paginate item list

server/handlers.go

@@ -12,6 +12,7 @@ import (
 	"strings"
 	"path/filepath"
 	"strconv"
+	"math"
 )
 
 func IndexHandler(rw http.ResponseWriter, req *http.Request) {
@@ -287,7 +288,12 @@ func ItemHandler(rw http.ResponseWriter, req *http.Request) {
 
 func ItemListHandler(rw http.ResponseWriter, req *http.Request) {
 	if req.Method == "GET" {
+		perPage := 20
+		curPage := 1
 		query := req.URL.Query()
+		if page, err := strconv.ParseInt(query.Get("page"), 10, 64); err == nil {
+			curPage = int(page)
+		}
 		filter := storage.ItemFilter{}
 		if folderID, err := strconv.ParseInt(query.Get("folder_id"), 10, 64); err == nil {
 			filter.FolderID = &folderID
@@ -299,9 +305,16 @@ func ItemListHandler(rw http.ResponseWriter, req *http.Request) {
 			statusValue := storage.StatusValues[status]
 			filter.Status = &statusValue
 		}
-		items := db(req).ListItems(filter)	
+		items := db(req).ListItems(filter, (curPage-1)*perPage, perPage)
+		count := db(req).CountItems(filter)
 		rw.WriteHeader(http.StatusOK)
-		writeJSON(rw, items)
+		writeJSON(rw, map[string]interface{}{
+			"page": map[string]int{
+				"cur": curPage,
+				"num": int(math.Ceil(float64(count) / float64(perPage))),
+			},
+			"list": items,
+		})
 	} else if req.Method == "PUT" {
 		query := req.URL.Query()
 		filter := storage.ItemFilter{}

storage/item.go

@@ -96,7 +96,7 @@ func (s *Storage) CreateItems(items []Item) bool {
 	return true
 }
 
-func (s *Storage) ListItems(filter ItemFilter) []Item {
+func listQueryPredicate(filter ItemFilter) (string, []interface{}) {
 	cond := make([]string, 0)
 	args := make([]interface{}, 0)
 	if filter.FolderID != nil {
@@ -116,7 +116,11 @@ func (s *Storage) ListItems(filter ItemFilter) []Item {
 	if len(cond) > 0 {
 		predicate = strings.Join(cond, " and ")
 	}
+	return predicate, args
+}
 
+func (s *Storage) ListItems(filter ItemFilter, offset, limit int) []Item {
+	predicate, args := listQueryPredicate(filter)
 	result := make([]Item, 0, 0)
 	query := fmt.Sprintf(`
 		select
@@ -126,7 +130,8 @@ func (s *Storage) ListItems(filter ItemFilter) []Item {
 		join feeds f on f.id = i.feed_id
 		where %s
 		order by i.date desc
-		`, predicate)
+		limit %d offset %d
+		`, predicate, limit, offset)
 	rows, err := s.db.Query(query, args...)
 	if err != nil {
 		s.log.Print(err)
@@ -157,6 +162,22 @@ func (s *Storage) ListItems(filter ItemFilter) []Item {
 	return result
 }
 
+func (s *Storage) CountItems(filter ItemFilter) int64 {
+	predicate, args := listQueryPredicate(filter)
+	query := fmt.Sprintf(`
+		select count(i.id)
+		from items i
+		join feeds f on f.id = i.feed_id
+		where %s`, predicate)
+	row := s.db.QueryRow(query, args...)
+	if row != nil {
+		var result int64
+		row.Scan(&result)
+		return result
+	}
+	return 0
+}
+
 func (s *Storage) UpdateItemStatus(item_id int64, status ItemStatus) bool {
 	_, err := s.db.Exec(`update items set status = ? where id = ?`, status, item_id)
 	return err == nil

template/index.html

@@ -77,9 +77,9 @@
                     <img src="./static/images/check.svg" alt="" style="width: 20px; height: 20px;">
                 </button>
             </div>
-            <div class="p-2 overflow-auto">
+            <div class="p-2 overflow-auto" v-scroll="loadMoreItems">
                 <label v-for="item in items" :key="item.id"
-                       class="nav-select mb-1"
+                       class="nav-select"
                        :class="{'text-muted'  : filterSelected=='all' && item.status=='read',
                                 'text-primary': filterSelected=='all' && item.status=='starred'}">
                     <input type="radio" name="item" :value="item.id" v-model="itemSelected">
@@ -93,6 +93,7 @@
                         </div>
                     </div>
                 </label>
+                <button class="btn btn-link btn-block loading my-3" v-if="itemsPage.cur < itemsPage.num"></button>
             </div>
         </div>
         <div class="vh-100 d-flex flex-column w-100">

template/static/javascripts/app.js

@@ -1,5 +1,24 @@
 'use strict';
 
+var debounce = function(callback, wait) {
+  var timeout
+  return function() {
+    var context = this, args = arguments
+    clearTimeout(timeout)
+    timeout = setTimeout(function() {
+      callback.apply(this, args)
+    }, wait)
+  }
+}
+
+Vue.directive('scroll', {
+  inserted: function(el, binding) {
+    el.addEventListener('scroll', debounce(function(event) {
+      binding.value(event, el)
+    }, 200))
+  },
+})
+
 var vm = new Vue({
   el: '#app',
   created: function() {
@@ -17,10 +36,17 @@ var vm = new Vue({
       'feeds': [],
       'feedSelected': null,
       'items': [],
+      'itemsPage': {
+        'cur': 1,
+        'num': 1,
+      },
       'itemSelected': null,
       'itemSelectedDetails': {},
       'settings': 'create',
-      'loading': {newfeed: 0},
+      'loading': {
+        'newfeed': false,
+        'items': false,
+      },
     }
   },
   computed: {
@@ -94,10 +120,29 @@ var vm = new Vue({
     },
     refreshItems: function() {
       var query = this.getItemsQuery()
-      api.items.list(query).then(function(items) {
-        vm.items = items
+      this.loading.items = true
+      var vm = this
+      api.items.list(query).then(function(data) {
+        vm.items = data.list
+        vm.itemsPage = data.page
+        vm.loading.items = false
       })
     },
+    loadMoreItems: function(event, el) {
+      if (this.itemsPage.cur >= this.itemsPage.num) return
+      if (this.loading.items) return
+      var closeToBottom = (el.scrollHeight - el.scrollTop - el.offsetHeight) < 50
+      if (closeToBottom) {
+        this.loading.moreitems = true
+        var query = this.getItemsQuery()
+        query.page = this.itemsPage.cur + 1
+        api.items.list(query).then(function(data) {
+          vm.items = vm.items.concat(data.list)
+          vm.itemsPage = data.page
+          vm.loading.items = false
+        })
+      }
+    },
     markItemsRead: function() {
       var vm = this
       var query = this.getItemsQuery()