solve the provlem of timeline updating

khaikang/urls.py

@@ -24,4 +24,6 @@ urlpatterns = [
     path('home/',  views.home, name='home'),
     path('signup/',  views.signup),
     path('api/post', views.api_post),
+    path('api/get_recent_posts_counter', views.api_get_recent_posts_counter),
+    path('api/get_latest_posts', views.api_get_latest_posts),
 ]

khaikang/views.py

@@ -6,6 +6,36 @@ from django.utils import timezone
 from django.contrib.auth.forms import UserCreationForm
 from django.shortcuts import redirect
 from django.contrib.auth.models import AnonymousUser
+from datetime import datetime
+from django.http import JsonResponse
+from django.core import serializers
+from django.db.models import Q
+
+def api_get_latest_posts(request):
+    if request.method == 'POST':
+        post_body_orig = request.body.decode('utf-8')
+        post_body_json = json.loads(post_body_orig)
+        latest_time = post_body_json["latest_time"]
+        latest_datetime_object = datetime.strptime(latest_time, '%Y-%m-%d %H:%M:%S.%f%z')
+        newer_posts = Post.objects.filter(post_time__gte=latest_datetime_object)
+        newer_posts_list = [{"id" : o.pk, 
+                            "post_time" :  datetime.strftime(o.post_time, "%Y-%m-%d %H:%M:%S.%f%z"),
+                            "poster_username" : o.poster.username,
+                            "poster_shown_name":o.poster.shown_name ,
+                            "text": o.text}
+                            for o in newer_posts]
+        return JsonResponse({'newer_posts':newer_posts_list})
+
+def api_get_recent_posts_counter(request):
+    if request.method == 'POST':
+        post_body_orig = request.body.decode('utf-8')
+        post_body_json = json.loads(post_body_orig)
+        latest_time = post_body_json["latest_time"]
+        latest_datetime_object = datetime.strptime(latest_time, '%Y-%m-%d %H:%M:%S.%f%z')
+        newer_posts_len = Post.objects.filter(post_time__gte=latest_datetime_object).exclude(Q(poster=request.user) & Q(post_time=latest_datetime_object)).__len__()
+        return JsonResponse({'newer_posts_num':newer_posts_len})
+
+
 
 def api_post(request):
     if request.method == 'POST':
@@ -58,14 +88,19 @@ def signup(request):
 
 def home(request):
 
+    if request.user == AnonymousUser():
+        return redirect('/account/login')   # redirect to main page
+    
     public_timeline_list = Post.objects.filter(privilage = 'public').order_by('-id')[:10]
     
-
-    print(public_timeline_list)
+    latest_received_time = timezone.now()
+    oldest_received_time = public_timeline_list[9].post_time
     
     template = loader.get_template('index.html')
 
     context = {
+        'latest_received_time' : latest_received_time,
+        'oldest_received_time' : oldest_received_time,
         'public_timeline_list': public_timeline_list,
     }
     return HttpResponse(template.render(context, request))

templates/index.html

@@ -26,20 +26,28 @@
   </form>
 
   <div id="public_timeline">
+    <div id="new_post_notifier" value=""></div>
+    <div id="latest_time" style="display: block;">{{latest_received_time|date:"Y-m-d H:i:s.u"}}+0000</div>
+
     {% for public_post in public_timeline_list %}
 
   <div id="post-{{public_post.id}}" class="post"><a href="user/{{public_post.poster}}">{{public_post.poster.shown_name}}</a>
-    at <a href="post/{{public_post.id}}" class="post-time">{{public_post.post_time|date:"Y-m-d H:i:s"}}+0000</a><br/>
-    {{public_post.text}}</div>
+    at <a href="post/{{public_post.id}}" class="post-time">{{public_post.post_time|date:"Y-m-d H:i:s.u"}}+0000</a><br/>
+    {{public_post.text}}<br/>
+    <span id="reply-{{public_post.id}}" value="{{public_post.id}}" class="reply">↩️</span>
+    - <span id="repost-{{public_post.id}}" value="{{public_post.id}}" class="repost">🔁</span> 
+    - <span id="fav-{{public_post.id}}" value="{{public_post.id}}" class="fav">⭐</span>
+</div>
   {% endfor %}
+  <div id="oldest_time" style="display: block;">{{oldest_received_time|date:"Y-m-d H:i:s.u"}}+0000</div>
+
   </div>
 
 
   <script>
 
-    function timezoneChanging(){
-        document.querySelectorAll(".post-time").forEach(
-            (x)=>{var date= new Date(x.innerHTML);
+
+timezoneChangingOne = (x)=>{var date= new Date(x.innerHTML);
                 var year = date.getFullYear().toString();
                 var month = (date.getMonth()+1).toString().padStart(2, '0');
                 var day = date.getDate().toString().padStart(2, '0');
@@ -48,9 +56,15 @@
                 var sec = date.getSeconds().toString().padStart(2, '0');
                 local_date_string = `${year}-${month}-${day} ${hour}:${min}:${sec}`;
                 x.innerHTML=local_date_string;}
+
+function timezoneChanging(){
+        document.querySelectorAll(".post-time").forEach(
+            x => timezoneChangingOne(x)
                 );
     }
 
+
+
     $name = (x) => document.getElementsByName(x);
     $ = (x) => document.getElementById(x);
     var httpRequest;
@@ -61,6 +75,8 @@
     post_text = $('post_text').value;
     post_privilage = $('privil_choosing').value;
 
+    if (post_text != ""){
+
         await fetch('/api/post', {
         method: 'POST',
         headers: {
@@ -72,7 +88,15 @@
             "text": post_text,
         })
         
-    });
+        }).then(response => {if (response.ok == true)
+            {$('post_text').value = "";
+            getLatestPosts(); // wait for a moment then get latest posts
+            }}
+            
+        );
+    }
+
+
 
 }
 
@@ -89,6 +113,79 @@ function adjust_post_text(){
     post_text.style.height = (post_text.scrollHeight)+"px";
 }
 
+
+async function getRecentPostsCounter(){
+    latest_time_string = $("latest_time").innerHTML;
+    await fetch('/api/get_recent_posts_counter', {
+        method: 'POST',
+        headers: {
+            "X-CSRFToken": "{{ csrf_token }}",
+            'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({
+            "latest_time" : latest_time_string,
+    })
+
+}).then(response => response.json())
+    .then(the_json => {console.log(the_json);let newer_posts_num = the_json['newer_posts_num'];
+if (newer_posts_num == 1)
+    {   $("new_post_notifier").style.display = "block";
+        $("new_post_notifier").innerHTML = `1 new post`}
+if (newer_posts_num > 1)
+    {   $("new_post_notifier").style.display = "block";
+        $("new_post_notifier").innerHTML = `${newer_posts_num} new posts`} });
+
+}
+
+var intervalID = window.setInterval(getRecentPostsCounter, 20000);
+
+
+
+async function getLatestPosts(){
+    latest_time_string = $("latest_time").innerHTML;
+    await fetch('/api/get_latest_posts', {
+        method: 'POST',
+        headers: {
+            "X-CSRFToken": "{{ csrf_token }}",
+            'Content-Type': 'application/json',
+        },
+        body: JSON.stringify({
+            "latest_time" : latest_time_string,
+    }) }).then(response => response.json())
+    .then(item => item['newer_posts'])
+    .then(posts => {posts.forEach(post => add_post_to_the_beginning(post));
+            $('new_post_notifier').style.display = "none";
+            var nowTime = new Date();
+            var nowTimeString = nowTime.toISOString();
+            $("latest_time").innerHTML = nowTimeString.substring(0,10) + " " + nowTimeString.substring(11,23) + "000+0000"; });
+}
+
+function add_post_to_the_beginning(post){
+    console.log(post);
+    var public_tl = $("public_timeline");
+    var new_div = document.createElement("div");
+    new_div.id =  `post-${post.id}`;
+    new_div.className = "post";
+    new_div.innerHTML = `<a href="user/${post.poster_username}">${post.poster_shown_name}</a>
+    at <a href="post/${post.id}" class="post-time">${post.post_time}</a><br>
+    ${post.text}<br>
+    <span id="reply-${post.id}" value="${post.id}" class="reply">↩️</span>
+    - <span id="repost-${post.id}" value="${post.id}" class="repost">🔁</span> 
+    - <span id="fav-${post.id}" value="${post.id}" class="fav">⭐</span>`;
+
+    new_div_timestamp = new_div.getElementsByClassName('post-time')[0];
+
+    timezoneChangingOne(new_div_timestamp);
+
+
+    public_tl.insertBefore(new_div, $('latest_time').nextSibling);
+
+}
+
+$("new_post_notifier").addEventListener('click', getLatestPosts);
+
+
+
 adjust_post_text();
 </script>
 {% endblock %}

templates/registration/logged_out.html

@@ -0,0 +1,10 @@
+{% extends "base_generic.html" %}
+
+
+{% block content %}
+
+You have logged out.
+
+go to <a href="/home">Main  Page</a>.
+
+{% endblock %}