="{{url_for('author', id=author.id) }}">{{author.name}}</a>
+            <a href="{{url_for('author', book_id=author.id) }}">{{author.name}}</a>
             {% if not loop.last %}
               &amp;
             {% endif %}
diff --git a/cps/templates/json.txt b/cps/templates/json.txt
index 9e86c41d..be69bf7c 100644
--- a/cps/templates/json.txt
+++ b/cps/templates/json.txt
@@ -36,7 +36,7 @@
   "timestamp": "{{entry.timestamp}}", 
   "thumbnail": "{{url_for('feed_get_cover', book_id=entry.id)}}",
   "main_format": {
-    "{{entry.data[0].format|lower}}": "{{ url_for('get_opds_download_link', book_id=entry.id, format=entry.data[0].format|lower)}}"
+    "{{entry.data[0].format|lower}}": "{{ url_for('get_opds_download_link', book_id=entry.id, book_format=entry.data[0].format|lower)}}"
   },
   "rating":{% if entry.ratings.__len__() > 0 %} "{{entry.ratings[0].rating}}.0"{% else %}0.0{% endif %},
   "authors": [
@@ -47,7 +47,7 @@
   "other_formats": {
   {% if entry.data.__len__() > 1 %}
   {% for format in entry.data[1:] %}
-    "{{format.format|lower}}": "{{ url_for('get_opds_download_link', book_id=entry.id, format=format.format|lower)}}"{% if not loop.last %},{% endif %}
+    "{{format.format|lower}}": "{{ url_for('get_opds_download_link', book_id=entry.id, book_format=format.format|lower)}}"{% if not loop.last %},{% endif %}
   {% endfor %}
   {% endif %} },
   "title_sort": "{{entry.sort}}"
diff --git a/cps/templates/list.html b/cps/templates/list.html
index 0a63b139..55d07e82 100644
--- a/cps/templates/list.html
+++ b/cps/templates/list.html
@@ -10,7 +10,7 @@
       {% endif %}
       <div class="row">
         <div class="col-xs-1" align="left"><span class="badge">{{entry.count}}</span></div>
-        <div class="col-xs-6"><a id="list_{{loop.index0}}" href="{{url_for(folder, id=entry[0].id )}}">{{entry[0].name}}</a></div>
+        <div class="col-xs-6"><a id="list_{{loop.index0}}" href="{{url_for(folder, book_id=entry[0].id )}}">{{entry[0].name}}</a></div>
       </div>
     {% endfor %}
   </div>
diff --git a/cps/templates/search.html b/cps/templates/search.html
index 79c86b84..7e82c1fc 100644
--- a/cps/templates/search.html
+++ b/cps/templates/search.html
@@ -15,7 +15,7 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
         {% if entry.has_cover is defined %}
-           <a href="{{ url_for('show_book', id=entry.id) }}">
+           <a href="{{ url_for('show_book', book_id=entry.id) }}">
             <img src="{{ url_for('get_cover', cover_path=entry.path.replace('\\','/')) }}" />
           </a>
         {% endif %}
@@ -24,7 +24,7 @@
         <p class="title">{{entry.title|shortentitle}}</p>
         <p class="author">
           {% for author in entry.authors %}
-            <a href="{{url_for('author', id=author.id ) }}">{{author.name}}</a>
+            <a href="{{url_for('author', book_id=author.id ) }}">{{author.name}}</a>
             {% if not loop.last %}
               &amp;
             {% endif %}
diff --git a/cps/templates/shelf.html b/cps/templates/shelf.html
index 1d1e91d2..b6e5d854 100644
--- a/cps/templates/shelf.html
+++ b/cps/templates/shelf.html
@@ -15,14 +15,14 @@
     <div class="col-sm-3 col-lg-2 col-xs-6 book">
       <div class="cover">
         {% if entry.has_cover is defined %}
-          <a href="{{ url_for('show_book', id=entry.id) }}">
+          <a href="{{ url_for('show_book', book_id=entry.id) }}">
             <img src="{{ url_for('get_cover', cover_path=entry.path.replace('\\','/')) }}" />
           </a>
         {% endif %}
       </div>
       <div class="meta">
         <p class="title">{{entry.title|shortentitle}}</p>
-        <p class="author"><a href="{{url_for('author', id=entry.authors[0].id) }}">{{entry.authors[0].name}}</a></p>
+        <p class="author"><a href="{{url_for('author', book_id=entry.authors[0].id) }}">{{entry.authors[0].name}}</a></p>
         {% if entry.ratings.__len__() > 0 %}
         <div class="rating">
           {% for number in range((entry.ratings[0].rating/2)|int(2)) %}
diff --git a/cps/templates/user_edit.html b/cps/templates/user_edit.html
index 6da290bd..ac2386a8 100644
--- a/cps/templates/user_edit.html
+++ b/cps/templates/user_edit.html
@@ -131,7 +131,7 @@
     <h2>{{_('Recent Downloads')}}</h2>
     {% for entry in downloads %}
       <div class="col-sm-2">
-        <a class="pull-left" href="{{ url_for('show_book', id=entry.id) }}">
+        <a class="pull-left" href="{{ url_for('show_book', book_id=entry.id) }}">
           <img class="media-object" width="100" src="{{ url_for('get_cover', cover_path=entry.path.replace('\\','/')) }}" alt="...">
         </a>
       </div>
diff --git a/cps/ub.py b/cps/ub.py
index 49a182b9..858501a6 100644
--- a/cps/ub.py
+++ b/cps/ub.py
@@ -93,9 +93,11 @@ class UserBase:
         else:
             return False
 
+    @staticmethod
     def is_active(self):
         return True
 
+    @staticmethod
     def is_anonymous(self):
         return False
 
@@ -526,7 +528,6 @@ def create_admin_user():
         session.commit()
     except Exception:
         session.rollback()
-        pass
 
 
 # Open session for database connection
diff --git a/cps/web.py b/cps/web.py
index a0492652..a436197c 100755
--- a/cps/web.py
+++ b/cps/web.py
@@ -403,10 +403,10 @@ def timestamptodate(date, fmt=None):
     )
     native = date.replace(tzinfo=None)
     if fmt:
-        format=fmt
+        time_format=fmt
     else:
-        format='%d %m %Y - %H:%S'
-    return native.strftime(format)
+        time_format='%d %m %Y - %H:%S'
+    return native.strftime(time_format)
 
 def admin_required(f):
     """
@@ -469,11 +469,11 @@ def edit_required(f):
 # Fill indexpage with all requested data from database
 def fill_indexpage(page, database, db_filter, order):
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
+        lang_filter = True
     if current_user.show_detail_random():
-        random = db.session.query(db.Books).filter(filter).order_by(func.random()).limit(config.config_random_books)
+        random = db.session.query(db.Books).filter(lang_filter).order_by(func.random()).limit(config.config_random_books)
     else:
         random = false
     off = int(int(config.config_books_per_page) * (page - 1))
@@ -588,15 +588,15 @@ def feed_normal_search():
 
 def feed_search(term):
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
+        lang_filter = True
     if term:
         entries = db.session.query(db.Books).filter(db.or_(db.Books.tags.any(db.Tags.name.like("%" + term + "%")),
                                                     db.Books.series.any(db.Series.name.like("%" + term + "%")),
                                                     db.Books.authors.any(db.Authors.name.like("%" + term + "%")),
                                                     db.Books.publishers.any(db.Publishers.name.like("%" + term + "%")),
-                                                    db.Books.title.like("%" + term + "%"))).filter(filter).all()
+                                                    db.Books.title.like("%" + term + "%"))).filter(lang_filter).all()
         entriescount = len(entries) if len(entries) > 0 else 1
         pagination = Pagination(1, entriescount, entriescount)
         xml = render_title_template('feed.xml', searchterm=term, entries=entries, pagination=pagination)
@@ -625,10 +625,10 @@ def feed_new():
 @requires_basic_auth_if_no_ano
 def feed_discover():
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
-    entries = db.session.query(db.Books).filter(filter).order_by(func.random()).limit(config.config_books_per_page)
+        lang_filter = True
+    entries = db.session.query(db.Books).filter(lang_filter).order_by(func.random()).limit(config.config_books_per_page)
     pagination = Pagination(1, config.config_books_per_page, int(config.config_books_per_page))
     xml = render_title_template('feed.xml', entries=entries, pagination=pagination)
     response = make_response(xml)
@@ -656,9 +656,9 @@ def feed_hot():
     if not off:
         off = 0
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
+        lang_filter = True
     all_books = ub.session.query(ub.Downloads, ub.func.count(ub.Downloads.book_id)).order_by(
         ub.func.count(ub.Downloads.book_id).desc()).group_by(ub.Downloads.book_id)
     hot_books = all_books.offset(off).limit(config.config_books_per_page)
@@ -667,7 +667,7 @@ def feed_hot():
         downloadBook = db.session.query(db.Books).filter(db.Books.id == book.Downloads.book_id).first()
         if downloadBook:
             entries.append(
-                db.session.query(db.Books).filter(filter).filter(db.Books.id == book.Downloads.book_id).first())
+                db.session.query(db.Books).filter(lang_filter).filter(db.Books.id == book.Downloads.book_id).first())
         else:
             ub.session.query(ub.Downloads).filter(book.Downloads.book_id == ub.Downloads.book_id).delete()
             ub.session.commit()
@@ -686,10 +686,10 @@ def feed_authorindex():
     if not off:
         off = 0
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
-    entries = db.session.query(db.Authors).join(db.books_authors_link).join(db.Books).filter(filter)\
+        lang_filter = True
+    entries = db.session.query(db.Authors).join(db.books_authors_link).join(db.Books).filter(lang_filter)\
         .group_by('books_authors_link.author').order_by(db.Authors.sort).limit(config.config_books_per_page).offset(off)
     pagination = Pagination((int(off) / (int(config.config_books_per_page)) + 1), config.config_books_per_page,
                             len(db.session.query(db.Authors).all()))
@@ -699,14 +699,14 @@ def feed_authorindex():
     return response
 
 
-@app.route("/opds/author/<int:id>")
+@app.route("/opds/author/<int:book_id>")
 @requires_basic_auth_if_no_ano
-def feed_author(id):
+def feed_author(book_id):
     off = request.args.get("offset")
     if not off:
         off = 0
     entries, random, pagination = fill_indexpage((int(off) / (int(config.config_books_per_page)) + 1),
-                    db.Books, db.Books.authors.any(db.Authors.id == id), db.Books.timestamp.desc())
+                    db.Books, db.Books.authors.any(db.Authors.id == book_id), db.Books.timestamp.desc())
     xml = render_title_template('feed.xml', entries=entries, pagination=pagination)
     response = make_response(xml)
     response.headers["Content-Type"] = "application/xml"
@@ -720,10 +720,10 @@ def feed_categoryindex():
     if not off:
         off = 0
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
-    entries = db.session.query(db.Tags).join(db.books_tags_link).join(db.Books).filter(filter).\
+        lang_filter = True
+    entries = db.session.query(db.Tags).join(db.books_tags_link).join(db.Books).filter(lang_filter).\
         group_by('books_tags_link.tag').order_by(db.Tags.name).offset(off).limit(config.config_books_per_page)
     pagination = Pagination((int(off) / (int(config.config_books_per_page)) + 1), config.config_books_per_page,
                             len(db.session.query(db.Tags).all()))
@@ -733,14 +733,14 @@ def feed_categoryindex():
     return response
 
 
-@app.route("/opds/category/<int:id>")
+@app.route("/opds/category/<int:book_id>")
 @requires_basic_auth_if_no_ano
-def feed_category(id):
+def feed_category(book_id):
     off = request.args.get("offset")
     if not off:
         off = 0
     entries, random, pagination = fill_indexpage((int(off) / (int(config.config_books_per_page)) + 1),
-                    db.Books, db.Books.tags.any(db.Tags.id == id), db.Books.timestamp.desc())
+                    db.Books, db.Books.tags.any(db.Tags.id == book_id), db.Books.timestamp.desc())
     xml = render_title_template('feed.xml', entries=entries, pagination=pagination)
     response = make_response(xml)
     response.headers["Content-Type"] = "application/xml"
@@ -754,10 +754,10 @@ def feed_seriesindex():
     if not off:
         off = 0
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
-    entries = db.session.query(db.Series).join(db.books_series_link).join(db.Books).filter(filter).\
+        lang_filter = True
+    entries = db.session.query(db.Series).join(db.books_series_link).join(db.Books).filter(lang_filter).\
         group_by('books_series_link.series').order_by(db.Series.sort).offset(off).all()
     pagination = Pagination((int(off) / (int(config.config_books_per_page)) + 1), config.config_books_per_page,
                             len(db.session.query(db.Series).all()))
@@ -767,14 +767,14 @@ def feed_seriesindex():
     return response
 
 
-@app.route("/opds/series/<int:id>")
+@app.route("/opds/series/<int:book_id>")
 @requires_basic_auth_if_no_ano
-def feed_series(id):
+def feed_series(book_id):
     off = request.args.get("offset")
     if not off:
         off = 0
     entries, random, pagination = fill_indexpage((int(off) / (int(config.config_books_per_page)) + 1),
-                    db.Books, db.Books.series.any(db.Series.id == id),db.Books.series_index)
+                    db.Books, db.Books.series.any(db.Series.id == book_id),db.Books.series_index)
     xml = render_title_template('feed.xml', entries=entries, pagination=pagination)
     response = make_response(xml)
     response.headers["Content-Type"] = "application/xml"
@@ -793,8 +793,8 @@ def do_gdrive_download(df, headers):
     download_url = df.metadata.get('downloadUrl')
     s = partial(total_size, 1024 * 1024) # I'm downloading BIG files, so 100M chunk size is fine for me
     def stream():
-        for bytes in s:
-            headers = {"Range" : 'bytes=%s-%s' % (bytes[0], bytes[1])}
+        for byte in s:
+            headers = {"Range" : 'bytes=%s-%s' % (byte[0], byte[1])}
             resp, content = df.auth.Get_Http_Object().request(download_url, headers=headers)
             if resp.status == 206 :
                 yield content
@@ -803,14 +803,14 @@ def do_gdrive_download(df, headers):
                 return
     return Response(stream_with_context(stream()), headers=headers)
 
-@app.route("/opds/download/<book_id>/<format>/")
+@app.route("/opds/download/<book_id>/<book_format>/")
 @requires_basic_auth_if_no_ano
 @download_required
-def get_opds_download_link(book_id, format):
+def get_opds_download_link(book_id, book_format):
     startTime=time.time()
-    format = format.split(".")[0]
+    book_format = book_format.split(".")[0]
     book = db.session.query(db.Books).filter(db.Books.id == book_id).first()
-    data = db.session.query(db.Data).filter(db.Data.book == book.id).filter(db.Data.format == format.upper()).first()
+    data = db.session.query(db.Data).filter(db.Data.book == book.id).filter(db.Data.format == book_format.upper()).first()
     app.logger.info (data.name)
     if current_user.is_authenticated:
         helper.update_download(book_id, int(current_user.id))
@@ -819,15 +819,15 @@ def get_opds_download_link(book_id, format):
         file_name = book.authors[0].name + '_' + file_name
     file_name = helper.get_valid_filename(file_name)
     headers = Headers ()
-    headers["Content-Disposition"] = "attachment; filename*=UTF-8''%s.%s" % (quote(file_name.encode('utf8')), format)
+    headers["Content-Disposition"] = "attachment; filename*=UTF-8''%s.%s" % (quote(file_name.encode('utf8')), book_format)
     app.logger.info (time.time()-startTime)
     startTime=time.time()
     if config.config_use_google_drive:
         app.logger.info(time.time() - startTime)
-        df=gdriveutils.getFileFromEbooksFolder(Gdrive.Instance().drive, book.path, data.name + "." + format)
+        df=gdriveutils.getFileFromEbooksFolder(Gdrive.Instance().drive, book.path, data.name + "." + book_format)
         return do_gdrive_download(df, headers)
     else:
-        response = make_response(send_from_directory(os.path.join(config.config_calibre_dir, book.path), data.name + "." + format))
+        response = make_response(send_from_directory(os.path.join(config.config_calibre_dir, book.path), data.name + "." + book_format))
         response.headers=headers
         return response
 
@@ -984,11 +984,11 @@ def index(page):
 @login_required_if_no_ano
 def hot_books(page):
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
+        lang_filter = True
     if current_user.show_detail_random():
-        random = db.session.query(db.Books).filter(filter).order_by(func.random()).limit(config.config_random_books)
+        random = db.session.query(db.Books).filter(lang_filter).order_by(func.random()).limit(config.config_random_books)
     else:
         random = false
     off = int(int(config.config_books_per_page) * (page - 1))
@@ -1000,7 +1000,7 @@ def hot_books(page):
         downloadBook = db.session.query(db.Books).filter(db.Books.id == book.Downloads.book_id).first()
         if downloadBook:
             entries.append(
-                db.session.query(db.Books).filter(filter).filter(db.Books.id == book.Downloads.book_id).first())
+                db.session.query(db.Books).filter(lang_filter).filter(db.Books.id == book.Downloads.book_id).first())
         else:
             ub.session.query(ub.Downloads).filter(book.Downloads.book_id == ub.Downloads.book_id).delete()
             ub.session.commit()
@@ -1033,22 +1033,22 @@ def discover(page):
 @login_required_if_no_ano
 def author_list():
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
+        lang_filter = True
     entries = db.session.query(db.Authors, func.count('books_authors_link.book').label('count')).join(
         db.books_authors_link).join(db.Books).filter(
-        filter).group_by('books_authors_link.author').order_by(db.Authors.sort).all()
+        lang_filter).group_by('books_authors_link.author').order_by(db.Authors.sort).all()
     return render_title_template('list.html', entries=entries, folder='author', title=_(u"Author list"))
 
 
-@app.route("/author/<int:id>", defaults={'page': 1})
-@app.route("/author/<int:id>/<int:page>'")
+@app.route("/author/<int:book_id>", defaults={'page': 1})
+@app.route("/author/<int:book_id>/<int:page>'")
 @login_required_if_no_ano
-def author(id,page):
-    entries, random, pagination = fill_indexpage(page, db.Books, db.Books.authors.any(db.Authors.id == id),
+def author(book_id,page):
+    entries, random, pagination = fill_indexpage(page, db.Books, db.Books.authors.any(db.Authors.id == book_id),
                                                  db.Books.timestamp.desc())
-    name = db.session.query(db.Authors).filter(db.Authors.id == id).first().name
+    name = db.session.query(db.Authors).filter(db.Authors.id == book_id).first().name
     if entries:
         return render_title_template('index.html', random=random, entries=entries, title=_(u"Author: %(name)s", name=name))
     else:
@@ -1060,22 +1060,22 @@ def author(id,page):
 @login_required_if_no_ano
 def series_list():
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
+        lang_filter = True
     entries = db.session.query(db.Series, func.count('books_series_link.book').label('count')).join(
         db.books_series_link).join(db.Books).filter(
-        filter).group_by('books_series_link.series').order_by(db.Series.sort).all()
+        lang_filter).group_by('books_series_link.series').order_by(db.Series.sort).all()
     return render_title_template('list.html', entries=entries, folder='series', title=_(u"Series list"))
 
 
-@app.route("/series/<int:id>/", defaults={'page': 1})
-@app.route("/series/<int:id>/<int:page>'")
+@app.route("/series/<int:book_id>/", defaults={'page': 1})
+@app.route("/series/<int:book_id>/<int:page>'")
 @login_required_if_no_ano
-def series(id, page):
-    entries, random, pagination = fill_indexpage(page, db.Books, db.Books.series.any(db.Series.id == id),
+def series(book_id, page):
+    entries, random, pagination = fill_indexpage(page, db.Books, db.Books.series.any(db.Series.id == book_id),
                                                  db.Books.series_index)
-    name=db.session.query(db.Series).filter(db.Series.id == id).first().name
+    name=db.session.query(db.Series).filter(db.Series.id == book_id).first().name
     if entries:
         return render_title_template('index.html', random=random, pagination=pagination, entries=entries,
                                      title=_(u"Series: %(serie)s", serie=name))
@@ -1133,52 +1133,52 @@ def language(name, page):
 @login_required_if_no_ano
 def category_list():
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
+        lang_filter = True
     entries = db.session.query(db.Tags, func.count('books_tags_link.book').label('count')).join(
         db.books_tags_link).join(db.Books).filter(
-        filter).group_by('books_tags_link.tag').all()
+        lang_filter).group_by('books_tags_link.tag').all()
     return render_title_template('list.html', entries=entries, folder='category', title=_(u"Category list"))
 
 
-@app.route("/category/<int:id>", defaults={'page': 1})
-@app.route('/category/<int:id>/<int:page>')
+@app.route("/category/<int:book_id>", defaults={'page': 1})
+@app.route('/category/<int:book_id>/<int:page>')
 @login_required_if_no_ano
-def category(id, page):
-    entries, random, pagination = fill_indexpage(page, db.Books, db.Books.tags.any(db.Tags.id == id),
+def category(book_id, page):
+    entries, random, pagination = fill_indexpage(page, db.Books, db.Books.tags.any(db.Tags.id == book_id),
                                                  db.Books.timestamp.desc())
 
-    name=db.session.query(db.Tags).filter(db.Tags.id == id).first().name
+    name=db.session.query(db.Tags).filter(db.Tags.id == book_id).first().name
     return render_title_template('index.html', random=random, entries=entries, pagination=pagination,
                                  title=_(u"Category: %(name)s", name=name))
 
 
-@app.route("/ajax/toggleread/<int:id>", methods=['POST'])
+@app.route("/ajax/toggleread/<int:book_id>", methods=['POST'])
 @login_required
-def toggle_read(id):
+def toggle_read(book_id):
     book = ub.session.query(ub.ReadBook).filter(ub.and_(ub.ReadBook.user_id == int(current_user.id),
-                                                                   ub.ReadBook.book_id == id)).first()
+                                                                   ub.ReadBook.book_id == book_id)).first()
     if book:
         book.is_read=not book.is_read
     else:
         readBook=ub.ReadBook()
         readBook.user_id=int(current_user.id)
-        readBook.book_id = id
+        readBook.book_id = book_id
         readBook.is_read=True
         book=readBook
     ub.session.merge(book)
     ub.session.commit()
     return ""
 
-@app.route("/book/<int:id>")
+@app.route("/book/<int:book_id>")
 @login_required_if_no_ano
-def show_book(id):
+def show_book(book_id):
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
-    entries = db.session.query(db.Books).filter(db.Books.id == id).filter(filter).first()
+        lang_filter = True
+    entries = db.session.query(db.Books).filter(db.Books.id == book_id).filter(lang_filter).first()
     if entries:
         for index in range(0, len(entries.languages)):
             try:
@@ -1198,7 +1198,7 @@ def show_book(id):
         else:
             cc=tmpcc
         book_in_shelfs = []
-        shelfs = ub.session.query(ub.BookShelf).filter(ub.BookShelf.book_id == id).all()
+        shelfs = ub.session.query(ub.BookShelf).filter(ub.BookShelf.book_id == book_id).all()
         for entry in shelfs:
             book_in_shelfs.append(entry.shelf)
 
@@ -1206,7 +1206,7 @@ def show_book(id):
                                     # title=entries.title, books_shelfs=book_in_shelfs)
         if not current_user.is_anonymous():
             matching_have_read_book=ub.session.query(ub.ReadBook).filter(ub.and_(ub.ReadBook.user_id == int(current_user.id),
-                                                                   ub.ReadBook.book_id == id)).all()
+                                                                   ub.ReadBook.book_id == book_id)).all()
             have_read=len(matching_have_read_book) > 0 and matching_have_read_book[0].is_read
         else:
             have_read=None
@@ -1337,13 +1337,13 @@ def on_received_watch_confirmation():
                     if not response['deleted'] and response['file']['title'] == 'metadata.db' and response['file']['md5Checksum'] != md5(dbpath):
                         tmpDir=tempfile.gettempdir()
                         app.logger.info ('Database file updated')
-                        copyfile (dbpath, tmpDir + "/metadata.db_" + str(current_milli_time()))
+                        copyfile (dbpath, os.path.join(tmpDir, "metadata.db_" + str(current_milli_time())))
                         app.logger.info ('Backing up existing and downloading updated metadata.db')
-                        gdriveutils.downloadFile(Gdrive.Instance().drive, None, "metadata.db", tmpDir + "/tmp_metadata.db")
+                        gdriveutils.downloadFile(Gdrive.Instance().drive, None, "metadata.db", os.path.join(tmpDir, "tmp_metadata.db"))
                         app.logger.info ('Setting up new DB')
-                        os.rename(tmpDir + "/tmp_metadata.db", dbpath)
+                        os.rename(os.path.join(tmpDir, "tmp_metadata.db"), dbpath)
                         db.setup_db()
-            except Exception, e:
+            except Exception as e:
                 app.logger.exception(e)
 
         updateMetaData()
@@ -1395,14 +1395,14 @@ def search():
     term = request.args.get("query").strip()
     if term:
         if current_user.filter_language() != "all":
-            filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+            lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
         else:
-            filter = True
+            lang_filter = True
         entries = db.session.query(db.Books).filter(db.or_(db.Books.tags.any(db.Tags.name.like("%" + term + "%")),
                                                     db.Books.series.any(db.Series.name.like("%" + term + "%")),
                                                     db.Books.authors.any(db.Authors.name.like("%" + term + "%")),
                                                     db.Books.publishers.any(db.Publishers.name.like("%" + term + "%")),
-                                                    db.Books.title.like("%" + term + "%"))).filter(filter).all()
+                                                    db.Books.title.like("%" + term + "%"))).filter(lang_filter).all()
         return render_title_template('search.html', searchterm=term, entries=entries)
     else:
         return render_title_template('search.html', searchterm="")
@@ -1563,15 +1563,15 @@ def feed_unread_books():
 def unread_books(page):
     return render_read_books(page, False)
 
-@app.route("/read/<int:book_id>/<format>")
+@app.route("/read/<int:book_id>/<book_format>")
 @login_required_if_no_ano
-def read_book(book_id, format):
+def read_book(book_id, book_format):
     book = db.session.query(db.Books).filter(db.Books.id == book_id).first()
     if book:
         book_dir = os.path.join(config.get_main_dir, "cps", "static", str(book_id))
         if not os.path.exists(book_dir):
             os.mkdir(book_dir)
-        if format.lower() == "epub":
+        if book_format.lower() == "epub":
             # check if mimetype file is exists
             mime_file = str(book_id) + "/mimetype"
             if not os.path.exists(mime_file):
@@ -1586,9 +1586,7 @@ def read_book(book_id, format):
                         try:
                             os.makedirs(newDir)
                         except OSError as exception:
-                            if exception.errno == errno.EEXIST:
-                                pass
-                            else:
+                            if  not exception.errno == errno.EEXIST:
                                 raise
                     if fileName:
                         fd = open(os.path.join(newDir, fileName), "wb")
@@ -1596,21 +1594,21 @@ def read_book(book_id, format):
                         fd.close()
                 zfile.close()
             return render_title_template('read.html', bookid=book_id, title=_(u"Read a Book"))
-        elif format.lower() == "pdf":
+        elif book_format.lower() == "pdf":
             all_name = str(book_id) + "/" + book.data[0].name + ".pdf"
             tmp_file = os.path.join(book_dir, book.data[0].name) + ".pdf"
             if not os.path.exists(tmp_file):
                 pdf_file = os.path.join(config.config_calibre_dir, book.path, book.data[0].name) + ".pdf"
                 copyfile(pdf_file, tmp_file)
             return render_title_template('readpdf.html', pdffile=all_name, title=_(u"Read a Book"))
-        elif format.lower() == "txt":
+        elif book_format.lower() == "txt":
             all_name = str(book_id) + "/" + book.data[0].name + ".txt"
             tmp_file = os.path.join(book_dir, book.data[0].name) + ".txt"
             if not os.path.exists(all_name):
                 txt_file = os.path.join(config.config_calibre_dir, book.path, book.data[0].name) + ".txt"
                 copyfile(txt_file, tmp_file)
             return render_title_template('readtxt.html', txtfile=all_name, title=_(u"Read a Book"))
-        elif format.lower() == "cbr":
+        elif book_format.lower() == "cbr":
             all_name = str(book_id) + "/" + book.data[0].name + ".cbr"
             tmp_file = os.path.join(book_dir, book.data[0].name) + ".cbr"
             if not os.path.exists(all_name):
@@ -1622,13 +1620,13 @@ def read_book(book_id, format):
         flash(_(u"Error opening eBook. File does not exist or file is not accessible:"), category="error")
         return redirect(url_for("index"))
 
-@app.route("/download/<int:book_id>/<format>")
+@app.route("/download/<int:book_id>/<book_format>")
 @login_required_if_no_ano
 @download_required
-def get_download_link(book_id, format):
-    format = format.split(".")[0]
+def get_download_link(book_id, book_format):
+    book_format = book_format.split(".")[0]
     book = db.session.query(db.Books).filter(db.Books.id == book_id).first()
-    data = db.session.query(db.Data).filter(db.Data.book == book.id).filter(db.Data.format == format.upper()).first()
+    data = db.session.query(db.Data).filter(db.Data.book == book.id).filter(db.Data.format == book_format.upper()).first()
     if data:
         # collect downloaded books only for registered user and not for anonymous user
         if current_user.is_authenticated:
@@ -1639,25 +1637,25 @@ def get_download_link(book_id, format):
         file_name = helper.get_valid_filename(file_name)
         headers = Headers ()
         try:
-            headers["Content-Type"] = mimetypes.types_map['.' + format]
-        except:
-            pass
-        headers["Content-Disposition"] = "attachment; filename*=UTF-8''%s.%s" % (quote(file_name.encode('utf-8')), format)
+            headers["Content-Type"] = mimetypes.types_map['.' + book_format]
+        except KeyError:
+            headers["Content-Type"] = "application/octet-stream"
+        headers["Content-Disposition"] = "attachment; filename*=UTF-8''%s.%s" % (quote(file_name.encode('utf-8')), book_format)
         if config.config_use_google_drive:
-            df=gdriveutils.getFileFromEbooksFolder(Gdrive.Instance().drive, book.path, '%s.%s' % (data.name, format))
+            df=gdriveutils.getFileFromEbooksFolder(Gdrive.Instance().drive, book.path, '%s.%s' % (data.name, book_format))
             return do_gdrive_download(df, headers)
         else:
-            response = make_response(send_from_directory(os.path.join(config.config_calibre_dir, book.path), data.name + "." + format))
+            response = make_response(send_from_directory(os.path.join(config.config_calibre_dir, book.path), data.name + "." + book_format))
             response.headers=headers
             return response
     else:
         abort(404)
 
-@app.route("/download/<int:book_id>/<format>/<anyname>")
+@app.route("/download/<int:book_id>/<book_format>/<anyname>")
 @login_required_if_no_ano
 @download_required
-def get_download_link_ext(book_id, format, anyname):
-    return get_download_link(book_id, format)
+def get_download_link_ext(book_id, book_format, anyname):
+    return get_download_link(book_id, book_format)
 
 @app.route('/register', methods=['GET', 'POST'])
 def register():
@@ -2370,10 +2368,10 @@ def edit_book(book_id):
     db.session.connection().connection.connection.create_function("title_sort", 1, db.title_sort)
     cc = db.session.query(db.Custom_Columns).filter(db.Custom_Columns.datatype.notin_(db.cc_exceptions)).all()
     if current_user.filter_language() != "all":
-        filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
+        lang_filter = db.Books.languages.any(db.Languages.lang_code == current_user.filter_language())
     else:
-        filter = True
-    book = db.session.query(db.Books).filter(db.Books.id == book_id).filter(filter).first()
+        lang_filter = True
+    book = db.session.query(db.Books).filter(db.Books.id == book_id).filter(lang_filter).first()
     author_names = []
     if book:
         for index in range(0, len(book.languages)):
@@ -2575,7 +2573,7 @@ def edit_book(book_id):
             if config.config_use_google_drive:
                 updateGdriveCalibreFromLocal()
             if "detail_view" in to_save:
-                return redirect(url_for('show_book', id=book.id))
+                return redirect(url_for('show_book', book_id=book.id))
             else:
                 return render_title_template('book_edit.html', book=book, authors=author_names, cc=cc,
                                              title=_(u"edit metadata"))
@@ -2597,9 +2595,9 @@ def upload():
     db.session.connection().connection.connection.create_function("title_sort", 1, db.title_sort)
     db.session.connection().connection.connection.create_function('uuid4', 0, lambda: str(uuid4()))
     if request.method == 'POST' and 'btn-upload' in request.files:
-        file = request.files['btn-upload']
-        if '.' in file.filename:
-            file_ext = file.filename.rsplit('.', 1)[-1].lower()
+        requested_file = request.files['btn-upload']
+        if '.' in requested_file.filename:
+            file_ext = requested_file.filename.rsplit('.', 1)[-1].lower()
             if file_ext not in ALLOWED_EXTENSIONS:
                 flash(
                     _('File extension "%s" is not allowed to be uploaded to this server' %
@@ -2610,7 +2608,7 @@ def upload():
         else:
             flash(_('File to be uploaded must have an extension'), category="error")
             return redirect(url_for('index'))
-        meta = uploader.upload(file)
+        meta = uploader.upload(requested_file)
 
         title = meta.title
         author = meta.author